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

Figure 9

(a) Total nitrogen retained in soil at 30 days of leaching and (b) total nitrogen retained in soil after 30 days of leaching (after subtracting the contribution of T0). 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.

(a)

(b)