In the study, scientists found that a weak link in soil science, botany, watershed ecology, and environmental science research is the relationship between the loss of soil nutrients and the evolution of land cover patterns in small watersheds. Land use, as a comprehensive reflection of various activities of human use of land, is closely related to soil nutrients. Land use patterns can affect the litter and residue of vegetation and affect the activities of soil microbes, which can cause changes in soil nutrients. Reasonable land use methods can improve the soil structure and increase the resistance of the soil to external environmental changes. Unreasonable land use patterns will lead to a decline in soil quality, accelerate erosion, and lead to soil degradation. This paper focuses on the Daijiagou Small Watershed in Changshou District, Chongqing City, aiming to analyze the differences in soil nutrients under different land use patterns in small watersheds and the distribution characteristics of soil nutrients on the slopes, so as to develop a well-recovered ecosystem for small watersheds. Fertilizer soil, improve soil quality and provide scientific basis.
The evolution of land-use landscape patterns leads to changes in soil nutrients, affecting the distribution and migration of soil nutrients. Especially on the same slope, the micro-landscape pattern often leads to high heterogeneity of soil nutrients. The changes in water and nutrients are closely related to the landscape structure. Landscape patterns and land use patterns regulate the circulation of water and nutrients. Different land use methods, soil erosion and other reasons will cause gradient distribution of soil nutrients on the same slope. With the pressure of population growth, the contradiction between man and land in the Daijiagou watershed has become increasingly prominent. The land reclamation coefficient remains high and the terrain is broken. There are mainly land use structures such as cultivated land, forest land, and unused land (grassland) on the hillslopes in the basin. Man-made disturbances resulted in various types of land use structures on the slope, which seriously affected the spatial distribution of soil nutrients.
Soil nutrient distribution on slope surface 3.1.1M1 Average content of soil nutrients in each slope position of slope structure type Table 1 shows that from the top of the slope to the slope foot, the organic matter content in the slope woodland> in-slope farmland> slope foot farmland, gradually decreases. . The high content of organic matter in the open forest land may be due to the fact that litter is greater than cultivated land and less human disturbance.
Although the slope farmland is larger than the slope foot farmland, the organic matter content is higher than that of the slope foot farmland. The reason for this analysis may be due to the distance from the residential area. The farmland in the middle of the slope is far away from the residential area. Farmers habitually grow some relatively seasonal crops. Compared with farmland at the foot of the slope, the farmer's farming frequency is much lower. The influence of human disturbance on the soil is often a factor that influences the content of soil organic matter. TN, TK, TP average content change trends are: sparse woodland> slope foot farmland> slope middle farmland, but the TN content in the slope farmland and slope foot farmland. The change was not obvious, and the change of TP content in the three slope positions was not obvious. The total amount of nutrients in the open forest land is the highest among the three slopes. The total amount of nutrients in the cultivated land in the slope is lower than that in the foot slope. This may be due to the large gradient of cultivated land in the slope, which is likely to cause the loss of soil nutrients under the effect of rainfall and runoff.
Related instruments: soil nutrient tester soil moisture recorder
Pharmaceutical intermediates are actually some chemical raw materials or products used in the synthesis process. Chemical products do not need that kind of production license. They can be produced in ordinary chemical plants. As long as they reach some grades, they can be synthesized appropriately.
Types of intermediates
Intermediates refer to semi-finished products, which are intermediate products in the production of certain products. For example, to produce a product, it can be produced from intermediates to save costs.
Intermediates are formed from cyclic compounds such as benzene, naphthalene, anthracene, etc. through sulfonation, alkali fusion, nitration, reduction, etc. For example, benzene is nitrated to nitrobenzene, and then reduced to aniline, which can be chemically processed into dyes, drugs, vulcanization accelerators, etc. Both nitrobenzene and aniline are intermediates.
There are also acyclic compounds such as methane, acetylene, propylene, butane, butene, etc. through dehydrogenation, polymerization, halogenation, hydrolysis and other reactions. For example, butane or butene is dehydrogenated to butadiene, which can be chemically processed into synthetic rubber, synthetic fibers, and the like.
Butadiene is an intermediate.
It originally refers to the intermediate products produced in the process of synthesizing chemical products such as spices, dyes, resins, drugs, plasticizers, rubber accelerators, etc. using coal tar or petroleum products as raw materials. It now generally refers to various intermediate products obtained in the process of organic synthesis.
5-Bromo-2 4-dichloropyrimidine,4-Bromo-2-fluorobenzoic acid,4-Bromo-2-fluorobenzaldehyde,6-(4-Aminophenyl)-4 5-dihydro-5-methyl-3(2H)-pyridazinone
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