When is the right time to apply potassium fertilizer to rice
AbstractThe suitable times for applying potassium fertilizer to rice are the tillering stage, the young panicle differentiation stage and the booting stage. Applying potassium fertilizer at these three stages can effectively increase the seed-setting rate of rice, reduce pest and disease damage and increase yield. Combined application with phosphate fertilizer and nitrogen fertilizer can give full play to the effectiveness of potassium topdressing, among which the ratio of nitrogen, phosphorus and potassium is preferably 1 : 0.5: 1.2.
I. Suitable times for applying potassium fertilizer to rice
1. Tillering stage: potassium fertilizer can help rice accumulate more water and improve its ability to resist drought, high temperatures and low temperatures.
2. Young panicle differentiation stage: after rice enters young panicle differentiation, it enters the second peak period of fertilizer uptake, and at this time potassium fertilizer can be applied reasonably.
3. Booting stage: applying potassium fertilizer at the booting stage can increase the seed-setting rate, resist lodging, and at the same time reduce pest and disease damage.
II. Methods of applying potassium fertilizer to rice
1. Follow the “four more, four less” principle, that is, apply more to fields with low potassium content and less to the opposite; apply more to early rice and less to late rice; apply more to tall-stem varieties and less to short-stem varieties; apply more to hybrid rice and less to conventional rice.
2. Combined application with phosphate fertilizer and nitrogen fertilizer can give full play to the effectiveness of potassium topdressing, among which the ratio of nitrogen, phosphorus and potassium is preferably 1 : 0.5: 1.2.
3. Also apply an appropriate amount of lime, because potassium chloride and potassium sulfate are acidic fertilizers, and long-term use will cause soil acidification, so applying an appropriate amount of lime can neutralize soil acidity and is beneficial to rice growth.
4. During the growth process of rice, scientific and rational application of potassium fertilizer plays a key role in cultivating robust seedlings, improving disease resistance, insect resistance, lodging resistance, the seed-setting rate, and achieving high and stable yields.
III. Types of potassium fertilizer
1. Potassium sulfate
(1) Pure potassium sulfate is white or gray crystals, with relatively weak hygroscopicity, is not easy to cake during storage, and is easily soluble in water. It is a quick-acting potassium fertilizer. Potassium sulfate is a physiologically acidic fertilizer. After being applied to the soil, potassium ions can be absorbed by crops and adsorbed by the soil.
(2) The sulfate radical is retained in the soil solution to form sulfuric acid, which increases soil acidity. Potassium sulfate can be used as a base fertilizer and topdressing, but potassium has very little mobility in the soil, so it is generally better used as a base fertilizer or early topdressing.
2. Potassium chloride
(1) Pure potassium chloride is also white crystals, sometimes slightly colored, or light brick red, hygroscopic, soluble in water, and is also a quick-acting potassium fertilizer.
(2) After potassium chloride is applied to the soil, potassium ions will be directly absorbed and utilized by crops, and will also exchange with cations on soil colloids. The remaining chloride ions correspondingly produce hydrochloric acid. Potassium chloride is also a physiologically acidic fertilizer.
3. Plant ash
(1) What is left from burning wood ordinarily is plant ash. This can also be used in rice fields. It is an alkaline fertilizer with a relatively complex composition, containing various mineral elements that plants have.
(2) Among them, it contains more potassium. Plant ash is also a quick-acting alkaline potassium fertilizer, mainly existing in the form of potassium carbonate, so it can be used as a base fertilizer and topdressing.