Precipitation & Humidity Temperature Wind Soil Forest Tundra Savanna Woodlands Grassland Deserts Arabian Shield Arabian Shelf

. . 1( Precipitation & Humidity1

. 005 ) 2241( . . . . 03 06 . . 03 . 06 . . 08-09% 05% . . . )( . . . 1- 2- 3- 4-

. ) ( . : 1- . 2- . 3- .

2

. : 1- . 2- . . ) (. . 3- .

)(: 3

2( Temperature . . 54 54 . . . 05 ) (

1-3 01 . 05 . . . 3 :- 1-4

5 . 2- . 3-

45 . ) (. .

) (: . . . . : 1- ) (. . 2-

5

) ( . ) ( . 63 ) (.

) ( . . . . . . . )3.0 ( 42 4 . : 1- . 2-

6

. . . . 3( Wind . . , . Orchid Heather 200.0 . . . . . )( . . . ) (Soil erosion . : 1- ) (

7

) (: . 2- . 3- . 4- )(barriers )1-6( 03-05% ) ( .

)(: . . 4( Soil . . )(Soil texture )(Soil structure .8

)( )(Soil texture ) (Sand ) (Silt )(Clay . 200.0 200.0-50.0 50.0-2 . ) (International system : Fraction Gravel Coarse sand Fine sand Silt Clay ) ( ) Diameter of particles( mm 2 2 2.0 2.0 20.0 20.0 200.0 200.0

. . ) ( . ) ( . .

9

) ( )(Soil structure-

)( . ) (Granular ) (Platy ) (Blocky ) (Prismatic ) ( ) (

. . Soil color-

. . A . 01

. . . : )(pH1-

pH 4-8 . pH 3.7- 5.9) ( .Barbur et al . pH 8.2-9.3. pH . ) (+H . pH . pH .pH pH ) ( . .pH pH 5.6-5.7 . ) ( pH pH . ) ( pH . ) ( . ) ( pH .

11

) (: pH

2- )(Electric Conductivity) (EC . . . . : . 1. . 2. 3. . 4. Electric Conductivity Meter .

21

( (mhos / cm / 0001 / ) 01 3 ( mmhos / cm / ) 601 . ( mhos / cm / = / 01 ) ppm/( = / 046 = / 63.0. )(Cation Exchange Capacity)(CEC3-

05% . 2 ,+NH4+, K+, Ca2+, Fe . 24) NO3-, PO42-, SO (. ) (Organic matter . ) (Leached . .

)(: 4- Organic matter . pH . . . .

31

: - 1- 2- 4- 5- 6-

3-

- . : 1- 2- 3- 4- 5- 6- Light . Photon . Quantum . . :- 1. . 2. ) ( . 3. .

41

. . 0008 00001 / 2,1-5,1 / / . . . . 1- . . . . . ) ( . . ) ( ) ( .

:Light 1 2% ) 57 08% 5 01% 1 2%(. 51

. : . . . . ) (. . ) (Epiderm . Quality Quantity Light Intensity .Duration - : Quality ) (. . . . : Photoperiodism . . - : 1 . = Lux 1 2 1 )390.0 1 ( 02 .

1- 2- 3- 4- 5- 6-

61

001 002 . 000.8 000.01 .

Light Saturation 000.5 000.01 . : 1- : 000.3 . 2- : . 001 002 Elilated . . Lactuca sativy Poa Liliaceae )(. - Duration . 21 52) 5.01 57.31 54) 8 61 42 : 1- :Neutral : . 2- :71

: 1- : : 2- : . . . . . . : . glucose

CO2 + H2O

O + esoculG

2

Respiration - = net assimilation Rate = Photosynthesis Respiration . . : Dark respiration Phto respiration . - 3 :C ) ( Phosphoglyceric acid - : ) .(Malic, Aspartic . - :CAM 2 CO 4 .C .

81

3 C 4 C 3C . . : - ) (. - . - . - . - . - . . . : Supplemental Illumination . : . Tungestens lamps Infrared . . Fluorescent 1 : 2 1 : 5 Phyto trones ) Growth chamber ( Computer . .Phyto trones

91