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spring the flower o f some species such as

Ranunculus chius, R. cornutus

Euphorbia farcta

give a

yellow colored background. Starting in the middle o f the spring* by their formation o f micro groups,

the

Trifolium purpureum

var.

purpureum

flowers give a purple background. In summer the

Ammi

majus

flowers give a white background. By the end o f May the dominant

Gramima

dry out and

grass give a pale background color. In the field, the drought season begins in May. The generative

density o f

Hordeum murinum

senopopulations constitutes 70% o f the grain cover. The drought that

results from the absence o f rain, from the summer till the end o f autumn, and extreme temperature

dries the stem o f

Hordeum murinum

out and becomes useless grain. Among these.

Trifolium

purpureum

var.

purpureum

constitute microgroups. In more salty soils, in pits and in drainage, it is

possible to see

Salicornia europea

and

Petrosimonia brachiata

micro groups. The grain cover o f the

field is very poor in including a large number o f species (I). Till the end o f the autumn the

underground waters declines to 1,5-2 m in depth under the soil. This results in drying out o f plants.

Seasonal variability o f the field gives it ati important pasture role. By the end o f the autumn,

alter two weeks o f rain, ephemerous seed starts to germinate. As a result, field takes a green

background color. The length o f the grass cover reaches 2-3 cm. Tliis length then increases to 3-5

cm and 10-15 cm by the end o f February and by the end o f May respectively. Some species reach 50 -

70 cm in length. In summer season

Ammi majus

starts to develop and becomes dominant or

codominant by its 80-90 cm length. In this season the increase in length o f the grain cover decreases

the productivity o f the pasture (Table 1).

Table 1. The seasonal dynamic and grass productivity o f the dominant formation o f the desert

steppe vegetation.

Formations

Season and Productivity (gr/m2)

__Spring

Summer

Autumn

W inter

livrdeumetum

r 294,4

195,2

213,0

10,1

Alhagieto-Hordeumeium

146,0

182,0

281,4

12,4

Prosopiseto-Hordeumetum

213,0

195,2

263,7

Ammieto-Hordeumetum

122,5

413,0

411,0

21,5

Ammieto-Cressacto-Hordeumetum

104,1

120,1

238,2

15,7

As seen in Table 1, the pasture

productivity

o f different formations exerts seasonal change

depending on the plant composition. This difference is directly related to the rational interrelation

ship o f annual and perennial plants and to the climatic properties o f the season.

The value o f the field as a pasture decreases from the end o f May to the end o f October. For

this reason it Is important to take advantage from the field as a pasture in this time period. To do

this, the microclimate should be changed by phytomeralation. For this purpose

Acacia tyanophylla

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