Compost and Crude Humic Substances Produced from Selected Wastes and Their Effects on Zea mays L. Nutrient Uptake and Growth

Table 5

Chemical properties of humic acids from different composts.

Property	Rice straw	Rice husk	Sawdust	EFB	Tan (2003) [3]
𝐸4/𝐸6	7.18^a (±0.07)	6.91^ab (±0.08)	6.15^d (±0.07)	6.62^c (±0.05)	7-8
Carbon (%)	55.29^b (±0.39)	55.29^b (±0.39)	56.84^a (±0.00)	56.07^ab (±0.39)	56–62
Phenolic (cmol kg^−1)	250.00^a (±0.00)	233.33^a (±33.33)	233.33^a (±33.33)	200.00^a (±0.00)	240–540
Carboxylic (cmol kg^−1)	366.67^ab (±8.33)	358.33^ab (±8.33)	383.33^a (±8.33)	341.67^b (±8.33)	150–440
Total acidity (cmol kg^−1)	616.67^a (±8.33)	591.67^a (±30.05)	616.67^a (±30.05)	541.67^a (±8.33)	500–700
Total K (%)	0.250^a (±0.03)	0.131^b (±0.02)	0.267^a (±0.03)	0.209^ab (±0.02)	nd
Total Ca (%)	0.054^b (±0.00)	0.050^b (±0.00)	0.081^a (±0.00)	0.056^b (±0.00)	nd
Total Mg (%)	0.020^b (±0.00)	0.065^a (±0.00)	0.019^b (±0.00)	0.012^b (±0.00)	nd
Total Na (%)	0.223^a (±0.03)	0.201^a (±0.01)	0.248^a (±0.02)	0.220^a (±0.01)	nd

Different alphabets within a row indicate significant difference between means using Tukey’s test at 𝑃≤0.05.
( ) values in parenthesis represent standard error of the mean.