Energy principles for determining the irrigation rate of agricultural crops

Abstract

The purpose of the study is to establish an analytical relationship between the irrigation norm and the sum of positive temperatures which will allow optimizing and rationalizing the use of natural resource potential without affecting the productivity of forage crops. There is established that the dynamics of soil moisture during the vegetation season on the meadow-alluvial soils of the Aral Sea region and sierozem soils of the south of Kazakhstan with the sum of positive temperatures is greater than 10°C. To justify the period of vegetation irrigation according to the indicators of the sum of effective temperatures, field studies were conducted and the materials obtained were analyzed. In addition, the establishment of pre-irrigation antecedent soil moisture based on preliminary calculations allows you to stabilize the microclimate of the irrigated area and increase the gross crop yield, save irrigation water. On cotton crops, irrigation must be carried out when the sum of the effective temperatures is 500...550°C, 800...850°C, 1100-1150°C and 1400°C from the beginning of sowing. At the same time, the excess yield control of raw cotton in production conditions is about 4.9 c/ha. On forage crops, watering should be carried out according to the accumulation of the sum of effective temperatures of400°C, subsequent watering every 200°C-250°C.. It follows from the calculations that the maize irrigation season should start from the second decade of May and end in late June with a watering rate of 650 to 800 m³/ha. Carrying out irrigation in accordance with the sum of positive temperatures allows you to save up to 2-3 watering with a total irrigation rate of1400 to 2400 m³/ha. and increases the gross yield of agricultural crops.