Sodium Contents in Dairy Cow Urine and Soil Aggregate Sizes Influence the Amount of Nitrogen Lost from Soil

Table 1

Soil pH and nutrients (-N, -N, exchangeable-K⁺, and exchangeable-Ca²⁺) in soil (mg kg⁻¹ soil) measured for each aggregate size. The soil : water ratio for the soil pH measurement was 2 : 5. The inorganic-N was measured using a colorimetric method. Exchangeable-K⁺ and -Ca²⁺ were measured using an atomic absorption method after the extraction with a NH₄COOH solution.

	Small	Medium	Large
pH	5.8 ± 0.1	5.8 ± 0.0	5.8 ± 0.0
-N mg kg^−1	25.8 ± 0.8	23.6 ± 1.7	18.8 ± 1.4
-N mg kg^−1	15.2 ± 0.7	17.7 ± 0.6	13.8 ± 1.0
K mg kg^−1	539.3 ± 9.6	552.3 ± 7.0	555 ± 17.1
Ca mg kg^−1	6392 ± 90.5	6307 ± 133.4	6118 ± 275.3
CEC meq kg^−1	421.3 ± 11.7	422.3 ± 10.5	416.7 ± 2.1
Organic matter %	6.5 ± 0.3	5.4 ± 0.1	5.2 ± 0.4
Soil texture
Sand %	13.7 ± 3.2	14.8 ± 3.5	18.4 ± 4.5
Silt %	56.7 ± 1.4	56.5 ± 6.5	51.8 ± 4.5
Clay %	29.5 ± 4.3	28.7 ± 3.3	29.8 ± 3.7