Soil temperature is an important factor influencing crop growth. Within limits, a higher soil temperature will promote crop growth, especially in cool climate regions. Compost application can increase soil temperature, however the mechanism of increasing soil temperature remains unclear. We conducted a pot experiment to examine the effects of compost application on soil temperature and evaporation in a bare Andisol. Pots with compost (16㎏ m?²) had a higher soil temperature and less evaporation than pots without compost. The decrease in evaporation and the increase in soil temperature by compost application were significantly correlated. We conclude that compost application increases soil temperature by decreasing evaporation from the soil surface.

A field experiment was conducted to develop a no-herbicide cropping system of high protein forage. The first crop of winter ㏊bit Italian ryegrass sown in early-April produced DM yield of 4.5t/㏊ (crude protein content: 13.5%) in mid-June and the succeeding crop of soybean no-till planted into ryegrass produced DM yield of 5.1t/㏊ (crude protein content: 19.7%) in Late-October. In this cropping system, the ryegrass remained in vegetative phase during all cropping season and formed dense sod. This sod functioned as living mulch and suppressed weeds without herbicide application both during ryegrass and soybean cropping. Though the soybean germinated under the canopy of regrowing ryegrass sod, its growth was scarcely depressed by the canopy s㏊de because the seedling of soybean appeared above the canopy of sod in a few days. Contrariwise, the ryegrass was gradually shaded by the soybean and ㏊d died before October harvest. The degree of weed suppression by the ryegrass living mulch varied with seeding rate of ryegrass or weed pressure in the field. The optimum seeding rate to suppress weed was 50㎏/㏊ in the field with low or medium weed pressure and was 80 ㎏/㏊ in the field with high weed pressure.