Nitrogen derived from water hyacinth and recovered in rice crops was measured by employing 15N-labeling techniques. Either 15N-labeled water hyacinth or 15N-ammonium sulphate was incorporated into soil separately. Derived N was significantly detected in shoot of rice at all stages (Tillering Stage, TS; Panicle Initiation Stage, PIS; Heading Stage, HS; and Harvesting Stage, HVS), while there was non-significant difference between treatments in derived N to root throughout the growth season. On the other hand, N was significantly recovered in shoot of rice at TS and PIS only. There were no significant differences between treatments in recovering N at all stages in root of rice crop. About 8.2 – 39.6% and 30.2 – 38.9% of N from water hyacinth and fertilizer, was recovered from the shoot of rice, respectively, whereas, only 1.1 – 5.7% and 2.2 – 5.9% from root of rice crop. It was proved that fertilizer derived more N than that derived by water hyacinth. N recovery of water hyacinth in rice crop in early stage was lower than that of fertilizer, however, in the late stages the figure was similar between the two
Didik Wisnu Widjajanto , Kozo Matsushita , Terumasa Honmura and Nobufumi Miyauchi , 2001. Studies on the Release of N from Water Hyacinth Incorporated into Soil-Crop Systems Using 15N-labeling Techniques. Pakistan Journal of Biological Sciences, 4: 1075-1077.