密度对苹果园产量和土壤水分利用影响的模拟

Simulation of Water Productivity and Soil Water Use of Different Planting Density Apple Orchard

以1965—2009年渭北旱塬洛川不同种植密度旱作苹果园地为研究对象,应用WinEPIC模型模拟,研究了密度对产量演变和深层土壤水分的动态变化规律。结果表明：各密度处理苹果园逐年产量呈现先增加后波动降低的趋势,种植密度越高,果园初期产量增长越快,后期由于土壤水分过耗量大,产量降幅变大。果园干旱胁迫日数波动趋势与降水量变化趋势相反,随着种植密度增大,干旱胁迫出现时间提早,干旱胁迫日数变大,0～15m逐年土壤有效含水量降低,土壤干层显现时间缩短,干层加深速度变快。综合考虑果园产量和土壤水分的可持续利用,建议渭北旱塬洛川旱作果园合理栽植密度为833～1 000株/hm^2,适宜利用年限为20～25年。

Taking apple orchards under six different planting density treatments during 1965—2009at Luochuan as research object.The WinEPIC model was used to simulated the dynamic changes of water productivity and deep soil desiccation of apple orchards.The results showed that simulated annual apple yield of different density apple orchards increased in the early growth stage and then decreased with fluctuation in Luochuan.The higher planting density,the higher annual yield was obtained at early growth stage,but the yield at late growth stage was decreased more for excessive consumption of soil water.Water stress days of apple orchards showed a growth trend which was opposed to the change trend of annual rainfall.With planting density increasing,water stress occurred earlier and water stress days got larger,simulated annual available soil water amounts in 0-15 msoil layer of apple orchards decreased.The higher planting destiny of treatment had,the faster increasing rate of desiccated soil layer depth could have and the earlier time for desiccated soil layer occurred as well.To summarize,taking yield and sustainable utilization of soil water into consideration,it suggested the suitable planting densities of apple orchards was 833-1 000plants/hm^2 and reasonable years for soil water sustainable use was 20-25 years in Luochuan.