Effects of changed hydrothermal regimes was studied on summer green gram (Vigna radiata L. Wilczek) cv SML – 134 at Punjab Agricultural University Ludhiana in summer season of 1999 and 2000. The treatments included 3 dates of sowing viz. 12th April (D1), 19th April (D2) and 26th April (D­3) (in main plots); 3 irrigation levels viz. 0.5 IW: CPE ratio (I1), 0.75 IW: CPE ratio (I2) and 1.0 IW: CPE ratio (I3) (in sub plots); and mulched (M1) (@ 5t/ha wheat straw mulch) and unmulched crop (in sub­sub plots), in a splitsplit plot design. The first sowing date D1 showed better results than by D2 and D3, respectively in terms of growth and yield. I3 had more vigorous growth than I2 and I1, respectively. Mulched crop performed better than unmulched crop. The crop yielded was less during 2000 than 1999. This may be due to more vegetative growth during 2000 and infestation of whitefly, in which crop experienced more frequent rainfall than 1999.

Keywords: Vigna Radiata L. Wilczek; Plant Height; Sowing Dates; Irrigation; Straw Mulching; Grain Yield; Straw Yield; Harvest Index.