推迟灌拔节水条件下种植模式对冬小麦抗倒伏特性和产量的影响

华北平原冬小麦在粮食生产中占据重要地位,受到灌溉用水短缺影响以及生育后期易倒伏减产的制约,冬小麦供需矛盾日益突出。该研究探究了推迟灌拔节水条件下不同种植模式对冬小麦抗倒伏特性的影响,设置宽幅精播(W)与常规种植(C)2种种植模式,每种种植模式设置灌拔节水60 mm(I1)和推迟10 d灌拔节水60 mm(I2)2种灌溉处理,研究冬小麦关键生育期茎秆物理指标,倒数第2节间茎杆力学、抗倒伏指数、蠕变变形量、产量及其组成等指标,探究冬小麦抗倒伏特性综合调优的种植模式和灌溉制度。结果表明,宽幅精播模式下推迟灌拔节水对抽穗期倒数第2节间茎杆抗折力有显著提升的趋势,显著提高了抗弯刚度,显著降低了蜡熟期倒数第2节间茎杆抗折力和抗弯刚度,以及植株蜡熟期鲜质量;宽幅精播模式下推迟灌拔节水显著提高了抽穗期抗倒伏指数,并提升了灌浆期抗倒伏指数,该处理在抽穗期、灌浆期和蜡熟期的抗倒伏指数平均值分别为2.03、1.58和1.87 N/(m·g)。冬小麦倒数第2节间茎杆在施加小于其极限抗折力的不同比例荷载时具有蠕变特性,宽幅精播模式下推迟灌拔节水茎杆蠕变极值平均值在抽穗期最大,灌浆期表现仍然较好,均由减速蠕变过渡到稳定蠕变阶段,蠕变极值范围介于0.6%～3.7%,蠕变极值平均值介于0.7%～2.5%。综合考虑抗倒伏指数和蠕变试验结果,冬小麦在宽幅精播模式下结合推迟10 d灌拔节水处理的抗倒伏特性最优。研究结果可为华北平原冬小麦节水高产提供理论依据和技术支持。

Effects of planting patterns on the lodging resistance characteristics and yield of winter wheat with delaying irrigation at the jointing stage

Winter wheat is the primary cropping system in grain production in the North China Plain. In this study, two planting patterns were applied, including the precision planting pattern (W) and conventional cultivation planting pattern (C), in order to clarify the effect of different planting pattern on lodging resistance of winter wheat with delaying irrigation at the jointing stage. In each planting pattern, the winter wheat was irrigated with 60 mm at the jointing stage (I1), and delaying irrigation 60 mm for 10 d at the jointing stage (I2). The main physical indexes of winter wheat stalk were measured, including the plant height, gravity center height, and fresh weight, as well as the diameter, fresh density, and the wall thickness of the basic secondary internode. A systematic investigation was made on the internode mechanical indexes, such as the bending resistance and bending rigidity of basic secondary internode, lodging resistance index, the creep deformation in the basic secondary internode of winter wheat at heading, filling and dough growth stage. The planting pattern and irrigation schedule were explored for comprehensive optimization on the lodging resistance of winter wheat. The results showed that there was a significant trend to improve the bending resistance strength in the basic secondary internode, and the bending rigidity significantly increased at the heading stage under the wide precision planting pattern with delaying irrigation at the jointing stage. However, the bending resistance strength and bending rigidity in the basic secondary internode, and the fresh weight were significantly reduced at the dough stage in this treatment. The wide precision planting pattern with delaying irrigation at the jointing stage significantly increased the lodging resistance index at the heading stage, and thereby improved the lodging resistance index at the dough stage, where the average lodging resistance index at the heading, filling, and waxing stage were 2.03, 1.58 and 1.87 N/(m·g), respectively. The basic secondary internode of winter wheat had creep characteristics under the proportional load less than its ultimate bending resistance strength. Specifically, the average maximum of creep strain was the highest at the heading stage, and it was still large at the filling stage under the wide precision planting pattern with delaying irrigation at the jointing stage. All of mechanical behavior was in the transition from the deceleration to stable creep stage, where the maximum creep strain ranged from 0.6%-3.7%, and the average maximum of creep strain ranged from 0.7%-2.5%. Combined with the lodging resistance index and creep test, the lodging resistance of winter wheat was the best under the condition of wide precision planting pattern with delaying irrigation for 10 d at the jointing stage. The findings can provide a promising theoretical basis and technical support for water saving and high yield of winter wheat in North China Plain.