The effects of conservation tillage on soil and nutrient losses were compared with those of conventional tillage in this study. Andosols sampled at Tama Hill in Tokyo were compacted in the plots, and then a slope model experiment was conducted under the simulated rainfall. Shaft tillage under weed cover (SW) was applied as a conservation tillage, and shallow rotary tillage (RSB) and deep rotary tillage (RDB) were as a conventional tillage. Additionally, no tillage under bare soil (NB) was set up as a control. Although the soils applied RSB and RDB decreased dry density, the pore structure was not sustained after the rainfall. However, the pores formed by weed roots in SW were sustained even after the rainfall, and enhanced percolation in the soil. So there was a tendency for surface runoff and the losses of soil, total nitrogen and phosphorus in SW to be lower than those in RSB, RDB and NB. In addition, the amounts of nutrient consumption by weeds in SW were remarkably lower than those by soil erosion. Total nitrogen and phosphorus losses from SW, even including the nutrient consumption by weeds, were only 1/3 and 5/9 of rotary tillage, respectively. Therefore, it was concluded that the pore structure formed by weed roots enhanced percolation and contributed to decrease soil and nutrient losses.

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This paper introduces a plan to supply foods for a crew from cultivated crops in the Closed Ecology Experiment Facilities (CEEF) reviewing referring fields of Advanced Life Support (ALS) research. First, crops' productivity data were obtained. Then feasibility of vegetarian menu based on cultivable crops in the CEEF was examined. Following that, a linear programming model was developed to optimize a cultivation plan to match food supply and nutritional requirements of a crew. Optimized plan was modified and then evaluated in a cultivation experiment. The results showed a feasibility of the plan in a viewpoint of nutrient supply though crop productivities showed errors from the expected.

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