NO-TILLAGE AND DRY PLOWING COMPARED WITH PUDDLING FOR WET-SEASON RICE ON AN ALLUVIAL SANDY CLAY-LOAM IN EASTERN INDIA

No-tillage and dry ploughing were compared with puddling under identical cultivation conditions for their effect on growth and yield of wet-season rice. The experiment was conducted on an alluvial sandy clay-loam soil over 5 years (1978–82) at Cuttack, India. In the preceding dry season, each plot was split into two halves for growing dry-season crops, with and without tillage. Growth of rice seedlings without applying N to the seed bed was faster and more vigorous after puddling, as shown by greater shoot and root weight per hill and a higher shoot:root ratio, and remained so until maturity. This was reflected in earlier flowering and maturity, followed by greater grain and straw yields. These results are attributed to the ability of the roots to obtain more N from the puddled soil. Under high water table conditions, extractable and soluble N in the root zone were not much influenced by tillage treatments. Grain and straw yields after no-tillage were similar to those produced by dry ploughing but smaller than those produced by puddling, although the differences were not significant in some years. Soil strength measured at the end of the rice-growing season in 1980 and 1981 was significantly greater after continuous no-tillage. The decreasing trend in grain and straw yield and number of panicle-bearing tillers/m2 from 1980 onwards after continuous no-tillage, was associated with increasing soil strength. The results suggest that, where percolation losses of water and nutrients are small, puddling, which is capital intensive and detrimental to soil structure, could be replaced by no-tillage accompanied by suitable N and weed management. However, continuous no-tillage is not recommended for a soil with a lower clay content because the soil will gradually harden with time. © 1990, Cambridge University Press. All rights reserved.