Want high yields from spring corn? Proper potassium fertilizer application is key
Spring corn grows slowly at the seedling stage, with sturdy plants and strong lodging resistance. Its yield per plant is relatively high, but it is susceptible to disease infection during hot, rainy seasons, which can affect spring corn yields. Mastering spring corn fertilization methods can help achieve high and stable yields. Apply organic fertilizer widely. Spring corn is a high-yield crop, and its yield level...
As corn yield levels increase, the supply of available soil potassium during key growth stages must increase accordingly. Results from many long-term corn positioning trials have proven that when yields increase by 10%-20%, potassium uptake also increases correspondingly. Appropriately raising the potassium content in corn tissues is necessary to maintain stable high yields. In the northern spring corn region, although soil available potassium content is at a relatively high level (such as 70-130 mg/kg), applying potassium fertilizer still has a yield-increasing effect. Especially in soils with medium available potassium content and limited slowly available potassium capacity, additional potassium fertilizer should be considered for high-yield fields. Therefore, when using yield targets as the main basis for recommending potassium application, paying attention to applying more potassium fertilizer to soils with lower available potassium content is a necessary measure to ensure high yields. It should also be noted that even when soil available potassium levels are medium, applying an appropriate amount of potassium fertilizer can still produce good results. The effect of increasing planting density on potassium demand. In current high-yield hybrid corn cultivation, yields are often greatly increased by increasing density, and at the same time, high-density plants also significantly increase potassium uptake from farmland. Therefore, when density increases, if potassium fertilizer is not applied accordingly or soil potassium availability is not improved, crops may fail to obtain sufficient potassium, and yields may decline or fail to reach the ideal level. However, after applying an additional 5-6 kg/mu of potassium fertilizer, yields did not decrease but instead increased somewhat, especially in corn plots with low available potassium content and irrigation conditions. Therefore, when making fertilizer recommendations for corn, in order to adapt to higher density and yield levels, the amount of potassium applied should be appropriately increased above the conventional rate.
In dense-planting high-yield corn cultivation, coordinating the balanced supply of potassium and nitrogen fertilizer is crucial. Under normal circumstances, excessive nitrogen is applied to achieve high-yield goals, which increases the plant's infection rate from diseases and pests such as stalk rot, root rot, and bacterial wilt. If potassium fertilizer supply is not increased accordingly, symptoms of nitrogen-potassium imbalance will develop. Potassium deficiency first weakens the breaking strength and epidermal thickness of corn stalks and leaves, which both increases the possibility of lodging and raises corn's sensitivity to insect pests and diseases. As is well known, among nutrient elements, both nitrogen and potassium have a major effect on corn disease resistance, but their directions of action differ: excessive nitrogen often increases corn's sensitivity to disease, while potassium acts in the opposite way and can increase crop disease resistance.
Field potassium deficiency diagnosis and topdressing remedial measures: When spring corn enters the jointing stage, the growth period from the small funnel stage to the large funnel stage is its rapid growth period, and demand for nitrogen, phosphorus, and potassium all increases. In actual production, it is customary to topdress only nitrogen fertilizer without paying attention to potassium topdressing. However, in high-yield dense-planting spring corn cultivation, whether topdressing is actually needed can be answered simply by observing plant growth conditions. That is, often around 9 or 10 in the morning, go to the corn field to look, especially on windy days. If you see spring corn leaves already wilting in the morning, then it is potassium deficiency. This is because for farmland that generally does not urgently need irrigation, normal healthy corn plants will not show leaf wilting in the morning; wilting after noon is normal. Potassium can affect the closing of leaf stomata and increase the plant's water-retention function. When potassium is deficient, stomatal resistance is high and the stomata cannot close normally, causing severe water loss in the corn plant and resulting in wilting. At this point, potassium fertilizer must be topdressed as a remedy. The most feasible measure is to topdress 5-8 kg/mu of potassium chloride, applied in furrows or holes, then covered with soil.