施氮量和农艺措施对稻茬麦产量及光合特性的影响OA

To investigate the effects of nitrogen application rate and agronomic measures on the rice stubble wheat seedling growth,photosynthesis and yield in the middle and late stages,a field experiment was conducted using the wheat cultivar Yangmai 25 as the test material.A randomized complete block design was adopted,comprising 2 nitrogen application levels:N1(90 kg/hm²)and N2(150 kg/hm²),and 5 agronomic treatments:T0(control),T1(seed sunning),T2(nutrient solution seed dressing),T3(foliar fertilizer spraying),and T4(nutrient substrate covering),giving a total of 10 treatment combinations.Growth indices,photosynthetic parameters,and yield components were determined for each treatment.The results showed that,in terms of growth and development,under the same agronomic measures,the N2 treatment exhibited higher shoot fresh weight,leaf age,stem base width,root dry weight,and number of secondary roots than the N1 treatment.At the jointing stage,under the same nitrogen application rate,the fresh weight of stems and leaves,leaf age,stem base width,root dry weight,and number of adventitious roots in treatments T1-T4 were all higher than those in T0,with the overall performance following the order of T4>T3>T2>T1.Regarding photosynthesis,under the same agronomic measures,increasing the nitrogen application rate enhanced the net photosynthetic rate,transpiration rate,and stomatal conductance at the flowering and mid-grain-filling stages,while reducing intercellular CO ₂ concentration.Under the same nitrogen application rate,the T1-T4 treatments showed higher photosynthetic rates,transpiration rates,and stomatal conductance than the T0 treatment,following the order T4>T3>T2>T1,whereas intercellular CO₂ concentration was lower than that of T0,with the order T4<T3<T2<T1.In terms of yield and its components,under the same agronomic measures,the N2 treatment produced higher spike number,grain number per spike,thousand-grain weight,and grain yield than the N1 treatment.Under the same nitrogen application rate,the T1-T4 treatments all outperformed T0 in these yield parameters,with the order T4>T3>T2>T1.Overall,these findings indicated that in wheat production following rice,appropriately increasing nitrogen application rate combined with complementary agronomic measures can effectively improve seedling growth and development,enhance photosynthesis during the mid-to-late growth stages,and ultimately increase grain yield.Among the combinations,increasing nitrogen application together with foliar fertilizer spraying or nutrient substrate covering achieve relatively better promoting effects.