Abstract
This experiment was carried out to ascertain the hypothesis that the total yield of a crop community will descend if the agricultural materials such as fertilizer are unevenly distributed such as the case an over and under supply of resources. An attempt to observe the relationships between the rice yield and rice plant communities with variant production structures which were caused by uneven fertilizer application in 1991 and 1992 in Tsukuba. The degrees of variation of crop growth, measured by variance, mainly occurred on the growth area closed to the rows where fertilizer had been applied. The total yield of the rice plant communities barely decreased in 1991, while, increased in 1992 with the variance. It was difficult to find a clear relationship between the yield of rice plant communities and uneven growth, with the variance. One of the factors affecting the higher productivity found in the rice plant community with the large growth variation might be the acceleration of the leaning effect of co-existence of easily-lodging among hard-lodging hills. It was estimated that the promoted yield in a rice plant community was not in proportion to the number of rice plants. In addition, we showed that there might be a correlation between the yield in the rice plant communities with variant production structures and the distribution of nitrogen density as an assumption of meteorological potentiality for productivity. The stratified random sampling used in these experiments was recognized as a proper method for the pattern found in a rice plant community.
