why manure and fertilizers are used togethet by farmers?

Answer 1

Fertilizers are manufactured from N2 into water soluble nitrates. This is applied at rates in excess of a crops needs in order to saturate the soil. However this form is shed easily from the soil. When rain leaches it out it takes other nutrients with it acidifying the soil. It takes things like magnesium and calcium out into the water. Manure contains organic nitrogen compounds (such as amino acids), ammonium (NH4-), or nitrate (NO3-) so some is soluble but not all thus over time more is fixed by bacteria. This slow release of nitrogen is manure's most important asset. It extends nitrogen availability and reduces leaching -- of particular importance in sandy soils. The problem is manure needs to be incorporated in the soil to be available to the bacteria while commercial fertilizer can be surface broadcast.
Farmers can have fertilizers custom blended for their soils needs. Manure applications typically exceed the annual capacity of the crop to remove phosphorus when application rates are based on crop nitrogen need with surface application. Available nitrogen from surface application can be as little as 60% compared to 90% if incorporated.

Manure from ruminant animals such as cows and sheep have an advantage over poultry manure, as far as ability to stabilize nutrients and produce humus. Poultry litter also contains odorous compounds that can dis-flavor vegetables.
The microflora in ruminant is beneficial to composts and soil.
N-P-K of several manures
Rabbit manure 2.4-1.4-0.6 Most concentrated of animal manures in fresh form.
Cow manure (dairy) 0.6-0.2-0.5 Often contains weed seeds, should be hot composted.
Steer manure 0.7-0.3-0.4 Often contains weed seeds, should be hot composted if fresh.
Chicken manure 1.1-0.8-0.5 Fast acting, breaks down quickest of all manures. Use carefully, may burn. Also, stinks like hell - composting definitely recommended.
Horse manure 0.7-0.3-0.6 Medium breakdown time, usually contains wood chips.
Duck manure 0.6-1.4-0.5
Sheep manure 0.7-0.3-0.9

The phosphate in fertilizers and manure is initially quite soluble and available. Most phosphate fertilizers are made by treating rock phosphate (the phosphate-bearing mineral that is mined) with acid to make it more soluble. Manure contains soluble phosphate, organic phosphate, and inorganic phosphate compounds that are quite available. Manure phosphorus is thought to be 80 to 100 percent as effective as that in commercial fertilizer; manure potassium, 100 percent as effective.

Answer 2

manure act as organic fertilizer, while traditional fertilizer is chemical fertilizer, in ancient, there are no chemical fertilizer we always take manure as main fertilizer, this manure has full nutrition of crop demands,
however, each nutrition is very limited,if we always take these fertilizer, the crop may be thin. after industrial innovation, we have develop all kinds of chemical fertilizer to meet demands of agriculture, however another problem happens, the grounp get harden after repeat application, also the cost of chemical fertilizer is too expensive to afford, based on supply theory, we can not really give up chemical fertilizer, on the other hand, we can not accept disadvantages of chemical fertilizer or manure,so we consider how to make them together, how to realize, people think that it is best way to make manure as base fertilizer while have chemical fertilizer as top dressing, and then , in this approach we not only solve the problem of loosen soil, but also get soil more fertile.
as the developing of industry, agriculture develops also, farmers are lazy of this complex procedure, they expect a new fertilizer to fulfill this function, so the first generation water soluble fertilizer emerge as time requires, it is Cocoly fertilizer, located in beautiful and famous global vegetable land-- Shouguang China, it has help numerous farmers get rich.

Answer 3

They are used by farmers because they both provide specific macro and micro nutrients which are required for plants to grow and be healthy. Manure is cheap and provides the most bascone while commercial fertalizers provide more plant specific or harder to get nutrients.

Answer 4

Manure is mainly nitrogen.
Fertilizers are potash, phosphorous, and nitrogen. If one has plenty of manure to spread on the field, you can buy fertilizer that is 0%, 16%, 16%.