Puddling and N management effects on crop response in a rice-wheat cropping system

Abstract

Coarse-textured soils are puddled to reduce high percolation losses of irrigation water under rice ( Oryza sativa L.). This practice, however, reduces yield of succeeding wheat ( Triticum aestivum L.) owing to deterioration in soil physical conditions. The 6 year field study reported in this paper evaluated the effects of puddling level and integrated N management on the development of subsurface compaction and growth and yield of rice and the following spring wheat grown in 1 year sequence on a sandy loam soil. Treatments were combinations of three puddling levels: low (one discing and one planking), medium (two discings and one planking), and high (four discings and one planking), and three nitrogen sources: (1) 120 kg N ha −1 from urea, (2) 60 kg N ha −1 from urea plus sesbania ( Sesbania aculeata Pers.) green manure, and (3) 60 kg N ha −1 from urea plus 20 Mg ha −1 farmyard manure. Percolation rate decreased from 14 mm day −1 with low puddling to 10 mm day −1 with high puddling, with a corresponding reduction in irrigation water requirement of rice of about 20%. Bulk density profiles in the 0–30 cm soil layer showed the formation of a compact layer at 15–20 cm depth, and bulk density increased with puddling level and cropping season. The impact of organic amendments in reducing bulk density was immediate, but the rate of increase in bulk density with time was the same in all the nitrogen sources. Organic amendments did not affect percolation rate and irrigation requirement of rice. Rice yields were not significantly affected by puddling and N source treatments throughout the study period. Residual effects of treatments on wheat yield were observed from the second season onwards. Interactive effects of puddling and N source on yields of rice and succeeding wheat were not significant. Yield differences in wheat between high and low puddling were 8% and 11% during the second and the fifth cropping season, respectively. This study indicates that medium puddling was optimum, as it reduced percolation without decreasing yield of succeeding wheat.