Effect of Feldspar, Compost and Biochar on Cultivating Cowpea (Vigna unguiculata ssp. unguiculata) Plant and Soil Sandy Clay Loam Properties

The crop production in Egypt relies completely on imports to meets its annual requirement of potash fertilizers besides; the high cost of conventional, water soluble K fertilizers constrains their use by most of the farmers in the country. This work was conducted cowpea (Vigna unguiculata ssp. unguiculata) plants cv. Dokki 126 at Ismailia Research Station, Agricultural Research Center (A.R.C), Egypt, during the two summer seasons of 2020 and 2021 to study the effect of some treatments as potassium feldspar, biochar and compost on soil sandy clay loam properties and the physical and chemical contents of cowpea. A randomized complete block design was used. The results show that the potassium feldspar + biochar + Compost significantly increased the vegetative growth expressed as plant length, number of leaves, number of branches, pod length, Pod diameter, Pod fresh weight, Pod dry weight, Plant fresh weight, Plant dry weight. Also the results indicated that soil pH and EC was not significantly affected in the soil treated with potassium feldspar + biochar + compost. There are positive significant effects on nutrient availability (NPK) in both seasons by using potassium feldspar + biochar + compost in soil. The application of OMW can improve soil quality indices (nutrients (N, P, and K), organic matter, pH, total porosity, bulk density.