秸秆还田对旱作冬小麦后茬土壤水分的影响及其APSIM模拟

模型作为一种作物生长机理模型，可敏感捕捉气候变化、土壤水分变化引致的系统组分响应，适用于降水不确定性地区的农业系统生产预测。为确定APSIM模型对秸秆还田等水土保持耕作拦截夏季降水的模拟功能，在甘肃黄土高原开展了秸秆还田处理，对冬小麦收获后休闲期土壤水分的影响及其APSIM模拟。结果表明：自然降水条件下，免耕+秸秆还田（S）处理下土壤水分蒸发量较休闲裸地（F）、耕作+覆草（TS）及传统耕作（T）降低16.7%~23.9%，裸地休闲或耕作会造成土壤水分流失，秸秆还田的保水作用明显，APSIM模拟可代表71%~92%的土壤水分变化；在人工模拟降水(66 mm·h^-1)情况下，土壤蒸发在2 t·hm^-2(SS)、4 t·hm^-2(LS)秸秆还田量下比裸露休闲地(F)分别降低了27.8%和49.4%，APSIM模拟值解释了96%~99%的土壤水分变化。表明本土化的APSIM模型可以描述研究区土壤水分变化，适用于农业系统研究。

Soil Moisture Content under Stubble Retention After Dry-framing Winter Wheat Harvest Based on APSIM Model

APSIM (Agricultural Production Systems Simulator) is a modeling framework which is enabled to simulate broad spectra of biophysical processes in farming system and is capable to predict a variety of scenarios. APSIM is also sensitive to climate change and different water conditions in dry farming area. In order to examine the application of APSIM model in dry farming area in the Loess Plateau, the values of soil moisture loss after winter wheat harvest were measured under different stubble retention treatments, and APSIM was used to predict the output. The results indicated that soil moisture evaporation under stubble retention (S) was 16.7%-23.9% lower than that under fallow (F), stubble mulching with tillage (TS) and tillage (T) treatment after a rainfall event. Simulation of APSIM model could be used to explain 71%-92% change of soil moisture content. Under a simulated rainfall with a rainfall intensity of 66 mm•h^-1, soil moisture evaporation was decreased by 27.8% under SS treatment (with stubble of 2 t•hm^-2) and 49.4% under LS treatment (with stubble of 4 t•hm^-2) compared with that under F treatment. APSIM model could be used to predict 96%-99% soil moisture loss. The results demonstrated that APSIM was satisfactory to predict the process of soil moisture loss through evaporation in dry farming region.