Agricultural nitrogen

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  • Enormous increases in agricultural productivity can properly be associated with the use of chemicals. This statement applies equally to crop production through the use offertilizers, herbicides, and pesticides, as to livestock production and the associated use of drugs, steroids, and other growth accelerators. There is, however, a dark side to this picture and it is important to balance the benefits which flow from the use of agricultural chemicals against their environmental impacts, which sometimes are seriously disadvantageous.

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  • Poverty is a severe problem in Africa, Asia, South America and even in pockets of the developed world. Addressing poverty alleviation via the expanded use of biological nitrogen fixation in agriculture was the theme of the 15th International Congress on Nitrogen Fixation.

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  • How do plants obtain their hydrogen and oxygen? Let us now consider the three gases, hydrogen, oxygen and nitrogen, which constitute the remainder of the organic part of plants. Hydrogen and oxygen compose water, which, if analyzed, yields simply these two gases. Plants perform such analysis, and in this way are able to obtain a sufficient supply of these materials, as their[Pg 24] sap is composed chiefly of water.

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  • Tham khảo sách 'biological nitrogen fixation: towards poverty alleviation through sustainable agriculture', khoa học tự nhiên, công nghệ sinh học phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả

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  • Farmers have a reputation for being innovators and experimenters, willing to adopt new practices when they perceive some benefit will be gained. Over the past 40 to 50 years, innovation in agriculture has been driven mainly by an emphasis on high yields and farm profit, resulting in remarkable returns but also an array of negative environmental side effects.

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  • If better management (BMP) was adopted in Vietnam there is evidence that the current trends and past environmental degradation can be stopped and even reversed, and shrimp production efficiency can be increased.

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  • All plants when carefully burned leave a portion of ash, ranging widely in quantity, averaging about 5 per cent, and often exceeding 10 per cent of the dry weight of the plant. This plant ash represents inorganic substances taken from the soil by the roots. In addition, the nitrogen of plants, averaging about 2 per cent and often amounting to 4 per cent, which, in burning, passes off in gaseous form, is also usually taken from the soil by the plant roots. A comparatively large quantity of the plant is, therefore, drawn directly from the soil. Among the ash...

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  • Cho phép nhập theo phiên âm Acacia tree species that grows fast, capable of improving land. The tree has thick foliage good defense capability. Wood is hard core, dark, fine grained, used as timber, timbering, flooring, plywood, pulp, firewood and charcoal. characteristics Tall trees, up to 30 environment. Strong capacity for regeneration. Acacia leaves large, there are four main tendons, leaves Acacia auriculiformis long, slightly curved, narrow and has two main tendons. Acacia hybrid between the two types of intermediate leaves Acacia auriculiformis and Acacia midrib with 3-4.

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  • The number of organic manures is almost countless. The most common of these have been described in the previous chapters on the excrements of animals. The more prominent of the remaining ones will now be considered. As a universal rule, it may be stated that all organic matter (every thing which has had vegetable or animal life) is capable of fertilizing plants. DEAD ANIMALS.

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  • In composting stable manure in the most economical manner, the evaporation of the organic parts and the leaching of the ashy (and other) portions must be avoided, while the condition of the mass is such as to admit of the perfect decomposition of the manure. Solid manures in their fresh state are of but very little use to plants. It is only as they are decomposed, and have their nitrogen turned into ammonia, and their other ingredients resolved into the condition required by plants, that they are of much value as fertilizers. We have seen that, if this decomposition...

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  • Trees as high as 25 - 30 m, small branches, self-pruning well, easy to grow by seed, long life, nitrogen fixation. Can grow on various soils, including poor soils, poor drainage. Grows fast, high-speed growth in the first few years. Song on a place if planted several consecutive cycles can lead to poor potassium and magnesium in the soil. Pit wood, pulp (wrapping paper), chipboard and wood stem as well due to the high heat of coal. In silvicultural crops used as the supporting soil improvement, shade....

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  • In composting stable manure in the most economical manner, the evaporation of the organic parts and the leaching of the ashy (and other) portions must be avoided, while the condition of the mass is such as to admit of the perfect decomposition of the manure. Solid manures in their fresh state are of but very little use to plants. It is only as they are decomposed, and have their nitrogen turned into ammonia, and their other ingredients resolved into the condition required by plants, that they are of much value as fertilizers. We have seen that, if this decomposition takes...

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  • The objective of waste water treatment is to prevent large quantities of substances to reach and impact the environment in high doses and concentrations. Areas of high population densitiy naturally are areas were production of sewage sludge is high (see Figure 1-1). Presently about 8 million t of sewage sludges (MAGOAROU 2000) are produced each year in the EU member states (Table 1-1). Its high content of organic materials, of nitrogen and phosphorous suggest their use as soil conditioner and fertilizer in agriculture.

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  • Non-point source controls washed off fields is the largest source of agricultural pollution in the United States. Farmers may utilize to reduce runoff flows and retain soil on their fields. Common techniques include contour plowing, crop mulching, crop rotation, planting perennial crops and installing riparian buffers. Nutrients nitrogen and phosphorus are typically applied to farmland as commercial fertilizer; animal manure; or spraying of municipal or industrial waste water (effluent) or sludge.

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  • Agriculture has been theorized to have become the dominant way of producing food since the Neolithic Revolution. Through early biotechnology, the earliest farmers selected and bred the best suited crops, having the highest yields, to produce enough food to support a growing population. As crops and fields became increasingly large and difficult to maintain, it was discovered that specific organisms and their by-products could effectively fertilize, restore nitrogen, and control pests.

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  • Applying much more phosphorus fertilizer and manure than crops can use builds up phosphorus in soil. After continuous over-fertilization, agricultural fields become a persistent reservoir for phosphorus that ends up polluting water bodies. Recent USGS study found that in the agricultural Midwest, many streams have their highest nitrogen concentrations in the spring, peaking in April-May.

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  • Every year, farm operators apply more than 12 million tons of nitrogen fertilizer and 8 million tons of phos- phorus fertilizer to agricultural land in the U.S. Unless carefully managed, much of it is carried off the fields by runoff or percolates into drainage systems, eventually ending up in streams, rivers, lakes and underground aquifers. Animal manure from livestock is also an important contributor to nutrient pollution, particularly phos- phorus.

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  • In most agricultural settings, commercial fertilizer provides only one source of N used for crop production. Animal manure, biological N fixation, mineralization from soil organic N, and deposition of N from the atmosphere can also contribute to soil fertility and surface water contamination. Because there are multiple sources and sinks of N in the soil, the relationship between N fertilizer application rate and nitrogen loss in drainage water is not always consistent across locations and across studies.

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  • Howarth et al. [10] developed an approach for estimating the net nitrogen inputs to a region N that is highly correlated with average nitrogen transport in the rivers draining temperate regions (Fig. 2). Net N input to a region was defined as sum of N in fertilizer used, biological N fixation of agricultural crops, oxidized N in atmospheric deposition in the region, and the N in food and feed imported to the region minus the N in food and feed exported from the region. This approach assumes that there is no net gain or loss of N from soil organic matter.

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  • In many settings nitrogen enrichment of surface water bodies has increased following the increased use of N fertilizers. The precise contribution of nitrogen fertilizers to surface water nitrogen has been difficult to quantify because there are multiple sources of nitrogen contributing to most water bodies, and, depending on environmental conditions, a certain portion of soil nitrogen may be converted to gaseous or immobile forms.

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