Quantifying Variability in Maize Yield Response to Nutrient Applications in the Northern Nigerian Savanna

Bello Shehu,Alpha Kamara,Jibrin Jibrin,Roel Merckx,Jairos Rurinda

doi:10.3390/agronomy8020018

Abstract

Diagnostic on-farm nutrient omission trials were conducted over two cropping seasons (2015 and 2016) to assess soil nutrients related constraints to maize yield in the northern Nigerian savanna agro-ecological zone and to quantify their variability. Two sets of trials were conducted side by side, one with an open pollinated maize variety (OPV) and the other one with a hybrid maize variety and each set had six equal treatments laid out in 198 farmers’ fields. The treatments comprised (i) a control, (ii) a PK (‘−N,’ without N), (iii) an NK (‘−P,’ without P), (iv) an NP (‘−K,’ without K), (v) an NPK and (vi) an NPK + S + Ca + Mg + Zn + B (‘+SMM,’ NPK plus secondary macro- and micro-nutrients). Moderate to a large variability in most soil characteristics was observed in the studied fields. Consequently, cluster analysis revealed three distinct yield-nutrient response classes common for the two types of maize varieties. These define classes were fields that have (i) no-response to any nutrient, (ii) a large response to N and P and (iii) a large response to N alone. Although overall yield performance of OPV and hybrid varieties was similar, a distinct fourth class was identified for the hybrid variety, (iv) fields with a large response to N and secondary macro- and micro-nutrients. The results indicate that the large variability in soil nutrients related constraints need to be accounted for to optimize maize yield in the northern Nigerian savanna. The development of field- and area-specific fertilizer recommendations is highly needed, using simple decision support tools that consider variable soil fertility conditions and yield responses as obtained from this study.

Highlights

Factors such as wide suitability boundaries and multiple socioeconomic uses make maize (Zea mays L.) the most widely grown cereal in Nigeria [1]
The results indicate that the large variability in soil nutrients related constraints need to be accounted for to optimize maize yield in the northern Nigerian savanna
Most soil characteristics of the studied fields reveal large variability, while in general they are all characterized by low contents of Total soil organic carbon (total C), Total nitrogen (total N), exchange capacity (ECEC) and available boron

Summary

Introduction

Factors such as wide suitability boundaries and multiple socioeconomic uses make maize (Zea mays L.) the most widely grown cereal in Nigeria [1]. Organization) data [2], the land area planted to maize in Nigeria increased from 1.38 to 5.20 million hectares (1961–2013). This substantial expansion of the land area devoted to maize cultivation largely resulted in an increase in production from 1.10 to 10.40 million metric tonnes over the same period [2]. Maize yield per unit area in Nigeria is still low, at about 2 tonnes per hectare (t·ha−1 ) [2]. Since opportunities to expand a cultivated area are limited [8], further increases in maize production will be derived from sustainable intensification on existing farmland

Methods

Results

Discussion

Conclusion