ABSTRACT

This work evaluated the response of irrigated rice fertilized with two sources of phosphorus in paddy soils with different phosphorus adsorption capacities. Also, it evaluated the phosphorus availability predictive ability for irrigated rice. We studied two soils with different maximum phosphorus adsorption capacities (MPAC), a Planosol (low MPAC) and a Gleysol (high MPAC). The experiment was conducted in a greenhouse evaluating two sources (rock phosphate and triple superphosphate) and six levels (0, 10, 20, 40, 80 and 160 mg kg⁻¹) of phosphorus. Phosphorus contents in the soil, in the soil solution and the dry matter weight of the plants were evaluated. Phosphorus contents in the soil were analyzed by extractors Mehlich-1 and Anion Exchange Resin. The Mehlich-1 extractor and the Anion Exchange Resin methods were equivalent in the ability to predict the availability of phosphorus for rice in both soils, with high and low MPAC. The highest response rates of rice to fertilization were 10 mg kg⁻¹ and 80 mg kg⁻¹ of phosphorus in the Planosol and Gleysol, respectively. This proves the hypothesis of the work that soils with higher MPAC require higher doses of phosphate to reach maximum dry matter production.

摘要

这项工作评估了两种磷源灌溉水稻在不同磷吸附能力的稻田中的响应。此外，它还评估了灌溉水稻的磷有效性预测能力。我们研究了两种具有不同最大磷吸附能力 (MPAC) 的土壤，即 Planosol（低 MPAC）和 Gleysol（高 MPAC）。该实验在温室中进行，评估两种来源（磷酸盐和三重过磷酸钙）和六个水平（0、10、20、40、80 和 160 mg kg ^-1) 磷。评估土壤中的磷含量、土壤溶液中的磷含量和植物的干物质重量。通过提取器 Mehlich-1 和阴离子交换树脂分析土壤中的磷含量。Mehlich-1 提取器和阴离子交换树脂方法在预测两种土壤中水稻磷的有效性方面的能力相当，具有高和低 MPAC。水稻对施肥的最高响应率分别为 Planosol 和 Gleysol中 10 mg kg ^-1和 80 mg kg ^-1的磷。这证明了具有较高 MPAC 的土壤需要较高剂量的磷酸盐才能达到最大干物质产量的工作假设。