Author(s): Sushil K Adhikari and Meera P Koirala

Abstract:

Background: Potato is a key food and cash crop in South Asia, yet yields on smallholder farms remain well below attainable levels because of under- and imbalanced fertiliser use, declining soil organic matter and limited access to soil testing services ^[1-3]. Integrated nutrient management (INM) and site-specific nutrient management (SSNM) have been proposed as strategies to close yield gaps, enhance nutrient use efficiency and sustain soil health in potato-based systems ^{[3, 5, 9-11, 14]}. This study evaluated the comparative performance of contrasting fertility management practices on potato yield, nutrient use efficiency and profitability under representative smallholder conditions.

Methods: On-farm experiments were conducted over two rabi seasons in smallholder potato clusters of the eastern Indo-Gangetic plains using a randomised complete block design with four treatments: farmer practice (FP), recommended dose of fertiliser (RDF), INM (farmyard manure plus 75-100% RDF) and SSNM (soil-test-based NPK rates adjusted to yield targets). The processing/ware cultivar ‘Kufri Chipsona-3’ or an analogous medium-duration cultivar was planted, and standard management was applied across treatments within sites. Total and marketable tuber yields, tuber size distribution, NPK uptake, partial factor productivity and agronomic efficiency were measured, along with net returns and benefit-cost ratio, and analysed using mixed-model ANOVA ^{[3, 5, 9-11, 14, 15]}.

Results: INM and SSNM significantly increased total and marketable tuber yields by approximately 38-44% over FP and 15-20% over RDF, with a higher proportion of medium and large marketable tubers, indicating improved size distribution. Both treatments enhanced partial factor productivity and agronomic efficiency of N relative to RDF, despite similar or lower N application rates, demonstrating more efficient nutrient recovery and use ^{[2, 3, 5, 9, 10]}. Economic analysis showed that INM and SSNM generated substantially higher net returns and benefit-cost ratios than FP and RDF, driven primarily by increased marketable yield and better input-output relationships ^{[3, 9-11, 14, 15]}.

Conclusion: The results confirm the hypothesis that integrated and site-specific fertility management strategies outperform current farmer practice and blanket fertiliser recommendations in South Asian smallholder potato systems. Scaling INM and SSNM, supported by soil-testing infrastructure, decision-support tools and extension services, offers a practical pathway to sustainably intensify potato production, improve nutrient use efficiency and increase smallholder incomes while contributing to long-term soil health.

DOI: 10.22271/27889289.2025.v5.i1a.221

Pages: 65-71 | Views: 69 | Downloads: 37

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