玉米高产栽培模式下钾肥的产量效应及其生理生态调控机制

Potassium fertilization played a vital role in high-yielding maize production in the North China Plain (NCP). Previous study reported that maize yield responses from applied K were greater under high-yielding production practices (HP) than conventional production practices (CP). However, the reasons for maize responses under HP in the fields with varying fertility are not well known. To explore the eco-physiological mechanisms of maize yield responses as affected by potassium fertilization under HP is of great importance for further improving maize yield. Factorial experiments are conducted in the fields with varying fertility using summer maize as the tested crop. Main plots are production practices, including CP (farmer practices) and HP. Subplots are potassium fertilizer rates. The specific objectives for this study are: (i) to determine maize yield responses to K fertilization as affected by CP and HP (ii) to quantify the dominant factors for yield responses (iii) to examine maize canopy characteristics and root distribution in the soil under HP as affected by potassium fertilization and (iv) to investigate the fate of added potassium and changes of other soil nutrients as affected by potassium fertilization in the field planting maize under HP. The research on eco-physiological mechanisms on maize yield responses as affected by potassium fertilization under HP will provide the theoretical basis for high-yielding maize production and sustainable potassium management in the NCP.

钾肥在华北平原玉米高产稳产中起着至关重要的作用。已有研究结果表明高产栽培模式下钾肥对华北平原玉米的增产作用高于普通栽培模式。在不同肥力土壤中玉米高产栽培模式下钾肥的产量效应尚不清楚。探讨钾素在玉米高产栽培中的生理生态调控机制对玉米产量的进一步提高具有重要的理论指导意义。本试验以夏玉米为研究对象，在不同肥力土壤上布置田间试验，以普通栽培模式（农民种植模式）和高产栽培模式为主处理，不同的钾肥施用量为副处理，研究玉米高产和普通栽培模式下钾肥的产量效应，明确影响玉米高产栽培模式中钾素产量效应的主要因素，研究钾肥对高产玉米冠层特性和根系分布的影响，明确钾肥在玉米高产田土壤中的去向及对其它养分的影响。从多个层面探讨玉米高产模式下钾肥产量效应的生理生态调控机制，为华北平原玉米高产栽培和钾素资源可持续管理提供理论依据。

探讨钾素在玉米高产栽培中的生理生态调控机制对玉米产量的进一步提高具有重要的理论指导意义。本试验以夏玉米为研究对象，优化田间管理措施从而达到高产，研究玉米高产栽培模式下在不同肥力土壤上钾肥的产量效应。试验结果表明高肥力土壤上适量施用钾肥具有显著增产作用，百粒重增加是夏玉米高产栽培模式下钾素增产作用的主要因素。而过量施用钾肥没有显著增产作用。在低肥力土壤上由于当地涝害导致减产，增施钾肥没有显著的增产作用。施用钾肥在拔节期促进茎的生长，而在开花期则促进了叶片和穗的生长，其生物量显著高于对照。施钾肥促进夏玉米拔节期和灌浆初期对氮和钾素的吸收和积累，主要表现在茎秆和籽粒中的积累。灌浆期穗位叶气体交换参数和冠层截光率以及根系在各个土层的分布各处理之间均没有显著差异。施入钾肥后对玉米收获期土壤中全钾、缓效钾和速效钾没有显著影响。适量施用钾肥显著提高了氮肥和磷肥利用率。本研究从多个层面探讨了玉米高产栽培模式下钾肥产量效应的生理生态调控机制，为华北平原玉米高产栽培和钾素资源可持续管理提供理论依据。