| 1. | Farmers rotate their crops so that the soil will remain fertile .
为保持土壤肥力，农民搞作物轮作。 |
| 2. | Crop rotation plus fertilizer application produces the highest crop yields and maintains the highest soil n and organic matter levels
作物轮作加施肥产生最高作物产量，并保持最高土壤氮和有机质水平。 |
| 3. | The sample temperature was controlled by a chromel _ alumel thermocouple with a precision on the order of 0 . 1
此次田间试验的目的，是研究这一方法能在多大程度上防止由于精细的作物轮作所产生的土壤退化。 |
| 4. | Crop rotations without addition of fertilizers help maintain soil organic carbon and n levels , but do not maintain high productivity levels
不施肥的作物轮作有助于维持土壤有机碳和氮水平，但不能维持高生产力水平。 |
| 5. | A combination of crop rotation and fertilizer addition supports the highest maize yield levels . fertilizer addition does not completely offset the effect of crop rotation
作物轮作与施肥相结合支持最高玉米产量水平。施肥并不完全抵消作物轮作效果。 |
| 6. | The aim of the field experiment was to investigate to what extent such a system could prevent soil degradation resulting from very intensive crop rotations
此次田间试验的目的，是研究这一方法能在多大程度上防止由于精细的作物轮作所产生的土壤退化。 |
| 7. | The wide range in yields is due to the particular farming practices which include crop rotation and length of fallow and their effect on soil moisture levels
产量之间差异较大是由于各自不同的农艺措施，这包括作物轮作、休闲时间长短及它们对土壤水分的影响。 |
| 8. | The principles of conservation agriculture include residue management , crop rotation , weed and disease management , fertilizer management , equipment and other agronomic issues
保护性农业的主要内容包括秸秆管理作物轮作杂草及病虫害防治施肥机具及其它农艺措施。 |
| 9. | Encouraged by the results , renewed experiments at these centres of work and new experiments at more number of centres representing different agroclimatic regions and involving different crop rotations and production factors were initiated
受到这些结果的鼓舞，除在这些试验中心进一步试验外，又扩充了几个试验中心，它们代表不同的农业气象类型区域，包括不同的作物轮作及不同的生产因素。 |
