在大田试验条件下，研究了水稻机械收割不同留茬高度（15、30、40 cm，分别表示低茬、中茬、高茬）对轮作紫云英生长、养分积累以及翻压还田后土壤养分、化学性状和微生物等的影响。结果表明：稻茬高度显著影响轮作紫云英生长、养分积累以及翻压还田效果。紫云英单位面积株数随留茬高度的降低而显著减少；除单株分枝数外，植株株高、茎粗、单株鲜、干重均表现为高茬处理>中茬处理>低茬处理，高、低茬处理间差异显著或极显著。产草量受稻茬高度影响明显，单位面积鲜、干草产量均随稻茬高度的降低而显著减少，高茬处理的紫云英鲜、干草产量均最高，分别达到19.22 t/hm2和3.27 t/hm2，较低茬处理每公顷增加15.21 t和2.53 t。不同稻茬高度处理的紫云英植株碳及氮、磷、钾含量无显著差异，植株养分积累量则随稻茬高度增加而显著增加，各养分积累量变化趋势一致；不同处理紫云英翻压还田后土壤pH变化差异不显著，但均较试验前略有上升；土壤电导率则表现为高茬处理大于中、低茬处理，处理间差异极显著；翻压后土壤养分变化差异较大，各养分含量均表现为随水稻留茬高度降低而减少的趋势，高茬处理土壤的有机质、全氮、碱解氮、有效磷、速效钾含量分别较低茬处理增加41.51%、27.35%、34.96%、68.78%、82.12%。不同处理紫云英翻压还田后，土壤可培养微生物数量存在差异。三大类微生物细菌、真菌、放线菌的数量均以高茬处理最高，除放线菌外，差异均达显著水平，其中，对细菌数量的影响最为明显，高茬处理极显著大于中、低茬处理，中、低茬处理间差异显著。综上，水稻留高茬（茬高40 cm）轮作紫云英可获得较高的生物量和养分积累，翻压还田后土壤培肥效果显著优于中、低茬（茬高≤30 cm）收割的处理。
A field experiment was conducted to study the effects of different rice stubble heights (15 cm, 30 cm and 40 cm, marked as low, middle and high stubble respectively) on the growth, nutrient accumulation of astragalus sinicus L. (Chinese milk vetch) and soil nutrients, chemical properties and microbes after milk vetch returned to the field. The results showed that rice stubble height significantly affected the growth, nutrient accumulation and soil fertilizing effects of milk vetch. The number of milk vetch per unit area decreased significantly with the decrease of stubble height. Plant height, stem diameter, fresh and dry weight of milk vetch per plant were in the order of high stubble > middle stubble > low stubble, except the number of branches per plant, and the difference was significant or extremely significant between high and low stubble. Grass yield of milk vetch was significantly affected by stubble height, and the fresh and hay yields of milk vetch per unit area decreased significantly with the decrease of stubble height. The fresh and hay yields of milk vetch under high stubble were the highest, reaching 19.22 t/hm2and 3.27 t/hm2, and increased by 15.21 t/hm2 and 2.53 t/hm2 compared with low stubble. There was no significant difference in the contents of carbon, nitrogen, phosphorus and potassium of milk vetch between different stubble heights, but the plant nutrient accumulation increased significantly with the increase of rice stubble height, and the accumulation trend was consistent for all nutrients. There was no significant difference in soil pH after milk vetch returned to field under different stubble heights, but it was slightly higher than that before the test. Soil conductivity was higher in high stubble than in middle and low stubble, and the differences between different stubble heights were all extremely significant. There were great differences in soil nutrients after milk vetch returned to field, and showed decreasing trend with the decrease of stubble height. The contents of organic matter, total nitrogen, alkali-hydrolyzable nitrogen, available phosphorus and potassium under high stubble increased by 41.51%, 27.35%, 34.96%, 68.78% and 82.12% respectively compared with those in low stubble. There were differences in culturable microbe population after milk vetch returned to field under different stubble heights. The numbers of bacteria, fungi and actinomycetes were the highest under high stubble, and the differences were significant except actinomycetes. Among them, the number of bacteria was most affected. The number of bacteria under high stubble was significantly larger than middle and low stubble, and the difference was significant between middle and low stubble. To sum up, rice high stubble (40 cm) could promote more the biomass, nutrient accumulation and soil fertilizing effect of milk vetch than those of medium and low stubble (≤ 30cm).
周影,王琳,魏启舜,郭成宝,殷宏宝,周学珍.稻茬高度影响轮作紫云英生长及还田效应[J].土壤,2021,53(5):977-982. ZHOU Ying, WANG Lin, WEI Qishun, GUO Chengbao, YIN Hongbao, ZHOU Xuezhen. Rice Stubble Height Affects Growth and Returning Effect of Chinese Milk Vetch (Astragalussinicus L.) Rotated with Rice[J]. Soils,2021,53(5):977-982复制