Optimising Fodder Maize Productivity across Soil Fertility Gradients: A Critical Review of Soil Test Crop Response Strategies for Sustainable Nutrient Management

Abstract

Fodder maize (Zea mays L.) is a high-biomass, nutrient-responsive forage whose economic value depends on both harvested mass and nutritive quality. Fertiliser recommendations based on regional averages can therefore be inefficient when fields differ markedly in native nitrogen, phosphorus and potassium supply, organic matter, pH, texture, previous management and residual fertility. This critical narrative review evaluates soil test crop response (STCR) and related targeted-yield strategies as a basis for improving fodder maize nutrient management across soil fertility gradients. Literature published principally from January 2010 to 26 June 2026 was considered, with older foundational methodological sources retained where necessary. The evidence shows that STCR offers a defensible framework because fertiliser rates are adjusted to a yield target and to measured soil nutrient supply rather than applied as a uniform dose. Maize studies across Alfisols, Vertisols, Inceptisols and related soils generally demonstrate improved target attainment, nutrient-use efficiency or economic performance when calibrated STCR or STCR-integrated plant nutrient supply approaches are compared with blanket recommendations. Nevertheless, transfer to fodder maize remains less secure than the broader maize literature suggests. Direct fodder studies confirm strong interactions among nitrogen rate, plant density, zinc supply, water regime, cultivar and harvest endpoint, while recent fodder-specific STCR work shows that deliberate fertility gradients can be established in lateritic soils. Yet contemporary multi-location validation of fodder-specific target equations, dry-matter removal, feed-quality safeguards, residual nutrient credits and environmental outcomes is still limited. The most defensible pathway is therefore an STCR-plus strategy: locally calibrated pre-season soil-test prescriptions, explicit organic nutrient credits, and in-season nitrogen adjustment using crop sensing, with potassium and micronutrient balance evaluated against whole-plant removal. Future research should prioritise multi-soil calibration and external validation using green-fodder yield, dry-matter yield, nutritive quality, nutrient recovery, profitability and soil nutrient balance as joint outcomes. STCR can support sustainable fodder maize intensification, but its reliability depends on calibration domain, measurement quality and repeated validation rather than on universal transfer of published equations.