EFFECT OF WATER-NITROGEN COUPLING ON YIELD AND WATER USE EFFICIENCY OF KIDNEY BEAN

In order to reveal the efficient utilization mechanism of water and fertilizer in Kidney bean with different water and nitrogen management modes, this article explores the effects of different water and nitrogen management modes on kidney bean physiology, growth and water use efficiency. Through pot experiment, this paper set 2 kinds of irrigation amount (W1: conventional irrigation, W2: controlled irrigation) and 5 different kinds of nitrogen application rate (NO: 0 kg/hm2, Ni: 25 kg/hm2, N2: 30 kg/hm2, N3:35 kg/hm2, N4:40 kg/hm2). This article observes the physiological growth and water use efficiency of Kidney bean. The results showed that the dry matter mass increased with the growth of nitrogen application and was positively correlated with the yield. Under conventional irrigation conditions, chlorophyll A, chlorophyll B, chlorophyll total, nitrate reductase activity, and yield of kidney bean leaves showed a trend of first increasing and then decreasing with the growth of nitrogen application. Under W1N3 treatment, they reached the maximum value and the water use efficiency was the highest. Under the controlled irrigation condition, the W2N4 treatment reached the maximum value. However, the W2N3 treatment reached the maximum value, which is only 4% higher than W2N4 treatment, with no significant difference. The yield and water use efficiency of W1N3 treatment were 33.31% and 24% higher than those of W2N4 treatment were. Therefore, in summary, W1N3 treatment (80% field water capacity, nitrogen application 35kg/hm2) is the optimal combination of water and nitrogen.