Evapotranspiration and water-use-efficiency of soybean and mustard under lysimeter in south-eastern Rajasthan

摘要

A study was conducted during 1986-87 to 1988-89 in weighing type lysimeter to work out evaportranspiration (ET) and water-use-efficiency (WUE) of soybean [Glycine max (L.) Merr.] and mustard [Brassica juncea (L.) Czernj & Cosson] by irrgating at 50per cent and 75 per cent depletion of available soil moisture, respectively. The results showed that soybean recorded 662 mm ET with grain yield of 4180 kg ha~(-1) within a crop period of 108 days. The water-use-efficiency was worked out to be 63 kg ha~(-1) cm~(-1) for grain and l 13 kg ha~(-1) cm~(-1) for total drymatter yield. ET of mustard was worked out as 430 mm with oilseeds yield of 2680 kg ha~(-1), and WUE of 62 kg ha~(-1) cm~(-1) for grain and 111 kg ha~(-1) cm~(-1) for total drymatter production within a crop period of 121 days. The average ET rate was 6.12 mm day~(-1) in soybean and 3.55 mm day~(-1) in mustard. Leaf area index (LAI) increased slowly upto 3 weeks of crop period but increased sharply thereafter The maximum LAI was observed 5.33 after 76 days of sowing in soybean and 5.03 after 67 days in mustard, and thereafter it declined sharply. ET of soybean had significant positive correlation with pan evaporation (r = + 0.76), sunshine hours (r = +0.75), mean maximum temperature (r=+0.69) and significant negative correlation with relative humidity (r=-0.65). In case of mustard, ET had significant positive correlation with pan evaporation (r = + 0.73) and sunshine hours (r = + 0.58).