Abstract

Purpose

Purple paddy soils cover about 66% of the paddy soils in Sichuan Basin. Complex interactions made the effects of potassium fertilizer application on NH₄⁺ adsorption more complicated and the behavior of NH₄⁺ and K⁺ interaction in purple paddy soils has rarely been evaluated. We hypothesize that correct management of these soils can enhance the efficiency of ammonium and potassium fertilizers. In order to determine correct management methods, it is important to understand the interaction of main nutrient cations NH₄⁺ and K⁺ and maturation hydroponics in purple paddy soils with different paddy cultivation times.

Materials and methods

A purple paddy soil chronosequence with cultivation history from 0 to 300 years was studied to understand the respective effects of SOM and mineralogy on NH₄⁺ and K⁺ sorption behavior by adsorption experiments using samples both before and after H₂O₂ oxidation.

Results and discussion

The study shows that maturation hydroponics influenced NH₄⁺ and K⁺ adsorption mainly through changing clay mineralogy and enhancing SOM accumulation. SOM and smectite play positive effects for NH₄⁺ adsorption. The K⁺ adsorption, however, is mainly affected by the smectite changes. The adsorption percentages are obviously higher at 25–50 mg L⁻¹ for each NH₄⁺ solution and higher at 50–100 mg L⁻¹ for each K⁺ solution. When ammonium and potassium were applied together, NH₄⁺ and K⁺ adsorption are mutually weakened. In addition, the percentage of K⁺ adsorption increased from 49.7–57.7% for the 100 mg L⁻¹ K⁺ solution to 50.9–58.5% for the 200 mg L⁻¹ K⁺ solution at 200 mg L⁻¹ of added NH₄⁺.

Conclusions

SOM enrichments could be a positive way to improve the ammonium fertilizer utilization efficiency in purple paddy soils. Potassium may be more vulnerable to loss at low K⁺ concentrations given that ammonium and potassium fertilizers were applied together and it should be separately applied to enhance the utilization efficiency of applied fertilizer.

中文翻译：

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紫色水稻土改善铵钾肥管理的时间序列研究

摘要

目的

紫色稻田覆盖四川盆地约66％的稻田土壤。复杂的相互作用使钾肥施用对NH ₄ ⁺吸附的影响更加复杂，并且很少评估紫色稻田土壤中NH ₄ ⁺和K ⁺相互作用的行为。我们假设对这些土壤的正确处理可以提高铵钾肥的利用率。为了确定正确的管理方法，了解不同水稻种植时间的紫色水稻土中主要养分阳离子NH ₄ ⁺和K ⁺与成熟水培的相互作用非常重要。

材料和方法

通过使用H ₂ O ₂氧化前后的样品进行吸附实验，研究了紫色水稻土的耕层序列，其耕作历史为0至300年，以了解SOM和矿物学对NH ₄ ⁺和K ⁺吸附行为的各自影响。

结果和讨论

研究表明，成熟的水培法主要通过改变粘土矿物学和增加SOM的积累来影响NH ₄ ⁺和K ^+的吸附。SOM和蒙脱石对NH ₄ ⁺吸附起积极作用。然而，钾⁺吸附主要受蒙脱石变化的影响。每种NH ₄ ⁺溶液在25–50 mg L ^-1时的吸附百分比明显更高，而每种K ⁺溶液在50–100 mg L ^-1时更高的吸附百分比。当铵和钾一起使用时，NH ₄ ⁺和K ⁺吸附相互削弱。此外，在添加NH _4的200 mg L ^-1时，K ⁺吸附的百分比从100 mg L ^-1  K ⁺溶液的49.7–57.7％增加到200 mg L ^-1  K ⁺溶液的50.9–58.5％。⁺。

结论

SOM富集可能是提高紫色稻田土壤铵肥利用率的积极途径。由于铵和钾肥料一起施用，钾在低K ⁺浓度下可能更容易流失，应分开施用，以提高施用肥料的利用效率。