Effect of Long-term Lantana Addition on Soil Phosphorus Fractions, Crop Yields and Phosphorus Uptake in Rice-Wheat Cropping in North-West Himalayan Acid Alfisols

The long-term effect of Lantana camara addition on overall improvement in soil productivity in rice-wheat cropping system was studied. A long-term experiment was started in the wet season (July-Nov.) of 1988 with four levels of lantana [0,10,20 and 30 t ha⁻¹ (fresh)] and three levels of Nat Palampur. Lantana biomass was added only to rice 10 to 15 days before transplanting! puddling every year. The levels of N were 45, 67.5 and 90 kg ha⁻¹ to rice (i.e. 50, 75 and 100% of recommended dose). The order of N levels was reversed for wheat (i.e. 100, 75 and 50% of recommended dose). Among P fractions. highest increase was observed in Al-P (36%) followed by Ca-P (29%) and lowest in red-P (9%) with lantana additions. The continuous additions of lantana for six years consecutively increased the total and available P about 13 and 69 per cent. respectively over nO addition of lantana. It is observed that among different P fractions. Fe-P and Al-P were the most important P fractions contributing to P nutrition of rice and wheat grown in a sequence. The yield and P uptake by rice and wheat also increased with additions of lantana and application of N.