Abstract—

A study was conducted with the purpose of comparing the efficiency of ammonium acetate (NH₄OAc), Mehlich 3 (M-3), Calcium Chloride (CaCl₂) and alpha MIR spectroscopy measurement, for the determination of available potassium (K) on 58 Ethiopian agricultural soils. Four soil reference groups were sampled for the study. The NH₄OAc extractant was used as standard method against which K values estimated by other methods were compared. Results showed that generally highly significant correlations existed among all the methods used for available K extraction. The coefficients of determination (R²) values between NH₄OAc method and the other methods were 0.90 (M-3), 0.70 (CaCl₂), and 0.37(spectral). A statistically poor relationship (R² = 0.07) was found between CaCl₂ and spectral methods. On an average, the K extracted by M-3 and CaCl₂ amounted to 106 and 49% of NH₄OAc K, respectively while the spectral method detected 196% of the NH₄OAc K. The highly significant correlation between different soil extraction methods indicated that any of the methods can be used to accurately predict the concentration of available K in the soil. The correlations between K concentration estimated by different methods and plant uptake (product of plant K concentration and dry matter yield) of K were the highest with M-3 and the lowest with spectral methods with R² values of 0.65, 0.64, 0.54 and 0.16 for M-3, NH₄OAc, CaCl₂ and spectral methods, respectively. It can, therefore, be generalized that the M- 3 is a suitable extractant for K in Ethiopian soils, but further study is recommended to determine how these relationships could be translated to plant K uptake under field condition. Besides, the spectral measurement of K as a soil test method for heterogeneous group of soils warrants further investigation and refinement.

中文翻译：

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几种埃塞俄比亚土壤中土壤萃取剂的比较和光谱反射率测量，以估算有效钾含量

摘要-

进行了一项研究，目的是比较乙酸铵（NH ₄ OAc），Mehlich 3（M-3），氯化钙（CaCl ₂）和αMIR光谱测量的效率，以测定有效钾（K）。 58埃塞俄比亚的农业土壤。抽样了四个土壤参考组用于研究。NH ₄ OAc萃取剂用作标准方法，将其与其他方法估算的K值进行比较。结果表明，在可利用的K提取所使用的所有方法之间通常存在高度显着的相关性。NH ₄ OAc方法与其他方法之间的测定系数（R ²）值为0.90（M-3），0.70（CaCl ₂）和0.37（光谱）。发现CaCl ₂和光谱方法之间的统计关系很差（R ² = 0.07）。平均而言，M-3和CaCl ₂提取的钾分别占NH ₄ OAc K的106和49％，而光谱法检测到NH ₄ OAc K的196％。不同土壤提取方法之间的高度显着相关性指出任何一种方法都可以用来准确预测土壤中有效钾的浓度。不同方法估算的钾浓度与植物吸收（植物钾浓度和干物质产量的乘积）之间的相关性在M-3条件下最高，而在光谱方法中R ²最低。M-3，NH ₄ OAc，CaCl ₂和光谱方法的数值分别为0.65、0.64、0.54和0.16 。因此，可以概括地说，M-3是埃塞俄比亚土壤中钾的合适提取剂，但建议进行进一步的研究以确定这些关系如何转化为田间条件下植物对钾的吸收。此外，作为土壤异质性土壤测试方法的钾光谱测量值得进一步研究和完善。