Response of yam varieties to soil moisture regime in Southwestern Nigeria

Abayomi Eruola

doi:10.36253/ijam-1324

Abstract

A field experiment was conducted on varietal response of white yam to moisture regime in Abeokuta. The experiment comprised three varieties of yam (Efuru, Ise-osi and Oniyere), three mulching options (grass, polythene and unmulched), and two planting dates (early and late). Treatments were replicated three times using RCBD lay-out. Model for selecting planting date involved relating potential evapotranspiration (PE) to precipitation (P) in the form of 0.1PE<P < 0.5PE, partitioned for attaining optimal planting date into early {T1= Σ(P-0.1PE) ≤ 0} and late {T2 = Σ(P-0.5PE) ≤ 0}, respectively. For humid period defined by P> PE, the physiological parameters and moisture agro-climatic indices measured during phenological stages of yam grown were analyzed with respect to treatments. Result showed that T1 defined as Σ(P-0.1PE) ≤ 10 mm appeared as the best model that significantly (P < 0.05) influenced emergence rate, phenological growth and tuber yield. All yam varieties evaluated were suitable for planting with respect to yield. Efuru and Ise-osi synchronized perfectly with Actual Water Availability and produced good vegetative growth with LAI of 1.08 and 0.91 leading to higher tuber yield of 12 and 11.64 tonnes ha-1, respectively. Grass mulch had tuber yield, 4-6 tonnes ha-1greater than the polythene and unmulched plots in all varieties. Mulching significantly (P< 0.05) increased tuber yield, 6-8 tonnes ha-1than the unmulched. Conclusively, early planting with grass mulch increased tuber yield.

Highlights

Water supply in terms of annual rainfall total is not a constraint to crop production in Southwest Nigeria (Ofori, etal. 2014)
The relationship between Actual Water Availability (AWA) and water requirement (WR) during the phenological stages, presented in figures 2 and 3 shows that though annual total water supply was adequate for the growth of yam for both experimental years, a long term moisture stress (AWA: WR < 1) resulting from short fall in AWA encountered before the onset of rainfall, perticularly during the emergence period was pronounced for the 2017 experimental year
This was noticed to cause loss of setts and disparity in emergence which led to growth retardation and reduction in tuber yield

Summary

Introduction

Water supply in terms of annual rainfall total is not a constraint to crop production in Southwest Nigeria (Ofori, etal. 2014). It is necessary to implement methods of soil water conservation in farming operation to improve crop production and reduce food insecurity in Africa and in particular Nigeria (Tiamiyu et al, 2015). Many of the methods rely on providing some kind of cover for the soil to minimize evapotranspiration and direct soil exposure to heat and sun. Examples of methods for reducing excess soil moisture loss include spreading manure or compost over the soil, Mulching, conservation tillage, crop rotation, Green manuring, among others. The selection of a specific variety largely depend on the way in which planting date is managed to prevent incidence of failure of agricultural crops, replanting and ultimate low yield that have characterized the agricultural food crops production in Nigeria

Methods

Results

Conclusion