Planting date and fertilizer type influenced soil quality indices and soybean (Glycine max L.) yields in derived savannah of Nigeria

J.C Nwite

doi:10.4314/as.v21i1.2

Abstract

Soybean is grown in many parts of Northern Nigeria, with little climatic challenges and soil organic matter. There is need to investigate possible influence of planting date of the crop in Southeastern Nigeria, an environment that is rather foreign to the crop. A study was carried out in 2018 and 2019 cropping seasons at Federal College of Agriculture, Ishiagu, Ebonyi State, to evaluate the influence of different planting dates and fertilizer types on selected soil physical and chemical properties, growth and yield of soybean. A split plot in a randomized complete block design was used with planting date (May and June) as the main plots, while six fertilizer types (poultry-droppings manure 5 t ha–1, swine-droppings manure 5 t ha–1, rice-husk dust 5 t ha–1, NPK 15:15:15 at 150 kg ha–1, urea at 100 kg ha–1 and the control) constituted the sub-plots. At crop maturity, some soil quality indices and pod and grain yields (t ha–1) of soybean were assessed. Soil organic carbon (SOC) and total nitrogen contents were significantly (p < 0.05) influenced by both planting date and fertilizer type in 2018 and 2019, while soil pH was improved significantly (p < 0.05) only by fertilizer type in these two cropping seasons. Mean-weight diameter of aggregates, soil bulk density and SOC stock as well as soybean yields were significantly (p < 0.05) influenced by both planting date and fertilizer type in the two seasons. Generally, planting in May improved soil total nitrogen and soybean pod yield whereas planting in June improved the other soil quality indices and soybean grain yield, the best soil amendment in either case being poultry-droppings manure but sometimes parameter-specific. The choice of planting date (May or June) in soybean production in the derived savannah and the soil amendment to use in the enterprise thus has both agronomic and environmental implications. Such a choice would depend on the indices of soil quality and/or the aspects of soybean yields (pod or grain) whose improvements the farmer intends to achieve at crop maturity.

Highlights

IntroductionMerrill) is the world’s leading source of oil and protein
Soybean is widely grown in the middle belt or the savannah zone of Nigeria (Okpara and Ibiam, 2000), but its production had presently expanded beyond the traditional production areas otherwise considered unsuitable or marginal for soybean production (Asiegbu and Okpara, 2002; Obalum et al, 2011a)
Some of the chemical components of the soil showed that N, P, K, Ca, Mg and Na contents including Soil organic carbon (SOC) concentration were low at the beginning of the study

Summary

Introduction

Merrill) is the world’s leading source of oil and protein. The spread of soybean from its native land of origins has been mainly due to its adaptability and predominant use as a food crop for human nutrition, source of protein for animals (Yusuf and Idowu, 2001). The planting time of soybean in these new areas varies due to differences in weather and soil type. Planting date is a critical factor affecting soybean growth, grain yield (Zhang et al, 2010), and grain quality (Rahman et al, 2005). Sowing date is the variable with the largest effect on crop yield (Calvino et al, 2003). Effects of planting date on soybean yield and other traits vary according to locations (Naeve et al, 2004). Environmental conditions associated with late sowing affect crop features related to the capture of radiation and other portions of crop resources such as vegetative growth at all phenological stages of the crop including the reproductive phases (Kantolic and Slafer, 2001)

Methods

Results

Conclusion