(1) The period of agricultural mechanization In the 1930s, tractor arable land was popularized in the United States. By 1959, the cultivation, sowing, harvesting, threshing, and cleaning of major crops such as wheat and corn in the United States had reached 100% mechanization. Since then, in order to meet the market demand for the diversification and large-scale development of family farms, the United States has continuously introduced small, multi-functional and multi-variety agricultural machinery and high-power, highly automated large-scale agricultural machinery.
(2) The period of agricultural chemistry. Agricultural chemistry includes the extensive use of fertilizers, pesticides (herbicides, insecticides), and soil amendments. After the Second World War, in order to increase agricultural output, the use of chemical fertilizers in American agriculture increased dramatically. At the same time, in order to improve the pH of the soil and the adverse effects of long-term application of chemical fertilizers, the United States has also increased the amount of soil amendments year by year. Since 1960, the use of herbicides has increased rapidly and has now surpassed insecticides.
(3) The period of improved varieties of agriculture. Around the 1970s, in order to adapt to the climate and soil requirements of different regions, the United States bred many hybrid varieties, and began to use biological genetic engineering methods, combining nuclear radiation technology and aerospace engineering technology to transform , Optimize the genetic genes of seeds to greatly improve the yield and quality of agricultural products. At the same time, many good breeds of livestock and poultry have been cultivated, and industrialized and large-scale breeding have been implemented.
After going through the above three stages and realizing agricultural modernization, American agriculture has not stopped there. With the application of computer technology and biotechnology, methods such as "precision agriculture" and "genetic agriculture" have emerged one after another. In particular, many super-large farms have moved towards "computer integrated adaptive production", which integrates market information, production parameter information (climate, soil, seeds, agricultural machinery, fertilizers, pesticides, energy, etc.), capital, labor information, etc., and selects The best planting plan, in the process of growth, according to the changes in the local microclimate of different plots, adaptive water spraying, fertilization, spraying, etc., agricultural production tends to be factoryized and automated, and the modernization level of American agriculture is continuously improved. At the forefront of the world.
