What are the characteristics, advantages and disadvantages of sand, loam and clay?

Sand, loam and clay are classified according to soil texture. Generally speaking, the sand content of sandy soil is above 50% and the clay content is below 30%. Therefore, its soil particles have large pores, few small pores, weak capillary action and poor water retention. However, sandy soil has good permeability and is not drought-tolerant, and soil microbial aerobic is dominant. Because of the loose texture, farming is convenient. Organic matter in sandy soil decomposes quickly, accumulates less, and nutrients are easy to leach out, resulting in nutrient deficiency. Fertilization in sandy soil takes effect quickly, crops grow early and develop quickly, but there is no stamina, which often leads to fertilizer deficiency and premature aging, low seed setting rate and incomplete seeds in the later stage. This kind of soil is neither fertile nor resistant to fertilizer. If too much fertilizer is applied at one time, it will not only cause loss and waste, but also cause crops to be crazy for a long time. Therefore, we should pay attention to a small amount of fertilization and apply more organic fertilizer and mud fertilizer. The characteristics of clay are just the opposite of that of sand. Its texture is sticky, its arable property is poor, and there is a lack of macropores among soil particles, so its ventilation and water permeability are poor. It is neither drought-resistant nor waterlogging-resistant, but it has strong water and fertilizer conservation, is fertilizer-resistant, is not easy to lose nutrients, is richer than sand, decomposes organic matter slowly, and is easy to accumulate humus. This kind of soil is rich in water, less in gas, with little change in ground temperature, cold soil, weak aerobic decomposition, slow decomposition and transformation of nutrients, late effect after fertilization, and the fertilizer has stamina to prevent the seedlings from getting old. Excessive fertilization will cause crops to be greedy and mature late. The nature of loam is between sand and clay, and its fertility is good. This kind of soil has the advantages of less contradiction between water and gas, ventilation and water permeability, moderate fertilizer supply and conservation ability, drought resistance and waterlogging resistance, strong stress resistance, wide variety adaptability and long suitable farming period, and is easy to cultivate high and stable yield soil. Wang Xiurong, South China Agricultural University.