Effects of Irrigation and Potassium Fertilizer Applications on Jujube Production

Highlights Moderate water deficit will help reduce agricultural investment. Application of potassium fertilizer can alleviate the effect of water deficit on fruit trees. Reasonable ratio of water and fertilizer is helpful to improve economic benefits. Abstract. The jujube planting industry is a key agricultural industry in Xinjiang, China. With an arid climate and limited water resources, Xinjiang must implement more efficient water-saving irrigation systems to guarantee the sustainable development of jujube planting industry. A two-factor, three-level test was adopted to explore how regulated deficit irrigation and different potassium fertilizer levels affected the growth and yield of jujube under drip irrigation. The results of analysis of variance showed that water deficit significantly affected photosynthetic characteristics, growth parameters, evapotranspiration, and yield. The effect of K-application level was focused on fruit volume and yield. However, when the ratio of water to fertilizer is unbalanced (150% K-application + severe water deficit), the growth of jujube trees be inhibited, and the fruit volume and economic benefits reduced by 7% and 11%, respectively. Means comparison indicated that growth parameters, evaporation, and yield under minor water deficit was lower than that under the adequate irrigation by 7%, 13%, and 6%, respectively; and economic performance was higher by 12%. Severe water deficit reduced growth parameters and economic benefits by 33% and 55%, respectively. Thus, minor water deficit irrigation significantly inhibited luxury transpiration and growth redundancy, improved water-use efficiency and increased economic performance. Severer water deficit may damage trees and negatively affect the jujube industry. With economic benefit analysis, 150% K-application with adequate irrigation and minor water deficit, 100% K-application with adequate irrigation and minor water deficit, 50% K-application with minor water deficit all achieve high economic benefits (14074~17261 RmB ha-1). However, when taking water restrictions, the environmental and economic costs of fertilizer, and the long-term effects of tree development into account, application of 100% K-application with minor water deficit (irrigation, 75% ETc; fertilizer, 200 kg ha-1 compound fertilizer+360 kg ha-1 potassium fertilizer) is recommended.