Effect of Compost, Blended (NPSZn), and Potassium Chloride Fertilizers on Soil Bulk Density and Moisture Content in Two Soil Textural Groups of Tigray, Northern Ethiopia

The growing needs for agricultural production require maintaining and improving soil fertility through fertilization. However, most research to date in Ethiopia particularly in the Tigray regional state has focused on the effects of soil chemical properties and relatively little work has been done on soil physical properties. The objective of this study was to assess the effects of compost, blended (NPSZn), and potassium chloride (KCl) fertilizers on soil bulk density (BD) and moisture content (SMC). Therefore, a field experiment was carried out for 2018-2019 years to study the influence of sole and combined application of compost, NPSZn, and KCl fertilizers on BD and SMC in clay loam and loamy sand soil textures in Tigray. Two compost (0 and 20 t·ha−1), three NPSZn (0, 60, and 120 kg·ha−1), and four KCl (0, 120, 210, and 300 kg·ha−1) rates replicated three times were arranged in split-split plot design and allocated to main, sub, and sub-subplots, respectively. BD (g·cm−3) and SMC (%) data were collected from 0 to 10 and 0 to 30 cm soil depths before and after harvesting in 2018 and 2019, respectively. Sole and combined application of the fertilizers considerably influenced BD and SMC in both soil textural groups and years. Compost applied in combination with NPSZn at 120 kg·ha−1 and KCl at 300 kg·ha−1 significantly reduced BD (1.24 g·cm−3 in 2018 and 1.22 g·cm−3 in 2019) in clay loam soils as compared to all treatments. Similarly, the lowest BD (1.5 g·cm−3 in 2018 and 1.47 g·cm−3 in 2019) was observed in loamy sand soils. The highest volumetric SMC (21% in both years) was observed in clay loam soil in plots treated with compost. Likewise, the highest SMC (12% in 2018 and 11% in 2019) was found in loamy sand soils in compost-treated plots. This study demonstrated that SMC and BD can be improved through compost and compost combined with NPSZn and KCl application, respectively, in the drylands of Northern Ethiopia.