the effect of concentration and time of supplementary nitrogen fertilizer spray application on grain yield and nitrogen use efficiency in rapeseed (hyola401) as a second crop in paddy fields were evaluated in a field experiment conducted in randomized complete block design with 3 replications at rice research institute of iran (rasht) in 2008. in this experiment two factors, concentration of so...

The behavior of As in paddy fields is of great interest considering high As contents of groundwater in several Asian countries where rice is the main staple. We determined the concentrations of Fe, Mn, and As in soil, soil water, and groundwater samples collected at different depths down to 2 m in an experimental paddy field in Japan during the cycle of flooded and non-flooded periods. In addit...

The Kumamoto area, Kyushu, Japan has 1,041km in area and about 1milion in population. This area is a greatest area in Japan which depends on groundwater for all of drinking water. Quantity of this local groundwater use is about 200MCM during the year. It is understood that the main recharging area of groundwater exist in the rice field zone which have high infiltrate height ahead of 100mm/ day ...

It is known that plant height is a suitable parameter for estimating crop biomass. The aim of this study was to confirm the validity of spatial plant height data, which is derived from terrestrial laser scanning (TLS), as a non-destructive estimator for biomass of paddy rice on the field scale. Beyond that, the spatial and temporal transferability of established biomass regression models were i...

there are human and animal health concerns related to drainage systems because nutrients, especially nitrogen and phosphorus, can contaminate water supplies. a field study was conducted on consolidated paddy fields of sari agricultural sciences and natural resources university, northern iran (36.3°n, 53.04°e), to determine the effect of subsurface drain depth and spacing on nitrogen (n) and pho...

A field experiment was conducted to provide a complete greenhouse gas (GHG) accounting for global warming potential (GWP), net GWP, and greenhouse gas intensity (GHGI) from no-tillage (NT) paddy fields with different amounts of oilseed rape residue mulch (0, 3000, 4000, and 6000 kg dry matter (DM) ha(-1)) during a rice-growing season after 3 years of oilseed rape-rice cultivation. Residue mulch...

crop rotation is one of the essential practices in sustainable agricultural systems, be-cause of its effects on soil fertility and other benefits including a reduction in weed compe-tition. a field experiment was conducted at chaparsar rice research station, tonekabon, iran, from 2002 to 2003 to assess the influence of crop rotation, time of planting, and till-age depth on rice (oryza sativa l....