For the apple tree autumn application base time, the traditional method is to apply base fertilizer in September or after fruit picking. The author has done the following tests according to the growth habits of Red Fuji apples, applying the same fertilizer and one mu of land every 10 days from August 20 to October 10. In the second year of spring observation, the 3 mu of land fertilized from August 20 to September 10 was almost the same, with early germination and full flower buds. Fertilization after September 20, the later the fertilization, the worse the growth. This proves that the best time for the autumn fertilizer is from August 20th to September 10th, which just verified the two nutritional stages in the growth habits of Red Fuji: the spring shoots use the last year to store nutrition, from late May to June. In the first ten years, the first nutrient stage was used; in late June, the leaves were used as the photosynthetic products of the leaves, which was the second nutrition stage. The tree grows alternately under the tree. When the spring shoots stop, the roots are at the peak of growth, the roots are stopped, the autumn shoots begin to develop, and the roots of the autumn shoots are at the peak of growth.

The author reviews the orchard diary in previous years. The red Fuji apple's autumn shoots are about to end in late September, which means that the root system is at the peak of growth at this time. The autumn base fertilizer should be deep-turned and rooted, in order to make it at the peak of root growth. The fertility is fully absorbed, and the base fertilizer must be applied half a month before the root growth. Therefore, the author believes that the red Fuji apple autumn base fertilizer is the best before the end of August to mid-September.