黑龙江垦区推广化肥深施技术７０年代中期以来，黑龙江垦区化肥施用量大辐度增加，由于当时多是浅施和种肥混施，经常造成较严重的烧种抑苗和挥发损失。１９７８年后，他们组织垦区内有关教学、科研单位和农场科研站，进行了化肥合理用量、比例及施肥技术专题研究，逐步摸... Since the mid-1970s, the intensive use of chemical fertilizers in Heilongjiang reclamation area has increased greatly. At that time, the application of shallow fertilizers and mixed fertilizers often resulted in more severe seedling suppression and volatilization losses. After 1978, they organized the teaching and research institutes and farm research stations in the reclamation area and conducted special studies on the rational dosage, proportion and fertilization of chemical fertilizers and gradually ...