摘要：

为明确河套灌区麦后复种油菜绿肥适宜播种时期,分别于2019年在内蒙古自治区巴彦淖尔市杭锦后旗和2022年在鄂尔多斯市达拉特旗开展田间试验。杭锦后旗试验点从2019年7月26日-8月15日共设置5个播期,每隔5 d设置1个播期处理,分别于7月26日、7月31日、8月5日、8月10日和8月15日播种;同样达拉特旗试验点从2022年7月22日-8月11日共设置5个播期,每隔5 d设置1个播期处理,以此研究不同播期对油菜绿肥生物量、养分含量及养分积累量的影响。结果表明,两试验点虽然生物量水平和气候条件有所差异,但整体趋势均表现为随着播期的推迟而下降;与第Ⅰ期播种相比,第Ⅴ期播种油菜生物量分别下降90.3%和75.4%,两点生育期内油菜平均活动积温、有效积温和日照时数分别下降469.9 ℃、409.9 ℃和179.1 h。同时于第Ⅰ,Ⅱ,Ⅲ期播种时,与施肥投入养分量(N 27.3 kg/hm²、P₂O₅ 34.5 kg/hm²)相比,油菜翻压还田养分量均高于投入量,且碳和钾还田量至少达到1 800,200 kg/hm²。因此,综合考虑油菜绿肥生物量以及还田养分量,河套灌区小麦收获后油菜可以适时早播,充分利用光温资源,促进油菜生长和养分积累。为达到5 t/hm²以上油菜还田量及获得更高的养分还田量,油菜生育期内应至少接受活动积温1 300 ℃、有效积温1 100 ℃以及有效日照时数640 h。

关键词: 麦后复种, 油菜绿肥, 播种时期, 生物量, 养分积累量

Abstract:

In order to determine the suitable sowing date of green manure for multiple cropping rape in Hetao irrigation area,field experiments were carried out in Hangjinhou Banner,Bayannur City,Inner Mongolia Autonomous Region in 2019 and Dalad Banner,Ordos City in 2022.There were five sowing dates in Hangjinhou Banner experimental site from July 26th to August 15th,2019,and one sowing date was set every five days,which were sown on July 26th,July 31st,August 5th,August 10th and August 15th,respectively.Similarly,from July 22nd to August 11th,2022,the experimental site in Dalad Banner was set up with five sowing dates,and one sowing date was set every five days to study the effects of different sowing dates on the green manure biomass,nutrient content and nutrient accumulation of rape.The results showed that although the biomass level and climate conditions of the two experimental sites were different,the overall trend showed a decline with the delay of sowing date.Compared with the first sowing stage,the rape biomass in the fifth sowing stage decreased by 90.3% and 75.4% respectively,and the average active accumulated temperature,effective accumulated temperature and sunshine hours in the two-point growth period decreased by 469.9 ℃,409.9 ℃ and 179.1 h,respectively.At the same time,when sowing in the first,second and third stages,compared with the nutrient input (N 27.3 kg/ha,P₂O₅ 34.5 kg/ha),the nutrient input of rape was higher than the input,and the amount of carbon and potassium returned to the field was at least C1 800 kg/ha and K₂O 200 kg/ha.Therefore,considering the biomass of rape green manure and the amount of nutrients returned to the field,rape could be sown early after wheat harvest in Hetao irrigation area,making full use of light and temperature resources to promote rape growth and nutrient accumulation.In order to achieve more than 5 t/ha of rape returning to the field and obtain a higher amount of nutrients returning to the field,at least 1 300 ℃ of active accumulated temperature,1 100 ℃ of effective accumulated temperature and 640 h of effective sunshine hours should be accepted during the rape growth period.

Key words: Multiple cropping after wheat, Rape green manure, Sowing period, Biomass, Nutrient accumulation