Conservation Bench Terraces for Rice in a Subhumid Climate

Rain‐fed crops in northern India produce less than the potential maximum due to moisture stress at crucial stages of plant development. Research was initiated on a conservation bench terrace (CBT) system to evaluate its potential to increase water supply for increasing and stabilizing rice production on 2.5% sloping land in the subhumid climate. The width ratios of the contributing area to the collection area (terrace benches) were 0:1, 1:1, 2:1, and 3:1. The contributing area was cropped with corn planted on the contour. Six years of research have shown that levelled benches received 0.25, 0.50, and 0.76 m 3 /m 2 of estimated runoff from the 1:1, 2:1, and 3:1 ratios, respectively. Consequently, measured soil water in the level benches was greater than the storage in level benches without a contributing area at the time of panicle emergence. The rice yields in the level benches with contributing areas were 21, 47, and 88%, respectively, greater on three ratios than yields on the level check without a contributing area. The 84% increase in rice grain yield on the 3:1 CBT was attributed to increased soil water content at panicle emergence. A major advantage of the CBT system was that chances of crop failure were reduced. The probability of obtaining rice yields of < 1,400 kg/ha was decreased from 50% on level bench to 16% in level benches with a 3:1 ratio. Similarly, the probability of achieving yields > 3,500 kg/ha was 50% in the 3:1 CBT system and 0% in the level bench (NW). Total dry matter production for the 3:1 CBT system was 1.7 times greater than the level check.