一、试验目的目前旱地直接压青面积不大,原因是旱地压青有时耗水过头,再加上降雨量分布不匀,所以效果不稳。可是在山西目前生产水平和自然降水的条件下,利用绿肥培养地力仍有一定的可能性。全省旱塬冬麦区常年降水量在400毫米以上,亩产只有百斤左右。通常生产100斤小麦约需水120毫米,利用自然降雨可以生长一定数量的绿肥。这就需要研究旱地压青技术,选择耗水少、产量高、易腐烂、肥效好的绿肥作物,供生产应用。二、试验材料与方法1979年在本院试验农场试验,石灰性褐土,质地为中壤。0—15厘米土层含氮0.097%,有效磷14.57ppm,有机质1.99%。试验地为 First, the purpose of the test At present, the direct area of ​​dry land is not large, due to over-pressure of green in the dry land sometimes, coupled with uneven distribution of rainfall, so the effect is not stable. However, under the conditions of present production level and natural precipitation in Shanxi, it is still possible to cultivate the land use of green manure. The annual precipitation in Dongmao District in the dryland of the province is above 400 mm, with only about 100 jin per mu. Usually produce about 100 kg of wheat about 120 mm of water, the use of natural rainfall can grow a certain amount of green manure. This requires the study of green technology in dry land, choose less water consumption, high yield, perishable, good fertilizer green manure for production and application. Second, the test materials and methods In 1979 in our hospital farm experiments, lime cinnamon soil texture for the soil. The 0-15 cm soil layer contains 0.097% nitrogen, 14.57 ppm available phosphorus, and 1.99% organic matter. Experimentally