ABSTRACT

This study investigated phosphorous (P) sorption characteristics under lime rates, and validated them under field conditions. Soil samples from nitisols and luvisols were taken, mixed with lime(tha⁻¹) at[0,0], [5.25, 3.75], [10.5, 7.5] and [15.75, 11.25], respectively, and incubated for 30 days. It was equilibrated with KH₂PO₄ at 0, 10, 20, 30, 40, and 50 mgPL⁻¹. The data were tested with Freundlich and Langmuir models. External P requirement (EPR) and changes in chemical properties were evaluated. The field validation on wheat involved rates of P (0, 8.2, 16.4, 24.6, 32.9, and 41.1 kg ha⁻¹) and lime (0, 650, and 1300 kgha⁻¹) in a randomized complete block design with three replications. Freundlich was found the best-fitted model. Freundlich coefficient (Kf) ranged from 212 to 45 mgPkg⁻¹ (nitisols) whereas it was 112.7 to 16.29 mgPkg⁻¹ (luvisols). EPR (kgPha⁻¹) without and the highest lime rate were: nitisols (142.5 and 52.32 kgPha⁻¹) and luvisols (124.84 and 25.94 kgPha⁻¹). Liming reduced EPR by 63.3% (nitisols) and 79.3% (luvisols). Liming increased soil pH from [4.55 to 6.60 in the nitisols, and 5.33 to 6.51 in luvisols]; exchangeable acidity (cmol(+)kg⁻¹) 3.84 to 0.01 nitisols, and 0.72–0.05 luvisols, and available P (mg/kg) 3.2–6.32 nitisol, and 2.74–8.72 luvisols. Furthermore, applying 32.9 kgPha⁻¹ x 1300 kgha⁻¹ lime resulted in grain yield (4345.2 kgha⁻¹) that was 449% more than the untreated crop (791.3 kgha⁻¹). The validation result suggested higher P than blanket P recommendation. It also justifies that excess P or lime alone cannot be a complete solution for P management and increased yield.

摘要

本研究调查了石灰速率下的磷 (P) 吸附特性，并在现场条件下对其进行了验证。取自 nitisols 和 luvisols 的土壤样品，分别与 [0,0]、[5.25, 3.75]、[10.5, 7.5] 和 [15.75, 11.25] 的石灰 (tha ^-1 ) 混合，并孵育 30 天。它用0、10、20、30、40和50mgPL ^-1的KH ₂ PO ₄平衡。使用 Freundlich 和 Langmuir 模型对数据进行了测试。评估了外部 P 要求 (EPR) 和化学性质的变化。小麦田间验证涉及 P（0、8.2、16.4、24.6、32.9 和 41.1 kg ha ^-1）和石灰（0、650 和 1300 kgha ^-1) 在具有三个重复的随机完整区组设计中。Freundlich 被认为是最适合的模型。Freundlich 系数 (Kf) 范围为 212 至 45 mgPkg ^-1 (nitisols)，而它为 112.7 至 16.29 mgPkg ^-1 (luvisols)。没有和最高石灰率的EPR (kgPha ^{-1 ) 是：nitisols (142.5 和 52.32 kgPha -1} ) 和 luvisols (124.84 和 25.94 kgPha ^-1 )。Liming 将 EPR 降低了 63.3%（nitisols）和 79.3%（luvisols）。石灰将土壤的 pH 值从 [nitisols 中的 4.55 增加到 6.60，luvisols 中的 5.33 到 6.51]；可交换酸度 (cmol(+)kg ^-1 ) 3.84 至 0.01 nitisols 和 0.72-0.05 luvisols，有效 P (mg/kg) 3.2-6.32 nitisol 和 2.74-8.72 luvisols。此外，应用 32.9 kgPha^-1 x 1300 kgha ^-1石灰导致谷物产量（4345.2 kgha ^-1）比未经处理的作物（791.3 kgha ^-1）高出449％。验证结果表明 P 高于一揽子 P 建议。这也证明了仅靠过量的磷或石灰不能成为磷管理和增加产量的完整解决方案。