Mineralization and Crop Uptake of Nitrogen from Textile Manufacturing Wastewater Sludge Cake

Table 3

Incubation experiment two. Ammonium-N and nitrate-N mineralized from different screen fractions of sludge applied at 400 mg N kg⁻¹ dry soil, as compared to controls with no sludge added. Means in a column followed by different letters (a, b, and c for NH₄–N; x, y, and z for NO₃–N) are significantly different at the 5% probability level.

Screen size (mm)	Day
	0	4	14
	mg NH4–N kg^−1 dry soil
Control	0.5 a	0.1 a	0.2 a
2	31.7 b	3.7 a	0.6 a
4	36.6 b	8.5 a	0.8 a
9.5	57.9 c	11.5 a	0.8 a
	mg NO3–N kg^−1 dry soil
Control	12.0 x	12.6 x	16.8 x
2	12.1 x	52.6 y	85.9 z
4	12.4 x	58.2 y	80.4 z
9.5	11.7 x	49.6 y	79.5 z