What is farmyard manure?

There are many types of farmyard manure, with wide sources and large quantities. It is easy to obtain and utilize locally, and the cost is relatively low. The characteristic of organic fertilizer is comprehensive nutrition. It contains not only nitrogen, phosphorus and potassium, but also calcium, magnesium, sulfur, iron and some trace elements. Most of these nutrients are in the state of organic matter and are difficult to be directly absorbed and utilized by crops. They must be gradually released through chemical and physical effects in the soil and fermentation and decomposition of microorganisms, so that the fertilizer effect is long-term and stable. In addition, the application of organic fertilizers can help promote the formation of soil aggregate structure, coordinate the air-water ratio in the soil, loosen the soil, and increase water retention, heat preservation, ventilation, and fertilizer retention capabilities. With the improvement of agricultural production levels and the development of green food production, the demand for organic fertilizers in farmland is becoming more and more urgent. Whether from the perspective of food safety or sustainable development of agricultural production, chemical fertilizers cannot completely replace farmyard manure. In the past, only chemical fertilizers were applied, and the plowing layer was shallow, prone to drought and floods. Chemical fertilizers burned seedlings, soil acidified, and soil fertility was insufficient. Moreover, the nutritional content of chemical fertilizers is too simple, and the crops grown have poor taste, reducing the quality of agricultural products. Therefore, in order to restore and maintain soil fertility, organic fertilizers must be applied. What we usually call "organic fertilizer" refers to traditional farmyard fertilizer.