The reasons for the occurrence of alopecia areata are closely related to the severity of the occurrence of varieties, soils, nutrients and fertilizers, climate, cultivation and management, and pests and diseases. (1) Because varieties have different adaptability to the external environment and resistance to adverse environments, when the adverse external environmental conditions exceed the adaptation range of the varieties, it is prone to alopecia areata. Such as Danyu 24, due to the high temperature and dry weather, coupled with a higher planting density, the occurrence of alopecia areata is more serious, resulting in a large number of corn production, and Liaoyu 18 is basically no occurrence of alopecia areata. (2) Soil salinity has high salinity, low grazing, shallow ploughing, poor water retention and fertility retention, and poor soil, baldness, and lack of kernels. (3) When nutrition, fertilizer, water and fertilizer are applied, N, P and K are improperly combined, and no organic fertilizer or trace fertilizer is applied or applied. Especially, phosphorus and boron are insufficient in the soil; in the middle and later stages of corn growth, water supply is insufficient, especially maize The lack of water and fertilizer during the grain filling period will affect the production and operation of organic matter, which will lead to the later spinning of corn, the reduction of pollen in the field, the shortening of the lifespan of pollen and filaments, and the lack of kernels in corn. (4) Continuous drought in the mid-term of maize production in the climate caused many times of leaf curling, or the flowering period encountered high temperature and dry weather. The shortage of soil moisture affected the development of male and female corn, or the period of maize loosening and rain affected the normal flowering and pollination; Or pollination when the weather is poor wind pollination, can cause alopecia areata. (5) extensive management and management of cultivation, or planting density is too large, resulting in poor ventilation and light in the field, lack of light, decreased photosynthesis of plants, reduced synthesis of organic matter, affecting the development of male and female ear, resulting in alopecia areata. (6) Degree of occurrence of pests and diseases Various corn leaf spot diseases and corn seedling blight, sheath blight, and occurrence of stem rot may affect the normal growth and development of corn, resulting in poor corn growth, especially corn worms in corn. A large number of tassels began to occur, causing corn to fail to flower and pollen normally, resulting in a lack of grain. Medical Equipment,Medical Dental Unit,Dental Medical Equipment,Medical Dental Equipment ZHEJIANG FOMOS MEDICAL TECHNOLOGY CO.,LTD. , https://www.ifomos.com