播期、播量对旱作小麦‘小偃60’生长发育、产量及水分利用的影响

Effects of sowing date and seeding density on growth, yield and water use efficiency of ‘Xiaoyan 60’ wheat under rainfed condition

  • 摘要: 在旱作条件下, 探讨播期及播量对小麦新品系‘小偃60’群体性状、产量及水分利用的影响, 可为小麦适雨栽培提供技术依据。试验于2014—2015年在中国科学院南皮生态农业试验站进行, 自10月15日至11月14日, 每6 d设置一个播期, 共设6个播期(T1~T6), 设播量不变(B1)和逐期增加播量(B2)两个处理: B1为300 kg·hm-2, T1到T6播量相同; B2为随播期推迟播量逐期增加, 每推迟1 d增加7.5 kghm-2, 各播期的播量分别为300 kg·hm-2 (T1)、345 kg·hm-2 (T2)、390 kg·hm-2 (T3)、435 kg·hm-2 (T4)、480 kg·hm-2 (T5)和525 kg·hm-2 (T6), 研究了不同播期和播量下‘小偃60’群体性状、产量及水分利用的变化规律。试验结果表明: 1)随播期推迟, 出苗时间延长、生育期推迟, 全生育缩短; 播量对生育期无显著影响。2)随播期推迟, 出苗率和单株成穗数逐渐降低; 播量增加, 基本苗及穗数提高。3)随播期推迟, 株高和生物量降低; 播量增加, 生物量提高, 株高无显著变化。4)随播期推迟, 籽粒产量下降; 逐期增加播量后, 11月2日前籽粒产量可达6 600 kghm2以上且无显著差异。5)若随播期推迟增加播量, 前4个播期产量、水分利用效率无显著变化, 皆达29 kghm2mm1以上。研究结果表明, ‘小偃60’是一个播期宽泛的品种, 随播期推迟产量下降, 但在一定播期范围内通过增加播量, 提高群体(穗数), 可以获得与适时播种相近的产量, 播量与播期推迟天数的理论关系为y=0.368 2x2+ 1.193 9x+316.7 (R2=0.983 9)。

     

    Abstract: Using drought resistant and high-yielding crop varieties is critical for high and stable crop productivity under rainfed farming condition. In this study, an experiment was conducted at Nanpi Eco-Agricultural Experimental Station of Chinese Academy of Sciences (116°40′E, 38°00′N) in 2014–2015 to investigate the performance of ‘Xiaoyan 60’ wheat cultivar under the rainfed condition. The objective of the study was to test the adaptability of ‘Xiaoyan 60’ wheat cultivar to late sowing and yield loss compensation by increased seeding rate. Treatments included two factors, sowing date and seeding density. Six sowing dates were set, which were from the 15th of October to the 14th of November with six days interval, and denoted as T1, T2, T3, T4, T5 and T6, respectively. Then there were two treatments of seeding densities — constant seeding rate (B1) and increased seeding rates with delayed sowing date (B2). In B1, sowing density was 300 kg·hm-2 for all sowing dates, whereas in B2, it started at 300 kg·hm-2 and progressively increased at 7.5 kg·hm-2·day1 with delayed sowing date. Thus the sowing densities at sowing dates in B2 treatments were 300 kg·hm-2 for T1, 345 kg·hm-2 for T2, 390 kg·hm-2 for T3, 435 kg·hm-2 for T4, 480 kg·hm-2 for T5 and 525 kg·hm-2 for T6. The population properties, growth, yield and water use characteristics were investigated under different treatments. The results showed that the plant population traits, yield and water use efficiency varied with sowing date and seeding density. The growth period shortened with delayed sowing date, the duration for all the growth stages was also shortened. In contrast, seeding rate had no effect on growth period, but positively influenced the number of seedlings, number of spikes and dry biomass amount. Also plant height was not affected by seeding density. Delayed sowing gradually decreased the rate of seedling emergence, number of spikes per plant, plant height and dry biomass. Similarly, grain yield decreased with delayed sowing. However, the grain yield reached 6 600 kg·hm-2 level through increase seeding density to compensate for delayed sowing. There was no significant difference among the first four sowing dates (from T1 to T4) for grain-yield-based water use efficiency, which was above 29 kg·hm-2·mm-1. Because ‘Xiaoyan 60’ wheat cultivar was strongly adaptable to late sowing, it was recommended for cultivation under the rainfed farming conditions. Yield loss due to delayed sowing was compensated for by increasing seeding rate, which ensured optimum plant population. The correlation between seeding density (y) and delayed days (x) of sowing could be decribed by the regression equation y = 0.368 2x2 + 1.193 9x+316.7 (R2 = 0.98).

     

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