What are the benefits of applying lime to red soil? How to judge whether the soil needs lime in the field?

Red soil is developed under the vegetation of tropical and subtropical rain forest, seasonal rain forest or evergreen broad-leaved forest. What are the benefits of using lime in red soil? How to judge whether the soil needs lime in the field?

The advantages of applying lime to red soil are as follows:

① reduces soil acidity and increases soil pH.

② reduces the adsorption of phosphorus by red soil, improves the effect of phosphate fertilizer, increases the availability of elements such as calcium and magnesium in soil, and reduces aluminum damage.

③ promotes the reproduction of microorganisms, which is not only conducive to the formation of humus, but also eliminate the harm of organic acids and some toxic substances produced in the process of organic decomposition.

④ promotes soil aggregation and improves soil physical properties, which is beneficial to the growth of plant roots.

However, the application of lime in acid soil should not be excessive or widely used in successive years, so as to prevent the deterioration of soil physical and chemical properties and the decrease of the availability of phosphorus, iron, boron, zinc and manganese.

PS: how to judge whether the soil needs lime in the field?

Lime is an alkaline substance that can improve acidic soil. However, too much lime will also bring adverse consequences, such as the decline of soil fertility, reducing the effect of phosphate fertilizer and so on. Therefore, it is necessary to look at the land and crops for rational use.

Look at the ground: generally strong acid soil lime can be more; on the contrary, it should be less. Whether the soil is acidic can be judged by "three observations": first, to observe whether there are acid-loving plants in wild plants, if there are azaleas (Yingshan red), chestnut, etc., it shows that the soil is acidic; second, to observe the color of the soil, usually the color of the acidic soil is red and yellow; the third is to observe the field water quality, such as turbid irrigation water, or even rust film, which shows that the soil is acidic. In the acid soil of Zhejiang Province, when planting rice, 50-75 kg of lime is applied every 667 square meters, and the amount of some cold soaked fields and rust paddy fields can be appropriately increased.

Look at crops: generally planting acid-resistant tea trees, potatoes and other crops do not need to apply lime, while acid-sensitive barley, sugar beet, etc., need to apply more lime.

In the application method, lime had better be combined with organic fertilizer. Rice, for example, is often returned to the field with straw before transplanting, and then ploughed into the soil. For dry land, it should be applied at the time of cultivated land after harvest, or at the time of sowing.

In addition, lime should not be applied at the same time with ammonium sulfate, ammonium chloride or rotten organic fertilizer to prevent ammonia volatilization.