EFFECTS OF LIME, PHOSPHORUS AND POTASSIUM ON CROP YIELDS OF DIFFERENT CROPPING PATTERNS IN ACID SOILS

Abstract

Experiments were conducted during 2012-2014 at HSTU farm (AEZ-1) and Farmer’s’field (FF) (AEZ-27) under Dinajpur district following two cropping patterns viz. Wheat-Mungbean-T.aman and Wheat-fallow-T.aman to evaluate the effects of lime, P and K on yields of crop as well as soil properties. There were seven treatment combinations viz. L0 (control), L1, L2, L1P, L2P, L1PK and L2PK. The experiments were laid out in Randomized Complete Block Design (RCBD) with 4 replications. The doses of lime were 0, 1 and 2 t ha-1 for both locations. The P was 20, 13 and 6 kg ha-1 for Wheat-Mungbean-T.aman at HSTU and 25, 22 and 12 kg ha-1 at FF respectively. The rate of K was 80, 32 and 50 kg ha-1 at HSTU and 61, 30 and 42 kg at FF. Other nutrients i.e. 15-100 kg N, 8-15 kg S, 1-2 kg Zn and 1-1.5 kg B were applied as basal irrespective of crops and locations on soil test basis (FRG 2012). Lime was added to the first crop only and its residual effects were evaluated on the succeeding crops over 2-crops cycles. The chemical fertilizers Urea, TSP, MoP, Gypsum, Zinc Sulphate and Boric acid were used as sources of N, P, K, S, Zn and B respectively. The varieties used were BARI Gom-26 for wheat, BU Mung-4 for mungbean and BRRI dhan57 for T.aman. Soil and plant samples were collected and analyzed. Application of lime, P and K significantly increased the growth and yield contributing characters, grain and straw yields of all crops irrespective of patterns at both locations. The direct and residual effects of lime were more prominent on crop yields followed by K and then P. The performance of different treatments was better at HSTU farm than Farmer’s field (FF). The yield of L1PK treatment was the highest; which was followed by L2PK for all crops and locations. In general, the crop yields of FF were relatively low due to higher acidity. The total uptake of P by crops was lower than the applied amount but the uptake of K was much higher than the added amount. The uptake of N, S, Fe, Mn, Zn and B were increased with the increase in yield due to different treatments. Soil pH was increased by 0.4-1.21 units irrespective of location and the higher values were observed with higher rates of lime application. The available P was increased in P treated plot and decreased in P control plot. The status of exchangeable K remained almost unchanged in treated plot but decrease in control plot. The status of available Zn, B, Fe and Mn were decreased over initial status but the status of total N and available S remained almost unchanged due to cropping and fertilization. The highest gross margin and BCR was found due to L1PK treatment for all crops and locations and this was followed by L2PK. Wheat-Mungbeam-T.aman cropping pattern was found more profitable than Wheat-fallow-T.aman cropping pattern. Economic analysis also showed dominance of 1 t ha-1 lime with P and K (L1PK) treatment combinations than others. This study recommends that amendment of soil with lime (dolomite) @ 1 t ha-1 with PK fertilizer inclusion of legume crop in cropping pattern might be an efficient practice for achieving sustainable soil fertility and crop yield in Old Himalayan Piedmont Plain (AEZ-1) and North Eastern Barind Tract (AEZ-27) soils of Bangladesh.