Soil testing is an important diagnostic tool for assessing crop-available soil potassium (K) and hence making appropriate fertilizer recommendation. This study was aimed at correlating grain yield response data to soil-test K extracted with ammonium acetate (NH4OAc), cold nitric acid (HNO3), sodium tetraphenylboron (NaTPB) and boiling HNO3 solution, based on 54 field trials conducted during 2011 to 2015 across 15 counties in Hubei province, China. The specific objectives were to establish abundance and deficiency indices of available soil-K (ASK) for rice (Oryza sativa L.) and make accurate K fertilizer recommendations. Potassium extracted with NaTPB and boiling HNO3 was 1.47 times and 3.61 times higher respectively than that extracted with cold HNO3, while K extracted with cold HNO3 was 1.32 times higher than that extracted with NH4OAc. There were significant logarithmic relationships between crop response and soil-test K. The R2 values for cold HNO3-K and NaTPB-K methods were much higher than for NH4OAc-K method. In order to calibrate the application, the abundance and deficiency indices of ASK categorized by cold HNO3-K in low, medium, high and very high ranges were <50 mg kg−1, 50 to 100 mg kg−1, 100 to 200 mg kg−1 and >200 mg kg−1 respectively, and that defined by NaTPB-K were <60 mg kg−1, 60 to 150 mg kg−1, 150 to 330 mg kg−1 and >330 mg kg−1, respectively. These values could be used to evaluate soil K supplying capacity and make appropriate K fertilizer recommendations for rice.
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机译:土壤测试是评估作物可用土壤钾(K)并因此提出适当肥料建议的重要诊断工具。这项研究旨在根据2011年至2015年进行的54次田间试验,将谷物产量响应数据与用乙酸铵(NH4OAc),冷硝酸(HNO3),四苯硼酸钠(NaTPB)和沸腾的HNO3溶液提取的土壤测试K进行关联。覆盖中国湖北省的15个县。具体目标是建立水稻(Oryza sativa L.)可用土壤钾素(ASK)的丰度和缺乏指数,并提出准确的钾肥推荐值。 NaTPB和沸腾的HNO3提取的钾分别比冷HNO3提取的钾高1.47倍和3.61倍,而冷HNO3提取的钾比NH4OAc提取的钾高1.32倍。作物响应和土壤试验K之间存在显着的对数关系。冷HNO3-K和NaTPB-K方法的R 2 sup>值远高于NH4OAc-K方法。为了校准应用,冷HNO3-K在低,中,高和非常高的范围内将ASK的丰度和不足指数分为<50 -1 sup>,50至100 tomg kg -1 sup>,100至200 mg kg -1 sup>和> 200 mg kg -1 sup>,NaTPB-K定义的<60 mg kg −1 sup>,60至150 mg kg -1 sup>,150至330 mg kg -1 sup>和> 330 mg kg − 1 sup>。这些值可用于评估土壤钾素供应能力,并为水稻提供适当的钾肥推荐。
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