]. .Agronomy & Crop Science 178, 251—257 (1997) •('• 1997 Blackwdl Wissenschafts-Verlag, Berlin f 0931-2250 Central Arid Zone Research Institute, Jodhpur, India Effects of Tillage and Cropping Systems on Soil Moisture Balance and Pearl Millet Yield Anurag Saxena, D. V. Singh and N. L. Joshi Authors" address: Dr Anurag Saxena, Dr D. V. Singh and Dr N. L. Joshi, Division of Arable Cropping Systems, Central Arid Zone Research Institute, Jodhpur, 342 003 India With 3 figures and 3 tables Received September IS, 1996: accepted December 10, 1996 Abstract A 2-year study was conducted to determine the effects of tillage and cropping systems on soil moisture balance, growth and yield of pear! millet {Pennisetum glaucum (L.) R.Br.). Three tillage treatments, viz. minimum tillage (one harrowing), conventional tillage (two harrowing, cross) and deep tillage (ploughing followed by two har- rowings), and four cropping systems, viz. monoculture of pear! millet, pearl miliet-clusterbean [Cyamopsis tetra- gonoloba (L.) Taub.) rotation, monoculture of pearl mil- let with 5 t ha"' farm yard manure (FYM), and inter- cropping of pearl millet and clusterbean, were compared. Deep tillage improved the soil moisture storage, water use efficiency and grain yield of pearl millet while con- sumptive use of water was higher with minimum tillage. Total dry matter yield with deep tillage and conventional tillage was 23.2 and 10.2 % higher than minimum tillage in the season 1, and the corresponding values for season 2 were 30.7 and 13.3%. The Pearl millct-clusterbean rotation and monoculture of pearl millet with the appli- cation of 5 t ha"' FYM gave 17.2 and 6.1 % higher yield than monoculture of pearl millet, respectively. Maximum water use efficiency was observed in rotation followed by FYM application. Key words: Tillage cropping system — pearl mil- let — consumptive use — water use efliciency Introduction Pearl millet {Pennisetum glaucum (L.) R.Br.) and clusterbean (Cyamopsis tetragonoloba (L.) Taub.) are grown extensively in arid tropics, an area of high risk resulting from erratic rainfall and low soil fertility. Monoculture of pearl millet is also a com- mon practice in these areas. A downward trend in pearl millet yield has been observed under mono- culture of this crop. This decline has been attributed to several agronomic factors including allelopathy (Saxena et al., 1995b). Growing a crop continuously on the same piece of land may have adverse effects on soil fertility because of continuous depletion of nutrients from a particular depth. Reduced ger- mination, poor plant growth and declining yield under monocropping of pearl millet have been observed even under better management conditions (Singh et al., 1985). These findings mdicate that the presence of a factor other than fertility, possibly tillage, influencing the performance of a cropping system on light textured soil. Proper soil tillage is a prerequisite for good crop stands, growth and yield. Excessive tillage, par- ticularly in light textured soils, disintegrates clods and exposes soil to wind and water erosion. Reduced tillage implied economy in time, labour and pet- roleum (Campbell et al., 1984) besides reduced soil moisture losses, maintenance of soil structure and increased cropping intensity. Some investigators (Gupta and Gupta, 1986; Gupta, 1987), however, reported reduction in crop yield due to no tillage. Sandy soils are vulnerable to erosion due to exces- sive tillage, whereas reduced tillage results in com- paction due to low organic matter content of these soils which seriously affects crop growth and yield (Gupta et al., 1983; Gupta, 1987). Deep tillage increased yields of millet (Doty et al., 1975), corn (Ibrahim and Miller, 1989), wheat (Gajri et al., 1991) and sorghum (linger, 1979) by encouraging vertical and horizontal proliferation of roots by reducing soi! strength. In view of the above contradictory reports, we wished to assess the effects of tillage and crop rotation on pearl millet production in arid areas. Materials and Methods The experiment was conducted at the Central Arid Zone Research Institute, Jodhpur (Latitude 26°18'N, Longitude 73°O1'3O"E), during 1993 (sea- U.S. Copyright Clearanc Cent., code Sta^ment: 0931-2250/97/7804-0251 S14.00/0