长期保护性耕作对冬小麦氮素积累和转运的影响

摘要

基于长期定位耕作试验(2006-2016年),探讨长期传统翻耕、免耕和深松耕作对冬小麦关键生育期0～100 cm土层土壤含水率的影响,分析长期免耕和深松耕作下冬小麦植株氮素积累和转运的特性.试验结果表明:长期免耕和深松耕作较传统翻耕均不同程度提高了0～100 cm土层土壤含水率,但在较干旱年份,不同生育期免耕蓄水保墒效果优于深松耕作.从冬小麦扬花期到成熟期,无论何种耕作方式氮素在茎和叶中的分配比例逐渐减小,在穗中的分配比例逐渐增大.扬花期,与传统翻耕相比,连续2a免耕分别提高茎、叶和穗的平均氮素积累量44.3％、80.5％和70.9％,而连续2a深松耕作未呈现显著变化;成熟期,连续2 a免耕和深松耕作较传统翻耕均显著降低了茎的平均氮素积累量,增加了籽粒的平均氮素积累量(P＜0.05),且免耕优于深松耕作.此外,与传统耕作相比,免耕显著提高冬小麦植株营养器官氮素转运量、转移率和营养器官对籽粒的贡献率(P＜0.05),而深松耕作仅在较干旱年份未明显提高冬小麦植株营养器官转运量和对籽粒的贡献率.综上,长期深松耕作并不能持续促进冬小麦植株氮素积累与转运,对于干旱少雨年份免耕优于深松耕作.%To study the effects of long-term conservation tillage (no-tillage and subsoiling) on nitrogen accumulation and translocation characteristics of winter wheat,a ten-year (2006-2016) field experiment was carried out,and the effects of different tillage treatments,including traditional tillage,no-tillage and subsoiling on the soil water content in 0 ～ 100 cm during the key winter wheat growth stages were analysed.The results showed that long-term no-tillage and subsoiling treatments significantly increased the soil water content in 0 ～ 100 cm and no-tillage treatment was superior to subsoiling treatment in the dry year.The nitrogen distribution ratio in stem and leaf was gradually decreased,while it was gradually increased in wheat are from flowering to harvesting stage under three tillage treatments.Compared with conventional tillage treatment,average nitrogen accumulation amounts in stem,leaf and ear under 2-year continuous no-tillage treatment were increased by 44.3％,80.5％ and 70.9％,respectively,and there was no significant increase under 2-year continuous subsoiling treatment at flowering stage.At harvesting stage,no-tillage and subsoiling treatments significantly decreased the nitrogen accumulation in stem,while significantly increased its ear accumulation amount compared with conventional tillage treatment.Moreover,no-tillage treatment significantly increased the nitrogen translocation amount of winter wheat vegetative organs,translocation ratio,contribution ratio to grain (P ＜ 0.05),while subsoiling treatment was non-sustainable to increase nitrogen translocation amount and ratio.In general,long-term effect of no-tillage treatment on nitrogen translocation of winter wheat was superior to that of subsoiling treatment,especially in the dry year.