The phrase "nitrogen long leaves, phosphorus long fruit, potassium fertilizer is not enough to grow firewood" is enough to illustrate the importance of potassium fertilizer in the process of crop growth and development. In viticulture, if we cannot meet the plant's demand for potassium fertilizer in time, it is difficult to promote the maturity of berries and the formation of aromatic substances and pigments, which eventually causes serious yield and quality reduction problems in the fruit.
It should be known that potassium plays an extremely important role in the transport of more than 60 enzymes in plants, as well as the transport of carbohydrates and the synthesis of proteins. Not only that, potassium fertilizer is also directly involved in crop metabolism, which can accelerate stem development, enhance photosynthesis and stress resistance, and promote the absorption and utilization of nitrogen fertilizer by crops, improve the sugar content of fruits, reduce acid content, and enhance storage resistance, thereby improving its yield and quality.
Some fruit friends asked, the benefits of potassium fertilizer are many, there are many types of potassium fertilizer on the market, common potassium fertilizers are potassium chloride, potassium sulfate, potassium nitrate, potassium dihydrogen phosphate, potassium humic acid, etc., how should we choose? Today we will talk about the selection and use of various potash fertilizers in grapes.
<h1 class="ql-align-justify" > potassium chloride</h1>
Potassium chloride is the most common potassium fertilizer, which is acidic and has the advantages of low price, high potassium content, strong availability and rapid effect. However, because it contains chloride ions, if it is used for a long time, it is easy to cause salinity and alkalinization of the soil, so it is not suitable for use in arid and water-scarce or saline soils, and it is more suitable for use as base fertilizer and topdressing in rainy production areas.
Previous theories said that it could not be used on grapes, but in fact it could not be generalized. Although more chlorine will affect the absorption of nitrate by plants and inhibit the activity of some enzymes, it is after all one of the essential elements for grape growth, and the cells of grapes also have a mechanism for balancing chloride ions. Therefore, as long as the purity of potassium chloride fertilizer is high enough and the amount of use is controlled, in addition to saline-alkaline soil, potassium chloride can be used on grapes.
<h1 class="ql-align-justify" > potassium sulfate</h1>
Theoretically, the potassium content of potassium sulfate is 54%, but in fact it is generally 50%. It is a chemically neutral, physiologically acidic fertilizer with low price, potassium, sulfur, no chlorine and good water solubility. In general, potassium sulfate is suitable for grape coloring from the late stage to the fruit ripening stage, which can promote the pink coloring of the fruit and increase the sweetness of the fruit.
However, if used for a long time or on soil with a high calcium content, it will aggravate soil acidification and form soil compaction. It is said that manganese poisoning in many fruit tree areas is caused by soil acidification, and the direct cause of soil acidification is the use of potassium sulfate for many years. Therefore, the southern grape producing areas with sour soils should not use potassium sulfate for a long time.
It should be noted that the quality of potassium sulfate and potassium sulfate compound fertilizer on the market is uneven, some are mixed processing substances of potassium chloride and potassium sulfate, some contain a lot of impurities, and in the processing technology, there is also a world of difference between brands. Therefore, we should be particularly cautious when choosing this type of fertilizer.
<h1 class="ql-align-justify" > potassium nitrate</h1>
Potassium nitrate is neutral in nature and is a chlorine-free potassium-containing potassium fertilizer containing nitrogen. It has medium price, high potassium content, strong water solubility and quick-acting, can supplement both potassium and nitrogen, and can be applied by soil retroactively or sprayed. Although long-term use of potassium nitrate will not acidify the soil, but because it contains nitrate nitrogen, it is easy to cause fertilizer loss when used in the field, so it is best not to use it as a bottom fertilizer.
In addition, the nitrogen fertilizer in potassium nitrate will cause the grapes to grow new shoots due to excessive nitrogen, causing the berries to delay ripening, so potassium nitrate is also not suitable for use when the crop is too much fertilizer or close to maturity. Potassium nitrate can be used during the growth period, normal growth period and fruit expansion period when grapes require relatively large nitrogen.
It is understood that many vineyards in the appellation are transformed from paddy fields, and we do not recommend using potassium nitrate in this case. Because potassium nitrate is not easy to bind to soil colloids, it is easily leached. In addition, potassium nitrate is not suitable for use during periods of heavy rainfall, because in the case of long-term hypoxia flooding, nitrate can easily be converted into nitrite and harmful to the roots of the plant.
In addition, some fruit friends used potassium nitrate and found that the grapes had a phenomenon of rejuvenation and poor color change.
Why? This is because the rejuvenation of grapes is caused by nitrogen deposition and excessive nitrogen content in the soil. If too much potassium nitrate is applied during the grape color transition period, nitrogen will be stored in the plant, which will seriously affect the color change of the grapes. Potassium nitrate is strictly speaking a compound fertilizer, which contains nitrogen and potassium fertilizers. Potassium nitrate in general contains up to 13.5% nitrogen.
<h1 class="ql-align-justify" > potassium dihydrogen phosphate </h1>
Potassium dihydrogen phosphate is a very good phosphorus and potassium dual element fertilizer, with high content, high purity, full water solubility, fast effect, wide range of application, high safety factor characteristics, suitable for different growth periods of grapes. Generally before and after flowering, we can use it to promote the germination of roots and flower bud differentiation, to provide energy for flowering and fruit setting; in the fruit coloring period, it can also promote the pink coloring of grapes and increase the sweetness of the fruit; after fruit picking, the use of potassium dihydrogen phosphate can effectively promote the old ripening of branches and improve the degree of lignification of the fruit.
Many fruit farmers believe that potassium dihydrogen phosphate can only be used for foliar spraying, in fact, it can also be applied to the soil, especially drip irrigation. When potassium dihydrogen phosphate is used as a flush fertilizer, the biggest advantage is that it exists mainly in the form of dihydrogen phosphate and hydrogen phosphate in the soil, and the absorption of phosphorus by grape plants is mainly based on dihydrogen phosphate and hydrogen phosphate. Therefore, water-soluble potassium dihydrogen phosphate can also improve alkaline soil conditions in the process of flush fertilization, so that the pH of the soil solution is buffered to a range acceptable to a crop. Of course, there are many potassium dihydrogen phosphate on the market that are fakes and need to be carefully selected.
<h1 class="ql-align-justify" > potassium humic acid</h1>
Potassium humic acid is a slow-acting organic solid potassium fertilizer, because the humic acid in it has strong biological activity, so it has a very strong adsorption, complexation, chelating. In addition to increasing the available potassium content in the soil, potassium humic acid can also reduce potassium loss and fixation, and improve the efficiency of crop potassium absorption and utilization.
Not only that, potassium humate has a good effect on activating soil, promoting crop growth and resistance. In particular, the compound potassium humic acid can also provide crops with nitrogen, phosphorus, potassium, organic matter and trace elements and other nutrients, which can promote crop growth, improve crop stress resistance, improve crop quality, protect the agricultural ecological environment, etc., and can be widely used in the base fertilizer, topdressing and foliar spraying of various crops.
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