pollution from feaces of livestock and poultry 1
The composition of feces and feces produced by different breeds and sizes of different livestock and poultry within a unit time is large, and is affected by seasons, regions, feeds, etc. According to reports, the meat-to-meat ratio of pigs in some advanced countries in Europe and the United States is 2. 4:1, and only a few in China currently reach 3.5:1; the weight of chicken is 1. 6:1, the world's advanced level. The ratio of the egg to the egg is 2. 4:1, and the country is 2. 6 to 3:1. It can be seen that the livestock and poultry raised in China are ingested with a large amount of food.
Excreted without digestion and absorption, both waste feed and pollute the environment. The recognized pollutants in livestock manure include suspended matter, organic matter, salt, sediment, bacteria, viruses and microorganisms, and N, P, K and other nutrients. These substances may cause environmental pollution during the collection, storage, transportation and land use of livestock and poultry manure, and it is easy to form non-point source pollution when entering water bodies.
Livestock and poultry manure becomes non-point source pollution mainly through the following ways: First, after the manure is applied as fertilizer, nitrogen and phosphorus in the feces are leached from the cultivated land; second, due to improper fecal storage in livestock and poultry production, nitrogen and phosphorus Leakage of nutrients; Third, improper storage and use of ammonia in the field to dissipate ammonia into the atmosphere; Fourth, there is no adequate wastewater treatment facility in rural areas, and pollutants are directly discharged into farmland. From the production of manure from livestock to field applications, the most common component of the loss of manure is nitrogen. Currently, in the US livestock waste management system, the loss of nitrogen is close to 75%. Most of the nitrogen is lost to the atmosphere by hydrolysis to ammonia. . About 50% of the nitrogen in fresh manure is organic nitrogen, 50% of nitrogen is inorganic nitrogen, and inorganic nitrogen is usually stored in the form of ammonia.
There is a large loss in collection, storage and transportation. In most manure management systems, 5% - 15% of organic phosphorus and potassium are lost during treatment. In open land systems, 50% of phosphorus and 40% of potassium can be mixed with soil by rainfall, infiltration and land surface. . Up to 80% of the nitrogen and phosphorus in the river and lake system can be lost, and most of the phosphorus is deposited in the sediment, which is difficult to remove in general treatment. The study found that in the infiltrated soil system, the concentrations of total nitrogen, ammonia nitrogen, dissolved phosphorus and total phosphorus increased linearly with the increase in the amount of livestock and poultry manure.
Provide the necessary moisture for the soil; Frequent application of manure can also increase soil resistance to weathering and water erosion, change soil air and tillage conditions, and increase soil organic matter and crop beneficial microbial growth. The downside is that excessive use of manure can jeopardize the quality of crops, soil, surface water and groundwater. In some cases (usually fresh poultry manure), high concentrations of nitrogen can burn crops; heavy use of manure can also cause accumulation of dissolved salts in the soil, increase soil salinity, and affect plant growth. According to reports, in 1999, 31% of pastures in Africa caused salinization of soil due to livestock manure contamination, and soil fertility declined.
The manure of livestock and poultry exists in the soil in the form of inorganic nitrogen and organic nitrogen. Inorganic nitrogen can be directly absorbed by the roots of plants for growth. The organic nitrogen in the soil can gradually form inorganic nitrogen over time, if there is enough time. The organic nitrogen in the feces can be converted into inorganic nitrogen available to plants. Nitrogen in livestock manure may also be lost in the soil by denitrification (inorganic nitrogen is lost by bioconversion to gaseous nitrogen). Because of nitrogen removal, nitrogen first needs to be oxidized to nitrate nitrogen and then to nitrogen or nitrogen. Oxidizing gases, this complex process relies on ventilation and infiltration conditions. For example, anaerobic bacteria decompose nitrate nitrogen to release nitrogen, so the more oxygen in the soil, the less nitrogen loss. This loss is also related to soil type and rainfall patterns. Heavy and humid soils provide ideal conditions for maximum nitrogen loss from denitrification. French scholar Jo SeM Artinez (2002) proposed a method for studying the complex transfer process of nitrogen storage, treatment and field use in animal manure using the N15 isotope. The loss of nitrate nitrogen in livestock manure is caused by the movement of filtered water under the roots of the plant, while in the area below the roots, nitrate is a potential groundwater pollutant. Soil type and rainfall are the main factors affecting nitrate nitrogen infiltration. The amount of fecal (mainly nitrogen) loss depends on soil physical conditions and fecal application rates and is affected by the season.
P in livestock manure can be lost in both particulate and dissolved form, and most P is easily adsorbed by the eroded soil. P is usually present in the soil a few centimeters above the surface (especially in less ploughed soil), and the amount of soluble P in the soil at the surface of the soil with the strongest surface runoff is also very high. When the manure is applied according to the standard of crop demand for N, the content of P in the soil will rise rapidly, and the content of P exceeds the crop requirement, and P in the soil accumulates. The consequence of this situation is that on the one hand, it breaks the balance of soil nutrients in the region, affects crop growth, and increases the content of animal and plant products P in the region through complex biological chains; on the other hand, the accumulation in the soil P will enter the water body through soil erosion and osmosis, making the water body eutrophic .
In addition, the use of high-density livestock manure can also lead to soil salinization. High salinity can reduce the activity of the organism in the soil, limit or harm the growth of the crop, especially in dry climate. Livestock and poultry manure can also spread some weed seeds, affecting the growth of normal crops in the soil. Livestock and poultry manure often contain some toxic metal elements such as arsenic, cobalt, copper and iron. These elements are mainly found in solids after solid-liquid separation of feces . Excessive application of livestock manure in the soil may lead to the accumulation of these elements in the soil, potentially harmful to plant growth. Livestock and poultry manure also contains a lot of bacteria, bacteria
After the livestock manure enters the soil, it usually survives for several months in the soil, mainly affected by soil type, temperature and soil water pressure.
TO BE CONTINUE.......
Excreted without digestion and absorption, both waste feed and pollute the environment. The recognized pollutants in livestock manure include suspended matter, organic matter, salt, sediment, bacteria, viruses and microorganisms, and N, P, K and other nutrients. These substances may cause environmental pollution during the collection, storage, transportation and land use of livestock and poultry manure, and it is easy to form non-point source pollution when entering water bodies.
Livestock and poultry manure becomes non-point source pollution mainly through the following ways: First, after the manure is applied as fertilizer, nitrogen and phosphorus in the feces are leached from the cultivated land; second, due to improper fecal storage in livestock and poultry production, nitrogen and phosphorus Leakage of nutrients; Third, improper storage and use of ammonia in the field to dissipate ammonia into the atmosphere; Fourth, there is no adequate wastewater treatment facility in rural areas, and pollutants are directly discharged into farmland. From the production of manure from livestock to field applications, the most common component of the loss of manure is nitrogen. Currently, in the US livestock waste management system, the loss of nitrogen is close to 75%. Most of the nitrogen is lost to the atmosphere by hydrolysis to ammonia. . About 50% of the nitrogen in fresh manure is organic nitrogen, 50% of nitrogen is inorganic nitrogen, and inorganic nitrogen is usually stored in the form of ammonia.
There is a large loss in collection, storage and transportation. In most manure management systems, 5% - 15% of organic phosphorus and potassium are lost during treatment. In open land systems, 50% of phosphorus and 40% of potassium can be mixed with soil by rainfall, infiltration and land surface. . Up to 80% of the nitrogen and phosphorus in the river and lake system can be lost, and most of the phosphorus is deposited in the sediment, which is difficult to remove in general treatment. The study found that in the infiltrated soil system, the concentrations of total nitrogen, ammonia nitrogen, dissolved phosphorus and total phosphorus increased linearly with the increase in the amount of livestock and poultry manure.
1 Soil-contaminated
The basic function of the soil is that it has fertility and can provide the conditions of water, nutrients, air and heat necessary for plant growth and development, that is, it can be used for crop growth; another basic function is to decompose organic matter. These two aspects constitute an important part of the natural circulation of the soil. Livestock and poultry manure have both favorable and unfavorable aspects to the soil. Under certain conditions, the two aspects may transform each other. The beneficial side of livestock manure is: can be applied to farmland as a fertilizer to fertilize the soil;Provide the necessary moisture for the soil; Frequent application of manure can also increase soil resistance to weathering and water erosion, change soil air and tillage conditions, and increase soil organic matter and crop beneficial microbial growth. The downside is that excessive use of manure can jeopardize the quality of crops, soil, surface water and groundwater. In some cases (usually fresh poultry manure), high concentrations of nitrogen can burn crops; heavy use of manure can also cause accumulation of dissolved salts in the soil, increase soil salinity, and affect plant growth. According to reports, in 1999, 31% of pastures in Africa caused salinization of soil due to livestock manure contamination, and soil fertility declined.
The manure of livestock and poultry exists in the soil in the form of inorganic nitrogen and organic nitrogen. Inorganic nitrogen can be directly absorbed by the roots of plants for growth. The organic nitrogen in the soil can gradually form inorganic nitrogen over time, if there is enough time. The organic nitrogen in the feces can be converted into inorganic nitrogen available to plants. Nitrogen in livestock manure may also be lost in the soil by denitrification (inorganic nitrogen is lost by bioconversion to gaseous nitrogen). Because of nitrogen removal, nitrogen first needs to be oxidized to nitrate nitrogen and then to nitrogen or nitrogen. Oxidizing gases, this complex process relies on ventilation and infiltration conditions. For example, anaerobic bacteria decompose nitrate nitrogen to release nitrogen, so the more oxygen in the soil, the less nitrogen loss. This loss is also related to soil type and rainfall patterns. Heavy and humid soils provide ideal conditions for maximum nitrogen loss from denitrification. French scholar Jo SeM Artinez (2002) proposed a method for studying the complex transfer process of nitrogen storage, treatment and field use in animal manure using the N15 isotope. The loss of nitrate nitrogen in livestock manure is caused by the movement of filtered water under the roots of the plant, while in the area below the roots, nitrate is a potential groundwater pollutant. Soil type and rainfall are the main factors affecting nitrate nitrogen infiltration. The amount of fecal (mainly nitrogen) loss depends on soil physical conditions and fecal application rates and is affected by the season.
P in livestock manure can be lost in both particulate and dissolved form, and most P is easily adsorbed by the eroded soil. P is usually present in the soil a few centimeters above the surface (especially in less ploughed soil), and the amount of soluble P in the soil at the surface of the soil with the strongest surface runoff is also very high. When the manure is applied according to the standard of crop demand for N, the content of P in the soil will rise rapidly, and the content of P exceeds the crop requirement, and P in the soil accumulates. The consequence of this situation is that on the one hand, it breaks the balance of soil nutrients in the region, affects crop growth, and increases the content of animal and plant products P in the region through complex biological chains; on the other hand, the accumulation in the soil P will enter the water body through soil erosion and osmosis, making the water body eutrophic .
In addition, the use of high-density livestock manure can also lead to soil salinization. High salinity can reduce the activity of the organism in the soil, limit or harm the growth of the crop, especially in dry climate. Livestock and poultry manure can also spread some weed seeds, affecting the growth of normal crops in the soil. Livestock and poultry manure often contain some toxic metal elements such as arsenic, cobalt, copper and iron. These elements are mainly found in solids after solid-liquid separation of feces . Excessive application of livestock manure in the soil may lead to the accumulation of these elements in the soil, potentially harmful to plant growth. Livestock and poultry manure also contains a lot of bacteria, bacteria
After the livestock manure enters the soil, it usually survives for several months in the soil, mainly affected by soil type, temperature and soil water pressure.
TO BE CONTINUE.......
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