EFFECT OF POTASSIUM APPLICATION ON CROP YIELDS UNDER WHEAT- RICE SYSTEM

Abstract

A field experiment was conducted to study the respo nse of wheat and rice to potassium during 2004-05. The basal dose of N at 120 kg, P 2O5 at 90 kg ha -1 was applied with K levels to both wheat and rice c rops. Wheat variety Naseer 2000 and rice variety IRRI 6 were used in the study. The experiment was carried out in R.C.B design with three replications. Potassium application significantly increased the grain yield of wheat fr om 2468 kg ha -1 in the control to 2789 kg ha -1 in the treatment receiving K at 60 kg ha -1 giving an increase of 13 % over control. The numbe r of tillers, spikes, spike length and plant height of wheat were also significantly increased by K application. The rice also showed positive response to K application and hence both yield and yield parameters were significantly greater in the K than in the check treatment. Paddy yield was increased significantly by K application up to 50 % over control. The number of spikes plant -1 , spike length and 1000 grain weight were also sign ificantly increased by K application over control. The applic ation of K significantly increased the number of sp ike m -2 and plant height over control, but differences among K treatments we re non-significant. The highest increase of 50% ove r control in paddy yield was recorded in treatment receiving K by both wheat and rice each time at 60 kg K 2O ha -1 . Potash applied to previous wheat increase paddy yield by 30.9% over control. The hig hest VCR (3.9:1) was obtained with treatment receiv ing K by rice only, the lowest VCR (2.0:1) was achieved with treatment receiving K by both wheat and rice.