Effect of nitrogen management on yield, water use and nutrient uptake of grain amaranth (Amaranthus hypochodriacus) under moisture stress

Abstract

An experiment was conducted at Sardarkrushinagar during 2004-05 and 2005-06 on sandy loam soil to find out response of grain amaranth to moisture stress ( viz., no moisture stress, stress at active vegetative stage; and stress at active vegetative as well as grain filling stage) and N management (No N, 40 kg N /ha, 40 kg N /ha with Azotobacter liquid and powder 60 kg N /ha, 60 kg N /ha with Azotobacter liquid and powder). The study revealed that without moisture stress grain amaranth gave 16.58 and 22.07 % higher grain yield over moisture stress im- posed at active vegetative stage and at 2 growth stages, respectively in pooled data. However, the lowest water use (5.30 kg/ha-mm) and expense efficiency (4.41 kg/ha-mm) was obtained with maximum water consumption (246.2 mm) under no moisture stress. Among the N management treatments, 60 kg N/ ha integrating seed inocula- tion with Azotobacter liquid culture brought remarkable improvement in stem thickness, length of main inflores- cence, number of lateral spikelets and 1,000 seed weight which resulted in increase in grain and stover yields. Ap- plication of 60 kg N /ha + Azotobacter liquid showed its superiority in terms of consumption of water (218.6 mm), water use (7.19 kg/ha-mm) and expense efficiency (6.17 kg/ha-mm). Integration of 60 kg N /ha + Azotobacter liq- uid culture realized 9.42 and 11.26 % higher N and P uptake over 60 kg N /ha alone. Significant contribution of seed inoculation was noted on yield with interactive effect of moisture stress and with higher level of N. It can be concluded that application of 60 kg N/ha alongwith seed inoculation ( Azotobacter liquid culture) under assured irri- gation recorded the maximum values of yield, water use, nutrient uptake, and net returns.