Assessment of agronomic and economic benefits of fertilizer use in maize production systems under variable farm size, climate and soil fertility conditions in Karnataka of Peninsular India


22 May 2017

2016 Annual Interpretive Summary

A study was initiated in Karnataka, to delineate farm typology based on biophysical and socio-economic aspects of farms and farmers, and use farm typology-based fertilizer recommendations to improve crop productivity and farmer profitability. Two emerging (Ballary and Koppal Taluks) and two established (Hadagali and Harpanahalli Taluks) maize-growing regions were identified and three villages were selected from each Taluk. In each village, 15 farmers were surveyed to gather information on different socio-economic and biophysical parameters of maize farmers. Data collected from the 180 farmers was screened through principal component analysis, and the surveyed farmers were categorized into six groups. Farmers representing different socio-economic groups were assigned with individual yield targets, and Nutrient Expert® (NE) maize was used to develop the nutrient recommendations for the assigned yield goals, which was compared with nutrient management based on soil test crop response approach (STCR), university recommendation (SR) and farmer practice (FP).

In Ballary Taluk, the nitrogen (N), P2O5, and K2O recommendation using NE across different farm types varied from 130-190, 0-10, and 55-81 kg/ha, with an average of 164, 4.5, and 66 kg/ha. In the STCR approach, the corresponding N, P2O5, and K2O use varied from 217 to 324, 41 to 190, and 14 to 89 kg/ha, with an average of 273, 144, and 64 kg/ha, respectively. Similarly, the average N, P2O5, and K2O recommendation in SR was 150, 75, and 37.5 kg/ha, while N, P2O5, and K2O use in FP varied from 105 to 190, 75 to 136, and 10 to 134 kg/ha respectively, with an average of 141, 120, and 75 kg/ha. Yield of maize with NE, STCR, SR, and FP varied from 6.2 to 8.3, 8.0 to 9.6, 6.9 to 7.5, and 5.5 to 8.1 t/ha respectively, and the mean yield of the respective treatments were 7.4, 8.7, 7.2, and 6.7 t/ha. The average maize yield with NE was 3 and 9% higher than SR and FFP respectively, and 17% lower than STCR. However, the NE treatment achieved 85% of the yield recorded with STCR with only 49% of the total nutrients used in STCR. The partial factor productivity (PFP) of the NE treatment (32 kg grain/kg NPK applied) was higher than STCR, SR, and FFP by 78, 14, and 60%, respectively.

While comparing NE with SR and FP in Huvina Hadagali and Harapanahalli Taluks, SR recorded the highest yield, followed by NE and FP. In Hadagali Taluk, the average yield was 6.9, 6.7, and 5.7 t/ha in SR, NE, and FP, respectively. The average maize yield in Harapanahalli Taluk was similar in SR and NE (6.7 t/ha), which was higher than FP (5.2 t/ha). The overall results of the study indicated that farm typology-based fertilizer recommendations, based on the NE tool, helped improve maize yields over SR and FFP, in addition to optimizing the nutrient use over STCR, SR and FFP.