Growth and water use efficiency of capsicum annuum in a silt loam soil treated three years previously with a single compost application and repeatedly dried

Abstract

Mulched compost can reduce irrigation requirements by decreasing soil evaporation. However, it is not known how long this effect lasts after a single compost application. Pepper (Capsicum annuum L.), cv. Giant Bell, plants were grown in a silt loam (Calcarosol) that had received mulched compost once three years previously and in a corresponding unamended control. After 41 days of sufficient water supply, plants were divided into two water regimes: 1) sufficient water supply until the end of the experiment (67 days) and 2) two transient drought cycles, separated by one week of sufficient water supply. Compost applied once three years previously increased soil organic C and total N and dry root mass and root length under well-watered and drought-stressed conditions. The single compost application increased total available water, total water used, and water availability to plants when well watered but did not affect gas exchange and had no effect on water use efficiency and recovery capacity of plants after drought stress. Even three years after application, mulched compost increases the ability of plants to take up water by stimulating root growth.