Growth and yield responses of cowpea genotypes to soluble and rock P fertilizers on acid, highly weathered soil from humid tropical West Africa

Abstract

Soils in tropical regions have inadequate levels of phosphorus and this apparently leads to reduced cowpea yield in Africa. Identifying phosphorus-efficient cultivars have the potential to reduce the demand for phosphorus fertilizer and increase the productivity of cowpea. This study was conducted to identify cowpea genotypes that maintain high yields under low soil phosphorus condition. A green-house experiment was conducted at the International Institute of Tropical Agriculture, Ibadan, Nigeria. Fifteen cowpea genotypes were used with two sources of phosphorus fertilisers: rock phosphate (60, 90 and 120 mg P kg −1 soil) and mono potassium phosphate (30, 60 and 90 mg P kg −1 soil) and compared to the control. The experiment was laid out in a strip plot arrangement with three replications. The findings suggested that large geneticvariability exist among the tested cowpea genotypes. IT90K-59 was identified as best phosphorus responder genotype for biomass production and IT90K-76 for grain yield at a rate of 60 mg P kg −1 soil as mono potassium phosphate .Danila and IT89KD-288 were identified as promising genotypes under no or minimal external P application. Five genotypes were identified as good responders to rock phosphate based on their grain yield production. The differential response of the genotypes to low soil phosphorus implies that these traits warrant effective selection for further improvement. Thus, identifying genotypes that can grow well in low phosphorus condition has the potential to reduce the quantity of mineral fertilizersand cost of production.

High soil phosphorus application significantly increased grain yield, phosphorus content but not zinc content of cowpea grains

“…Increased performance of cowpea, as measured by indices of high dry matter yield, increased content of phosphorous (P) in shoots, and high grain yield was observed with increasing supply of P in the growth media under both sand-nutrient solution and eld environments. This corroborates several earlier reports on cowpea's response to the addition of P fertilizer under greenhouse and eld conditions (Adusei et al, 2016;Gyan-Ansah et al, 2016;Kolawole et al, 2008;Krasilnikoff et al, 2003;Saidou et al, 2012;Sanginga et al, 2000). The grain Zn content of cowpea genotypes evaluated in this study showed no signi cant differences (p > 0.05) across the various P levels applied to the soil.…”

“…For cowpeas, two complementary approaches have been recommended to achieve a high yield on soils with low available P; rst is the use of improved agronomic approaches such as application of phosphate fertilizers, and second is the development of elite varieties with high P use e ciency (Oladiran et al, 2012;Sanginga et al, 2000;Simpson et al, 2011). Varieties with improved P e ciencies use different mechanisms including increased solubilization and mobilization of soil P, improved root architecture traits, increased ability to acquire P and accumulate it in edible tissues (Adusei et al, 2016;Gyan-Ansah et al, 2016;Saidou et al, 2012;Sanginga et al, 2000). Application of fertilizers supplying major nutrients like nitrogen-phosphorous-potassium (NPK), with little or no consideration of micronutrient requirements, may lead to a reduced amount of micronutrients in the edible tissues that serve as food for people (Zhang et al, 2012), since the micronutrient content of grains depend largely on the supply from soil nutrient pool and micronutrients-containing fertilizers (White & Broadley, 2009;Zhang et al, 2012).…”

High Soil Phosphorus Application Significantly Increased Grain Yield, Phosphorus Content but Not Zinc Content of Cowpea Grains

“…High grain yield was observed with an increasing supply of P in the growth media in the field environment. This corroborates several earlier reports on cowpea's response to the addition of P fertilizer under greenhouse and field conditions [27][28][29][30]41,42]. The grain Zn content of cowpea genotypes evaluated in this study showed no significant differences (p > 0.05) across the various P levels applied to the soil.…”

“…Two complementary approaches have been recommended to achieve high cowpea yield on soils with low available P. First is the use of improved agronomic approaches such as application of phosphate fertilizers, and second is the development of elite varieties with high P use efficiency [25][26][27]. Varieties with improved P efficiencies use different mechanisms, including increased solubilization and mobilization of soil P, improved root architecture traits, and increased ability to acquire P and accumulate it in edible tissues [27][28][29][30].…”

Differential responses of two cowpea (Virgina unguiculata L.Walp.) genotypes to pre-emergence herbicides in the savannah woodland and rainforest agroclimatic regions of Sierra Leone

“…Cowpea (Vigna unguiculata (L) Walp.) belonging to fabaceae family and genus Vigna is one of the widely cultivated annual herbaceous legume crop in the savannah region of West Africa [1,2,3]. According to [4] and [5] the world estimated annual production of cowpea is about 4.5 million tonnes from a land area of 12.6 million hectares and West Africa accounts for about 80% of the estimated total land area under cowpea cultivation.…”