Statistical yielding models of some irrigated vegetable crops in dependence on water use and heat supply

Abstract

Statistical analysis is helpful for better understanding of the processes which take place in agricultural ecosystems. Par-ticular attention should be paid to the processes of crops’ productivity formation under the influence of natural and anthro-pogenic factors. The goal of our study was to provide new theoretical knowledge about the dependence of vegetable crops’ productivity on water supply and heat income. The study was conducted in the irrigated conditions of the semi-arid cold Steppe zone on the fields of the Institute of Irrigated Agriculture of NAAS, Kherson, Ukraine. We studied the historical data of productivity of three most common in the region vegetable crops: potato, tomato, onion. The crops were cultivated by using the generally accepted in the region agrotechnology. Historical yielding and meteorological data of the period 1990–2016 were used to develop the models of the vegetable crops’ productivity. We used two approaches: development of pair linear models in three categories (“yield – water use”, “yield – sum of the effective air temperatures above 10°C”); development of complex linear regression models taking into account such factors as total water use, and temperature re-gime during the crops’ vegetation. Pair linear models of the crops’ productivity showed that the highest effect on the yieldsof potato and onion has the water use index (R2 of 0.9350 and 0.9689, respectively), and on the yield of tomato – tempera-ture regime (R2 of 0.9573). The results of pair analysis were proved by the multiple regression analysis that revealed the same tendencies in the crop yield formation depending on the studied factors.