Investigation on an effective index for introducing biodiversity into agricultural site and application to co-existent cropping systems at paddy field

点击翻译按钮获取中文摘要

We contributed our two papers on this research to the related Scientific Journal in 2008. In the 2007 experiment to evaluate holistically the mutually-related factors with environmental loads and rice grain yield, we designed the new experiment with two factors including nutrient shortage and excess fertilizing effects at a paddy field. In the 2007 experiment, we eventually focused on the changes of environmental loads of methane production and water quality occurred at a paddy field. In the 2007 experiment, concentration of total nitrogen (TN) increased noticeably at the three periods including a basal fertilization with pudding and two top dressings, but concentration of phosphorus (TP) increased only at the period of a basal fertilization. The linear correlation was observed between accumulated methane production during growing season (MP) and rice grain yield, and the order were as follows, no-fertilizer plot<the standard three elements plot<the standard three elements + manure plot<duplicated nitrogen plot. Then we drew a radar chart for MP per unit rice grain yield, TN and TP per unit rice grain yield based on the standard three elements plot with index value of 100 for their comparison, and discussed their holistic fertilizing efficiency to satisfy both environmental and productive requirements. The most important keyword is "sustainability" in this research. In regard to present situation of monoculture with a shortsighted efficiency at agricultural site, an introduction of new systems including polyculture leaves some unsolved problems. But we must try to propose various and sound options for future generation beyond some obstacles.