造墒与播后镇压对小麦冬前耗水和生长发育的影响
Effects of pre-sowing irrigation and post-sowing soil compaction on water use and growth of winter wheat
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摘要: 为明确造墒和播后镇压对小麦冬前耗水和群体与个体特征及产量的影响, 为确定播后镇压技术和提高小麦水分利用效率提供依据, 分别于2013—2014年和2014—2015年小麦生长季在河北省衡水市选用当地小麦品种‘衡4399’, 分9月15日(I9.15)、9月20日(I9.20)、9月25日(I9.25)和9月30日(I9.30)4期造墒, 以不造墒为对照(CK), 每期处理又设每延米0 kg(G0)、95 kg(G95)和120 kg(G120) 3个水平镇压的冬小麦田间试验。冬前对土壤水分和小麦幼苗生长情况进行动态监测, 翌年成熟期考察产量性状并测产。结果表明, 播种时土壤水分含量高, 冬前阶段农田蒸散量也高。同一造墒不同镇压处理比较, I9.30处理以G95田间蒸散量最低, 其他处理均以G120蒸散量最低, 处理间差异显著。对苗情的影响, 同一造墒不同镇压比较, 苗期单株生物量、叶面积、群体总茎数以G120与G95处理较高, 以G0处理较低, 处理间显著水平不同; 同一镇压不同造墒处理间比较, 不造墒的CK总茎数显著减少, 产量显著较低, 且年际变化不稳定。造墒与镇压对穗数影响较大, 其中造墒处理穗数显著高于CK, 镇压处理对穗数的影响表现一致: G120>G95>G0。以上处理对产量与对穗数的影响一致: 造墒处理间产量差异水平不同, 但以CK最低; 镇压处理间产量差异不显著, 但以G0最低。造墒和镇压对产量的交互作用不显著。综上可见, 墒情适宜是小麦播后镇压的基础, 镇压又是提墒壮苗的保障。河北地区小麦造墒水提前到9月20—25日, 播种后采用95 kgm1镇压器便于田间操作且镇压效果较好。Abstract: In order to clarify the effect of pre-sowing irrigation and post-sowing soil compaction on water use, growth and yield of winter wheat, a field experiment was conducted in Hengshui City in 2013–2014 and 2014–2015. The experiment included 4 treatments of pre-sowing irrigation of winter wheat — irrigation dates of Sep. 15 (I9.15), Sep. 20 (I9.20), Sep. 25 (I9.25) and Sep. 30 (I9.30) and no irrigation as control (CK) treatment. Each treatment consisted of 3 levels of soil compaction intensity after sowing per meter— 120 kg (G120), 95 kg (G95) and 0 kg (G0). The ‘Heng 4399’ winter wheat variety was used in the field experiment and the soil moisture content, growth and grain yield monitored during the wheat growth period. The results of the study showed that evapotranspiration of wheat before winter wheat overwinter time was positively associated with soil moisture at sowing time. There were significant differences in evapotranspiration among different soil compaction treatments under the same irrigation date. Comparison among different irrigation dates showed that early irrigation lowered soil moisture and evapotranspiration at wheat sowing stage, which was the reverse for late irrigation treatments. The minimum evapotranspiration was observed in G95 treatment under I9.30 irrigation date, while it was observed in G120 treatment under others irrigation dates. For different soil compaction treatments under the same irrigation date treatment, the order of the number of spikes was G120 > G95 > G0. Biomass accumulation, leaf area, stem number and grain yield were lowest in G0 treatment, while were higher under both G120 and G95 conditions. Stem number, spikes number and grain yield were lowest in CK treatment. Although irrigation time significantly influenced spike number, no significant interaction was noted between soil compaction and pre-sowing irrigation. The results demonstrated that the most suitable soil moisture for seed germination depended on the degree of soil compaction. Thus it was possible to use soil compaction to regulate soil moisture and invigorate seedling. The study suggested that the best period for early irrigation was from Sep. 20th to Sep. 25th. The most appropriate weight of roller was about 95 kg per meter.