磷肥施用对水稻生长和磷素吸收的影响

采用田间微区试验研究不同磷肥的施用位置和类型对姜堰、广德两地水稻生长、磷素吸收以及施肥后地表水磷浓度的影响,为水稻根区施磷提供科学依据。磷肥种类为磷酸二氢钙(MCP)和磷酸氢二铵(DAP),施用方式有:1表面撒施;2偏3 cm,深5 cm穴施;3偏12 cm,深5 cm穴施。结果显示施磷对两地水稻均无显著增产,姜堰地区水稻产量显著高于广德。不同施磷位置对水稻吸磷量有显著影响,姜堰、广德两地MCP偏3 cm处理的水稻总吸磷量较MCP偏12 cm处理分别高13%和12%,且DAP偏12 cm处理的水稻总吸磷量显著高于MCP偏12 cm处理,两地增幅分别达到12%和16%,磷肥撒施虽然在水稻分蘖期有较高的吸磷量,但在水稻成熟期不如磷肥偏3 cm穴施。施肥第10天的地表水总磷浓度以磷肥表面撒施处理较高,比磷肥穴施处理分别高245%(姜堰)和94%(广德)。以上结果表明:1适当位置的磷肥穴施不但能够促进水稻对磷的吸收,还能有效缓解径流排水造成的磷流失;2磷酸氢二铵的磷肥适宜施用距离范围较磷酸二氢钙远。

Effects of Application Methods of Phosphorus Fertilizers on the Growth and P Absorption of Rice in Jiangyan and Guangde Regions

A field micro-plot experiment was conducted to determine the effects of different placements and species of phosphorus (P) fertilizers on rice growth, P uptake by rice and P concentration in surface water after fertilization, providing a scientific basis for root zone P fertilization. P fertilizer species included mono-calcium phosphate (MCP) and diammonium phosphate (DAP), P fertilizer application methods included: 1) surface broadcasting; 2) point placement with 5 cm below and 3 cm away from seedling; 3) point placement with 5 cm below and 12 cm away from seedling. The results showed that no differences were observed between P and P-free treatments in rice yield in both regions, and rice yield in Jiangyan was greater than that in Guangde. Total P uptake by rice was significantly affected by P applied placements. The yield for 3 cm-point placement of MCP was 13% and 12% higher than that for 12 cm-point placement of MCP in Jiangyan and Guangde, respectively. The yield for the treatment with DAP was significantly higher than that with MCP in 12 cm-point placement, and increased percentages were 12% and 16% in Jiangyan and Guangde, respectively. Although relatively high total P uptake by rice was found in surface broadcasting treatments at tillering stage, 3 cm-point placement performed better than surface broadcasting at maturing stage. After 10 days of fertilization, P concentration in surface water for surface broadcasting treatment was 245% (Jiangyan) and 94% (Guangde) higher than that for point placement treatment. These results suggested that: 1) reasonable point placement of P application not only promoted P uptake by rice, but also inhibited P loss from paddy fields with surface water drainage; 2) DAP could place relatively more far away from seedling than MCP.