Effects of nitrogen fertilizer methods and transplanting a culture of rice [Oryza sativa] using paper mulch on the amount of pollutants discharged out of paddy field systems and the evaluation of the effects
2008
Ootsuka, E.(Chiba-ken. Agriculture Research Center (Japan)) | Yamamoto, Y. | Kaneko, F. | Singyouji, T.
The prevention of water pollution requires a rice paddy field cultivation that decreases the amount of water pollutant runoff, such as nitrogen runoff, from paddy fields. As a measure to decrease levels of T-N runoff, COD, and turbidity, transplanting a culture of rice using paper mulch was combined with a side line type fertilizer application or a single application of fertilizer in nursery boxes to evaluate effects of the combinations to decrease environmental load. 1. The amount of T-N runoff out of paddy fields increased with puddling and transplanting. The amount comprised 48% of the total amount of runoff in May, when puddling and transplanting were carried out. 2. Nitrogen in basal dressing was readily eluted out into the surface water of paddy fields at the time of puddling when a broadcast application of fertilizer was made to the plow layer of a conventional plot. However, the elution was limited when the side line type fertilizer application was made at the time of transplanting. Both the single application of fertilizer in nursery boxes and the side line type fertilizer application decreased the amount of T-N runoff. Both of the applications were judged good techniques for environmental conservation. 3. Transplanting a culture of rice using paper mulch was judged a good technique for environmental conservation because it not only replaced the use of herbicides but also covered soil surface to keep water turbidity from increasing.
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