Integration of composts with NPK improved soil fertility, growth and yield of sorghum in sandy desert soils of Sudan

Abstract

Sandy desert soil in Sudan are characterised by low content of organic matter, small water holding capacity and low crop productivity. Methods to enhance crop productivity on these environments, such as land application of composts, are of great importance. Field experiments were conducted on a sandy soil to determine the effects of two types of composted manures on growth and yield of two sorghum varieties grown under rainfed conditions. Two sorghum cultivars (Butana and Arfa Gadmak were sown under chicken manure (CM) compost (5 t ha-1), CM compost with NPK (36 kg ha-1), farm manure (FM) compost (20 t ha-1), FM compost with NPK (36 kg ha-1), CM compost with FM compost (1:1, wt/wt, 12.5 t ha-1), CM and FM composts with NPK (36 kg ha-1), only NPK (36 kg ha-1) and control (no composts or NPK). Application of composts increased organic soil carbon by 50% and available phosphorous (P) between 43 to 105%, whereas, pH and bulk density were decreased by 2 and 6%, respectively. Soil moisture contents in compost treated plots were 56-98% higher than control plots. Mixing compost with NPK increased leaf area index over NPK alone by 28% but the highest values were found in plots treated with chicken compost or integrated with NPK compared to NPK application alone. Incorporation of compost increased dry matter yield compared to control by 17-53% and increased grain yield by 1.8 to 3.1 fold in both sorghum varieties. Grain yield from plots treated with NPK, sole chicken compost or combined with NPK were similar for both varieties in both seasons. In general, the trend of grain yield of sorghum was in the order of NPK = chicken compost with NPK = chicken compost = farm manure compost with NPK mixed compost with NPK > farm manure > control. In conclusion, integrating composts with NPK improved fertility of sandy soils, sorghum growth and yield.