Soil Properties and Wheat Growth and Nutrients as Affected by Compost Amendment Under Saline Water Irrigation

Abstract

A greenhouse experiment was conducted to test and compare the suitability of saline compost and saline irrigation water for nutrient status amendment of a slightly productive sandy clay loam soil, to study the macronutrient utilization and dry matter production of wheat ( Triticum aestivum c.v. Gemmiza 7) grown in a modified soil environment and to determine the effects of compost and saline irrigation water on soil productivity. The sandy clay loam soil was treated with compost of five rates (0, 24, 36, 48, and 60 m 3 ha −1, equivalent to 0, 3, 4.5, and 6 g kg −1 soil, respectively) and irrigation water of four salinity levels (0.50 (tap water), 4.9, 6.3, and 8.7 dS m −1). The results indicated that at harvest, the electrical conductivity (EC) of the soil was significantly ( P < 0.05) changed by the compost application as compared to the control. In general, the soil salinity significantly increased with increasing application rates of compost. Soluble salts, K, Cl, HCO 3, Na, Ca, and Mg, were significantly increased by the compost treatment. Soil sodium adsorption ratio (SAR) was significantly affected by the salinity levels of the irrigation water, and showed a slight response to the compost application. The soil organic carbon content was also significantly ( P < 0.05) affected by application of compost, with a maximum value of 31.03 g kg −1 recorded at the compost rate of 60 m 3 ha −1 and the irrigation water salinity level of 8.7 dS m −1 and a minimum value of 12.05 g kg −1 observed in the control. The compost application produced remarkable increases in wheat shoot dry matter production. The maximum dry matter production (75.11 g pot −1) occurred with 60 m 3 ha −1 compost and normal irrigation water, with a minimum of 19.83 g pot −1 with no addition of compost and irrigation water at a salinity level of 8.70 dS m −1. Significant increases in wheat shoot contents of K, N, P, Na, and Cl were observed with addition of compost. The relatively high shoot N values may be attributed to increases in N availability in the tested soil caused by the compost application. Similarly, significant increases in the shoot contents of Na and Cl may be ascribed to the increase in soil soluble K and Cl. The increases in shoot P, N, and K contributed to the growth stimulation since P supplied by the compost was probably responsible in saline and alkaline soils where P solubility was very low.