Effect of Fertilizers Alone and in Combination with Manure on Physical Properties and Productivity of Entisol under Rice-Based Cropping Systems

Results of a long term field trial after the 10th year of cropping on fertilizers, farmyard manure and blue green algae under rice-wheat and rice-winter maize cropping systems in calcareous silt loam soil (Calciorthent) have been discussed. The continuous addition of balanced fertilizers (NPK) did not show any deteriorating effect on physical properties of the soil; rather it significantly increased aggregation and water transmission characteristics and reduced bulk density and penetration resistance of the soil. The effectiveness of manurial treatment on aggregation, water transmission and hardness of the soil was observed. Grain yield of rice, wheat and winter maize crops were also enhanced significantly with continuous application of balanced fertilizer, FYM and BGA (blue-green algae) separately as well as in combination. About half of the nutrient application could be substituted with long-term application of 10 t FYM plus 13 kg BGA as algal crust ha⁻¹ in combination with NPK (50%).