Integrated use of farmyard manure, gypsum and inorganic fertilizer for sustainable rice production on salt affected soil in Northwest Nigeria

Abstract

Saline soil and nutrient imbalance critically constrain crop productivity in the Kola and Kardi districts of Kebbi State, Nigeria. Although soil amendments have proven effective in restoring soil fertility, their adoption among smallholder farmers remains limited. During the 2021 cropping season, a comprehensive field survey was conducted to assess farmers’ nutrient management practices and identify significant constraints to soil productivity. The findings revealed suboptimal, inconsistent management practices that exacerbate soil fertility decline caused by salinity. Consequently, a field experiment was established to demonstrate to farmers the synergistic effects of farmyard manure (FYM), gypsum (G), and NPK fertilizer on the growth and yield performance of rice cultivated on salt-affected soils. The experiment was laid on a randomized complete block design with five replications, comprising application rates of 15 t ha?¹ FYM, 1.5 t ha?¹ gypsum, 250 kg ha?¹ NPK (20:10:10), and 100 kg ha?¹ urea. Integrated nutrient management consistently enhanced rice yield and yield components across all growth stages compared with the farmer practice.  The integrated treatment (G + FYM + NPK) produced the highest grain yield, achieving 5.7 t ha?¹ and 5.5 t ha?¹ in Kola and Kardi, respectively, compared with 1.9 t ha?¹ and 1.7 t ha?¹ under the farmers’ practice. The combination of organic and inorganic amendments, supported by farmer training and participatory demonstration, offers a viable and scalable pathway for restoring degraded soils and bridging the rice yield gap in northwestern Nigeria.