紫花苜蓿个体性状对土壤磷素供给能力的响应研究

Response of alfalfa individual traits to soil phosphorus supply level

摘要:

磷元素是影响紫花苜蓿生产的主要限制因素之一,通过研究苜蓿个体性状对不同土壤磷素供给水平的响应,有助于揭示磷元素对苜蓿生产力的影响途径,进而为苜蓿产业的发展提供理论依据。本研究利用有效磷( P₂O₅)含量低于3 mg/kg的土壤设置(P₂O₅)0,30,90,180 mg/kg 4个磷肥添加梯度,形成4种具有不同磷素供给水平的土壤,采用室内盆栽试验方法从个体水平上研究了苜蓿形态、生物量及分配、植株含水量对不同土壤磷素供给水平的响应。结果表明:1)低磷供给明显降低了苜蓿株高、生物量及侧枝总长,改变了苜蓿个体形态特征,贡献率分析表明侧枝总长、株高是土壤磷素供给能力影响苜蓿单株生物量的主要途径;2)苜蓿各器官的生物量分配对土壤磷素供给能力响应不敏感,各分配指标在处理间差异不显著;3)苜蓿植株含水量随着土壤磷元素供给能力的改善而显著降低。本试验在总结前人研究的基础上,进一步从个体水平上探索苜蓿对土壤磷元素供给能力的响应,有助于厘清土壤磷素供给能力改变苜蓿生产力的过程与途径,进而为苜蓿产业的发展提供理论依据。

Abstract:

Phosphorus is one of the main limiting factors affecting alfalfa production.The research work on the response of alfalfa individual traits to different soil phosphorus supply levels is helpful to reveal the pathway of phosphorus affecting the alfalfa productivity and provide a theoretical basis for the alfalfa industry.The low available phosphorus content soil (less than 3 mg P₂O₅/kg) was used to design 4 phosphorus supply levels (0,30,90 and 180 mg P₂O₅/kg) through phosphate fertilizer addition.The response of alfalfa morphology,biomass,biomass distribution,and plant water content to different soil phosphorus supply levels was studied in greenhouse.Results showed that: 1) Low phosphorus supply level significantly reduced the plant height,biomass and total branch length,and altered the alfalfa individual morphological characteristics.Contribution rate analysis showed that the soil phosphorus supply level influenced alfalfa individual biomass via total branch length and plant height;2) The biomass allocation was not sensitive to soil phosphorus supply level.There were no significant differences among treatments in terms of allocation indicators;3) The water content significantly decreased along with the improvement of soil phosphorus supply capacity.