borge & medewerkers
TRANSCRIPT
BORGE & MEDEWERKERS
AGRI TECHNOVATIONABSA
AGRICOL BARENBRUG SA
BESTER GROENEWALD & VENNOTE (GEOKTROIEERDE REKENMEESTERS)
DEPARTEMENT LANDBOU: WES-KAAP (LANGGEWENS NAVORSINGSPLAAS)
DEPARTEMENT LANDBOU: WES-KAAP (PLANTWETENSKAPPE)
KAAP AGRIKIMLEIGH CHEMICALS SA
LIMAGRAIN ZAAD SOUTH AFRICALNR-KGI
LIZE SIGNSMOS PRODUKTENITROPHOSKA
OVERBERGPIONEER
PNSSENSAKO
SYNGENTAUNIVERSITEIT STELLENBOSCH: DEPARTEMENT VAN
AGRONOMIEUNIVERSITEIT STELLENBOSCH: PLANTETEELTLABORATORIUM
VERSKEIE PRODUSENTEYARA
TITELS VAN PROEWE VIR BESIGTIGING
SPREKERS E-POS ADDRES
Limagrain Zaad South Africa: Kleingraan groenvoere.
Dirk Coetzee [email protected]
Limagrain Zaad South Africa: Dekgewasse.
Dirk Coetzee [email protected]
Barenbrug SA: Dekgewasse en Weidings.
Ivan Jansen van Rensburg & Jaco Kellerman
Barenbrug SA: Kleingrane.Ivan Jansen van Rensburg & Jaco
Agricol: Canola kultivars. Jan Botes [email protected]
Agricol: Weidings kultivars. Christof Muller [email protected]
Agricol: Kleingraan kultivars. Ian Van der Heever [email protected]
Agricol: Dekgewasse. Christof Muller [email protected]
Wes-Kaapse Departement van Landbou: Ondersoek na smoorgewasse vir
die verbetering van biodiversiteit in kleingraan produksiestelsels van die
Swartland.
Kim van den [email protected]@elsenburg.com
Sensako/Syngenta: Koringkultivars.Driecus Lesch & Wessel
Universiteit van Stellenbosch- Planteteeltlaboratorium: Korog
kultivars. Henzel Saul & Lezaan Hess [email protected]; [email protected]
Western Cape Department of Agriculture/University of Stellenbosch: Considerations for liming management in the Swartland: Soil tillage, placement,
form and fineness of lime.
JP Pellisier & Johan Labuschagne [email protected]
Western Cape Department of Agriculture/University of Stellenbosch: Plant densities and nitrogen application
rate for wheat production in the Swartland: Results from 2020 season
Karlo van Blerk & Johan Labuschagne
Western Cape Department of Agriculture/University of Stellenbosch: Can infrequent tillage practices reduce
weed pressure and agrochemical application in a dryland cropping
system?
Flackson Tshuma & Dr. Johan Labuschagne
Wes-Kaapse Departement van Landbou: Canola kultivars
Piet Lombard [email protected]
Wes-Kaapse Departement van Landbou: Peulplant kultivars
Piet Lombard & Hanneke Augestyn [email protected]
Wes-Kaap Dept. Landbou: Evaluasie van canola kultivars vir weerstand teen
swartstam.Huibré Schreuder & Gert van Coller [email protected]
Mos Produkte: Die gebruik van Mos EnerG as blaarbespuiting.
Corrie van der Westhuizen [email protected]
Nitrophoska: Effek van variërende NitroPoly-S toedienings op koring en
canola produksie in die Swartland.Karen Truter & Johan Cronjé [email protected]
Yara: Die effek van gebalanseerde voeding op canola opbrengs en
stikstofverbruiksdoeltreffendheid.Jacques Smith & Derick Becker [email protected]
Kimleigh Chemicals SA: Verbetering van Stikstof(N) effektiwiteit op kleingraan.
André Britz [email protected]
LNR-KGI: Koring kultivar ontwikkeling. Dr. Ian Heyns [email protected]
LNR-KGI: Nasionale Koring Kultivar Evaluasie resultate vir 2020 in die
Swartland.Petrus Delport [email protected]
1. KULTIVARSCanola kultivarevaluasie in die SwartlandPJA Lombard, L Smorenburg en J Strauss
BOODSKAP VIR DIE PLAAS:
• Koel en nat lente (Augustus en September) beïnvloed canola-opbrengs positief. Groter effek kan verwag word, as vir van die ander gewasse. Ons hoop 2021 is weer gunstig vir saadopbrengs.
• Die oordrag van sulfonielureumresidu’s in die grond in die Swartland is ‘n groter risiko as in die Overberg weens die Swartland se droër somers.
• Vier nuwe kultivars word in 2021 in die proewe getoets.
NASIONALE KULTIVARPROEWE Die Wes-Kaapse Departement van Landbou doen jaarliks kultivarevaluasieproewe in die Swartland. Gedurende 2020 is die aantal proewe in die Swartland beperk tot 2 lokaliteite en daar is ‘n totaal van 14 kultivars in die kultivarevaluasieprogram getoets. Daar was vier konvensionele, vier CL- (ClearfieldR, Imasamoks-tolerant) en vyf van die TT-groep (Triasien-tolerant), asook ‘n kombinasietipe kultivar
(naamlik Imasamoks- en Triasien- tolerante kultivar, Hyola 580CT) ingesluit in die proewe. Geen nuwe kultivars was getoets nie en alle kultivars was basterkultivars.
Die reënval op Langgewens in die Swartland was 12 mm minder as die langtermyn gemiddelde, terwyl die reënval tydens Junie, Julie en Augustus beter was as die langtermyn gemiddelde. Die temperature en veral die maksimumtemperatuur was bogemiddeld hoog. Die maksimum temperatuur vanaf Mei tot Julie was tussen 1.3°C (Mei 2020) tot 2.4°C (Junie) hoër as die langtermyngemiddelde. Die temperature, tesame met die reënval, was waarskynlik ideal vir gewasverbouing tot Julie. Canolaplante is baie gevoelig vir hoë temperature tydens blom tot en met die einde van die saadvulperiode. Gedurende die periode was die maksimum- (1.1°C) en minimumtemperature (1.4°C) laer as die langtermyn gemiddeld. Die koeler temperature het ook in September voorgekom. Die sameloop van klimaatsomstandighede in 2020 het tot gevolg gehad dat baie goeie saadopbrengste voorgekom het.
Figuur 1: Maandelikse reënval vir 2020 sowel as langtermyn by Langgewens.
Figuur 2: Maandelikse minimum- en maksimum temperatuur by Langgewens vir 2020 en langtermyn.
RESULTATE
Die opbrengsresultate vir 2018 tot 2020 is opgesom in Tabel 1. Die “Clearfield (CL)” en “Triasien tolerante (TT)” kultivars se data is geskei van die konvensionele tipes. Die nuwe kombinasie-tipe kultivar, naamlik Imasamoks- en Triasien-tolerante kultivar (Hyola 580CT), is by die TT-groep ingesluit. Dit is uiters belangrik dat kultivars stabiele en hoë opbrengste oor seisoene en areas gee.
Tabel 1: Swartland saadopbrengste uitgedruk as persentasie vir 2018 tot 2020
2018 2019 2020 2018-2020
2019 & 2020
Quartz 107 127 113 113 2 117 2
Diamond 117 127 114 117 1 119 1
CB Tango 99 108 86 95 4 93 4
Hyola 50 98 101 97 98 3 99 3
Konv. Gem. 105 116 103 106 107
44Y90 108 97 117 109 2 110 2
45Y91 99 92 112 103 3 106 3
43Y92 110 114 115 112 1 115 1
45Y93 94 106 102 4
Cl Gem.
106 99 112 108 108
Alpha TT 95 104 97 97 1 99 1
Hyola 350 102 100 88 95 2 92 3
Hyola 650 TT 88 85 87 86 4 86 4
Hyola 559 TT 90 89 94 91 3 93 2
Hyola 555 TT 88 83 84 85 5 84 6
Hyola 580 CT 78 89 85 5
TT Gem. 92 90 90 91 90
Die twee konvensionele kultivars nl. Diamond en Quarts, het in 2018, 2019 en 2020 die beste gevaar binne die konvensionele groep. Hulle het oor die afgelope twee seisoene 17% (Diamond) & 13% (Quarts) beter gevaar as die proefgemiddeld by Langgewens. CB Tango en Hyola 50 kon in die Swartland vir die 2018/19-seisoen nie ‘n gemiddelde opbrengs handhaaf wat beter was as die proefgemiddelde nie.
In die Swartland het 44Y90 die hoogste persentasie saadopbrengs gegee gedurende 2020, gevolg deur 43Y92. Die Cl-kultivar 43Y92 het vir die afgelope twee- en driejaar siklusse die hoogste gemiddelde opbrengs opgelewer.
Die TT-kultivars word baie in die Swartland gebruik om te help met onkruidbestuur. Triasien onkruiddoders is ‘n Groep C1-produk, wat produsente ‘n alternatiewe opsie gee om weestandbiedende raaigrasonkruide te beheer. Dis belangrik om te besef dat die opbrengs van TT-kultivars betekenisvol laer is as die opbrengs van die ander twee canolagroepe.
Die kultivar Alpha TT het die beste gevaar binne die TT-groep. Alpha se gemiddelde opbrengs was 97-99% van die proefgemiddelde vir die Swartland. Dit is ‘n nuwe standaard wat nie voorheen deur TT-kultivars bereik kon word nie.
Wat leer ons uit 2020?
Die 2020 seisoen was in die Wes-Kaap langer as normaal weens die laer as normale temperature gedurende die blom en saadvulperiode.
Kultivar soos 45Y93 kon wys wat sy potensiaal is in lang groeiseisoen. Korter groeiseisoenkultivar soos Hyola 350 TT kon moontlik nie die gunstige lente ten volle benut nie. Ons is nou wel baie bewus van die opbrengspotensiaal van ons kultivars en besef maar
net weer watter beperkende rol die natuur kan speel.
CANOLA 2022 - GROTER WINSGEWENDHEID -
HOE KIES EK?
Wanneer produsente besluit om hul oppervlak onder canola te vergroot, moet hulle nog paar punte in gedagte hou bo en behalwe opbrengs:
1. Die opbrengspotensiaalDie gemiddelde saadopbrengsopbrengs van die TT-kultivars was 17-18% laer (2 & 3 seisoene) as die CL-kultivars.
2. Onkruidbestuur (konvensionele-, Cl- of TT-kultivar). Sulfonielureum (SU) oordrag in die grond in die Swartland is ‘n groter risiko as in die Overberg weens die droër somers. Konvensionele en TT-kultivars is baie sensitief vir SU-oordrag in die grond. TT-kultivars se voordeel is dat spesifieke probleemonkruide beter beheer kan word as wat die geval met die ander kultivars is.
3. Fisiologiese ontwikkelingstempo Produsente moet versigtig wees vir stadige kultivars in sekere areas waar die reën soms vroeg afsny in die seisoen (L.W. grootste deel van die Swartland)
4. SwartstamProdusente moet kultivars wissel. Lang rotasiestelsel van elke vierde jaar is optimaal. Swambespuiting moet slegs gedoen word wanneer nodig. In areas met hoë druk of vir kultivar met swak swartstamweerstand kan op die 4-6- blaarstadium gespuit word.
5. Is die saad van die kultivar van u keuse beskikbaar? Inligting en eienskappe van die verskillende kultivars word in Tabel 1 opgesom. Die inligting sluit in dae tot blom en tydperk van blom, sowel as opbrengspotensiaal. Die swartstamindeks word in twee kolomme verdeel. Die 2de kolom gee die swartstamindeks nadat saad met Jockeyj, Saltros of Ilivoi behandel is. Dis belangrik om kennis te neem dat daar meer chemiese opsies bestaan t.o.v. saadbehandeling van canolasaad. Die keuse van saadbehandeling word egter deur die maatskappy wat die saad invoer vasgestel.
Klimaat in die Wes-Kaap is wisselvallig en kan ook wissel binne ‘n seisoen. As ons terugkyk na die 2020 seisoen, was dit bogemiddeld warm voor die reproduktiewe fase van canola begin het, waarna dit verander het na onder gemiddeld. Ons moet nooit die uiters warm September gedurende 2019 in die hele Wes-Kaap vergeet en hoe dit die opbrengspotensiaal drasties verlaag het nie. Dit is onmoontlik om voorsiening te maak vir sulke klimaatsuiterstes. Nogtans is goed aangepaste kultivars noodsaaklik vir sukses. Kultivars met té lang groeiseisoen, bring verhoogde risiko’s in die meeste areas. Dis slegs geskik vir areas met koue klimaat en lang groeiseisoen.
TABEL 1: KULTIVAR EIENSKAPPE VAN DIE
KULTIVARS IN 2018 TOT 2020 GETOETS
Kultivar Tipe Jaar 1ste
toets
Groei-periode Dae tot blom
2019 & 20
Dae tot eindblom (Lang.)
2018 & 19
Opbrengs(% van
proefgem)Swartl.
2019-20
Opbrengs(% van
proefgem)Rûens
2019-20
Swart-stam indeks
Swartst.Indeks + Jock-
eyj /Saltros/Ilivoi
Swartst.Indeks + Jock-
eyj /Saltros/Ilivoi
Hyola 50 Konv K2 Seed 2009 laat laat 99 93 w2016 w2016(j) w2016(j)
CB Tango Konv Agricol 2013 vroeg* vroeg* 93 93 mv2014 mw2014(j) mw2014(j)
Diamond Konv Agricol 2015 vroeg vroeg 119 108 mw2020 w2020(jsi) w2020(jsi)
Quartz Konv Agricol 2018 med. vroeg med.vr. 117 115 W2020 w2019(j) w2019(j)
44Y90 CL Pioneer 2016 med. med. vr. 110 112 w2020 w2020(jsi) w2020(jsi)
45Y91 CL Pioneer 2016 laat laat 106 106 w-mw2020 w2020(jsi) w2020(jsi)
43Y92 CL Pioneer 2017 med. vroeg med. vr. 115 110 w2020 w2020(i) w2020(i)
45Y93 CL Pioneer 2019 laat2019 laat2019 102 110 w2020 w2020(si) w2020(si)
Hyola 555 TT TT K2 Seed 2011 med. vroeg med. vr. 84 85 mw2014 w2014(j) w2014(j)
Hyola 559 TT TT Barenbr. 2014 med. vroeg med. 93 86 w2020 w2020(s) w2020(s)
Hyola 650 TT TT Barenbr. 2017 med. med. 86 93 w2017 - -
Alpha TT TT Agricol 2017 med. vroeg med. vr. 99 99mv-
mw2018w2018(j) w2018(j)
Hyola 350 TT TT K2 Seed 2018 vroeg vroeg 92 90 w2020 w2020(jsi) w2020(jsi)
Hyola 580 CT Cl &TT Barenbr. 2019med.
vroeg2019med.2019 85 89 w2020 w2020(jsi) w2020(jsi)
w = weerstand; mw = matige weerstand; mv = matig vatbaar; v = vatbaar. * Stadig ontkiem (datums aangepas). Saadbehandeling: Jockey = j, Saltro = s en Ilivo = i Data verkry vanuit Australië in “Blackleg Management Guide Fact Sheet” (2014 - 2020).
Limagrain Zaad South Africa
Limagrain Zaad South Africa beproef vanjaar heelwat
nuwe basters wat reeds baie potensiaal in Australië toon.
Dit sluit TT-, CL-, CT- en konvensionele basters in. Hyola
350 TT is tans die enigste kommersieel beskikbare baster, maar dit sal binnekort verander:
LIMAGRAIN ZAAD SOUTH AFRICA
SKOG 2021 - CANOLA
Kultivars Volwassenheid TegnologieOlie-
potensiaal
Verdraagsaam teen swaswart-
stamgroepe
Omval-Weerstand(1 - swak9 - goed)
Pitvastheid(1 - swak9 - goed)
Hyola 350 TT(kommersieel)
Vroeg Triazine potensiaal ABDF 8 8
Hyola Blazer TT(eksperimenteel)
Medium-vroeg Triazine Hoog ADF 9 8
Hyola Equinox CL(eksperimenteel)
Medium Clearfield Hoog ADF 8 8
Hyola Enforcer CT(eksperimenteel)
Medium-vroeg Triazine en Hoog ADF 7 8
Konvensionele basters (eksperimenteel)
Daar is drie nuwe opwindende konvensionele basters wat beproef word: een vroeg, een medium en een medium-laat tot volwassenheid. Al drie beskik ook goeie swartstam verdraagsaamheid, olie- en
opbrengspotensiaal.
Hyola 350 TT by SKOG 2020.
Limagrain Zaad South Africa
LIMAGRAIN ZAAD SOUTH AFRICA
SKOG 2021 - HAWERKULTIVARS
Simonsberg: Lente-tipe hawerkultivar (115-120 dae tot 10% aarverskyning). Veeldoelige kultivar - weiding, hooi, kuilvoer en graan. Gewilde, beproefde kultivar in die goedkoper hawersaad mark.
Saddle: Lente-tipe hawerkultivar (115-120 dae tot 10% aarverskyning). Geskik vir beweiding, kuilvoer- en hooi-produksie. Beskik oor minstens ‘n 10-15% hoër opbrengspotensiaal as Simonsberg (gebasseer op 2020 proewe). Sterk vestiging en vinnige produksie. Goeie swamsiekte-weerstand.
Horsepower: Lente-tipe hawerkultivar. Raak ongeveer 10-14 dae later reproduktief as Simonsberg en Saddle. Baie goeie wei-, kuilvoer- en hooi-kultivar. Goeie opbrengspotensiaal danksy die effens langer vegetatiewe groeitydperk en goeie swamsiekte-weerstand.
Rushmore: Eksperimenteel. Uit dieselfde stal as Horsepower en Saddle. Soortgelyke groeilengte as Horsepower. Baie belowende kultivar! Hou hierdie spasie dop!
Daar is ongeveer 10-14 dae verskil tussen die aarverskyning van Horsepower (links) en Saddle (regs).
integrated management system. These systems use precautionary measures like remote sensing and disease pressure estimations from environmental conditions, as well as disease control methods like fungicides, host resistance and agronomical practices aimed at reducing disease levels. Studies have shown that higher plant densities correlate to higher plant disease pressure. If combined with higher nitrogen application rates, the risk of disease multiplies with more vigorous growth and more plants per m². This could have an influence on the optimal planting density and nitrogen rate strategy used by wheat growers.
There are many studies on wheat plant densities and nitrogen application rates as separate agronomical factors, but there are few studies showing these two factors as having a combined influence on grain yield. The results are also influenced by environmental factors, thus a study of these two factors in the Swartland should reveal important information for the growers. There is also very little research on the influence these two factors have on the disease pressure on wheat cultivars used in the Swartland. A study on this subject in the Swartland area could prove to be of great importance for the wheat industry in the Western Cape.
2. Wheat productivity and quality
Wheat development, productivity and quality were monitored by determining plant population, above-ground biomass production, leaf area index (LAI), the final number of tillers, yield, hectolitre mass (HLM), thousand kernel mass (TKM), as well as gluten and protein content in the grains. Disease progression for powdery mildew (witroes) was also determined over a 10-week period. Interesting results from the first season are summarised by the figures below.
1. Introduction
Nitrogen is an important macronutrient and regulates tiller bud growth through regulating endogenous hormones and N metabolism. An increase in N application rate increases tiller density and reduces tiller mortality. The increased tiller density will increase the number of spikes per unit area and can lead to a higher yield potential. The increase in N rates mainly contributes to an increase in grain yields in early-emerging tillers. Higher N rates also increase the grains per area produced by tillers. Farmers often apply N fertilisers in excess, in the hope of higher grain yields. Over-application of N fertiliser contributes little to grain yield and reduces nitrogen use efficiency. Studies have also shown that, although increased plant densities results in less tillers per plant, the number of tillers per unit area may remain constant.
Higher plant densities can increase grain yield potential due to increased spikelet numbers per unit area. Dense planting also maximises leaf area index, ensuring that plant photosynthesis meets the higher yield requirements. However, if plant densities keep increasing, lower yields and quality can be expected, due to the higher number of spikes per unit area accompanied by reduction in kernels per spike and thousand kernel mass. In contrast, too low plant densities may not be able to produce enough tillers to ensure high yields when environmental conditions are favourable to ensure high yields.
To find the balance between N rate and plant density proves to be a challenge in cropping systems. If the correct balance is found, it can lead to significant higher yields and better nitrogen use efficiency. Wheat disease can destroy entire harvests if not treated. Wheat diseases is best managed with an
2. BEMESTINGSeed density and nitrogen fertilisation: Can it be used as a management tool to optimise
crop productivity and disease control?
KR van Blerk2, J Labuschagne1, P Swanepoel2, G van Coller1
1Western Cape Department of Agriculture, Private Bag X1, Elsenburg 76072Stellenbosch University, Private Bag X1, Matieland, 7602
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Figure 2.1: Biomass production (t/ha) 90 days after emergence for fungicide treated and untreated plots
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Figure 2.2: Biomass production (t/ha) 150 days after emergence for fungicide treated and untreated plots
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Figure 2.3: Yield (t/ha) for fungicide treated and untreated plots
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Figure 2.4: Protein content (%) in wheat grains for fungicide treated and untreated plots. Bars with similar letters on top are not significantly different from each other.
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Figure 2.5: Disease progression of plants visually infected with powdery mildew over a 10-week period at different N-levels (0, 60, and 90). N60 and N90 had a significantly (P ≤ 0.05) higher disease incidence than N0, but did not differ significantly from each other.
Figure 2.6: Disease progression of plants visually infected with powdery mildew over a 10-week period at different seeding densities. Seeding density had no significant (P > 0.05) on powdery mildew incidence.
3. Discussion
Nitrogen had a substantial influence not biomass yield at 90 days after emergence. The plants reached the end of their leave production stage and thus was highly dependent on nitrogen. Fungicides had a large influence on the plots with a higher plant population and nitrogen rate. With the fungicide treatment the plants could maintain more of its leaves and that resulted in a higher biomass.
At the higher plant populations and nitrogen rates the microclimate could have been more favourable to diseases and this resulted in a bigger influence from the fungicide treatment on these plots. The industry average nitrogen rate of 60 kg/N produced more biomass on the plots that was treated with a fungicide and at the higher plant populations, this could indicate that higher nitrogen rates could be conducive to disease severity at high plant populations.
This was evident when considering the effect of different N-levels on powdery mildew incidence over a 10-week period. The decrease in disease incidence noted toward the end of the 10-week period can be ascribed to the plants maturing, resulting in less green foliar tissue available to become infected. There were no statistical influences from the different plant populations on biomass or incidence of powdery mildew.
Biomass production at 150 days after emergence, physiological maturity, was only influenced by nitrogen application rate and fungicide treatment. The fungicide treatment had an influence at all plant populations and nitrogen rates. Temperatures warmed
up at this growth stage and this could have created a microclimate favourable for diseases like powdery mildew.
The yield was also mainly influenced by nitrogen rates and fungicide treatments especially at higher plant populations. As expected, the main difference in nitrogen rate was observed between the 0 and 60 kg N rates. Differences was not observed between the 90 and 60 kg N rates, in fact on many occasions the 60 kg N outperformed the 90 kg N. Plant populations did not influence the yield.
The protein content of the grain was only influenced by nitrogen rates. Plant populations and fungicide treatment had no significant influences. The higher the nitrogen rate was the higher the protein content was in the grain. Nitrogen is thus a major contributing factor to grain protein. The higher nitrogen levels available at the end of the season probably made the difference in protein content.
4. Conclusions and recommendations
Conclusions or recommendations will only be finalised after completion of the study after at least 2 years of data capturing.
5. Acknowledgements
Special thanks to Western Cape Department of Agriculture, and Stellenbosch University.
For more information contact Dr Johan Labuschagne E-mail: [email protected]
Soil physical processes: Soil acidity reduces the stability of soil aggregates (i.e. a ‘powdery soil’) which renders the soil prone to crust, leading to reduced water infiltration rate and poor germination of seedlings (particularly small-seeded crops like canola).
Soil biological processes: Beneficial soil microorganisms thrive in non-acid soils, particularly bacteria. Soil acidity may therefore lead to reduced organic matter breakdown and nutrient cycling by soil microorganisms. Nitrogen fixation within the soil via rhizobacteria is hindered under severe acidic conditions. In combination this leads to greater dependency on synthetic fertilisers.
Soil acidity is commonly corrected by applying limestone (lime). To control soil acidity in no-tillage systems, lime is broadcaston the surface without incorporation through tillage. It is well accepted that lime does not have an effect on reducing soil acidity beyond the point of placement, as lime has low mobility within soil. As a result of long-term no-tillage, the following can occur: high pH in the soil surface layers, and low pH deeper into the soil, as well as stratification of other immobile nutrients (like phosphorus) and organic matter accumulation in the top layer of soil..
This problem is often not picked up in soil tests as soil samples are taken to 150 mm or deeper, diluting the stratification effect. Erroneous soil fertility test results lead to inappropriate soil amelioration
1. Introduction
Conservation Agriculture (CA) has been proven to be one of the most effective strategies to improve the sustainability of crop farming systems in the Western Cape. No-tillage, a key principle of CA, is one of the most important strategies to improve and sustain yield in the long term. Crop rotation systems in the Western Cape are commonly based on small grains, where more than 60% of farmers have fully adopted CA while more than 90% of farmers have already converted to no-tillage systems. No-tillage involves seeds being placed directly into soil with seed-drills with either tine or disc openers.
However CA, particularly no-tillage, has its limitations, one of these being soil acidity and pH stratification with depth. Soil acidity is considered a major yield-limiting factor for many crops. Acid soil not only has direct chemical effects on plant root development, but also affects soil physical and biological processes. Examples of the effects of acidic soil conditions are listed below:
Soil chemical processes: Soil acidity may lead to toxicity of hydrogen ions and heavy metals (aluminium, iron, manganese), deficiency of calcium, magnesium, potassium, phosphorus, boron, nitrogen, or molybdenum. Although sufficient nutrient levels are maintained within a soil, pH often regulates its accessibility by crop roots. This will restrict root growth, leading to poor nutrient and water uptake – and consequent reduced yield.
CONSIDERATIONS FOR LIMING MANAGEMENT IN THE SWARTLAND: SOIL TILLAGE, PLACEMENT, FORM
AND FINENESS OF LIME
J Pellissier2, Dr P Swanepoel2, Dr J Labuschagne1, Dr A Hardie3
1Western Cape Department of Agriculture, Private Bag X1, Elsenburg 76072Department of Agronomy, Stellenbosch University, Private Bag X1, Matieland, 7602
3Department of Soil Science, Stellenbosch University, Private Bag X1, Matieland, 7602
and fertilisation recommendations and limits plant productivity. If soil pH varies beyond the optimal range at any soil layer, growth and yield are expected to be reduced, regardless of whether the average soil pH across different depths is optimal. Due to the widespread nature of sub-soil acidity across the Western Cape, this is a relevant issue for all grain producing farmers in this region and elsewhere in South Africa. The aim of this study is to address major limitations of conservation agriculture which include but are not limited to:
• immobility of lime in no-tillage systems• pH stratification by depth• subsoil Al toxicity• long-term reduction of soil productivity & crop
production
Thus, to determine which liming strategies in terms of the lime form, fineness, soil disturbance as well as in combination with gypsumare most effective in addressing the abovementioned limitations.
2. Workplan and experimental design
A soil with severe subsoil acidity and distinct pH stratification following conservation agriculture practices (i.e., no-tillage) for more than eight years was identified in the Swartland near Moorreesburg, Western Cape. An experimental trial was designed consisting of nine treatments (table 1) and four replications. Treatment blocks of 4.5 m x 15 m were allocated to compensate for tillage operations. Lime requirements were estimated according to standard methods (Modified Eksteen method) used in the Western Cape. Lime application rates were adapted according to each lime product’s calcium carbonate equivalent (CCE) to achieve uniformity between liming treatments regarding CCE. Gypsum application rates were determined based on calcium content.
A top performing wheat cultivar SST 0166 was chosen, based on local cultivar evaluations. Prior to planting, soil fertility status was corrected according to soil tests and recommended guidelines, except for soil acidity and calcium. Nitrogen was applied according to requirements determined by soil analysis at appropriate intervals. Weeds, pests and diseases were controlled chemically, using appropriate
pesticides. Seed will be harvested with a small plot combine harvester.
3. Soil sampling and analyses
One composite soil sample comprising of five sub-samples per treatment plot per depth increment, was collected. Soil depth increments are 0 – 5 cm, 5 – 10 cm, 10 – 20 cm and 20 – 30 cm depths. Soil sampling and standard chemical analyses will be done at pre-planting (April), mid-season (August) and end-season (November) intervals.
4. Agronomic measurements and analyses
Plant population will be determined three weeks after crop emergence by counting the number of seedlings in 1 meter row lengths per plot. Aboveground plant samples will be collected every 30 days after emergence up to physiological maturity, in order to determine leaf area index and biomass yield. During sampling, a border of at least 1 m will not be sampled to eliminate border effects. Samples will be taken by randomly selecting 20 plants from each plot.
Plant parts will be separated in to leaves, stems and seeds (where appropriate in certain growth stages) to determine Ca and Mg content. At 90 days after emergence, the number of ear bearing tillers per plant will be determined. Other yield components (spikelets per spike, seeds per spikelet and average mass per seed) will be determined at harvesting. Wheat yield (kg ha-1) will be determined as well as thousand-kernel mass (g), N content (%) and hectolitre mass (kg hl-1).
5. Economic analysis
Sensitivity analyses will be conducted to determine the economic implication of each liming treatment, (pelletised lime, hydrated lime, lime/gypsum).
6. Acknowledgements
Special thanks to Western Cape Department of Agriculture, Western Cape Agricultural Research Trust and Stellenbosch University. For more information contact Dr Johan Labuschagne E-mail: [email protected]
Nr Treatment
1 Control (no soil disturbance; no lime)
2 Surface application of Titan calcitic lime
3 Surface application of Titan calcitic lime, following tillage with mouldboard plough
4 Surface application of Titan calcitic lime, following tillage with chisel plough
5 Surface application of partially hydrated aglime (Ag-Hydrate)
6 Pelletised lime (Reacti Cal) placed at the normal rate
7 Surface application of gypsum (CaSO4.2H2O) at normal rate - 100%
8 Surface application of lime and gypsum mixture of 66.7 % lime and 33.3% gypsum
9 Surface application of lime and gypsum mixture of 33.3 % lime and 66.6% gypsum
Table 1: Treatments design and specifications
EFFEK VAN GEBALANSEERDE PLANT-
VOEDING OP CANOLA OPBRENGS EN
STIKSTOFVERBRUIKSDOELTREFFENDHEID
Inleiding
Canola (Brassica napus) was vir die eerste keer in 1994 in wisselboustelsels in Suid-Afrika verbou. Sedertdien het produksie aanhou toeneem soos die voordele van canola erken word. Canola aanplantings in die Wes-Kaap is gemiddeld ongeveer 75 000 ha vanaf 2015. Canola pryse het in die laaste twee jaar aansienlik gestyg wat dit dus meer aantreklik maak vir produsente. Met die afname in gars aanplantings het canola aanplantings in 2021 toegeneem tot ongeveer 96 000 ha wat dus die belangrikheid van die gewas in produksiestelsels bevestig. Canola het ‘n hoër natuurlike behoefte aan voedingstowwe in vergelyking met ander gewasse, soos koring en gars (Tabel 1). Bemesting speel dus ‘n kritiese rol in suksesvolle canola produksie.
Die rol van gebalanseerde plantvoeding tot opbrengs word algemeen onderskat in droëland verbouiing. Gebalanseerde voeding het nie net ‘n direkte invloed op opbrengs nie maar ook op grond gesondheid. Dit word bevestig deur Liebig (1843) se wet van die Minimum wat sê, “gewas opbrengs is eweredig aan die van die mees beperkende element.” Algemene verskynsels wat gepaard gaan met ongebalanseerde
plantvoeding is, erosie, verliese aan organiese koolstof, myn van beperkende voedingstowwe, grondversuring asook versouting. Om volhoubaar te wees moet gebalanseerde plantvoeding, wat aangepas is tot plaaslike produksie toestande, die rugraat van alle gewasproduksietegnieke uitmaak. Wanneer gewasse ge-oes word, word voedingstofelemente vanuit die grond verwyder en saam met die oes weggevat. Indien hierdie elemente nie vervang of teruggesit word nie sal grond gesondheid daaronder lei.
Die onvolhoubare bestuur deur elemente uit die grond te neem en nie weer te vervang nie lei tot verliese aan opbrengs wat nie net ‘n finansiele implikasie het nie maar ook lei tot ‘n vermindering in biomassa wat direk bydrae tot die verlies van organiese koolstof in die grond. Hierdie organiese poel huisves ‘n enorme biologiese voedselketting en ekosisteemdiens wat onvervangbaar is. Een element kan nie die rol van ‘n ander vervang nie, dus is produksie afhanklik van gebalaseerde voeding. Indien produksie optimaal is, kan goenoegsame materiaal tot die koolstof poel gevoeg word, sonder grond degradasie, wat die eksositeem optimaal laat funksioneer. ‘n Grond en plant ekosisteem wat optimaal funksioneer is die sleutel tot volhoubaarheid.
Tabel 1: Algemene ontrekking syfers van stikstof (N), fosfaat (P), kalium (K) en swael (S) van canola teenoor koring.
Kg/ton/ha
N P K S
Canola 40 7 9 10
Koring 22 4 5 2.5
Doel van die studie:
Ondersoek die effek van gebalanseerde plantvoeding op canola produksie asook die effek daarvan op stokstofverbruiksdoeltreffendheid.
• Bepaal die bydraende rol van stikstof (N), fosfaat (P), kalium (K) en swael (S) tot opbrengs.• Bepaal die effek van fosfaat plasing (bandplaas vs. breedwerpig) op opbrengs• Bepaal die effektiwiteit van ‘n algemene blaarvoedingsprogram vir opbrengs verhoging.• Bepaal die effek van boor (B) as blaarvoeding op opbrengs
Plantdatum: 12 Mei 2021
Tipe Planter: Rovic mespunt 30cm rywydte
Plantdigtheid 2.7 kg / ha (Werklike opkoms = 45 plante/m2)
Kultivar: Alpha TT
Gewasrotasie: Koring - Hawer - Canola
Met plant * Verwys na behandelings
Bemesting: 1ste Bobemesting 2-3 blaar (11 Junie) – Ammoniumnitraat (+ swael) + kalium
2de Bobemesting 10% blomstadium (26 Julie) – Ammoniumnitraat (+ swael)
Blaarvoeding Rosette stadium en 10% blom – Verwys na behandelings
1ste spuit Atrazine @ 2L/ha
Onkruidbeheer: 1ste spuit Prosaro (14 Julie)
Swambeheer: 2de spuit Prosaro (13 Aug)
Proef inligting:
Grondontleding:
Behandelings
• Totaal ewekansige ontwerp met 3 herhalings
PROEF A: Plantvoeding eliminasie proef
Nr Behandelings (Plantvoeding)
Met plant 1ste bobemesting
2de bobemesting
Totaal
N P K S N P K S N P K Sz N P K S
1 Kontrole 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
2 N 0 0 0 0 45 0 0 0 35 0 0 0 80 0 0 0
3 NK 0 0 8 0 45 0 15 0 35 0 0 0 80 0 23 0
4 NPK 0 16 8 0 45 0 15 0 35 0 0 0 80 16 23 0
5 NPK (P breedwerpig) 0 16 8 0 45 0 15 0 35 0 0 0 80 16 23 0
6 NPKS 0 16 8 0 45 0 15 11 35 0 0 9 80 16 23 20
* Behandelings 1-6 het ‘n volledige blaarvoedingsprogram ontvang gebasseer op grondontleding
PROEF B: YaraVita Blaarvoedings proef
Nr BehandelingsTyd van toediening
Rosette 10% Blom
7 Control 0 0
8 YaraVita Brassitrel Pro 2L/ha 2L/ha
9 YaraVita Bortrac 1L/ha 1L/ha
10 Brassitrel x Bortrac 2L/ha Brassitrel 1L/ha Bortrac
* Bemestingsprogram vir behandelings 7-10: 80N; 16P;23K;20S
FOTOS2 Augustus 2021
Kontrole(0N; 0P; 0K; 0S
Slegs Stikstof(45N; 0P; 0K; 0S)
Gebalanseerde plantvoeding (45N; 16P; 23K; 20S)
VERBETERING VAN STIKSTOF(N) EFFEKTIWITEIT
DEUR INHIBEERDERS
Doel om vervlugtiging en/of loging van Stikstof(N) te beperk, derhalwe beter benutting deur gewas
Plantdatum : 18 Mei 2020 [Bruto perseel van 3m x 10m]Plantmengsel : 25 N, 12 P, 8 K, 4 S [NPK ’ratio’ van 6.3.2(37), 6.3.2(31)]Plantestand getel : 8 Junie 2020
Bobemesting datum : 1 Julie en 15 Julie 2020 [Twee bobemestings]Bobemesting : 75 N, 11 S Totaal NPK Kg/Ha : 100 N, 12 P, 8 K, 15 S
Plantmonsters : 14 Augustus 2020, hele plant as monster geneem [Bogrondse groei, wortels uit-gesluit] Datum geoes : 16 November 2020 [Stroop 1.5m x 10m perseel]
Proefuitleg : Ewekansige blok ontwerpPlaagbeheer [Insekte, swam, onkruide] behartig deur Welgevallen span [Universiteit Stellenbosch]
Behandelings : Beide plant en bobemesting Stikstof(N) bron is dieselfde behandel [Ton/ha] A [5.67] – Inhibeerder [Ureum HB behandel]B [5.18] – Inhibeerder [Ureum HB behandel]C [5.35] – Aktiveerder [Ureum HB behandel]D [5.05] – Ureum HB [Onbehandeld]E [4.53] – Inhibeerder [KAN behandel] F [5.42] – KAN [Onbehandeld]G [5.22] – Aktiveerder plus mikro-elemente [Ureum HB behandel]H [4.30] – Nulperseel [Geen NPK of behandeling]
Fig 1: Opbrengs vergelyking, alle behandelings A tot G verskil betekenisvol van Nulperseel [Kontrole] LSD (0.05) = 0.61Proef sal weer in 2021 herhaal word
André Britz Pri.Sci.Nat +27 82 457 1793 [email protected] Kimleigh Chemicals SA
EFFEK VAN VARIëRENDE NITROPOLY-S TOEDIENINGS OP KORING EN CANOLA IN DIE SWARTLAND
Inleiding
In ideale omstandighede streef ons daarna om plante met gebalanseerde, toeganklike voeding optimaal te voed om sodoende maksimum produksie van hoë gehalte te behaal, sonder om die omgewing nadelig te beinvloed. Ons streef daarna om op gesonde grond te boer, want dit is die sleutel tot volhoubare gewasproduksie.
Om dit te bereik is korrekte, tydige en voldoende bemesting en grond regstellings nodig om te verseker dat die voedingstatus van die grond mettertyd verbeter en nie verswak nie. Dit kan slegs gebeur indien ‘n gebalanseerde bemestingprogram, wat die noodsaaklike makro- en mikro elemente voorsien, gebruik word om gesonde gewasse te kweek en terselfdetyd die grondvoedingstatus te verbeter.
Verskeie faktore dra by tot die sukses van ‘n bemestingprogram. Nie net die tipe bemestingproduk nie, maar ook die tydsberekening, hoeveelheid, oplosbaarheid en plasing, speel ‘n beduidende rol in die sukses van die program. Die belangrikheid van die grondtipe en grondontledings kan nie hierby uitgesluit word nie. Besluite wat daarop gebasseer word, moet positief bydra tot gebalanseerde bemesting, met die inagname van spesifieke benodighede van die beoogde gewas.
Liebig se Wet van Minimum herinner ons dat gewasproduksie en opbrengs beperk word deur die mees beperkendste faktor. In kort lê die wet klem daarop dat selfs elemente wat in kleiner hoeveelhede deur gewasse benodig word, nie as “onbelangrik” geag kan word nie. Verder geld die wet nie net vir voedingstowwe nie, maar ook vir grondfisiese eienskappe en klimaatskondisies.
Die meerderheid van die tyd word daar hoofsaaklik gefokus op stikstof (N) en fosfaat (P) as die belangrikste plantvoedingstowwe. Kalium (K), wat ook ‘n makro-element is, word taamlik afgeskeep teenoor die eersgenoemde twee elemente (veral in die Swartland). Swawel (S) word as belangrik geag wanneer gewasse met hoë swawel-behoeftes, soos canola, verbou word. Verder word swawel, kalsium (Ca) en magnesium (Mg) as byprodukte van bemestingstowwe, kalke en/of gips toegevoeg, en nie noodwendig as individuele voedingstowwe in kleingraan bemestingprogramme ingeskryf nie, alhoewel elkeen belangrike rolle in die gewasse se ontwikkeling speel. Mikro-elemente (B, Cl, Cu, Fe, Mn, Mo en Zn) is in kleiner hoeveelhede nodig, en word gewoonlik op grond van grondontledings en tekortsimptome aanbeveel of reggestel.
‘n Nuwe multi-voedingstofkunsmis wat kan bydra tot ‘n gebalanseerde bemestingprogram is Nitrophoska
se NitroPoly-S. Dit is ‘n enkelkorrel-produk wat van nature uit vier noodsaaklike plantvoedingstowwe bestaan, naamlik swawel (19.2%), kalium (11.6%), kalsium (12.2%) en magnesium (3.6%). Al die elemente kom in hul sulfaatvorm voor, wat dit ten volle opneembaar vir gewasse maak. Dáárom die naam NitroPoly-S, waar “Poly-S” na die meervuldige sulfaat verbindings verwys en die “Nitro” na Nitrophoska. Die produk, afkomstig van die mineraal Polyhalite, word gemyn, fyngemaal en verskeep vanuit die Boulby-myn in Brittanje. Die mineraal het ‘n unieke oplosbaarheidspatroon wat verseker dat die elemente geleidelik oor die groeiseisoen vrygestel word. Dié eienskap hou die voordeel in dat minder loging en minder grondversuring plaasvind, in vergelyking met ander sulfaatbronne. Die soutindeks is laag en die pH neutraal, wat beteken dat die produk in nabye kontak met soutgevoelige gewasse geplaas kan word, sonder enige nadelige gevolge. Die produk beskik nie net oor unieke chemiese eienskappe nie, maar ook oor goeie fisiese eienskappe. Die kristal-vormige produk het deursnee van 2 tot 4 mm, wat uitstekende verspreidingseienskappe verseker. Verder kan die produk onverdun toegedien word, of in mengsels saam met suiwer stikstof en/of ander voedingstowwe. Die produk kan breedwerpig uitgestrooi of in plantermengsels gebruik word, afhangende van die gewas se benodigheid.
Hoekom is daar ‘n plek vir NitroPoly-S in die Wes-Kaap se wintergraan boerderypraktyke?
Soos voorheen genoem bevat die multi-voedingstofkunsmis vier noodsaaklike voedingstowwe. Swawel word in die sufaatvorm deur plante opgeneem, in min of meer dieselfde hoeveelhede as fosfate. Die element maak deel uit van aminosure wat boustene is vir proteiene en dra verder ook by tot die omskakeling van lig- na chemiese energie. Saam met magnesium stimuleer swawel olieproduksie. Kalium speel ‘n rol by die vervoer van stikstof in die plant.
Verder kom die element nie in strukturele dele van die plant voor nie, maar in die selsap. Om hierdie rede het dit ‘n groot invloed op die oop- en toemaak van huidmondjies asook die tempo van fotosintese. In die plant kom kalsium as kalsiumpektaat in die middellamella van selwande voor. Kalsium is betrokke by selverdeling en selvergroting en stimuleer proteiensintese. Die element het verder ‘n stimulerende effek op nitraatopname. Magnesium vorm die kern van die chlorofil-molekuul, waarsonder fotosintese nie kan plaasvind nie. Magnesium dra ook by tot fosfaatopname en die vervoer daarvan in plante. Die element aktiveer verskeie ensiemsisteme wat betrokke is by koolhidraat- en stikstofmetabolisme en oliesintese.
NitroPoly-S bevat dus ‘n kombinasie van die bogenoemde voedingstowwe wat saam met stikstof en fosfaat gebruik kan word om ‘n gebalanseerde bemestingprogram saam te stel. Die multi-voedingstof produk word wêreldwyd suksevol
kommersieël en in proewe gebruik om gesonder gewasse met hoër opbrengste te verbou.
Doel:Die mineraal Polyhalite, word suksesvol in die binneland van Suid-Afrika, op ‘n verskeidenheid van gewasse gebruik, maar aanplantings hiermee in die Wes-Kaap spesifiek vir canola en koring is beperk. Algemene proefresultate, wat wêreldwyd gedoen is op canola en koring, beveel breedwerpige toediening van hoeveelhede tot 250 kg/ha NitroPoly-S aan. Die proef op Langgewens is opgestel om te bepaal of kleiner hoeveelhede NitroPoly-S in die plantermengsel ‘n bydraende effek tot kwaliteit en opbrengs van die gewasse het.
Die doel was dus om;
1. Die hoeveelheid NitroPoly-S wat veilig direk by die saad geplaas kan word, sonder om gewas groei en opbrengs te benadeel, te bevestig.
2. Kleiner hoeveelhede (< 80 kg/ha), wat in plantermengsels aanbeveel kan word, op die proef te stel.
3. Blaarontledings te gebruik om te bepaal of verskillende toedienings van NitroPoly-S, meer gebalanseerde voeding tot gevolg het.
4. Kwaliteit en opbrengs te bepaal by verskillende toedienings van NitroPoly-S, spesifiek vanuit die plantermengsel.
Materiale en Metodes
Twee aparte proewe vir onderskeidelik canola en koring was op SKOG te Langgewens geplant. Albei gewasse was in die droog met ‘n skyfplanter geplant. Canola (cv. 44Y90) op 11 Mei 2021 en koring (SST0127) op 10 Mei 2021. Grondontledings was vooraf geneem om die voedingstatus van die grond te bepaal. Verskillende hoeveelhede NitroPoly-S was neergesit met plant terwyl kopbemesting daarna konstant gehou was vir al die behandelings. Canola is met 44 kg/ha MAP(35) met onderskeidelik 0, 20, 40, 60 en 80 kg/ha NitroPoly-S geplant. Koring is met 55 kg/ha MAP(35) met onderskeidelik 0, 20, 40, 60 of 80 kg/ha NitroPoly-S geplant.
As gevolg van praktiese redes is lae hoeveelhede stikstof met plant by die saad neergesit, om daarvoor te kompenseer is die eerste KAN-kopbemesting (40N) kort na opkoms breedwerpig toegedien op beide gewasse. ‘n Verdere 40N en 60N (40N + 20N) is onderskeidelik op die canola en koring uitgestrooi vir verdere kopbemesting.
Behandelings is vier keer herhaal, elkeen op ‘n perseel wat 4.4 x 12 m groot is. Gedurende die seisoen was standaard praktyke gebruik om onkruid en swamme te beheer in die proewe. Die canola en koring proef is apart hanteer. Twee stelle blaarmonsters, chlorofilmetings en NDVI-beelde is vir elkeen van die gewasse geneem. Opbrengs en kwaliteit sal aan die einde van die groeiseisoen bepaal word.
Samevatting
‘n Gebalansseerde bemestingsprogram, wat kyk na beide die instandhouding en opbou van die grondvrugbaarheid, is belangrik vir ‘n volhoubare gewasproduksiestelsel. NitroPoly-S, as ‘n multi-voedingstofkunsmis, is ‘n goeie produk om ‘n bemestingsprogram aan te vul met vier noodsaaklike voedingstowwe. Die produk nuut op die mark in die Wes-Kaap, en proefresul-tate is dus beperk. Tenspyte daarvan word die produk reeds met groot sukses wêreldwyd in kommersiële boerderystelsels gebruik, en daarom sien ons uit na die huidige seisoen se op-brengs en kwaliteit resultate.
Foto 1 (Canola): 40 kg NitroPoly-S per hektaar (links) teenoor 60 kg NitroPoly-S per hektaar (LINKS).
Foto 2 (Koring): 40 kg NitroPoly-S per hektaar (links) teenoor 20 kg NitroPoly-S per hektaar (REGS).
Limagrain Zaad South Africa
LIMAGRAIN ZAAD SOUTH AFRICASKOG 2021 -
DEKGEWASSE
3. DEKGEWASSE, KUILVOER, HOOI,
GRONDGESONDHEID
Boere het nie almal dieselfde behoefte as dit by dekgewasaanplantings kom nie. Voorskrifmengsels moet op grond van elke boer se individuele behoefte gemaak word. Limagrain Zaad South Africa beskik oor die regte produkte en kennis oor hoe hierdie produkte mekaar in ‘n mengsel kan komplimenteer om ‘n spesifieke doelwit te bereik.
SKOG Dekgewasmengsel 1
Demonstrasie doelwit - Diversiteit, algemene grondgesondheid en opbrengs:
• Horsepower withawer (15kg/ha)• NCD Grazer stoelrog (15kg/ha)• Saia swarthawer (10kg/ha)• Namoi wieke (8kg/ha)• Nooitgedacht Japannese radys (1kg/ha)• Sub Zero voerradys (0.5kg/ha)
SKOG Dekgewasmengsel 2
Demonstrasie doelwit - Breëblaar diversiteit wat ‘n opsie bied om gras-onkruid uit te spuit:• Magnus voererte (20kg/ha)• Mandelup soetlupiene (12kg/ha)• Namoi wieke (8kg/ha)• Nooitgedacht Japannese radys (2kg/ha)• Sub Zero voerradys (1kg/ha)
SKOG 2020 se dekgewas demonstrasies het daargestelde doelwitte bereik.
4. STELSELS
CAN INFREQUENT TILLAGE PRACTICES COMPENSATE FOR
REDUCED SYNTHETIC AGROCHEMICAL APPLICATION WITHOUT YIELD LOSSES
IN A DRYLAND CROPPING SYSTEM?
F Tshuma2,3, J Labuschagne1, P Swanepoel2, F Rayns3 and J Bennett31 Western Cape Department of Agriculture, Private Bag X1, Elsenburg 7607
2 Stellenbosch University, Private Bag X1, Matieland, 7602
3 Coventry University, Coventry, England
1. Introduction
Continuous intensive tillage with aggressive implements such as the mouldboard may lead to the breakdown of soil aggregates. The smaller soil aggregates can increase the chances of soil erosion by wind and water, leading to loss of the fertile topsoil and decline in soil quality. Soils of poor quality tend to lead to poor crop productivity. To improve soil quality, reduced tillage, including no-tillage has been widely advocated and adopted in South Africa and across the world.
Amongst other things, no-tillage can lead to improved soil aggregate stability, reduced soil erosion, improved water infiltration, increased soil microbial activity and a reduced carbon footprint. Despite the benefits, prolonged no-tillage has been associated with increased weed pressure, soil nutrient stratification, inability to incorporate lime and fertiliser to a deeper depth, as well as soil compaction. Producers who practise no-tillage are forced to rely on synthetic herbicides to control weeds. Excessive and repeated use of synthetic herbicides has led to the development of
herbicide-resistant weeds, such as ryegrass (Lolium spp.), plantain (Plantago lanceolata L.) and horseweed (Conyza spp.). Furthermore, agrochemicals (synthetic herbicides, fungicides and pesticides) have been blamed for increasing environmental damage by killing beneficial insects and harming human health. There is, therefore, a need to reduce the quantity of synthetic agrochemicals applied in agriculture and to convert current farming systems to more environmentally friendly agro ecological farming systems. One option for reducing the quantity of synthetic agrochemicals can be to substitute them with some environmentally friendly bio-chemicals or organic compounds. In this article, the term ‘bio-chemical’ refers to chemical inputs derived from natural compounds.
Strategic tillage is one-off tillage, which is intentionally applied to solve specific problems that are identified in a no-tillage field and could effectively reduce weeds and may enable a reduction in the application of synthetic agrochemicals.
An alternative method to reduce weed pressure in a no-tillage system is to conduct infrequent
tillage. Infrequent tillage involves the application of alternating tillage practices which include tillage and no-tillage. The phase of no-tillage can be one, two or three consecutive years which are followed by a year in which tillage is conducted. Some research on infrequent tillage has been conducted in the Western Cape region of South Africa. However, globally there is a paucity of information on the effects of infrequent tillage practices on crop yield and quality in systems that apply standard, reduced, or minimum quantities of synthetic agrochemicals. In this article, the terms standard, reduced, and minimum (when highlighted in bold) represent the level of synthetic agrochemical application.
This research aimed to determine the long-term effects of different tillage practices on wheat and canola yield and quality in a dryland crop rotation system that applied either standard, reduced, or minimum synthetic agrochemicals. 2. Research site and treatments
The research was conducted at Langgewens Research Farm (33°17²0.78²S, 18°42²28.09²² E) of the Western Cape Department of Agriculture, in the Swartland region of South Africa. The research described in this article was conducted between 2018 and 2020. Wheat cultivar SST 056 was
planted on 11th May 2018 at a rate of 100 kg ha-1. Canola cultivar Alfa TT was planted on 30th April 2019 at a rate of 3 kg ha-1. In 2020, wheat cultivar SST 0166 was planted on 12th May at a rate of 90 kg ha-1. Harvesting was conducted at the end of October of each year. Seven tillage treatments were investigated (Table 1). Table 1: Summary of tillage treatments, abbreviations and the implements used at Langgewens Research Farm.
3. Synthetic agrochemical application
Three levels of synthetic agrochemical applications were investigated:
1. The standard application of synthetic agrochemicals was determined by the Langgewens Technical Committee according to best practices for the region.
2. iThe system with reduced application of synthetic agrochemicals. Some of the synthetic agrochemicals were replaced by bio-chemicals. In this article, the term bio-chemical does not imply organic certification. The bio-chemicals were manufactured and supplied by Real IPM.
3. In the system with minimum use of synthetic agrochemicals, a single application of synthetic agrochemicals was conducted.
Tillage treatment Abbreviation Tools used and tillage intensity
Mouldboard MB Ploughing with a chisel (tine) plough to a depth of 150 mm, followed by the mouldboard plough to a depth of 200 mm and field cultivator to a depth of 50 mm.
Tine-tillage TT Tillage with a chisel plough to a depth of 150 mm, followed by field cultivator to a depth of 50 mm.
Shallow tine-tillage ST Tillage with a chisel plough to a depth of 75 mm
ST applied every 2nd year in rotation with NT
ST-NT Tillage with a chisel plough to a depth of 75 mm was conducted once every two years.
ST applied every 3rd year in rotation with NT
ST-NT-NT Tillage with a chisel plough to a depth of 75 mm was conducted once every three years.
ST applied every 4th year in rotation with NT
ST-NT-NT-NT Tillage with a chisel plough to a depth of 75 mm was conducted once every four years.
No-tillage NT Tillage was not conducted.
4. Results
4.1 Wheat crops
In 2018, at 90 days after establishment (DAE), the aboveground biomass production ranged from 7407 kg ha 1 in the TT treatment to 9127 kg ha-1 in the ST-NT treatment. In 2020, the crop management system with the standard use of synthetic agrochemicals had greater aboveground biomass while the system with minimum use of synthetic agrochemicals had the lowest. The system with the standard use of synthetic agrochemicals resulted in aboveground biomass which was 23 and 167% more than the systems with reduced, and minimum synthetic agrochemicals, respectively (results not shown). At plant physiological maturity in 2018, the aboveground
biomass in the crop management system with the standard use of synthetic agrochemicals (11624 kg ha-1) was 20% greater than that in the system with reduced use of synthetic agrochemicals which had 9722 kg ha-1. The biomass ranged from 9159 kg ha-1 in the NT treatment to 12014 kg ha-1 in the MB treatment (results not shown). In 2020, the experiment in the system with minimum use of synthetic agrochemicals was terminated at 90 DAE due to severe weed infestation. There was 21% more aboveground biomass produced in the system with the standard use of synthetic agrochemicals than in the system with reduced synthetic agrochemicals (results not shown).
In 2018, the number of wheat-bearing tillers was generally highest in the infrequent treatment ST-NT-
Figure 1: The wheat grain yield in (a) 2018 as influenced by the interactions between the crop management system and tillage sequence, and (b) 2020 as influenced by the crop management system and tillage sequence at Langgewens Research Farm. The different letters on top of the bars denote a significant difference. MB = Mouldboard at 200 mm depth; TT = Tine-tillage at 150 mm depth; ST = Shallow tine-tillage at 75 mm depth; NT = No-tillage. The underlined treatment in the sequence indicates the treatment for each year.
NT-NT and lowest in the ST-NT sequence. Except for the NT and ST-NT-NT tillage sequences, there were no differences between the crop management system with standard and reduced synthetic agrochemicals for the tillage sequences. In 2020, there were 19% more tillers in the system with the standard use of synthetic agrochemicals than in reduced synthetic agrochemicals.
For the 2018 wheat grain yield, the crop management system with the standard use of synthetic agrochemicals had a higher wheat grain yield than the system with reduced use of synthetic agrochemicals (Figure 1a). The biggest difference between the two crop management systems was in the ST-NT-NT and NT treatments, where the system with the standard use of synthetic agrochemicals had 84 and 38% more grain, respectively. Of the seven tillage sequences, grain yield in the systems with standard, as well as the reduced use of synthetic agrochemicals did not differ in four tillage sequences.
In 2020, the grain yield was 18% more in the system with the standard use of synthetic agrochemicals than in the system with reduced synthetic agrochemicals (results not shown). Three of the seven tillage sequences resulted in grain yield that did not differ between the crop management systems with either standard or reduced use of synthetic agrochemicals (Figure 1b). The largest differences in grain yield between the two systems were in the ST-NT, ST-NT-NT and TT tillage sequences, in which the system with the standard use of synthetic agrochemicals had 32%, 31% and 27% more grain than the system with reduced use of synthetic agrochemicals. Compared to other tillage sequences, the ST and ST-NT-NT-NT treatments led to relatively higher wheat grain yield (although not always significant) in the system with reduced use
of synthetic agrochemicals (Figure 1b).In 2018 and 2020, the thousand kernel mass and hectolitre mass were both unaffected by any treatment. In 2018, the thousand kernel mass ranged from 38 to 39 g whilst the hectolitre mass averaged 82 g hL-1. In 2020, the thousand kernel mass ranged from 37 to 39 g. The hectolitre mass ranged from 82 g hL-1 in the MB sequence to 83 g hL-1 in the NT sequence (results not shown).
Tillage sequence affected the 2018 and 2020 wheat grain protein content. In 2018, the MB treatment led to a grain protein content of 13.8%, but did not differ from that in the ST-NT-NT-NT treatment (13.5%). Wheat grains from the NT treatment had 13.1% protein content. In 2020, the MB treatment resulted in grain protein content which was 6% and 13% greater than that of the infrequent tillage ST-NT-NT-NT and NT treatments, respectively. There were no significant differences between the grain protein content in the TT, ST, ST-NT, ST-NT-NT and ST-NT-NT-NT (results not shown). 4.2 Canola crop
At physiological maturity, the system with standard application of synthetic agrochemicals resulted in greater aboveground biomass than the systems with either reduced or minimum use of synthetic agrochemicals, by 19% and 34% respectively. The systems with reduced and minimum use of synthetic agrochemicals did not differ from each other. Canola seed yield generally decreased with a reduction in synthetic agrochemical application, such that the system with standard application of synthetic agrochemicals had the highest yield. The lowest canola seed yield occurred in the systems with minimum use of synthetic agrochemicals. The systems with the standard use of synthetic agrochemicals had a seed yield which was 9% and
46% more than the yield in the systems with either reduced or minimum use of synthetic agrochemicals (results not shown). Of the seven tillage treatments, the ST and the ST-NT-NT-NT tillage sequences were the only tillage treatments that led to differences in canola seed yield between the crop management systems with standard, and reduced use of synthetic agrochemicals (Figure 2). The yield of canola seed oil generally increased with a reduction in tillage intensity. The MB treatment resulted in the lowest canola seed oil yield (37.3%) whilst the ST-NT sequence had the highest (41.6%) yield. Canola seed oil content from the TT, ST, ST-NT-NT, ST-NT-NT-NT and NT sequences did not differ from one another and ranged from 39.9% to 41.4%. Canola seeds from the ST-NT sequence had 11% and 3% more oil content than those from the MB and ST-NT-NT-NT sequences, respectively. No differences were found in the thousand seed mass (2.6 - 2.7 g) of canola.
4. Conclusions and practical implications
The yield differences between the systems with standard and reduced use of synthetic agrochemicals were expected as populations of soil microorganisms and beneficial insects need time to adapt to the new environment. The process of converting from standard use of synthetic agrochemicals to agrochemical-free or certified organic farming is marked by a general decline in crop yield in the initial year.
Our results from the systems with standard as well as reduced use of synthetic agrochemicals, however, show that it is possible to reduce the quantity of synthetic agrochemicals that are applied in the fields. There were no differences in grain or seed yield in four of the seven tillage treatments in
2018 (Figure 1a), five out of seven in 2019 (Figure 2) and three out of seven in 2020 (Figure 1b). The bio-chemicals were likely more effective in pest and disease control rather than in aiding crop growth through weed suppression. There was no noticeable pest or disease attack within any part of the trial site, but weeds were problematic in the systems with reduced and minimum use of synthetic agrochemicals.
The economic feasibility of using bio-chemicals in arable farming was beyond the scope of this research but would need to be evaluated to encourage producers to reduce the quantity of synthetic agrochemicals they apply. In addition, the farming problems cannot be overcome by the simple substitution of individual inputs. Therefore, to reduce reliance on synthetic agrochemicals, it may be beneficial to change the management strategies to include livestock, competitive crops, cover crops, plant density and row spacing (MacLaren et al. 2021).
We recommend that producers prevent frequent, intensive tillage and adopt the NT or infrequent tillage practices during the process of converting from standard to reduced use of synthetic agrochemicals. Future studies should evaluate the economic feasibility of applying bio-chemicals in arable farming and the weed pressure over the long run when reduced use of agrochemicals are followed.
5. Acknowledgements
Western Cape Agricultural Research Trust, Stellenbosch University and Coventry University for financial assistance. For more information contact Dr Johan Labuschagne. E-mail: [email protected]
Figure 2: The differences in canola seed yield in each of the tillage sequences and crop management system at Langgewens Research Farm in 2019. The different letters on top of the bars denote a significant difference. DAE = Days after establishment; MB = Mouldboard at 200 mm depth; TT = Tine-tillage at 150 mm depth; ST = Shallow tine-tillage at 75 mm depth; NT = No-tillage. The underlined treatment in the sequence indicates the treatment for 2019.
CROP ROTATION TRIALS LANGGEWENS
THE LONG-TERM CROP ROTATION TRIAL
2020 PRODUCTION YEAR (25TH YEAR OF THE LONG TERM TRIAL)
The total rainfall for 2020 was 377 mm of which only 330 mm was recorded from April to September. This was 102 mm more than the total for 2019 (Table 1).
The new disc seeder from Piket was again used to plant the whole trial, except for the component trial areas within the bigger plots. Planting occurred from the last week in April to the middle of May.
Rainfall was well spread throughout the season as can be seen from figure 1.
Table 1. Average rainfall figures for the 2015 to 2020 and long term for Langgewens.
2020 2019 2018 2017 2016 2015 LT
Total 377 274 396 218 416 208 426
Apr to Sep
330 228 341 175 355 170 380
Figure 1. Monthly rainfall figures recorded for Langgewens during 2020.
Canola production
All Canola camps were planted on the 23rd of April. All canola plots were plant-ed to 44Y92. The season was favourable for canola production. The highest yield of 2873 kg/ha was obtained in system G where canola followed medic pasture (Figure 2).
The crop in this system only received 14.5 kg op applied nitrogen in total. The aver-age yield of canola was 2108 kg/ha. The differences between the average canola yields in different systems can be seen in figure 3.
Figure 3. Canola production within the different systems. (W = wheat, C = canola, L = legume cover crop).
Figure 2. Canola production within the different plots.
Lupin production
As was the case since 2016, all lupine camps were planted to a cover crop. In the previous two seasons a combination of 70% legume and 30% grass mixture was used, while it was decided to plant a pure legume mix in 2018. Following some weed issues experienced in 2018 with early termination of the cover crop it was decided to return to the 70/30 mixture in 2019. The reason why the change was done was the long term lupin yield at Langgewens averaged around 1 ton/ha and with the ridge and furrow system in place in the camps the lupin in the furrows died early due to waterlogging which gave ryegrass areas to proliferate. The same effect was negated by the cover crop mixture with the variety of species within the mix filling the spaces where waterlogging could occur. By keep the mixture predominantly legume we ensure that there is nitrogen available in the next season and the integrity of the system is kept. During the
2020 season these plots were grazed with sheep and compared the grazing of the covers vs medic pastures. The end result was that the grazing of the 2 ha of cover crops vs 4 ha of medic had a R7500 difference in income over the same period. This was due to the number of animals that can be carried on the cover crops versus the medics.
Wheat production
Management protocols developed by the Technical committee were followed but adjusted during season as a function of variable climatic conditions. Wheat (SST0166) was planted from the 30th of April to the 5th of May with the Piket disc seeder. Mean wheat yield over all systems was 3949 kg/ha and ranged between 1900 kg/ha and 5483 kg/ha (Figure 4). These yields were about 800kg/ha more than the 2019 yields. The grading varied from B1 and B3. This was also the highest average yield ever obtained from the trials.
Figure 6. Wheat production in the dif-ferent crop sequences (W =wheat, C = canola, L = legume cover crop, M = medic pasture).
Figure 4. Wheat production on the different plots within the trial. The or-ange line indicates the trial average.
In figure 5 the effect of preceding crops on the yield of wheat is shown.
All wheat was planted with 6 kg nitrogen. Wheat following a legume received a topdressing of 40kg N, while wheat following either wheat or canola received a topdressing of 50N. All the wheat following medics received 12 kg/ha. The highest yield was obtained in system G where the wheat following medics gave 5483 kg/ha with only 18kg of added nitrogen in total.
Sheep production – Animal management procedures followed those described in previous reports. We have decided to change the sheep type over the next two years to a smaller framed sheep in order to have enough feed throughout the year. The mutton
merinos will be replaced with Latelle. Lambs were “weaned” and marketed together with ewes that were to be replaced on the same date.
Economics:
All crops and systems showed good margins for the 2020 production year. Please note that even though negative margins was obtained for the cover crop plots in system C and D, these systems still out performed the monoculture system A.
Table 2. System differences in input cost and gross margins during the 2020 production season
System SequenceSystem
Input cost per ha Gross Margin per ha
A WWWW 4175 6247
B WWWC 4714 7753
C WCWL 4540 7416
D WWLC 4084 7872
E MWMW 3136 8990
F McWMcW 3015 7169
G MWMC 3463 8402
H McWMcW+s 3037 10811
The total rainfall for 2020 was 377 mm of which only 330 mm was recorded from April to September. This was 102 mm more than the total for 2019 (Table 1). The trail was planted with the Kuhn double disc seeder. Planting occurred from the last week in April to the middle of May. Rainfall was well spread as can be seen from figure 1.
Table 1. Average rainfall figures for the 2016 to 2020 and long term for Langgewens.
2020 2019 2018 2017 2016 LT
Total 377 274 396 218 416 426
Apr to Sep 330 228 341 175 355 380
Figure 1. Monthly rainfall figures recorded for Langgewens during 2020 and long-term.
NEW CROP ROTATION TRIAL2020 PRODUCTION YEAR
(5TH YEAR OF THE NEW LONG TERM TRIAL)
Seeding rates
The seeding rates of all crops are shown in table 2. All crops germinated well. Table 2. Seeding rates for all crops seeded in 2020
Seeding density kg/ha
Wheat 60
Barley 60
Oats 70
Canola 3.5
Peas/Lupin 100
Chickpeas 100
Vetch 24
Cereal Cover 60
Legume Cover 70
The seeding rate of each differed only depending on the type of cover crop. In the cereal mix needed higher densities of the cereals forming the mix and the legume mix higher rates of the legumes.
Wheat production
The three systems used in the new long term trial at Langgewens vary in crop diversity. In two of the systems wheat makes up 50% of the planted area, while the third system has only 30% wheat.
SST0166 was planted. The 2020 season was favorable for the development of high yield potentials and thus the second highest average yield ever, was obtained. The average for the new trial was 3924 kg/ha and ranged between 1754 kg/ha and 4994 kg/ha as can be seen in figure 2. The 4th rep showed a much lower average compared
to the others because of the soil quality of that part of the trial. If we discard the 4th rep the average wheat production climbs to 4241 kg/ha. The wheat was planted with 3.3 kg N and received single topdressing of either 20kg N/ha or 40kg N/ha. If the wheat followed a legume crop or legume cover it received the lower topdressing. This was done to manage the lowering of inputs according to the system.
Figure 2. Wheat yield during 2020 per plot.
Wheat yield in the three reps varied and is represented in Figure 3. Grading varied between B2 and B3. A breakdown of the grading in the trial is showed in table 3.
Figure 3. Average wheat yield per rep in 2020
Table 3. Wheat quality indicators of the 2020 season
% HLM Crude Protein
B2 35.3 82.8 10.9
B3 64.7 83.1 9.8
Ave 82.9 10,2
Table 4 summaries the performance of wheat following different preceding crops within the trial. Wheat following a non-legume received a total of 53.3 kg nitrogen for the season, while wheat following a legume received 23.3 kg N.
Table 4. Performance of wheat following different crops in 2018. The average yield for each combination is given as well as the highest plot yield.
Yield kg/ha Best
Canola/Wheat 3874 4365
Chickpea/Wheat 4088 4879
Cereal Cover/Wheat 3964 4475
Wheat/Wheat 3933 4860
Pea-Lupin mix/Wheat 4050 4994
Vetch/Wheat 4316 4618
Legume cover/Wheat 3677 4907
Barley production
The 2020 season was the fourth time barley for malting purposes was planted at Langgewens. The cultivar SabbiHessekwa was used. The barley was planted with 3.3 kg N and received no topdressing at all, because of the previous year’s poor grading due to a too high protein content. All barley was graded as malting quality. Barley forms part of only one of
the three systems tested in the new trial. There were therefore only 4 plots planted to barley. The average yield over all 4 reps was 4755 kg/ha which was more than a ton higher than the 2019 season. The data from the four seasons suggests that barley production is a viable option in the middle Swartland. Management strategies needs to be refined.
Figure 4. Barley production during 2020 for the different reps.
Oats production
Oats (SSH491) was planted in only one of the three systems. Production was aimed at the breakfast cereal market. The average yield was 4250 kg/ha, which was 2373 kg/ha more than in 2019 (Figure 5). Die dry warm August resulted in none of the plots realizing breakfast grade.
Figure 5. Oat production in 2020.
Canola production
Canola was seeded in all three systems tested in the new trial at Langgewens. System 1 had 30% of the total area planted to canola, while systems 2 and 3 had 10% each. 44Y90 was seeded in all three systems.
Canola germinated after being planted early. Germination was not as good as expected, which had
an effect on the yield. The possible cause was a weed knockdown with a combination herbicide mix that was sprayed and planting followed too quickly. The overall average yield was 1712 kg/ha which was 220 kg/ha less than in 2019 (Figure 6). As was the case in wheat, rep4 showed the lowest average of the 4 reps (Figure 7). In the different systems canola follows either wheat or barley. Average yields following barley was higher than those following wheat.
Figure 6. Canola production in 2020 in all plots
Figure 7. Average canola yields per rep in 2020
Linseed production (Chickpea)
The 2020 production season was decided the second season that chickpeas was planted. The linseed has potential but there is a need to test different cultivars for suitability in our growing conditions. Again the chickpeas were not competing with weeds and there is no herbicides registered on the crop in South Africa.
Chickpea was only planted in system 3 and accounted for 10% of the area. The crop shows promise but some herbicide issues and rhizobium availability needs to be sorted out. Much more crop specific production knowledge and experience with locally adapted
cultivars is needed before the crop can reach its potential in the Western Cape.
Peas/Lupin production
During the 2018 technical meeting it was decided to replace the Faba beans with a mix of peas and lupin. The two previous production seasons showed that the cost of producing faba beans might be too high, since low yields left the plots with negative gross margins, which impacted the overall system gross margins of the systems. The pea/lupine mix was planted at a seeding rate of 100kg/ha (50 kg/ha of each). Dominance of varied from plot to plot. Yields are shown in figure 8.
Figure 8. Pea/lupine production in 2020 in all four reps.
Vetch production
Vetch shows excellent promise as a pasture crop or cover crop in the dryland systems.
Cover crops
The utilization of cover crops does not have a negative influence on soil. Utilizing cover crops influence the amount of material more than the amount of nutrients in cover crop residue. Grazing has a positive effect on cover crops in terms of soil nitrogen. When utilization does not have a negative effect on cover crops, it will increase profit margins.
Economics
Table 5 gives a snap shot of the first two reps of the trial in terms of the input costs and gross margins for each crop. Cover crops and vetch we seen as a fodder crop and gross margins were not determined.
Dr Johann StraussResearch and Technology Development ServicesDirectorate Plant [email protected]
Table 5. Summary of economics per crop
Crop Input Cost Gross Margin
Wheat 4586 11139
Barley 3483 16883
Canola 6592 7070
Lupine/peas 3758 -2600
Vetch 2924
Oats 4093 12243
Legume Cover 1909
Cereal cover 1604