Cotton cultivation technology system
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High-density type: represented by the United States, Russia's Central Asian countries, North Africa, Egypt, and Xinjiang, China, with a planting density of 120,000 hm-2 or more. The frost-free period of these cotton-planting areas is short, relying on large groups to fight for more bells.
Low Density: represented by the Indian Upland Cotton Region, the Yangtze River Valley in China, and the South China Cotton Region. The planting density is only about 30,000 hm-2. These cotton-planting areas have long frost-free periods or lack of frost, water and fertilizer conditions are good, the unlimited growth habits of cotton are used, and fruit branches are left over 20 times, relying on large individuals to win more bells. Due to the "sparse trees", the pruning requirements are not strict.
Medium and dense type: including Pakistan in South Asia, Cameroon in West Africa and Mali, etc., with China's North China cotton area is the most typical, the general density of 50,000 to 90,000 hm-2. In these areas, the frost-free period is medium, and the distribution of rainfall varies greatly from year to year, and human resources are abundant. For the purpose of prolonging the growing period, full use of caloric resources, management, intensive cultivation, repeated topdressing of nitrogenous fertilizers, strict pruning (so-called "five-step pruning method") . It is characterized by a large range of changes in cotton bolls and manual control of plant type. The formation and development of cotton planting technology in Hebei has undergone three stages. 1 Ancient cotton-planting technology Hebei cotton-planting began in the Tang Dynasty, advocated in the Ming Dynasty, and flourished in the Qing Dynasty. The cotton cultivation technology system has basically taken shape in the early Qing Dynasty. During the Qing Qianlong period, the cotton figures and texts of the cotton farmers were systematically summarized. Among them, there are six aspects of cultivation techniques: (1) seed treatment (breeding), and drying (black and black core seed collection, winter harvest And exposure), seed selection (emphasis of solid) and dressing of fire ash (Wo to boiling soup, waiting for its cold, and firewood ash); (2) farming, plowing turning hoe hoe (kind of sand folder Earth, in the spring and autumn, the frequency of plows is fine and classified as ravines. Irrigation (the first type of cotton must be drilled first, and one well can fill forty acres). Fine); (3) sowing, deep sowing (deep desire of species, complex soil to be real--this method is suitable for maintaining seedlings in the drylands), sowing date (early before the valley rain is cotton, over grain rain is late cotton); (4) sparsely seedlings, The density of old seedlings was about 30,000 hm-2, and the new method was 75,000 hm-2. (5) The tip was made. The seedlings were shot one-half to the top, and the branching feet were half-to-tip, indicating their mutual obscuring effect. (Do not order to knead, it is intensive and real thick), the time should be three volts; (6) picking, picking at any time after bolling, drying for storage, the price of different distinguish yellow white cotton. It can be seen that Hebei Province has formed a systematic cotton cultivation technology system in the 18th century, which is a type of medium density. 2 The intensive cultivation stage After the 20th century, with the introduction of upland cotton, modern cotton planting methods were introduced to form complementary technologies, which were mainly embodied in the construction of improved varieties, pest control, and chemical fertilizer application. In the 1950s, due to the extensive attention given to cotton, the preliminary results of physiological research were combined with the experience of model workers and cotton planters, and beneficial measures would be considered to be extremely effective. Cotton became the most technically and labor-intensive field cultivation crop.
