播后镇压和冬前灌溉对土壤条件和冬小麦生育特性的影响

为揭示冬灌和镇压的作用,以冬小麦品种石新828和石麦12号为材料,研究了冬灌和镇压措施对麦田土壤水热条件和冬小麦生育特性的影响。结果表明,与不冬灌相比,冬灌条件下,冬季和春季土壤含水量提高,土壤温度较稳定。与不镇压相比,镇压处理的冬前和起身期土壤含水量及冬前夜间土壤温度提高。冬灌处理冬小麦在越冬后各时期的总茎数、LAI、干物质积累量有所降低,开花期叶片光合速率显著下降,灌浆后期叶片SPAD值下降也较快,每穗总小穗数、结实小穗数、穗粒数和产量均减少。镇压使小麦开花前干物质积累量减少,但对成熟期干物质积累量影响不显著,因为开花后光合速率提高,叶片SPAD值下降较缓慢,开花后干物质积累较多。镇压处理成熟期的单位面积穗数降低,但由于穗粒数和千粒重提高,镇压与不镇压的产量差异不显著。从本研究结果看,冬灌是一项防冻保苗的有效措施,与播后镇压配合可减缓冬季低温和温度剧烈变化对小麦的不利影响。

Effects of Post sowing Soil Compaction and Pre winter Irrigation on Soil Conditions and Growth and Development of Winter Wheat

In order to clarify the effects of post sowing soil compaction and pre winter irrigation on soil conditions and growth and development of winter wheat, a field experiment was carried out during 2012-2013 growing year at Gaobeidian, Hebei province, using two wheat cultivars, Shimai 12 and Shixin 828. The experiments for the two cultivars were designed as split plot arrangement, with irrigation as main plots (with and without pre winter irrigation, respectively), and soil compaction as split plots (with and without soil compaction after sowing, respectively). The data from the two cultivars had similar tendency, so that the averages of the two cultivars were used in the paper. The results showed that, the soil water contents during winter and spring were higher, and the soil temperature was more stable under the treatment with pre winter irrigation than that without pre winter irrigation. Compared with no soil compaction, the soil water contents during pre winter period and at double ridge stage increased, and the pre winter soil temperature was higher at night. The number of culms, LAI, dry matter accumulation amounts at all the growth stages was lower, and the photosynthetic rate of leaves at anthesis and chlorophyll SPAD at late grain filling was significant lower, the numbers of total spikelets, fertile spikelets, grains per spike and grain yield tended to decrease under the treatment with pre winter irrigation than that without pre winter irrigation. The pre anthesis dry matter accumulation of the treatment with compaction was lower. But the dry matter accumulation amounts were not significantly different between those with and without compaction at maturity, because the photosynthetic rate and chlorophyll SPAD of leaves of the treatment with compaction decreased slowly after anthesis, so that more dry matters were accumulated after anthesis. The spikes per hectare with compaction was less than that without compaction, but the grain yield difference between the treatments with compaction and without compaction was not significant, because more grains per spike and the higher 1 000 grain weight was obtained in the treatment with compaction. According to the results of the study, pre winter irrigation is an effective measure to protect wheat seedlings from freezing injury, but in terms of improving yield and water use efficiency, it is not needed under the conditions of sufficient soil moisture after sowing. Under such conditions, post sowing soil compaction should be applied to alleviate the adverse effect of low temperature and temperature fluctuation on winter wheat.