1.The soil is mostly acidic,the pH value is too low,the magnesium leaching is serious,the release of magnesium is obviously inhibited,and the average content of exchangeable magnesium in the soil is lower than the critical level,and the magnesium deficiency is serious.
2.Grapes are potassium-producing crops,but excessive potassium inhibits the absorption of magnesium by the roots of the grapes and transports magnesium ions to the above-ground parts,causing magnesium deficiency.
3.Magnesium and calcium,ammonium ions also have antagonistic effects,therefore,the soil calcium content is too high or the application of calcium and nitrogen fertilizers will reduce the absorption of magnesium by plants.
4.Years of high yields took away a lot of magnesium,but did not replenish in time,resulting in magnesium deficiency.
Many fruit farmers believe that magnesium is a medium-sized element,the demand for grapes is not large,and it only occurs on the old leaves,and the impact on the fruits is small…These misunderstandings are also important reasons for the lack of magnesium in grapes.
How to supplement magnesium for grape?
Pre-growth period: At this time,it is in the critical period of magnesium nutrition,which is generally applied in the form of base fertilizer,and the effect is obvious.
Grape fruiting period: Grape magnesium deficiency occurs mainly in the late growth stage.At this time,a large amount of potassium fertilizer application will inevitably exacerbate the symptoms of magnesium deficiency.In addition to magnesium,the lack of magnesium affects the current year’s output,causing premature senescence of the yellow leaves and early leaves.It will also cause the grapes to spend less flowers in the coming year,so we must pay attention to supplement.
Application of magnesium fertilizer,rhizosphere application and foliar application.
1 Phosphorus in soil has a strong immobilization effect on magnesium and is difficult to be absorbed by roots.It is recommended to choose chelated magnesium.
2 For acidic soils,it should be timely adjusted to avoid magnesium deficiency caused by magnesium leaching.
3 Magnesium fertilizer must be combined with other fertilizers to be effective.
4 foliar spray magnesium,the effect is significant,but not lasting,should be sprayed several times.
5 excessive application of magnesium fertilizer not only leads to the imbalance of nutrient elements,but also affects the absorption of other elements by plants.