What are the reasons for soybean yield reduction from continuous cropping?
Soybean is a very common yet also very important food crop in China. It has a wide planting area, and the various soy products derived from soybean also have very large market demand in China. Therefore, there are still very many people growing soybean now, and when we grow soybean, we must not practice continuous cropping. Otherwise, it will reduce soybean yield. So what are the reasons for soybean yield reduction from continuous cropping? Let's take a look below!
1. Nutrient factors
Continuous soybean cropping, like many vegetable crops, will damage the soil's nutrient structure if the same land is planted year after year. Because soybean absorbs the same nutrients from the soil every year, the nutrients in the soil are continuously depleted in a one-sided way. As a result, it later cannot meet the nutrient needs of soybean growth, causing poor soybean plant development and reduced yield. Moreover, during development, soybean also produces a hydrolysis effect. This effect causes the total nitrogen content in the soil to rise sharply, while the content of available potassium and available phosphorus is largely reduced because of it, seriously affecting the normal growth of soybean.
2. Pest and disease factors
If soybean is continuously cropped on the same land, then various pests and diseases are extremely likely to occur, posing a serious threat to soybean growth. For example, in soil under continuous soybean cropping, there are very many bacterial spot disease, cyst nematodes, and sclerotinia disease, etc., that spread by parasitizing soybean. The pathogens and eggs of these pests and diseases all overwinter in that plot. In the second year, once the environment is suitable, the conditions for disease occurrence can be regained, continuing to harm the soybean planted in the second year. Year after year, the occurrence of pests and diseases becomes more and more serious, and the yield will naturally drop sharply.
3. Biological factors
Another main reason for soybean yield reduction from continuous cropping is biological factors. If soybean is continuously planted on the same land for more than 3 years, then the microbial population in the soil will undergo very great changes, producing more putrefactive bacteria. These include various microorganisms that reduce soybean germination rate and harm the roots. Among them, fungi in particular inhibit the growth and development of continuously cropped soybean, and no matter what life activity continuously cropped soybean carries out, some organic substances produced by its plants act as inhibitors, causing great damage to the soil structure, and soybean yield is reduced because of this.
4. Plant factors
Continuous soybean cropping has a very great impact on the soil's nutrient structure, making the soil nutrient structure too simple. Its physicochemical properties and biological activity will also change because of this, producing serious pests and diseases, causing poor soybean development and declining plant growth. The distribution of the plant canopy will also become unbalanced because of this. Generally, the leaf area in the middle layer shrinks because of this, and the leaves become yellow and wilted. Production capacity declines, and the soybean plant accumulates insufficient nutrients, thus leading to reduced yield.
The above is a brief introduction to the reasons for soybean yield reduction from continuous cropping. That is all for today's introduction. This article is for reference only. Thank you everyone for reading and supporting.