Key Technical Points for Soil, Fertilizer and Water Management in Jujube Orchards

After jujube trees enter the full fruit-bearing stage, doing a good job of soil, fertilizer and water management and maintaining a good tree vigor are the prerequisites for high yield and quality. The soil, fertilizer and water management of jujube trees in the full fruit-bearing stage can be summarized as “two tillages, four fertilizations and three waterings”.

The two tillages refer to deep plowing and intertillage. Deep plowing can loosen the soil in the jujube orchard, deepen the distribution layer of the jujube tree root system, and expand the range over which the roots absorb nutrients. Deep plowing can be carried out in spring and autumn. Intertillage is repeated shallow plowing during the growing season, which helps reduce water evaporation, improve soil aeration conditions, promote nutrient uptake by jujube trees and prevent the return of salinity and alkalinity.

The four fertilizations refer to base fertilizer, bud fertilizer, flowering-stage fertilizer and fruit-setting fertilizer. (1) Applying base fertilizer in autumn. Applying base fertilizer before jujube harvest is best, as it helps accumulate a large amount of stored nutrients and lays the foundation for a high yield the following year. The base fertilizer should be mainly organic fertilizer, and may be appropriately combined with some quick-acting fertilizers. (2) Topdressing before bud break. This is generally carried out in early April of the following year. Jujube orchards that did not receive base fertilizer in autumn should pay even more attention to the application of bud fertilizer. Bud fertilizer is extremely beneficial for bud break, flower bud differentiation and young fruit development. (3) Topdressing at the flowering stage. Jujube flower bud differentiation has the characteristics of differentiating in the current year, differentiating multiple times, differentiating as the tree grows, a short differentiation period and a large number of differentiated buds. Therefore, jujube trees have a large number of flowers and a long flowering period, and consume a large amount of nutrients. If nutrition cannot keep up, it will inevitably lead to serious flower and fruit drop, and topdressing at the flowering stage can reduce fruit drop. Topdressing at the flowering stage can be applied to the soil or as a foliar spray. When spraying fertilizer at the flowering stage, adding 30×10-6 gibberellin gives an even better effect in increasing the fruit-setting rate. (4) Fruit-setting fertilizer. This is generally topdressed around mid-July, when young fruits are growing vigorously. This topdressing is directly related to the yield and quality of jujubes. The fruit-setting fertilizer is best as a nitrogen, phosphorus and potassium compound fertilizer, and can be applied to the soil or sprayed on the foliage.

Jujube trees in the full fruit-bearing stage have the highest yield and also the greatest fertilizer requirement. Each jujube tree in the full fruit-bearing stage must be applied annually with 100 kg of organic fertilizer, 1 kg of quick-acting nitrogen fertilizer, 2.5 kg of superphosphate and 2.5 kg of plant ash.

The three waterings refer to the three guaranteed water supplies each year corresponding to the three topdressings, namely water for promoting bud break, water at the flowering stage and water for young fruits. Water at the flowering stage can prevent the scorched-flower phenomenon caused by drought and reduce flower and fruit drop, and is generally irrigated before bark girdling. In addition to the above three waterings, some regions also have the habit of irrigating with freezing water to promote tree development.