The use of manure as fertilizer is traditional in land management for sustainable agriculture. They are used most effectively when combined with other measures including crop rotation, planting grass cover for green manure, using lime and other natural materials, and fertilizers with Appropriate adjustment for microbial activities.
The most common form of using manure is either in raw form (fresh or dried) or in composted form. This article outlines the advantages and required conditions when using manure in either of the above two forms.
I. USING RAW FERTILIZER- PROBLEMS AND SOLUTIONS.
Coarse manure is an excellent source of raw materials for organic vegetable cultivation. It provides nutrients, organic humus and stimulates microbial activities in the soil to create fertility. However, some types of manure are not recommended for a variety of reasons, including concerns about crop quality, food contamination, unbalanced soil nutrients, weed problems and soil contamination. environmental pollution.
1. Concern about the quality of agricultural products:
We have known for a long time that improper use of raw manure can reverse the effect on the quality of vegetables such as potatoes, cucumbers, and gourds. squash, radish, broccoli, cabbage…
Because when manure decomposes in the soil, chemical compounds such as Skatole, Indole, and Phenol compounds are released and absorbed by plants. This event can cause loss of natural flavor and odor when these fruits and vegetables are cooked for consumption. For this reason, raw manure should not be applied directly to growing vegetables.
2. Contamination with toxic substances:
Some types of manure contain toxic residues such as irritants, antibiotics, antiseptics, pathogenic bacteria and other organic elements. Many of these toxins can be removed through high-temperature aerobic incubation. Since then, it is recommended to apply proper composting techniques to decompose and eliminate the above residues before using to fertilize vegetables. However, some types of manure, such as pig manure, dog manure, and cat manure, are still not recommended because recent studies have shown that Salmonella and E.Coli bacteria can still exist even if the manure has been thoroughly composted. Technically, they are not completely eliminated as previously thought. The possibility of disease transmission makes raw manure not recommended for use as fertilizer or top dressing for vegetables, especially raw manure should not be used as a fertilizer for root or leafy vegetables, especially with types that can be eaten raw.
Some advice:
– If using raw manure, it should be applied at least 60 days before harvesting for vegetables eaten raw. If possible, avoid applying raw manure after planting.
– Do not use manure mixed with water and then water vegetables.
– Do not use dog feces, cat feces, and pig feces to fertilize vegetables because these types of feces contain parasites that can spread to humans.
– You should thoroughly wash vegetables that have been fertilized with raw manure before eating.
3. Nutritional imbalance.
The use of raw manure often causes nutritional imbalance in farmland. Events that trigger this condition may include:
a. Manure is often rich in certain nutrients such as phosphorus or potassium. Normally it is very good for farming, but heavy and repeated use will cause an excess of one or two elements, causing nutritional imbalance. A typical example can be given as follows: Excessive use of raw chicken manure has caused an excess of phosphorus in the soil and nearby water bodies are polluted by phosphorus. Excess substances also prevent plants from absorbing other minerals. An excess of phosphorus prevents plants from absorbing copper and zinc. Excess potassium reduces the effectiveness of Boron, Manganese and even Magnesium.
b. Continuous use of raw manure will cause the soil to become acidic. When manure decomposes, it often releases many different organic acids. These organic acids support the process of converting minerals into a form that is easy for plants to absorb. This is a benefit of using manure but is rarely recognized. However, over time, the rapid metabolism of minerals will cause the calcium in the soil to be depleted and as a result, the acidity in the soil exceeds the optimal level for most crops. Although raw manure does provide calcium to the soil, it is not enough to counteract the tendency to increase soil acidity. One possible solution is to add calcium (Use shell powder, bone meal or other sources of calcium mixed in).
c. Some fresh manure contains large amounts of nitrogen and mineral salts. When used to fertilize cultivated crops, these mineral salts can have the same consequences as applying too much chemical fertilizers. In excess quantities, they can burn the roots of seedlings, reduce their resistance to pests and reduce the storage time of agricultural products. Excess soil salinity is often associated with over-application of manure in areas where natural leaching capacity is poor. When applying too much manure to the point that it can cause salt contamination in the soil, people often prevent it by mixing carbonate lime powder into the soil after applying manure and watering it thoroughly to wash away the salt.< /p>
The best way to avoid nutrient imbalances is to monitor the soil using appropriate analytical methods. From there, farmers can use lime powder or other fertilizers to adjust to ensure nutritional balance or set a strict regime on the amount of manure used.
Primary analysis of manure is also recommended to know the nutritional value of each type. The exact nutrient content of each type of manure depends not only on the type of animal raised but also on the nutritional diet, type of bedding material, amount of liquid added, collection method and technique. processing techniques.
4. Weed problem:
The use of raw manure is often associated with weed growth problems. In some cases, this problem may be due to grass seeds contained in fertilizers mixed into the soil for beds and beds. However, in some cases, the strong growth of weeds after applying manure is not due to the grass seeds available in the manure but due to the stimulating properties of manure on grass seeds available in the soil. The widespread and lush growth of weeds can be due to biological activities, the presence of organic acids or increased soil fertility. Depending on the type of weed growing, the cause may stem from the nutritional imbalance mentioned above. Excess potassium and nitrogen especially affect weed problems. In addition to monitoring soil and manure nutrients, attention to fertilization also contributes to reducing widespread weed growth.
5. Environmental pollution:
When nutrients in raw manure are washed away or seeped into the ground from farms or storage areas, they not only cause pollution but also cause losses to farmer. When seeped into underground water levels, Nitrate compounds in manure as well as from other fertilizer sources cause many problems related to human health. When washed away by water, nutrients cause eutrophication, making pond, river and stream water too rich in nutrients, causing algae to grow. The serious consequences of losing too many nutrients may have to be considered beyond the simple issues posed at the beginning. For example, excess nitrate from agricultural lands in a river basin can cause Death Zones in that river, oxygen-depleted areas that threaten shrimp, fish and other animals. creatures that live underwater.
The way manure is collected, stored and treated before being used on farmland is very important in preserving and maintaining the stability of valuable nutrients and organic humus.
Minimizing nutrient loss due to leaching or seepage into the ground is a matter of both quantity and timing of fertilization. Applying more fertilizer than the plant needs will increase the chance of nutrient loss, especially in areas prone to heavy rain. The same goes for fertilizer application time. For example, manure spread on bare ground with a steep slope will certainly be washed away, especially in areas with frequent heavy rains.
The technique of composting in the soil (spreading the fertilizer evenly on the surface and then plowing and mixing it into the soil) or applying it to ground cover grasses are two recommended methods to conserve nutrients that will be used. for the next crop. Of course, ground cover grasses must be carefully selected, not weeds. This is a technique of growing grass to absorb all the dissolved nutrients in the soil, preventing nutrients from seeping into underground water levels or being washed away, then using them as a source of green manure. .
II. COMPOSTED MANURE:
A properly technical composting process will convert animal manure, bedding materials and other raw products into organic humus, which is a relatively stable, nutritious ingredient. Supports chemical reactions, found in fertile soils. In stabilized organic humus, there is no free ammonium nitrogen or soluble nitrate compounds, but there is a large amount of protein in the form of proteins, amino acids and other biological components. Other nutrients are also kept stable in composted manure.
Using properly composted manure reduces many of the negative events associated with using raw manure. Composted manure is considered a safe fertilizer because it does not burn plant roots, and also does not cause short-term nutritional imbalance. They can be used to directly fertilize growing vegetables and fruits without much worry. Currently, there are many types of organic fertilizers made from decomposed manure and other substances added to enrich and balance nutrition such as phosphorus rock powder, nutritious plant waste products, and other waste products. animals such as blood powder, processed bone powder…
The quality of composted manure depends on the raw materials used and the composting technique. If not supplemented with any other substance, composted chicken manure, although more stable in quality than fresh chicken manure, still has excess phosphorus and lack of calcium. Continuous use for a long time can cause nutritional imbalance in the soil similar to the phenomenon of using raw manure mentioned above. To avoid this situation, it is recommended to analyze and test manure, soil and compost to know their nutrient content.
III. WHEN SHOULD YOU FERTILIZE YOUR FIELD:
In general, manure is most effective when applied immediately before planting and pruning. However, if it has been composted and decomposed properly, it is safer and can be used as a top-dressing fertilizer while the vegetable plants are growing. According to the experience of a commercial vegetable farmer, crops such as squash, corn, and beans grow best and most effectively when decomposed manure is spread evenly and plowed into the soil immediately. before planting. For leafy vegetables, the results are similar and it is recommended to only use composted manure. Vegetables such as cabbage, tomatoes, potatoes and root vegetables grow best and most effectively if manure is used from the previous crop.
To make the most of the nutrients in manure, the plowing method gives the best results. According to this method, people spread manure evenly on the ground and then immediately plow or hoe and bury it into the soil. Studies have shown that if manure is spread on the ground and left for more than 4 days, 21% of nutrients are lost. If the plow buries the manure into the soil immediately after spreading, this loss is reduced to only 5%.
IV.CONCLUSION:
Manure, including raw or composted manure, can be used to grow vegetables. If used properly and pay attention to the nutritional balance in farmland, manure can completely replace artificial chemical fertilizers. Especially closely combining organic farming methods such as crop rotation, planting grass cover and then plowing, intercropping vegetables with the ability to fix nitrogen (legumes).
In other words, farmers need to pay full attention to the nutritional balance in the soil by regularly monitoring soil nutrients, and at the same time carefully learning about the nutritional value of each intended type of manure. use. From there, you just need to adjust the amount of manure used and add a few other nutrient sources to supplement the nutrients that manure lacks. /.