Percolation losses of water in relation to pre-puddling tillage and puddling intensity in a puddled sandy loam rice (Oryza sativa L.) field

Effects of puddling in rice (Oryza sativa L.), especially the water loss, depend upon the extent of initial manipulation by pre-puddling tillage. The interactive effects of pre-puddling tillage and puddling intensity were studied for 3 years (2000–2002) in a field experiment at Punjab Agricultural University, Ludhiana, India, on a sandy loam soil (coarse loamy, calcareous, mixed, hyperthermic Typic Ustochrept). Treatments included three levels of pre-puddling tillage-one discing followed by a tine cultivation and planking, one discing followed by two tine cultivations and plankings and one discing followed by four tine cultivations and plankings; and three levels of puddling-one, two and four cultivations in ponded water each followed by planking. Increasing pre-puddling tillage intensity to four operations decreased percolation rate of water by 22–40% from that with one operation. Four puddling operations decreased percolation rate of soils by 30% from that with one puddling operation. This led to decrease in irrigation water used by 22–27% when pre-puddling tillage intensity increased from one to four operations. During an irrigation cycle, the percolation rate of soils decreased with time (days 1–4 after irrigation), the extent of decrease being same at all the levels of pre-puddling tillage. Higher levels of puddling increased the clay content of 0–1, 1–2 and 2–3 cm soil layers, the increase being more pronounced at higher levels of pre-puddling tillage. Puddling index, ratio of initial to final volume of settled sediments, was not affected by pre-puddling tillage intensity. It, however, increased with increasing levels of puddling intensity. Puddling index was also not a function of clay content of the surface soil layers (0–3 cm).