施肥进步在粮食增产中的贡献及其地理分异

采用中长期田间试验对８种模拟施肥模型在温带的海伦试验站、暖温带的沈阳试验站和亚热带的桃源试验站进行了６～１０年试验，以比较、评价施肥在粮食生产中的贡献．结果发现，施肥在作物产量形成中的贡献随施肥制度和气候的热量因素所影响；在最佳施肥条件下，施肥在产量中的贡献率分别为海伦（温带）３０％、沈阳（暖温带）３８％、桃源（亚热带）４４％．按这一实验结果可以一般地估计：当其他技术条件不变时，施肥在产量形成中的贡献率最高可达３０～４５％，随所在地区气候的热量条件而不同．

Contribution of fertilization development in food production and its geographic differentiation.

Long-term field trials on eight simulated models representing the fundamental types of fertilization system in China have been carried out from north to south at three field stations in the eastern humid region of China. The results indicate that the contribution of fertilization to crop yield was significantly influenced by the fertilization system adopted and the thermal condition of local climate. In the case of optimum fertilization system, the largest contribution rate was 30%(average of ten years) at Hailun station (temperate zone), 38%(six years) at Shenyang station (warmer temperate zone) and 44% (seven years) at Taoyuan station (subtropical zone), impling the existence of geographic differentiation controlled by the thermal factor of climate. Therefore, the largest contribution rate of fertilization in the forming of crop yield can be generally estimated from 30% to 45%, depending on the climate condition and with no change of other techniques adopted in farming.