Water requirements for carrot crop with sprinkler irrigation under Russian conditions

Abstract

This work aims to calculate of water requirements for carrot under sprinkler irrigation in sandy loam soil at Selkovo village, Sergiev Posad District, Moscow Region, Russia, situated at 56° 35' N latitude, and 38° 09' E longitude. The average yields were 54 ton/ha for the first season and 58.8 ton/ha for the second season for carrot. The total water requirements were 344 mm (3440 m3/ha) and 338 mm (3380 m3/ha), during two successive seasons respectively. The average of temperature of July 17.8 oC at the average of relative humidity of 61%. The relationships between water requirements (E, mm/day) and deficits relative humidity (ds, mbar) having the following formula: Е = a dsb (1) Where, a, b - empirical coefficients of the regression equation. At using experimental data through the two seasons of carrot. That equal a = 1.06 and b = 0.86 then the relation become (Е = 1.06 ds0.86) and the correlation coefficient was 0.959±0.073. This means that in 91.9% of the water consumption of carrot variations in these conditions due to variations in deficits air humidity. For calculating carrot water requirements under sprinkler irrigation was found as Е = КF KC а dsb considering КF– Coefficient depending on wetting pattern under sprinkler and КC – Crop coefficient. The experimental data for growth seasons during calculation the crop coefficient of carrot through growth season was found as КC = 0.649 + 0.128 tr – 0.011 tr2 considering tr as decade number.