Effect of irrigation regimes and nitrogen on yield, oil content max) and nutrient uptake of soybean (Glycine

Abstract

An experiment was conducted during the rainy season (kharif) of 1993 and 1994 to study the effect of irrigation regimes and nitrogen on yield and quality of soybean [Glycine m a (L.) Merr.]. The treatments comprised 5 irrigation regimes [irrigation at 0.4, 0.6 and 0.8 irrigation water : cumulative pan evaporation (IW : CPE) ratio and crop growth stages along with control] in 1993 and 4 irrigation regimes (irrigation at 0.6, 0.8 IW : CPE and crop growth stages along with control) in 1994 and 4 nitrogen levels (20, 40, 60 and 80 kg Nlha). The seed, stover, oil and protein yields of soybean were significantly higher under 0.8 IW : CPE ratio. The maximum oil and protein contents in soybean seeds were recorded when the crop was irrigated at 0.8 IW : CPE ratio, while minimum in the control (rainfed). The N and P uptake in seed and stover and the total uptake were maximum under 0.8 IW : CPE ratio. However, the chlorophyll content of leaves was gradually decreased with increase in irrigation regimes. Application of nitrogen up to 60 kglha increased seed, stover, oil and protein yields of soybean. However, the oil content of seeds was maximum when the crop was fertilized with 20 kg Nlha, and it decreased at 60 kg Nka. Conversely the protein content of the seeds was increased with increasing levels of N up to 60 kg Nlha. The N and P uptake both by seed and stover and total uptake significantly increased with the increase in N up to 60 kglha. The chlorophyll content of leaves was found maximum at 80 kg Nlha when estimated at 60 days after sowing.