The Mulching is given to cover the soil for the protection of microorganisms in the soil against Winds, Severe sunlight, rains, and cold temperatures. The main purpose of mulching is to create humus in the soil, which helps plants overall growth. Avoids soil erosion and protect the soil from heat & rains. Conserve moisture through atmospheric humidity and also reduces at most 90% of irrigation water. Mulching also creates a micro-climate that is favorable for the earthworms and other microorganisms. Finally, mulching makes soil fertile and prosperous.
The end product of mulching is Humus. Humus is rich in nutrients. Plants require nutrients in abundance. The soil fertility is directly proportional to the amount of humus present in the soil. More the humus in the soil, then there won’t be any requirement of chemical fertilizers. A complete guide to Humus and its uses are explained here. To increase the humus content in the soil, there should be a continuous decomposition process on the soil. Farmers will benefit abundantly when humus is increased in his soil.
Humus is composed of Organic Carbon and Organic Nitrogen mainly. Carbon is 10 parts and Nitrogen is 1 part. The 10:1 ratio of carbon and nitrogen is called a C: N ratio. The organic carbon has three types. But only stable carbon will take part in the creation of humus. So each type and stage of the plant will affect the creation of humus. Choosing the right plant and the right stage for mulching are essential. Not all of them create your humus.
Types of Mulch
Most of the monocot crops and legume tree branches act very well when they are used as mulch. Only after maturation of crops like corn, wheat, paddy, Sugarcane, Millets, Dencha, Sunhemp should be cut down and used as mulch. The stable carbon in the mature crops helps to increase biomass and also all the advantages of mulching are available.
2. Live mulching
Dicot crops (alfalfa, green gram), any creeper plants, beans, watermelon, ridge gourd, bottle gourd and many more which cover the soil will be best suited for live mulching. Once its matured can be used as straw mulching. Live mulching is usually seen in fruit orchards, as it acts as a double advantage. Live mulch crops act as a mulch and also gives produce.
What to Mulch?
Not all plants which decompose create humus. When our final goal is to create humus and make soil fertile, need to give a thought on what plants should we use to mulch. As we discussed above, there are three types of Carbon.
It is situated in the dried material of plants that are cut down before the flowering stage and used as mulch. When the decomposition starts the volatile carbon is released and immediately combines with atmospheric oxygen to form Carbon dioxide by the oxidation process. This escapes to air and doesn’t take part in the formation of humus. So this can’t be used for mulching. A simple thought, have you ever seen in Nature that plants die before flowering? Plants die only after a seed is produced(after maturation). Non-Natural way can’t give us results.
It is present in the plant that is cut down during the flowering stage and used for mulching. This unstable carbon only stays for a few days in the soil during decomposition. Again during the oxidation process, it escaped into the atmosphere. Even Unstable Carbon or during flowering stage plants should not be cut down to create mulch.
When the plant is cut down after complete maturation or after the seeding stage, the released carbon will be stable. The stable carbon will stay in the soil to help in humus creation. The stable carbon is decomposed very slowly and helps in the creation of humus. Mimicking nature is the best way we can practice farming. Use the biomass for mulching only after seed maturation.
Best Mulching Formula
Choosing the plants and Stages of its stages will help in Mulching. The crops belonging to the Gramineae family suits best for mulching. The C: N ratio of these crops is 80:1. Gramineae family includes millets, Corn, Wheat, Paddy, Sugarcane and lot more. What is mulching in agriculture? Mulching is done to create humus and make the soil fertile. Humus will create when Carbon combines with Nitrogen along with other micro activities.
When the Gramineae crops have an 80:1 ratio of C: N, that means when the dried(matured) crops decomposed completely it generates 80kg of Carbon and 1 Kg of Nitrogen. While the formation of Humus 1Kg of Nitrogen is combined with 10 kg of Carbon to form Humus. The rest of the 70kg Carbon requires an additional 7kg of nitrogen to form Humus. When this amount of nitrogen is not present the additional carbon gets released to the atmosphere.
In order to trap the additional carbon to form humus, we need more nitrogen. Nitrogen in abundance will be available by means of leguminous biomass mulching or leguminous intercrops. Most of the leguminous crops are dicots. A mixture of Dicot and monocot biomass helps in the generation of humus. The best mulching formula is a mixture of monocot and dicot crops. The intercrops and mixed crops should be a mixture of dicot and monocot crops. The perfect mixture is 2/3rd dicot legume and 1/3rd monocot is the best Mulching formula.
Do not bury the mulch
Mulching is best when compared to Mulch during and composting. Mulching increases the yield of crops. Sometimes we follow unnatural methods in Agriculture. We got to asses about any practice before following it, whether it’s happening in Nature. If the practice is not present in Nature then do not follow it.
Have you ever seen in the forest that plants die early and get buried in the soil to form biomass? The answer would be Never, Right? Yes, it’s so obvious. What happens when we bury the mulch? Burring any biomass in the soil is not natural. Because it does not exist in nature. When you bury any mulching crops like Dhencha or Sun hemp in the soil, the anaerobic bacteria act upon it. It doesn’t decompose, it starts to rot. This form of Anaerobic activity causes excessive heat in the soil which kills microbes and also affects the plants.
The anaerobic bacteria gets multiplied by utilizing all the buried biomass. These bacteria consume a lot of nitrogen which is present in the soil. When the number of bacteria increases the nitrogen utility also increases. The process creates a shortage of nitrogen to plants. The crops develop pale yellow leaves and also develop diseases related to nitrogen deficiency. Always burying the green manure or burying mulch in the soil is very dangerous for the crops.
Advantages of mulching
- Mulching reduces the evaporation of the moisture from the soil up to 90% whether its a straw mulching or dense live mulching.
- The weed population is controlled. Due to straw mulching or dense live mulching, the sunlight reaching the ground is reduced. If there is no sunlight the germination of weeds is not possible. The importance of mulching is not controlling the weed
- population but also significantly reducing the number of labors (farm workers) required.
- The favorable microclimate is created which keeps the temperature around 25 to 32 deg Celsius, 65 to 70% of humidity and also darkness for the microorganisms and earthworms to flourish.
- Humus is created by the mixture of 2/3rd dicot legume and 1/3rd monocot. Humus is rich in nutrients which is essentials for crops to grow and produce.
- Mulch is used to stop soil erosion. Rains water is conserved and the water table is increased.
- Mulching Saves the standing crop from blowing winds.
- Earthworms’ population increases with mulching.
- Mulching crops give produce and fodder to farm animals like cows, sheep, goats.
- The rate of Photosynthesis increases due to the increase the production of CO2 with mulching.
- The food cycle is balanced by Mulching as many organisms thrive under the microclimate.
- Mulching absorbs a huge quantity of moisture from the atmosphere and makes it available to roots.
- Mulching stops the exchange of soil heat and atmosphere heat. So cold winters and hot summers won’t be a problem for the crops.
- The PH of the soil is controlled by Mulching at 6 to 7.
Examples of Live mulching
Dhencha (Sesbania rostrata), Sun hemp, Green gram, Pigeon pea, red gram, creeper beans, alfalfa
Examples of Straw mulching – straw/Cut down branches
Sugarcane trash, millets, Corn, Wheat, Paddy, Gliricidia, Drumstick, Sesbania grandiflora, Sal tree(Shorea robusta), Leucaena leucocephala (River tamarind)