不同磷素水平对紫花苜蓿磷累积动态和种子产量构成因子的影响

Effects of Phosphorus Application Levels on Phosphorus Accumulation and Seed Yield Factors of Alfalfa (Medicago sativa)

为研究晋北轻度盐碱地区紫花苜蓿(Medicago sativa)种子生产过程中磷素(Phosphorus,P)吸收规律,并探索适宜的施磷水平,本试验以苜蓿品种‘巨能2号’、‘3010’和‘WL366HQ’为材料,进行不同磷素水平(100,160,220,280 kg·hm-2)对不同生长时期的苜蓿干物质累积、磷素累积量、繁殖器官磷素累积及收获指数的动态变化以及对种子产量构成因子的相关研究。结果表明:3个苜蓿品种的干物质累积量、磷素累积量、磷素分配率、磷素收获指数的动态变化规律不一致,‘巨能2号’在盛花期的P 100处理下(即施磷量为100 kg·hm-2),植株和繁殖器官的磷素累积量最大,而在P 220处理下(即施磷量为220 kg·hm-2)表现出最高的磷素收获指数;‘3010’和‘WL366HQ’均在结荚期的P 160处理下(即施磷量为160 kg·hm-2)植株和繁殖器官的磷素累积量和磷素收获指数最大。综合分析认为,适宜施磷量可有效提高种子荚果数、结荚率和种子产量,在晋北地区较合理的施肥时期和适量为:‘巨能2号’宜在返青期施磷肥220 kg·hm-2;‘3010’和‘WL366HQ’宜在返青期施磷肥160 kg·hm-2。

In order to study the phosphorus(P)absorption rules in the seed production of alfalfa(Medicago Sativa)and explore the appropriate measures of phosphorus application in the mild saline area in north Shanxi province,we carried out different phosphorus levels experiments.Three alfalfa cultivars,‘MagnumⅡ’,‘3010’and‘WL366HQ’were selected to determine seed quality,P harvest index and the dynamics of P accumulation and distribution in alfalfa plants.The results showed that dry matter accumulation amount,P accumulation amount,distribution of phosphorus removal rate,dynamic change law of P harvest index among three alfalfa varieties were different.‘MagnumⅡ’showed the largest P accumulation in plant and reproductive organs under P 100 treatment(100 kg·hm-2 phosphoric fertilizer application rate),but the highest P harvest index occurred under the P 220 treatment.Both‘3010’and‘WL366HQ’alfalfa had the highest P accumulation in plants and reproductive organs at the pod bearing stage and the highest P harvest index under P 160 treatment(160 kg·hm-2).It indicated that the increase of suitable phosphorus application could effectively improve seed pod number,pod bearing rate and seed yield and the more reasonable fertilization period and appropriate amount in this region were:P 220 kg·hm-2 for alfalfa‘MagnumⅡ’in the green period;P 160 kg·hm-2 for‘3010’and‘WL366HQ’alfalfa during green period.