应用DNDC模型模拟沟垄集雨种植对陕西省玉米产量的影响

Effects of Simulation of Rainfall Harvesting with Ridge and Furrow System on Maize Yield in Shaanxi Province by Use of DNDC Model

利用DNDC模型分析沟垄集雨种植模式下农田水分和玉米产量的时空变化特征,为确定沟垄集雨种植技术的适宜区域以及该技术在陕西省农业生产中的进一步应用推广提供科学依据。利用陕西省2001-2010年19个气象站点观测资料,采用DNDC模型模拟沟垄集雨(PF)和传统平作(CK)种植下陕西省玉米田土壤水分和玉米产量。2001-2010年陕西省年均降雨量为609.2mm,且南至北呈现出逐渐递减的趋势,陕西南部地区的降雨量最高,其次是关中地区,陕西北部地区的降雨量最低。沟垄集雨种植模式下,土壤蒸发量从北至南呈现逐渐增加的趋势,土壤蒸发量在170mm以下的地区分布在陕西省北部,土壤蒸发量在190mm以上的地区分布在陕西南部。和平作种植模式相比,沟垄集雨种植模式下,陕西北部富县、黄陵、洛川、黄龙和宜川5个县土壤储水量提高到145mm以上,陕西中部宝鸡、凤翔、岐山、扶风4个县(市)土壤储水量提高到126mm以上,陕西北部6个县和中部14个县玉米生长水分胁迫减弱;与平作相比,沟垄集雨模式下,陕西省大部分区域产量变异数降低,说明沟垄集雨技术能降低年际间降雨量变化对产量的影响,具有较强的稳产效应。沟垄集雨和平作种植模式下陕西10a玉米总产量分别为1 320万t和1 140万t,沟垄集雨较平作模式增产180万t,提高16%。沟垄集雨种植玉米的增产效应从北至南呈现出逐渐降低的趋势,与年均降雨量的空间分布规律相反,陕西北部年均降雨量低于500mm的地区增产效果最高,陕西南部年均降雨量高于800mm的地区,沟垄集雨种植模式对产量的提高具有负效应。

The spatial-temporal characteristics of soil moisture and maize yield under plastic-covered ridge and furrow systemby use of DNDC model were studied in this paper, the purpose is to determin the suitable area for rainfall harvesting technology by plastic covered ridge and furrow system and provide a scientific basis its wide application in Shaanxi province. In this study, the observation data of 19 meteorological stations in Shaanxi province from 2001--2010 were used. Soil moisture and maize yield in Shaanxi province by plastic-covered ridge and furrow and conventional flat planting were assessed by DNDC model. The mean amount of rainfall was 609.2 mm from 2001 and 2010, which gradually increased from north to south in Shaanxi province. The southwest area of Shaanxi province had the most amount of rainfall, followed by Guanzhong area, and the north of Shaanxi province had the least amount of rainfall. Under the ridge and furrow planting by rainfall harvesting system, the soil evapo- ration showed a trend of graduate increase from north to south in Shaanxi province, the ｜ocationsless than 170 mm of annual soil evaporation distributed in the north of Shaanxi province, and the locations more than 190 mm of annual soil evaporation distributed in the south of Shaanxi province. Compared with flat planting, soil water storage with plastic-covered ridge and furrow planting in 5 counties of Fuxian, Huangling, Luochuan, Huanglong and Yichuan in northern Shaanxi increased by more than 145 mm; soil water storage in Baoji, Fengxiang, Qishan, and Fufeng 4 in central Shaanxi increased by more than 126 mm. Soil moisture stress of 10 a in 6 areas in north of Shaanxi and 14 areas in central of Shaanxi were decreased, The results showed that the effect of annual precipitation change on yield re- duced under plastic covered ridge and furrow planting, plastic covered ridge and furrow planting pres- ented a better effect on stabling yield. The 10 a maize yield of plastic covered ridge and furrow and flat planting in Shaanxi province were 13.2 million t and 11.4 million tons, respectively. Compared with flat planting, with plastic-covered ridge and furrow planting, maize yield increased 1.8 million tons, which increased by 16%. The increased yield effect with plastic-covered ridge and furrow planting presented a trend of gradual decrease from north to south, comparing with the spatial distribution of the average of annual rainfall, yield-increasing effect was most significant in the areas with the average annual rainfall less than 500 mm, the areas with more than 800 mm of the average annual rainfall, ridge and furrow planting for rainfall harvesting system had a negative effect on yield-increasing.