Improving Ammonium and Nitrate Release from Urea Using Clinoptilolite Zeolite and Compost Produced from Agricultural Wastes

Figure 7

Cumulative amounts of ammonium and nitrate leached over 30 days of leaching experiment (a, b). Cumulative amounts of ammonium and nitrate leached (after subtracting the contribution of T0) over 30 days of leaching experiment (c, d). Note. T0: 64 g soil (no urea); T1: 64 g soil + 7.40 g urea (no additives); T2: 64 g soil + 7.40 g urea + 6 g clinoptilolite zeolite; T3: 64 g soil + 7.40 g urea + 1.54 g compost; T4: 64 g soil + 7.40 g urea + 1.54 g compost + 6 g clinoptilolite zeolite. Means with different letters indicate significant difference between treatments by Tukey’s test at . Note. Bar represents standard error of the mean.

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