The influence of different aged Black Saxaul plants on distribution, growth and accumulation of aboveground phytomass of Poa Bulboza L.

Abstract

Abstract The purpose of this study was to determine the nature and degree of influence of different-aged plants of Black Saxaul on Bulbous Bluegrass - one of the dominant species of sagebrush-ephemeral pastures. The study was conducted using phytometer method in the conditions of the desert zone of Uzbekistan on the ephemeroid-wormwood-black saxaul phytocenosis, formed as a result of self-seeding on inter-band spaces of pasture-protective Black Saxaul plantations. It is established that the character of the phytogenic influence of Saxaul on Bluegrass can be characterized as ambiguous conjugacy: in the minimal phytogenic field, the character of this influence is negative and therefore is gradually replaced, as a result of which the number of this species-phytometer significantly decreases, there are zones where bluegrass is absent. Growing specimens are stunted and poorly developed, so they accumulate insignificant aboveground phytomass. The character of the influence of Saxaul in the outer part of the phytogenic field on bluegrass was positive. Therefore, it is numerous here, grows better and accumulates 1,5-3 times more aboveground phytomass than outside the phytogenic field (control). Within the phytogenic field of Black Saxaul for Bluegrass Bulbous most “environmentally comfortable place” is the border of the internal and external parts of this field. In this part of the phytogenic field, due to its ecological and biological properties, the number of phytometer species reaches the highest value; they grow rapidly and accumulate the largest aboveground phytomass. The degree of influence depends on the age status of the Black Saxaul.The highest degree of influence on the abundance, growth and formation of over ground phytomass of Bluegrass Bulbous is observed in the phytogenic field of middle-aged species-edificators: the minimum field increases and reaches its maximum in the area where Bluegrass Bulbous is completely displaced, and on the border of internal and external parts and in the outer part opposed to a phytogenic one field due to the positive influence of species-edificators of the number of phytometra increases sharply, the values of the linear growth of shoots and accumulation of aboveground biomass reach the highest values. The smallest phytogenic effect of the edifier species on the phytometer species is observed in the phytogenic field of virginal plants of the black saxaul. The phytogenic effect on bluegrass is distributed in virginal individuals of the active species outside the crown at a distance of 90 cm, in young generative - by 120 cm and in middle-aged generative - by 150 cm and even 180 cm. When further removed, the distribution, growth and formation of aboveground phytomass of the phytometer species does not depend on the edifier species.