坡地打结沟垄集雨种植的系统效率和关键技术研究

Drought and soil erosion are main factors which limited agricultural production in semi-arid Loess Hilly areas. Many researches have done on rainwater harvesting with ridges and furrows on flat fields, but not on slope fields, especial on rainwater harvesting with ridges, furrows and tied-ridges. Runoff efficiency of standard ridges (ridges width was 40-45cm without planting in furrows) was found after observing precipitation and runoff with the same receive areas at the same time. Runoff storage efficiency, overall efficiency, soil water, soil nutrition, crop yields, water use efficiency and economic benefits were studied to determine the optimum tied-ridge distances and the optimum arrangements, under different of slops (5 o, 10 oand 15 o), tied-ridge distances (2, 4 and 6 m) and arrangements (staggered tied-ridges and non-staggered tied-ridges) in rainwater harvesting planting with ridges, furrows and tied-ridges. Runoff amount of furrows in rainwater harvesting with standard ridges and furrows (widths of ridge and furrow were 40-45cm and 60 cm, respectively, with potato or maize planting in furrows) was found after observing precipitation and runoff with the same receive areas at the same time. Then soil water infiltration was calculated to determine the the optimum height of tied-ridge according to precipitation, water balance equation and dam broken effects. Key technologies of rainwater harvesting with ridges, furrows and tied-ridges were studied in different precipitation regions in semi-arid areas combining experiments of runoff efficiency observation and crops planting with experiments of soil water infiltration observation.

干旱和水土流失限制半干旱黄土丘陵区农业生产。国内外研究者主要从事平地传统沟垄集雨种植技术研究，对坡地打结沟垄集雨种植技术研究较少。本项目观测坡地标准集雨垄 (垄宽40-45cm，沟内不种植作物) 的径流，揭示坡地标准集雨垄的径流效率；以传统沟垄集雨种植为对照，研究不同坡度（5 o、10 o和15 o)、打结距离（2、4和6 m)和排列方式（交错排列和非交错排列)打结沟垄集雨种植的径流贮存效率、系统效率、土壤水分和养分、产量、水分利用效率和经济效益等，明确坡地打结沟垄集雨种植的适宜打结距离和适宜排列方式；观测不同坡度传统标准沟垄集雨种植(沟宽60cm，垄宽40-45cm，沟内种植作物)沟中径流，计算沟中入渗，依降雨量、水分平衡方程和溃坝效应，计算坡地打结沟垄集雨种植的适宜打结垄高度。结合径流、大田种植、大田入渗等试验与气象数据，研究我国半干旱区不同降雨区间坡地打结沟垄集雨种植的关键技术。

干旱和水土流失是制约半干旱黄土高原丘陵区粮食安全生产和经济发展的主要因素，坡耕地是该区域径流和泥沙流失产生的主要策源地。为寻求半干旱区控制水土流失和提高降水资源利用率的最佳坡地垄沟集雨种植方式，在定西市安家沟流域基地布置大田试验。(1) 采用完全随机设计，研究不同坡度 (0°、5°和10°) 标准集雨垄的径流效率和临界产流降雨量；(2) 采用完全随机区组设计，以传统耕作为对照，在坡度5°和10°研究打结方式 (无打结垄和打结垄) 对径流贮存效率、系统效率、小区径流效率、泥沙流失、土壤养分流失、土壤贮水量、紫花苜蓿干草产量、水分利用效率 (WUE) 和营养品质的影响。连续4a (2015-2018) 主要结果如下：.通过回归分析法，坡度0°、5°和10°标准集雨垄的临界产流降雨量分别为0.46、0.71和0.22 mm，径流效率分别为83.5%、97.6%和96.4%。 .坡度5°时，平作、无打结垄和打结垄的平均径流贮存效率分别为88%、91%和93%，系统效率分别为0%、79%和82%；坡度10°时，平作、无打结垄和打结垄的平均径流贮存效率分别为85%、89%和91%，系统效率分别为0%、85%和88%。坡度5°的径流贮存效率 (91%) 略高于坡度10° (88%)，坡度5°的系统效率 (54%) 略小于坡度10° (58%)。.与平作相比，坡度5°时，无打结垄和打结垄的小区径流效率分别降低34.9%和52.1%，泥沙流失量分别降低91.2%和94.5%；坡度10°时，无打结垄和打结垄的小区径流效率分别降低40.1%和53.8%，泥沙流失量分别降低88.4%和93.6。坡度10°的小区径流效率和泥沙流失量分别是坡度5°的1.3和2.1倍。.与平作相比，坡度5°时，无打结垄和打结垄的紫花苜蓿干草产量分别提高41.4%和17.7%，WUE分别提高8.41和5.88 kg hm-2 mm-1，坡度10°时，无打结垄和打结垄的紫花苜蓿干草产量分别提高37.5%和16.0%，WUE分别提高6.24和4.34 kg hm-2 mm-1。坡度5°紫花苜蓿干草产量和WUE与坡度10°差异不显著。.在我国半干旱黄土高原丘陵区垄沟集雨种植系统中，无打结垄和打结垄集雨种植具有较好水土保持和增产效果，其中无打结垄增产效果最为明显，打结垄水土保持效果最为明显。