一、用地、养地相结合的重要性建国以来不断提高科学种田水平。如平整土地、兴修水利、选用良种、改革耕作制、扩大复种面积、由一茬变二茬甚至种三茬。如此长期下去只重视用地提高复种指数,不注意养地,势必造成土壤肥力递减。目前有机肥不论从质量上或数量上都远不能满足生产的需要。工业生产的氮肥品种80％以上是碳铵各氨水,由于运输、贮存、施用过程中的挥发损 First, the importance of combining land, raising land Since the founding of the People’s Republic of China, China has continuously raised the standard of scientific farming. Such as leveling the land, water conservancy construction, selection of elite, reform of farming system, expand the area of ​​multiple cropping, change from one crop to two crop or even grow three crop. Therefore, long-term focus only on land for multiple cropping index, do not pay attention to raising land, will inevitably lead to diminishing soil fertility. At present, organic fertilizers are far from meeting the needs of production either qualitatively or quantitatively. More than 80% of the nitrogenous fertilizer produced in the industry is ammonium bicarbonate. Due to the volatile loss during transportation, storage and application