长期留茬免耕对河西绿洲灌区春小麦产量及稳定性的影响

    Effects of long-term no-tillage with crop stubbles on yield and stability of spring wheat in Hexi Oasis Irrigated Areas

    • 摘要: 为探寻河西绿洲灌区春小麦高效可持续生产耕作措施,基于2004年设置的长期留茬免耕田间定位试验,针对单作小麦、春小麦/玉米、春小麦/大豆3种典型春小麦种植方式,在长期留茬免耕和传统翻耕条件下,通过分析2004-2018年小麦产量、产量构成要素及农艺性状的演变特征来诠释长期留茬免耕对春小麦产量的影响,同时分析评价产量的稳定性和可持续性,旨在为区域内春小麦的高效可持续生产提供理论依据。结果表明,单作小麦、春小麦/玉米和春小麦/大豆3种种植方式下的春小麦籽粒产量在年际间变动较大,呈锯齿状波动。与传统翻耕处理相比,留茬免耕的增产效应随种植年限的延长而不断增强,长期留茬免耕可以提高春小麦产量的稳定性和可持续性,而且间作相比单作可以更好地维持产量的可持续稳定生产能力。产量构成要素之间的叠加效应可以显著提高小麦籽粒产量,其中,2004-2012年留茬免耕主要通过显著提高穗粒数来增加小麦产量;2013-2018年,单作小麦和春小麦/大豆时,留茬免耕主要通过显著提高千粒质量来增加小麦产量,春小麦/玉米时,留茬免耕主要通过显著增加穗长来促进小麦生长,进而显著提高小麦产量。气温、降雨量和穗粒数在春小麦产量中起主要作用,收获指数和气温在春小麦产量稳定性中起主要作用,穗长和产量在春小麦产量可持续性中起主要作用。综上,留茬免耕是河西绿洲灌区单作小麦、春小麦/玉米和春小麦/大豆3种春小麦种植方式下切实可行的耕作措施。

       

      Abstract: This study aims to explore the tillage practices for the efficient and sustainable production of spring wheat in Hexi Oasis Irrigated Areas. A long-term no-tillage with stubble field experiment was conducted in the Wuwei area (38°07′N, 102°59′E), Gansu Province in China from 2004 to 2018. A split block design was also arranged in the experiment. The treatments included two tillage practices with No-Tillage with Stubble (NTS) and Traditional ploughed fallow (TS), where the subplots were three planting patterns with the Single Wheat (W), the Intercropping of Wheat and Maize (W/M), and the Intercropping of Wheat and Soybean (W/S). There were a total of six treatments each with three replicates. A systematic investigation was made to clarify the effects of long-term no-tillage with the crop stubbles on the spring wheat yield, in terms of the spring wheat yield, yield components, and evolution of agronomic characters. The stability and sustainability of crop yield were also analyzed under the different planting patterns of spring wheat. The research period was divided into 2004-2012 and 2013-2018. The varieties of planting crops were changed uniformly in 2013, according to the crop yields. The results showed that there was a zigzag annual fluctuation in the grain yield of spring wheat, indicating the overall upward trend under the three spring wheat planting patterns of W, W/M, and W/S. The varieties of spring wheat posed no influence over the yield increase of no-tillage with the stubble before and after the year 2012, compared with the traditional ploughed fallow treatment. The average grain yield increased significantly, as the grain number per spike increased from 2004 to 2012, particularly with the extension of planting years. Specifically, the spring wheat variety of "Yongliang 4" significantly increased by 8.25% (W), 5.65% (W/M), and 4.30% (W/S) (P<0.05), respectively, under the tillage practices of no-tillage with stubble. Furthermore, the average grain yield increased by 10.47% (W) and 10.20% (W/M) (P<0.05), respectively, for the spring wheat variety of "Longchun 26" under the planting patterns of no-tillage with stubble, as the 1 000-grain weight of spring wheat increased from 2013 to 2018. It infers that the spring wheat growth was promoted by the higher spike length suitable for the higher spring wheat yield under the W/M planting patterns in the no-tillage with stubble. There was also no significant effect of the long-term no-tillage with the stubble on the spike number and harvest index of spring wheat under the planting patterns (P>0.05). More importantly, there was no full consistence with the yield of spring wheat in the yield components. The reason was that the yield of spring wheat significantly increased by the superposition among the yield components under the tillage practices of long-term no-tillage with stubble. Meanwhile, the long-term no-tillage with stubble reduced the inter-annual fluctuation of spring wheat yield, further improving the stability and sustainability of spring wheat yield. Particularly, the intercropping greatly contributed to the more sustainable and stable yield production capacity, compared with the monoculture. Path analysis showed that the mean daily temperature, precipitation, and grain number per spike played important roles in the spring wheat yield. By contrast, the stability of spring wheat yield depended mainly on the harvest index and the mean daily temperature. Additionally, the spike length and yield determined the yield sustainability of spring wheat. Therefore, the no-tillage with stubble was the feasible tillage practice under the spring wheat planting patterns of W, W/M, and W/S in the Hexi Oasis Irrigated Areas with the extremely serious degradation of wind erosion.

       

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