Ammonium nitrate-impregnated woodchips: a slow-release nitrogen fertilizer for plants

Different types of fertilizers are widely used throughout the world for successful crop production. Chemical fertilizers have some adverse effects on the environment if used indiscriminately and are a major source of soil and water pollution. To minimize environmental pollution, use of slow-release fertilizer (SRF) in agricultural practices is an important and effective method. Different materials have been used so far to formulate SRF, but SRF from wood is a unique technique which reflects a new dimension of wood use. In this aspect, present study was designed to develop a slow-release nitrogen fertilizer using three kinds of woodchips: Japanese red pine (Pinus densiflora S. et Z.), eunsasi poplar (Populus tomentiglandulosa T. Lee), and konara oak (Quercus serrata Thunb.). Fertilizers were prepared from woodchips after full-cell treated with a saturated solution (2140 g/l at 25A degrees C) of ammonium nitrate (NH4NO3). The morphology of woodchip fertilizer was investigated by using a field-emission electron microscope (FE-SEM) equipped with an energy-dispersive X-ray (EDX) spectrometer to locate NH4NO3 in woodchips. Deposition of nitrogen in the cell lumen was verified by FE-SEM. Deposition inside the cell wall was confirmed by EDX mapping. This study also evaluated the release pattern of nitrogen from impregnated woodchips in distilled water for 768 h and found that nitrogen was released from poplar, pine, and oak in a slow-release pattern. The encapsulated nutrient in the void volume of wood facilitated the slow release. The above findings confirm that woodchip fertilizers can be used as a slow-release nitrogen source for plants.