Friday , September 22 2017

Fertilizers




  • The increasing number in population means higher demand for food. Threats in agricultural production such as pests, loss of soil fertility and lack of nutrients may result in low percentage of plants to harvest. If these problems are not addressed, there would not be enough crops which compose a big fraction of our food supply to sustain the needs of the people. Hence, the importance of using fertilizers rises.

    Fertilizers are substances containing chemical elements such as manure or mixture of nitrates that improves the growth of plants. They give nutrition to the crops. When added to soil or water, plants can develop tolerance against pests like weeds, insects and diseases. This means that the need for herbicides and insecticides are reduced producing healthier crops. Diseases can also be eliminated which gives aesthetic value to the harvest.

    Apart from pests, one big problem of agriculture is the soil condition. Drought and lack of water are some of the issues in crop production. Dry farms tend to create very low and uncertain yields. Changes in weather like uneven distribution of rainfall or long breaks of rainy season result to either excessive amount of rainfall or deficiency in water when it is highly needed. Fertilizers help plants to overcome these situations by increasing their capacity to hold more water and improve the rooting depth. The potassium found in fertilizers is meant to make the stalks and straws of plants stronger.

    Fertilizers do not only assist in increasing yields and promoting healthy growth of plants but also in their development. They contain nitrogen which acts as a growth booster which can be characterized by the green color of plants. Phosphorus substance in fertilizers aids in the faster formation of seeds and root development.

    The importance of fertilizers stretches in every corner of our planet. Lack of supply for food would be evident without them.

    Nutrient deficiency

    Soil fertility

    Soil fertility largely depends on its nutrient status: the amounts and rates of nutrient supplies for plant growth. An adequate nutrient supply is an essential factor in plant growth. If there is an adequate supply of nutrients in the soil, plants are likely to grow well and produce high yields. If even one of the nutrients needed is in short supply, plant growth is limited and yields are reduced.

    Soil fertility

    Soil fertility largely depends on its nutrient status: the amounts and rates of nutrient supplies for plant growth. An adequate nutrient supply is an essential factor in plant growth. If there is an adequate supply of nutrients in the soil, plants are likely to grow well and produce high yields. If even one of the nutrients needed is in short supply, plant growth is limited and yields are reduced.

    “Law of minimum” 

    The law of minimum says that one nutrient cannot be substituted for another. Plant growth is limited by the nutrient that is least available when all other elements are present in adequate quantities. The “law of minimum” can be illustrated with a water barrel, with staves of different lengths that represent particular nutrient availability. The barrels capacity to hold water is determined by the shortest stave. Similarly, plant growth is limited by shortages of the least available nutrients. Once the limiting factor (nutrient) has been corrected, yield and growth will increase until the next limiting factor is encountered.

    Balanced nutrition is important in obtaining maximum yields. The most usual limitations concern nitrogen, phosphorus and potassium, followed by sulphur.

    Nutrients are depleted with each harvest

    Where nature is untouched a closed nutrient cycle exists. Plant take up nutrients for growth from soil and release them back during their life cycle so nutrients are maintained in this cycle. When man introduces agriculture this cycle is broken. Nutrients are taken out of the soil together with plants during each harvest.
    This loss is partly offset by the decomposition of organic matter in the soil and the gradual accumulation of soil minerals. But this natural process is far too slow. Without an external input, the capacity of the soil to supply plants with nutrients is progressively reduced with every harvest.

    Why mineral fertilizers?

    Mineral fertilizers supply soil with depleted nutrients

    Mineral fertilizers are necessary to replace the nutrients that have been removed from the soil. They can provide an optimal nutrient balance, tailored to the demands of the specific crop, soil and climate conditions, increasing crop yield and quality whilst also minimizing environmental impacts.
    Fertilizers ensure the most effective use of both land and water. Where rainfall is low or crops are irrigated, the yield per unit of water used may be substantially increased and the rooting depth of the crop increased through fertilizer application.

    Fertilizers help feed the world

    The FAO has stated that “after land and water, fertilizers are probably the most important input leading to increased yields”. It is inherently difficult to estimate the share of fertilizers in increasing agricultural output since so many factors are involved. But in the ‘Developed World’, after 150 years of increasing fertilizer use, it is thought that roughly half of the present agricultural output may be attributed to fertilizers.

    Between 1961 and 1965 the world cereal area averaged 677 million hectares and annual cereal production was 988 million tonnes. The average area between 2000 and 2008 was 699 million ha and 2100 million tonnes i.e. an increase of 3% in the cereal area and 113% in the production. The benefits of these improvements would not have been realised without fertilizers.

    It has been estimated that mineral fertilizers contribute about 40% of the nitrogen taken up by the world’s crops. Since crops provide about 75% of all nitrogen in human protein consumption – either directly, or indirectly through animals – it follows that nearly one third of this protein depends on fertilizers.

    “Law of minimum” 

    The law of minimum says that one nutrient cannot be substituted for another. Plant growth is limited by the nutrient that is least available when all other elements are present in adequate quantities. The “law of minimum” can be illustrated with a water barrel, with staves of different lengths that represent particular nutrient availability. The barrels capacity to hold water is determined by the shortest stave. Similarly, plant growth is limited by shortages of the least available nutrients. Once the limiting factor (nutrient) has been corrected, yield and growth will increase until the next limiting factor is encountered.

    Balanced nutrition is important in obtaining maximum yields. The most usual limitations concern nitrogen, phosphorus and potassium, followed by sulphur.

    Nutrients are depleted with each harvest

    Where nature is untouched a closed nutrient cycle exists. Plant take up nutrients for growth from soil and release them back during their life cycle so nutrients are maintained in this cycle. When man introduces agriculture this cycle is broken. Nutrients are taken out of the soil together with plants during each harvest.
    This loss is partly offset by the decomposition of organic matter in the soil and the gradual accumulation of soil minerals. But this natural process is far too slow. Without an external input, the capacity of the soil to supply plants with nutrients is progressively reduced with every harvest.

    Why mineral fertilizers?

    Mineral fertilizers supply soil with depleted nutrients 

    Mineral fertilizers are necessary to replace the nutrients that have been removed from the soil. They can provide an optimal nutrient balance, tailored to the demands of the specific crop, soil and climate conditions, increasing crop yield and quality whilst also minimizing environmental impacts.
    Fertilizers ensure the most effective use of both land and water. Where rainfall is low or crops are irrigated, the yield per unit of water used may be substantially increased and the rooting depth of the crop increased through fertilizer application.

    Fertilizers help feed the world

    The FAO has stated that “after land and water, fertilizers are probably the most important input leading to increased yields”. It is inherently difficult to estimate the share of fertilizers in increasing agricultural output since so many factors are involved. But in the ‘Developed World’, after 150 years of increasing fertilizer use, it is thought that roughly half of the present agricultural output may be attributed to fertilizers.

    Between 1961 and 1965 the world cereal area averaged 677 million hectares and annual cereal production was 988 million tonnes. The average area between 2000 and 2008 was 699 million ha and 2100 million tonnes i.e. an increase of 3% in the cereal area and 113% in the production. The benefits of these improvements would not have been realised without fertilizers.

    It has been estimated that mineral fertilizers contribute about 40% of the nitrogen taken up by the world’s crops. Since crops provide about 75% of all nitrogen in human protein consumption – either directly, or indirectly through animals – it follows that nearly one third of this protein depends on fertilizers.

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