Integration of Organic Amendments with Chemical Fertilizers Boosts Crop Yields, Nutrient Uptake, and Soil Fertility in Farm and Char Lands

Improving crop productivity and soil fertility through the balanced application of inorganic and organic nutrient sources is a sustainable approach in modern agriculture. Char land soils, widely distributed in riverine Bangladesh, are generally low in organic matter status and deficient in necessary nutrient elements for crop production. Addressing this challenge, the present study was conducted to investigate the effects of various organic nutrient sources with inorganic fertilizers on crop yields, nutrient uptake, and soil fertility in farm (L1) and char land (L2) of Brahmaputra River in Mymensingh, Bangladesh from 2022 (Y1) to 2023 (Y2). For each location, eight treatments viz. T1 (Control), T2 [100% recommended fertilizer dose (RFD)], T3 (75% RFD), T4 (75% N from RFD + 25% N from cow dung), T5 (75% N from RFD + 25% N from poultry manure), T6 (75% N from RFD + 25% N from vermicompost), T7 (75% N from RFD + 25% N from household compost) and T8 (75% N from RFD + 25% N from rice straw compost) were arranged in a randomized complete block design with three replications using Wheat–Mungbean–T. Aman rice cropping pattern where three way interaction was considered for results. Treatment T5 performed the best in both years in both locations as it enhanced the yield components (p < 0.05) and caused yield increment over control. The yield improvement in Char land soils was higher than that in farm soils. For all three crops, treatment T5 consistently augmented the uptake of nitrogen, phosphorus, potassium, and sulphur by different parts of the crops and improved soil fertility properties such as organic matter status, cation exchange capacity, total nitrogen, available phosphorus, and sulphur as well as exchangeable potassium in both locations in both years. Cost and return analysis of different treatments for the whole cropping system showed that the highest marginal benefit-cost ratio (16.35 and 15.07) and gross return (about Tk 768,595/ha and 728,341/ha) were obtained from the T5 treatment in farm soils and Char land soils, respectively. Followed by poultry manure, vermicompost performed well in addition to mineral fertilizers for improving crop yield and soil fertility but its economic efficiency was less due to high input cost. These findings may be useful to the smallholder farmers in char areas, who could benefit from increased productivity, reduced reliance on chemical fertilizers, and improved soil health, contributing to the long-term sustainability of char land agriculture.