How to do Nutrient Management in Organic Agriculture?
Nutrition is the most important part of any growth process. Be it organisms or plants, without proper nutrition it is impossible for it to grow. Also, nutrition isn’t just limited to plants and animals, it is also an important aspect of a soil’s fertility. The various nutrients present in the soil helps immensely in facilitating the growth of a plant.
It is due to the absence of such nutrients that the growth becomes stunted and results in the losses for the farmers at individual level and to the agricultural sector as a whole.
In the conventional farming methods in which the use of artificial fertilizers has become so prevalent, the fertility of the soil gets affected which takes the form of various other problems including soil erosion. This is the reason why many farmers have shifted from the conventional methods to organic methods of farming. With the rising awareness about organic farming and its benefits, it seems that organic farming has a bright future ahead.
Importance of Nutrient Management
Artificial fertilizers have damaged the soils and it becomes all the way more important for an efficient nutrient management system to be employed in organic farming. Nutrients in soil are extremely important to support crop production and the growing demands in food supply requires the soil to be fertile to support various practices like crop production and intercropping. As the nutrients present in the soil are used up by the crops, it is important to replace those nutrients in order to maintain soil fertility.
Agriculture is the backbone of any economy and soil is the backbone of agriculture. Without a fertile soil it is impossible to keep up with the demands of a huge populous country like India. Hence, an efficient nutrient management system has a great significance in a large country like India.
How to do Nutrient Management in Organic Farming?
There are various methods through which we could do nutrient management in an efficient and smart way.
These are:
- Compost and Vermicompost
- Green Manure
- Animal manure
- Mineral fertilizers
- Microbial fertilizers
Below, we will discuss these methods in detail.
Composting
Also known as controlled decomposition, composting refers to the process that converts plant materials into a fertilizer that enriches the soil and replenishes the nutrients in the soil. In the composting process, decomposition occurs at a faster speed that results in the organic fertilizer of a very high quality.
It requires a precise combination of green and brown organic materials. Here, green organic materials refer to the leaves, grasses and food scraps etc. while the brown organic materials refer to the wood, dry leaves and branches.
It is important to carefully add the two kinds of organic materials in the right amount as the Green organic materials contain more nitrogen, whereas the Brown organic materials contain more carbon. As anything is harmful in extreme amounts, hence to add both the kinds of materials in the right amount requires the skill that comes with experience and experimentation.
Stages of Composting
Generally, there are four stages associated with composting:
- Mesophilic Stage
The microorganisms begin to reproduce by breaking down carbon and nitrogen. These microorganisms are known as Mesophilic microorganisms (microorganisms that grow between 20-40 degrees). This activity raises the temperature of the compost to about 40 degrees.
- Thermophilic Stage
In this stage, the temperature of the compost rises over 40 degrees and the mesophilic microorganisms are replaced by the thermophiles (microorganisms that reproduce at temperatures between 40 and 70 degrees). Here, the more complex nutrients like nitrogen and complex carbons are broken down into their simpler forms.
- Cooling Stage
After the complex nutrients have been broken down into their simpler forms, the temperature of the compost decreases and the mesophilic microorganisms appear again.
- Maturation Stage
This stage requires the compost to be at room temperature, so that the humus is completely decomposed.
Different Methods of Composting:
- Direct Composting
Being the oldest and the most commonly used method of composting, it basically refers to simply digging a pit on the ground and burying the organic matter.
- Open Air Composting
This method of composting uses naturally occurring microbes which feed on garden microbes where these microbes break down the materials into a compost by using Oxygen as their specific agent.
- Tumbler Composting
This is a mechanized form of composting using a tumbler. A tumbler is a sealed container that can be rotated to mix the composting materials. A compost tumbler maintains a high temperature inside which speeds up the decomposition process of organic wastes.
- Vermicomposting
This process of composting uses worms to decompose organic wastes into fertilizers known as vermicompost or worm compost.
- EMO Composting
Also known as Effective Microorganisms, this method can be used indoors as per one’s requirement. Effective Microorganisms are a mixture of relevant microorganisms that work together to provide benefits to the plants and soil.
- Combination Composting
This method of composting employs various other methods like open air composting, direct composting, vermicomposting and EMO composting. Since it is a combination of the above processes, it is hence known as Combination composting.
- Mechanical Composting
It is a fully mechanical process of composting that efficiently uses electricity to create heat required for decomposition of organic wastes and also rotates the contents for an extremely fast decomposition in a day or two.
- Commercial Composting
This method of composting is done on a commercial scale. The compost is spread in long rows using wastes such as wood clippings, sawdust etc. that is turned at regular periods (3-4 days). It is a less expensive method of composting that doesn’t have much of a nutrient value. It is commonly used by those farmers who cannot afford the expensive compost.
What are the Benefits of Composting?
There are a number of benefits associated with composting in terms of nutrient management in organic farming. Below are mentioned some of the benefits of composting:
- Prevents Soil Erosion
- Helps in growing healthier crops
- Helps in conserving water
- Helps in waste management
- Improves soil fertility
How to Select a Suitable Composting Method?
Not all the methods could be adopted everywhere, so it becomes extremely crucial to select a particular method that suits the goal of the agriculturalist.
There are a number of factors that need to be thoroughly considered before selecting a composting method.
- Farm size
The farm size decides the kind of method that needs to be employed. In case of a large farm, the commercial composting would be more suitable whereas for a small farm or home, the open-air composting or dry composting would be more practical.
- Capital investment
With a large capital investment, compost tumblers could be employed for composting whereas in case of a small capital, there are several methods like vermicomposting or the use of EMOs.
- Goals
If the goal of the farmers is just to sustain themselves, then the less expensive methods could be employed on a small scale but if the goal is to carry out huge commercial farming, then mechanical composting and tumbler composting could be an added benefit.
Suggestions for Composting
Balancing the Green and Brown organic matter is extremely important for a good compost. The Green organic materials (lawn clippings, leaves, etc.) contain more nitrogen, whereas the Brown organic materials (branches, twigs, dead leaves etc.) contain more carbon. Mixing these in right amounts is important to avail maximum benefit out of composting.
The compost pile should be neither too wet nor too dry as it might affect the reproduction of microorganisms which would further hinder the decomposition process.
Green Manures
Green Manures basically refer to the plants that are grown to accumulate nutrients for the main crop. The plant (green manure) releases nutrients once it is worked into the soil and gets fully decomposed within a few days.
Benefits of using Green Manures:
- It prevents soil erosion.
- It decomposes and releases the nutrients in just the right amount for the soil.
- It encourages the activity of the organisms present in the soil which improves the soil structure and water retention.
- It is an inexpensive way of increasing soil fertility and the nutrients in the soil.
How to Use Green Manures:
When using green manures, there are some points which need to be kept in mind such as:
- Time of working the green manure into the soil
The green manures must be worked in the soil, when the plants are still young and fresh. As older the plants get, the more time it would take for decomposition. Chopping the plants into smaller pieces is recommended for easier decomposition.
- Time Gap
The time gap between working the green manure into the soil and the planting of the next crop should not be longer than 2 weeks, to prevent the possible loss of nutrients from the manure.
- The correct depth of incorporation
The green manures should be worked into the soil surface, and not too deep in the ground. In heavy soils, it should be incorporated 5-15 cm deep while in light soils it should be incorporated 10-20 cm deep.
Suggestions for Green Manures
- The green manures should not be intercropped with the main crop as then it would compete for the nutrients, thus completely discarding its purpose.
- A little patience is required while using green manures, as it is a long term process and its benefits may not be immediately visible.
- Use of green manures requires labor hence it is highly recommended for small scale farms.
Animal fertilizers
Animal fertilizers usually consist of animal excreta and bedding material such as grass or straw. It is an extremely valuable organic manure which is used by almost every small-scale organic farmer. It helps immensely in the waste management by incorporating the animal wastes into manures for the farm.
Benefits of Using Animal Fertilizers
- It increases the pH levels of acidic soils.
- It improves the water retention capacity of the soil.
- It also helps in improving the macro-structure of the soil.
- It increases soil fertility by providing N, P, K, S, Ca, Mg, Na and other elements like Fe, Mn, Cu and Zn.
Suggestions for Animal Fertilizers
- Animal fertilizer is best used over small farms, as it contains limited amounts of nutrients for crops in large farms.
- Storage of animal manure is highly important as it directly affects its quality. Manure stored under anaerobic conditions usually end up in an inferior quality.
Mineral fertilizers
The fertilizers based on ground natural rocks containing nutrients essential for the growth of plants are known as mineral fertilizers.
It is not completely good for the environment when it contains easily soluble nutrients, as it could harm soil life and result in an imbalance in plant nutrition. Also there is a question of its sustainability as its procurement involves the degradation of natural resources.
Types of Mineral Fertilizers:
- Plant Ashes
- Lime
- Rock Phosphate
- Stone Powder
Suggestions for Mineral Fertilizers
It must not be used in large amounts, as some nitrogen based fertilizers have been proven to help in the acidification of soils.
Microbial fertilizers
Microbial fertilizers mainly contain biologically active microbes that promote the growth of plants by increasing the nutrients required by the plants. They mainly consist of bacteria, algae or fungi. Apart from supplying nutrients to the plants, they also help to restore the biodiversity of the soil.
Some commonly found ingredients in microbial fertilizers are:
- Rhizobium
- Azospirillum
- Pseudomonas
- Mycorrhiza
- Azotobacter
They should not be used if the organisms are dead, because then they would not serve any purpose.
Conclusion
These were the methods of how nutrient management is carried out in organic farming. These are the less expensive and sustainable methods of increasing and maintaining the organic matter and nutrients in the soil for the steady and healthy growth of crops.
