To determine the effects of recent warming trends on agricultural production in Japan, in 2003 and 2005, surveys of the public institutes of agricultural research in 47 prefectures were conducted. The results suggest that recent warming trends have already significantly affected nearly all types of crops and livestock in Japan. All 47 prefectures reported warming effects on fruit tree cultivation and over 70% of prefectures recognized the effects on rice, vegetable and flower cultivation. Horticultural crops and rice are likely to be more sensitive to global warming than other agricultural crops and livestock. Our survey elucidated many effects of recent warming, such as phenological changes in many crops, increases in fruit coloring disorders and incidences of chalky rice kernels, reductions in yields of wheat, barley, vegetables, flowers, milk and eggs, and alterations in the type of disease and pest.

Long-term temporal changes in natural 15 N abundance (δ 15 N value) in paddy soils from long-term field experiments with livestock manure and rice straw composts, and in the composts used for the experiments, were investigated. These field experiments using livestock manure and rice straw composts had been conducted since 1973 and 1968, respectively. In both experiments, control plots to which no compost had been applied were also maintained. The δ

To estimate the fate of nitrogen (N) derived from cattle manure compost with sawdust (CMC) in a paddy field in the cool climate region of Japan, well-composted 15 N-labeled CMC was applied to a microplot field experiment. Throughout the experimental period of three crop seasons, N from CMC was taken up by rice plants without a marked decline. The percentages of N taken up derived from CMC to applied N as CMC (%CNRp) were 2-3% for each year. The N from CMC was taken up by rice plants over the entire growth period by 1-2, 2 and 2-3% as %CNRp at the panicle initiation, heading and maturity stages, respectively. A significant positive linear correlation was found between the cumulative compost N uptake and the number of days transformed to standard temperature (25°C) over the entire experimental period, including the fallow season. The %CNRp was identical at CMC application rates ranging from 1 to 4 kg m -2. Using 15 N-labeled CMC, the results showed that well-composted CMC was a stable N source for rice plants for at least 3 years, regardless of the CMC application rate (ranging from 1 to 4 kg m -2 ) in the cool climate region of Japan. The distribution of CMC N was 7% in the rice plants accumulated over 3 years, 66-69% in the soil and 24-27% was un-recovered at the end of the third crop season.