How to apply sufficient base fertilizer when planting plum trees

Currently most plum orchards have less than 1% organic matter, and some plum orchards are even below 0.5%, far below the requirements of high-quality, high-yield orchards, so the amount of base fertilizer must be increased. If the dual needs of tree growth and soil improvement are taken into account at the same time, the application rate of organic fertilizer should be kept at the standard of 1 to 3 jin of fertilizer per jin of fruit. Therefore, for a medium-yield plum orchard with a yield of about 1500 kg per mu, the amount of organic fertilizer used must not be less than 3000 kg.

The most suitable time to apply base fertilizer is autumn (1 month before leaf fall), followed by the period from leaf fall to before the soil freezes, and from thawing in spring to before bud break. When base fertilizer is applied in autumn, the fertilizer has enough time to decompose, and it can also allow broken roots to heal and send out new roots, because this is precisely the peak period of root growth, when the roots have strong absorptive capacity; after absorption, it can raise the level of stored nutrients in the tree, and can promote the development and plumpness of flower buds, a relatively high nutrient reserve in the tree, and the timely supply of nutrients in the soil in early spring, which can meet the needs of spring bud break and leaf expansion, flowering and fruit setting, and new shoot growth. If base fertilizer is applied after leaf fall or in spring, the fertilizer effect takes effect later, has little effect on the early spring growth and development of fruit trees, and by the time the fertilizer is absorbed and used in large amounts, it is often already the period of vigorous new shoot growth. For orchards in mountainous areas that are dry and have no irrigation conditions, because the base fertilizer cannot be irrigated immediately after application, the base fertilizer can also be applied in the rainy season while there is soil moisture. However, the organic fertilizer must be fully decomposed, refined fertilizer, the application must be fast, and care must be taken not to damage the coarse roots.

When the source of organic fertilizer is insufficient, straw, weeds, and the like can also be used as a supplement and mixed with organic fertilizer. It is worth noting that although the source of organic fertilizer is limited, the principle of ensuring a local area and ensuring the concentrated distribution layer of the root system must be followed, and concentrated hole application should be used to give full play to the fertilizer effect of organic fertilizer. Concentrated hole application means digging holes about 50 cm deep and 30 to 40 cm in diameter from the edge of the tree canopy inward, with the number depending on the amount of fertilizer, then mixing the organic fertilizer with soil at 1:3 or adding some straw as well, filling it into the holes, and then watering. In addition, phosphorus and potassium fertilizers, and even zinc and iron fertilizers, can be mixed with organic fertilizer to improve their utilization rate.