氮肥运筹模式对小麦茎秆抗倒性能的影响

Effects of Nitrogenous Fertilizer Application Model on Culm Lodging Resistance in Winter Wheat

以高产强筋小麦品种烟农19为试验材料,通过不同施氮水平(202.5、270.0和337.5kghm-2)和不同基追比例的施肥试验,对小麦茎秆结构和细胞壁化学成分及茎秆抗倒指数(CLRI,茎秆机械强度/茎秆重心高度)等生理生化指标进行了研究。结果表明,氮肥运筹模式显著影响小麦茎秆抗倒能力。基部节间长度和含氮量均随施氮水平和基肥比例的增加而增加,基部节间粗度、秆壁厚度、节间充实度、机械强度则表现相反。而细胞壁纤维素、木质素含量和CLRI则随施氮水平的增加呈现出先增后降的趋势,但随基肥比例的增加而下降。CLRI与基部节间粗度、壁厚、充实度及机械强度呈极显著正相关,而与基部节间长度和氮含量呈极显著负相关。CLRI可作为小麦抗茎倒伏能力的综合评价指标。

Culm lodging is a common problem in wheat （Triticum aestivum L.） production causing yield loss and quality deterioration of grain. Weak mechanical strength of the 1st and 2nd basal internodes of culm is the major reason for wheat lodging during late growth period. It is well known that the mechanical strength is closely related to cellulose and lignin contents in culm, which are easily affected by nitrogen fertilizer. Accordingly, lodging resistance can be improved through proper nitrogen application. However, few reports have been found on it so far. We attempted to set up a nitrogen application regime for increasing longing resistance in high-yielding winter wheat through measuring the structure parameters of culm, chemical components of culm cell walls, and the culm lodging resistance index （CLRI）. In the present experiment, we employed a wheat cultivar ＂Yannong 19＂ with high yield and strong-gluten content in the field with basic nutrition status in 0-20 cm soil layer as organic matter of 2.13%, total N of 1.5 g kg^-1, available N of 115.6 mg kg^-1, available P of 22.8 mg kg^-1, and available K of 142.5 mg kg^-1. N fertilizer treatments were set up by randomized block design with three application rates （202.5, 270.0, and 337.5 kg ha^-1, respectively） and three basal-topdressing ratios at pre-sowing, jointing, and booting stages （3：5：2, 5：5：0, and 7：3：0, respectively）. The planting density was 2.25×10^6 plants ha^-1. The results showed that N fertilizer application model significantly affected lodging-resistant capability. Lengths of the 1st and 2nd basal internodes and their N contents increased with the increase of nitrogen levels, especially the basal nitrogen proportion. The cell wall cellulose and lignin contents, and culm lodging resistance index showed the trend of low-high-low in the 3 N levels, but kept decreasing when more basal nitrogen was applied. CLRI was positively correlated with the diameter of basal internodes （r = 0.9254^＊＊）, thickness of culm wall （r = 0.9087^＊＊）, filling degree （r = 0.9218^＊＊） and mechanical strength （r=0.9662^＊＊） of culm, but negatively correlated with the length （r = -0.8421^＊＊） and the nitrogen content （r = -0.8658^＊＊）. The study also indicated the potential of CLRI for wheat lodging evaluation.