氮钾配施下施磷对冬小麦群体发育特性、冠层光截获及产量的影响

【目的】明确一定氮钾配施条件下不同施磷水平对冬小麦群体发育特性、冠层截获光合有效辐射(IPAR)及产量的影响,同时分析IPAR与LAI之间的相关性,为在一定氮钾配施下筛选出适宜的磷肥用量提供理论依据。【方法】以郑麦7698为试验材料,设低氮低钾N_1K_1(N 225 kg·hm~(-2)、K_2O 150 kg·hm~(-2))、低氮高钾N_1K2(N 225 kg·hm~(-2)、K_2O 225 kg·hm~(-2))、高氮低钾N_2K_1(N 300 kg·hm~(-2)、K_2O 150 kg·hm~(-2))、高氮高钾N_2K_2(N 300 kg·hm~(-2)、K_2O 225 kg·hm~(-2))4个氮钾配施比例,每个氮钾配施设置5个施磷水平:P0(不施磷)、P1(P_2O_5 150 kg·hm~(-2))、P_2(P_2O_5 225 kg·hm~(-2))、P~(-2)3(P_2O_5 300 kg·hm2)、P4(P_2O_5 375 kg·hm-),共20个处理。对小麦群体动态、叶面积指数(LAI)、开花后干物质积累、冠层截获光合有效辐射(IPAR)、产量等指标进行测定分析。【结果】(1)在4种氮钾配施下,施P_2O_5 0—225 kg·hm~(-2)时,随施磷量的增加,总茎蘖数、开花后干物质积累及LAI均增加,施P_2O_5超过225 kg·hm~(-2)时,各指标均有所下降,以施P_2O_5 225 kg·hm~(-2)水平群体指标最佳。(2)氮钾配施固定条件下,不同施磷水平小麦冠层截获光合有效辐射值(IPAR)的大小顺序均为P_2P1P3P4P0,且P_2水平IPAR值最高,增幅最大。不同氮钾配施下以N_1K_1条件IPAR增幅最多。(3)4种氮钾配施条件下IPAR与LAI均呈指数正相关关系,N_1K_1、N_1K2、N_2K_1、N_2K_2条件下不同施磷水平小麦IPAR与LAI的拟合系数分别为0.8492、0.8363、0.7321、0.8081。产量与LAI在二阶多项式函数关系上拟合度较好,拟合系数为0.7145。(4)从3个年度各处理产量来看,适当增施磷肥有利于提高小麦的籽粒产量,但磷肥增加到一定程度小麦产量又呈下降趋势,不同氮钾配施下N_1K_1处理产量水平最高,氮钾配施固定条件下,不同施磷水平的产量及增产率均为P_2(P_2O_5 225 kg·hm~-2))时最高。【结论】本研究条件下,N_1K_1P_2(N_225 kg·hm~(-2)、K_2O 150 kg·hm~(-2)、P_2O_5 225 kg·hm~(-2))处理可以优化小麦群体结构,提高LAI,增加开花后干物质积累,提高IPAR和籽粒产量。

Effects of Phosphorus on Winter Wheat Population Characteristics,Canopy Intercepted Photosynthetically Active Radiation and Yield Under Certain Nitrogen-Potassium Rates

【Objective】The objectives of this study were to investigate the effect of phosphate (P) fertilizer on winter wheat population development, canopy intercepted photosynthetically active radiation (IPAR) and yield under certain nitrogen and potassic (NK) fertilizer levels and to study the relationship between IPAR and leaf area index (LAI) and provide a theoretical foundation for P fertilizer application.【Method】 Zhengmai7698 was used in this study. Four NK fertilizer combinations were designed: Low nitrogen and low potassium (N₁K₁, N 225 kg·hm^-2+K₂O 150 kg·hm^-2), low nitrogen and high potassium (N₁K₂, N 225 kg·hm^-2+K₂O 225 kg·hm^-2), high nitrogen and low potassium (N₂K₁, N 300 kg·hm^-2+K₂O 150 kg·hm^-2), high nitrogen and high potassium (N₂K₂, N 300 kg·hm^-2+K₂O 225 kg·hm^-2). Five P fertilizer application levels were used under each NK fertilizer combinations: P₀ (P₂O₅ 0 kg·hm^-2), P₁ (P₂O₅ 150 kg·hm^-2), P₂ (P₂O₅ 225 kg·hm^-2), P₃ (P₂O₅ 300 kg·hm^-2) and P₄ (P₂O₅ 375 kg·hm^-2). The dynamics of wheat population, LAI, dry matter accumulation after flowering, IPAR and wheat grain yield were measured and analyzed using Data Processing System (DPS) software.【Result】(1)Under the four NK fertilizer combinations, total tillers per stem, dry matter accumulation after flowering and LAI increased with the P (P₂O₅) fertilizer rate changed from 0 kg·hm^-2 to 225 kg·hm^-2_, peaked at 225 kg·hm^-2_, and decreased thereafter. (2) The response of IPAR to different P fertilizer under certain NK fertilizer combination showed the order as P₂＞P₁＞P₃＞P₄＞P₀. The highest IPAR was found in N₁K₁ among all the NK fertilizer combinations. (3) IPAR was positively related to LAI under the four NK fertilizer combinations. The fitting index between IPAR and LAI were 0.8492, 0.8363, 0.7321, 0.8081 under N₁K₁, N₁K₂, N₂K₁, and N₂K₂ combinations. Correlation analysis showed that there existed a quadratic polynomical relation between yield and LAI. The fitting index was 0.7145. (4)Wheat grain yield benefited from P fertilizer (P₂O₅) application when its rate increased from 0 to 225 kg·hm^-2. N₁K₁ had the highest grain yield. Compared to all other P fertilizer rates, P₂ (P₂O₅ 225 kg·hm^-2) demonstrated the highest grain yield and rate of grain increase.【Conclusion】 N₁K₁P₂ (N 225 kg·hm^-2+ K₂O 150 kg·hm^-2 + P₂O₅ 225 kg·hm^-2) was the best NPK combination, which resulted the best canopy structure, optimal LAI, highest dry matter accumulation after flowering, enhanced IPAR and the highest grain yield.