Why manure and fertilizers are used in fields?

Hint: In agriculture, farmers use a variety of substances to enhance the growth and yield of crops, for example, manure, fertilizers and pesticides respectively. Manures are organic in nature, while fertilizers are synthetic.

Complete answer: A manure is the natural organic substance that is used in the crop field to nourish the soil and to maintain the vitality of agricultural land and fertility of the soil. Manure is a natural substance that is formed by animal faeces like cow dung or other biodegradable materials like uncooked food wastes. Such waste products like animal excrement or plant wastes are used to prepare manure along with the help of some microbes or invertebrates like earthworms. Manure is applied in the crop filed to increase the cop productivity natural without destroying the soil quality. While fertilizers are man-made, i.e. they are not found naturally, they are prepared chemically by the various processes, mainly fertilizers are composed of three elements that are called NPK called nitrogen, phosphorus and potassium fertilizers. All these elements form different salts with different composition and applied to the field before sowing or after sowing. Such fertilizers are used according to the need of the crop field and the element which is less available in the field soil, the less availability of such elements may inhibit the growth of crop plant and yield.

Note: Currently the use of artificial fertilizers are used to increase the crop productivity, which in turn is a threat to the environment. The excessive use of such chemicals changes or degrades the soil property and microflora of the soil which affect the soil property. Sometimes fertilizers runoff during rain which contaminates the water stream and leaches out to contaminate the groundwater.