Response of maize to different nutrient sources under different landscape positions in cereal mixed farming systems of tropical agroecosystems

Abstract

Nutrient omission trials were conducted on farmers’ fields in 2020 and 2022. The experiment included nine treatments: three treatments with nitrogen (N), phosphorus (P), potassium (K), sulfur (S), zinc (Zn), and boron (B) as individual, blended, and compound fertilizer; four treatments with the omission of K, S, Zn, or B; NP-only; and control without any nutrient. Treatments were arranged in a randomized complete block design with three replications under foot slope (FS), mid-slope (MS), and hillslope (HS) positions. Results showed that soil properties and maize yield significantly varied among landscape positions, with substantial soil fertility and yield increasing trends from HS to FS position. The highest grain yield (6.18 t ha⁻¹) was recorded at the FS position, with the respective yield increments of 14% and 16% compared to the MS and HS positions. Applying all nutrients in blended form resulted in the highest grain yield (6.52 t ha⁻¹), but it was not significantly different from yields of compound and individual fertilizer forms. Applying all nutrients in blended form increased grain yield by 7.4% and 264.2% compared to the NP-only and the control, respectively, indicating the non-significant effects of K, S, Zn, and B on yield. Overall, N and P are the most yield-limiting nutrients for maize production, and site-specific NP fertilizer recommendations targeting landscape position are required to enhance nutrient use efficiency and sustainably intensify maize yield. Developing site-specific fertilizer recommendations advisory will enhance nutrient use efficiency, increase and sustain yield, and benefit farmers while improving soil and environmental quality.