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Research develops organic fertilizer from plant biomass

Produced from aboveground biomass (part of the plant that sticks out of the ground) of legume species, N-green is a nitrogen-rich plant organic fertilizer (N) and easy to apply. “It has the essential nutrients for plants: match, potassium, calcium, magnesium, sulfur; and micronutrients, like boron, ferro, manganese, molybdenum and zinc", explains researcher Ednaldo Araújo, of Embrapa Agrobiology (RJ).

Compared to other organic materials, the nitrogen concentration in green-N is high: near 4%. That is why, it is indicated as a source of nitrogen fertilization.

Scientific studies have shown that the fertilizer developed by Embrapa Agrobiology researchers reduces the losses that occur when it is applied to the crop.. While in commercial products, volatilization losses (gas transformation) arrive at 50%, in N-green it is maximum 15%, resulting in savings for the farmer.

Knowing that mash fertilizers have limitations regarding field application, they are not suitable for use in fertilizer dispensing machines and favor nitrogen losses due to ammonia volatilization, the researchers have developed a product in the form of granules or pellets.

"The idea is to provide farmers with a standardized fertilizer in terms of nutrient content and particle size, high density and low volume, which facilitates the application in the field", complements Araújo.

At first, the product was developed for application in leafy vegetables, where field tests pointed to a product with excellent results. But the response was also good in corn and bean crops. The expectation is that when made available by the industry, the product also has good acceptance for application in ornamental plants as a source of nitrogen.

Production process

According to the researchers, to produce green N, a nitrogen-fixing legume with high capacity to generate organic matter at low production cost is needed.. "We seek to take advantage of two biological processes that are abundant in nature, photosynthesis and biological nitrogen fixation, that allow carbon and nitrogen to accumulate from plant biomass", details José Guilherme, researcher at Embrapa Agrobiology.

Most nitrogen-fixing leguminous plants have good nutrient concentration and can be used for green-N production.. But gliricide (Gliricidia sepium) is the one that has been most used because it is a perennial plant, which allows pruning up to four times a year and offers a large biomass production capacity, no high implementation costs.

With one hectare of gliricidia it is possible to produce up to 6 tons of green N per year. But this amount can vary depending on the spacing in which the planting is done. "From the moment we have biomass, we have a whole protocol to produce N-green, which involves the best way to dry, to grind and even to produce the pellets or grains", Araújo scores. After collection, the production of green N takes seven to ten days.

N-green can fill this gap in the market and tends to have its shelf cost lower than similar products

Use in organic agriculture

One of the bottlenecks for the expansion of organic agriculture is the lack of nitrogen. To meet the demand for this nutrient, farmers often use agroforestry residues, which feature about 3% of N, which is suitable for use as organic fertilizer. Although, the variation in this percentage, in addition to problems related to chemical and biological contaminants, limits its use.

The lack of standardization also increases uncertainties regarding the results of using these products. That is why, one of the most widespread residues is castor bean pie, which presents approximately 5% of nitrogen. But, in this case, the limiting is the value, superior in about 400% in relation to the cost of urea, which is the most used nitrogen fertilizer in conventional agriculture in Brazil.

To Ednaldo Araújo, N-green can fill this gap in the market and tends to have its shelf cost lower than similar products. "It is important to emphasize that this is not about replacing the use of green manure in crops, because even with the use of fertilizer species, it is necessary to do all the management and also the nitrogen supply. This replacement can be performed by N-green", punctuates the researcher. Araújo also clarifies that because there is a need for large areas for planting the legume and a factory to transform the biomass into grains or pellets, Green-N tends to be a fertilizer produced by entrepreneurs through cooperatives or industries.

N-green X manure fertilizer

One of the main organic sources of nitrogen used in conventional agriculture is manure. But not every producer has animals on his property, which makes it difficult to obtain the input. For these farmers, N-green also tends to be a good alternative, because in addition to having a much higher concentration of nitrogen, does not need to be composted and has very low risk of contamination, unlike manure.

Advanced tests measured the product's efficiency

For N-Green Efficiency Studies, the researchers performed advanced tests using stable isotope (variant of the chemical element nitrogen) which works as a nitrogen path marker, from fertilizer release to plant absorption.

The results reveal that the efficiency of N-green is of 10%, that is, decade 100 kilos placed on the plant, she absorbs 10, in the first cycle, which is similar to other organic fertilizers. The research is now advancing in the study to reduce the costs of production and collection of biomass.

Whether in organic agriculture, where the use of organic and contaminant-free vegetable fertilizers is a requirement, or in conventional agriculture, where high costs limit the use of organic fertilizers, N-green can be an alternative or a complement. The researcher Ednaldo Araújo emphasizes that a country with continental dimensions and a tropical climate like Brazil has a natural aptitude to produce biomass. "And why not produce this biomass and put it on the market to meet the existing demand?”, ends.


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