Soil Nutrient Dynamics Under Organic and Inorganic Amendments Determine Chile (Capsicum annuum L.) Growth and Yield

Abstract

Integrated organic–inorganic soil amendments have been proposed as a strategy to improve soil fertility while maintaining crop productivity, yet their effects on seasonal nutrient dynamics and chile (Capsicum annuum L.) performance remain unclear. Two chile cultivars (‘NuMex Odyssey’, ‘NuMex Sandia Select’) were tested to evaluate the effects of organic and inorganic amendments on soil nutrient dynamics, chile vegetative growth, and fruit yield and dimensions across key growth stages. The amendments included an unamended control (CK), half-rate (CF) and full-rate (CFCF) chemical fertilizer, and three integrated amendments consisting of composted manure–biochar blend (CFMB), composted manure (CFM), and pea residues (CFP) applied at a 1:1 ratio with chemical fertilizer on a plant-available nitrogen (PAN) basis. CFCF produced the highest early-season availability of N, P, and K, whereas CFP and CFM provided a more gradual nutrient release pattern, maintaining PAN comparable to CFCF through flowering and sustaining P and K availability through harvest. ‘NuMex Sandia Select’ exhibited greater yield responsiveness to soil amendments, while ‘NuMex Odyssey’ produced fewer but higher dimension fruits. CFP maintained fruit yields comparable to CFCF while producing lower vegetative biomass. Correlation analyses showed that significant nutrient–plant relationships were concentrated at harvest, with soil NO3−-N associated with fruit number and NH4+-N with fruit dimensions. These findings indicate that partial substitution of mineral fertilizer with organic amendments may sustain nutrient availability and chile productivity while providing a more gradual nutrient release throughout the growing season.