Eight key points to grasp firmly in autumn nursery management
1. Apply fertilizer in the right amount. There are usually two ways to apply topdressing. ① Underground topdressing. Generally, quick-acting fertilizers such as urea are sufficient. Open a furrow between the rows, apply the fertilizer into the furrow, and then cover it with soil. The fertilizer can also be diluted and evenly sprayed onto the seedbed (ridge, border), then the plants rinsed with clean water. Under normal circumstances, apply 15-20 kg of urea per mu, then apply again after 15 days, and 2-3 applications are enough. ② Foliar topdressing. In autumn, combine it with pesticide spraying and spray 0.2% urea plus 0.3% potassium dihydrogen phosphate solution. For broadleaf tree species, it is best not to fertilize again after the Beginning of Autumn, to prevent the seedlings from growing excessively.
2. Water in time. During the rapid growth period of seedlings, watering should follow the method of applying more water less often. Each irrigation should soak through and be even, to prevent washing away the seedlings and damaging the stems and roots. Water immediately after each topdressing; if it rains and soil moisture is good, do not water. In the later stage of seedling growth, watering should be properly controlled (except in especially dry conditions, irrigation is generally not needed). If the seedlings will not leave the nursery before winter, be sure to water them well for overwintering.
3. Drainage and waterlogging prevention. There is often more rain in autumn. Once seedlings are waterlogged, it greatly affects timely removal from the nursery. Therefore, nursery drainage facilities should be inspected in time, drainage ditches should be dug well, and standing water in the nursery should be found and removed early. Areas and plots damaged by rainwater erosion should be repaired in time to ensure the nursery land is level and drainage is smooth.
4. Cultivation and weeding. Most nursery borders are covered with plastic film, so cultivation is generally not needed; simply pull out weeds. When pulling weeds within the film, work carefully and do not injure the seedlings. If herbicides are used to kill weeds, test first to avoid phytotoxicity. On the border ridges and both sides, hoe once after each rainfall or watering to preserve soil moisture, and remove weeds at the same time. Where plastic film is not used, cultivation can loosen the soil, reduce evaporation, and play a role in drought resistance and moisture preservation. Usually, cultivate and weed promptly after each rainfall or watering. Cultivation should be deepened gradually each time, but do not injure or press down the seedlings. For cuttings of broadleaf trees, control the growth of excessive lateral roots and promptly pinch out buds and remove tillers.
5. Prevent and control diseases. In hot and humid weather, pests and diseases are prone to breed. According to the growth and pathological condition of the seedlings, prevent possible pests and diseases and promptly control those that have already occurred. After pinching the seedlings in autumn, spray once with 1:0.7:200 Bordeaux mixture. If downy mildew is found, spray once with 78% Kobo 600 times solution or 80% fosetyl-aluminum 300-500 times solution. In autumn, the leaves have already aged and the new shoots have basically stopped growing; at this time, use mainly 1:1:180 or 1:1.5:180 Bordeaux mixture.
6. Prevent and control insect pests. Improving the seedlings' utilization of nutrients and light and promoting the growth and development of the root system can effectively enhance the seedlings' resistance to pests and diseases. In the season when insect pests occur, just add pest-control chemicals when spraying fungicides. Usually, 1000-1500 times solution of dichlorvos or 1000-1500 times solution of Longwei No. 1 can be selected. It is best to avoid the high temperatures at noon when spraying, and spray after 4 p.m.
7. Remove from the nursery scientifically. After the seedlings lose their leaves, they should not be removed from the nursery immediately; this is the process by which nutrients continue to be stored in the roots. In late autumn and early winter, investigate the seedlings in the nursery, check the types, varieties, and quantities of seedlings, prepare packaging materials and transport tools, determine temporary heeling-in and overwintering sites, and make preparations for removal from the nursery. Generally speaking, removal from the nursery around "Minor Snow" is more suitable. When lifting and removing seedlings from the nursery, reduce root damage as much as possible. After lifting the seedlings, immediately move them to a shady, windless place, and select and grade the seedlings according to nursery removal specifications, handling them separately. Different places have different requirements for nursery removal specifications, but the general conditions that should be met are good root growth, relatively complete main and lateral roots and more fibrous roots, robust branches, full development reaching a certain height and thickness, and no serious pests, diseases, or mechanical damage. Those that do not meet the nursery removal requirements must absolutely not leave the nursery. While grading, trim them at the same time, mainly cutting off injured branches and tips with pests or diseases, unfilled autumn shoots, and deformed root systems that are too long and carry pests or diseases. The cuts should be smooth to facilitate early healing. To make packaging and transport easier, overly long and excessive branches and tips may also be properly pruned.