Effects of Organic Fertilizers on Yield and Quality of Cowpeas and Available Nutrients in Soil Under Continuous Cropping Cultivation

In a field experiment, effects of various organic fertilizers on the yield and quality of cowpeas (Vigna unguiculata) and the available nutrients in the soil under continuous cropping cultivation were studied. The results showed thatin the blossoming/fruiting period, the alkali hydrolyzable nitrogen, available phosphorus, and available potassium in soil were higherby 10.35%-45.59%, 29.42%-49.12%, and 18.90%-38.41%, respectively,when the organic than the chemical fertilizer was applied.When the chicken manure, xxx, or xxx was applied, the death ratesof cowpea seedlings werereduced by 61.35%, 23.72%,or 49.05%, respectively, as compared to the chemical fertilization; the crop yieldsincreased by 41.39%, 22.97%,or 41.39%, respectively; the soluble protein,starch,total sugar,reducing sugar, and Vc increased by 3.40%-9.51%, 4.96%-13.66%,12.37%-32.96%,11.29%-27.50%, and 17.19%-25.05%, respectively; and the organic acid and nitrite contents reduced by 12.90%-35.48% and 16.48%-12.90%, respectively.Among the different organic fertilizers, chicken manure significantly improved the available nutrients in soil, and at the same time,upgraded the soluble protein, total sugar, reducing sugar, Vc, nitrite, and other quality indicesfor the cowpeas raised with its application. It was, therefore, recommended to be used as the fertilizer incontinuous cropping practice of cowpeas.