补灌量和覆盖量耦合变化下旱地春小麦叶面积指数对产量的影响

目的]免耕覆盖中补灌量和秸秆覆盖量耦合变化下春小麦叶面积指数对产量有较大影响。方法]本研究以甘肃省定西市安定区1979—2019年历史气象数据为基础，运用APSIM模型对补灌量与覆盖量耦合变化时旱地春小麦的叶面积指数和产量及其构成因素进行模拟，并采用DPS软件进行分析实验，研究补灌量和覆盖量耦合下旱地春小麦叶面积指数对产量的影响机制。结果]结果表明：在试验设计范围内, 不同春小麦叶面积指数对春小麦千粒质量的影响效应在开花-灌浆期为向上的二次抛物线变化。其他时期，不同春小麦叶面积指数对春小麦产量和千粒质量的影响效应为向下的二次抛物线变化, 不同春小麦叶面积指数对春小麦籽粒数的影响效应为向上的二次抛物线变化。试验变化范围内，各个时期春小麦千粒质量均未出现阈值，分蘖—拔节期，春小麦产量未出现阈值，春小麦籽粒数出现阈值，春小麦叶面积指数为1.72时春小麦籽粒数出现最小值为8716.59/m2 。其他时期，春小麦产量和籽粒数出现阈值，在春小麦叶面积指数为0.94，2.31，1.67，1.18，1.24，0.79时春小麦产量出现最大值为3818.71kg/hm2，3827.06kg/hm2，3851.41kg/hm2，3904.35kg/hm2，3819.03kg/hm2，3853.72kg/hm2。春小麦叶面积指数为0.77，2.01，1.44，1.07，1.00，0.70时春小麦籽粒数出现最小值为9579.34/m2，8745.26/m2，9638.01/m2，9050.71/m2，8554.04/m2，9038.38/m2。春小麦叶面积指数对产量和千粒质量呈正效应，对籽粒数呈负效应。结论]合理调节春小麦叶面积指数，可以促进透光性速率的提高、光合产物的产生，对春小麦产量的提高具有积极的意义。

Effects of supplementary irrigation and Mulch on leaf area index of spring wheat in Dryland

Objective] Leaf area index (LAI) of spring wheat had a great effect on yield under the coupling change of supplemental irrigation amount and straw mulching amount in no-tillage mulching. Methods] Based on the historical meteorological data from 1979 to 2019 in Anding District, Dingxi City, Gansu Province, the APSIM model was used to simulate leaf area index (LAI), yield and its component factors of dryland spring wheat under the coupling change of supplemental irrigation amount and cover amount, and DPS software was used for analysis and experiment. To study the effect mechanism of leaf area index (LAI) on yield of dryland spring wheat under the coupling of supplemental irrigation and mulching amount. Results] The results showed that in the experimental design range, the effect of different leaf area index (LAI) on thousand grain weight of spring wheat changed in an upward quadratic parabola during the period of flowering and grain filling. In other periods, the effects of different spring wheat leaf area index on spring wheat yield and grain weight showed downward quadratic parabola changes, while the effects of different spring wheat leaf area index on spring wheat grain number showed upward quadratic parabola changes. In the experimental range, there was no threshold for thousand grain weight of spring wheat in each period, and there was no threshold for grain number of spring wheat in tiller-jointing stage. The minimum value of grain number of spring wheat was 8716.59/m2 when leaf area index of spring wheat was 1.72. When leaf area index of spring wheat was 0.94,2.31,1.67,1.18,1.24,0.79,he maximum yield of spring wheat was 3818.71kg/hm2,3827.06kg/hm2,3851.41kg/hm2.3904.35kg/hm2, 3819.03kg/hm2, 3853.72kg/hm2. When leaf area index of spring wheat was 0.77, 2.01,1.44,1.07,1.00,0.70,the minimum grain number of spring wheat was 9579.34/m2,8745.26/m2,9638.01/m2,9050.71/m2,8554.04/m2,9038.38/m2. Leaf area index of spring wheat had positive effect on yield and grain weight, but negative effect on grain number. CONCLUSION]Reasonable adjustment of leaf area index of spring wheat can promote the increase of light transmittance rate and the production of photosynthate, which has positive significance for the increase of spring wheat yield.