Study reveals how plant density and fertilization affect corn cultivation

Research reveals that one of the success factors in corn (Zea mays) production systems for dry grains, at the agribusiness level, is the balance of plant density. The best densities are between 60 and 80 thousand plants per hectare, according to researcher Milton Cardoso, from Embrapa Meio-Norte (Teresina, PI), member of the project Management of the soil-water-plant system for corn in the Meio-Norte region of Brazil. Brazil. 

His work also revealed that for family farming, the “best arrangement” varies in the “range of 45 to 55 thousand plants per hectare”. In the production of green ears, according to the scientist's study, the “best range” is between 40 and 50 thousand plants per hectare. Finding the balance point in density is difficult, as the arrangement of plants “is influenced by the genotype, environment, production system, sowing time and other factors”, explains Cardoso.

To reach the results with dry grains, the researcher worked on two experiments, in Teresina and in the municipality of Magalhães de Almeida, in eastern Maranhão, from 2017 to 2019. The densities of 4, 6, 8 and 10 plants were evaluated per square meter, with three Embrapa corn cultivars, the BRS 473 variety, and four hybrids. 

For the BRS 473 variety, the best results obtained in dry grain productivity were five to six tons per hectare. For the 2020 BRS double hybrid, the range was 5,5 to seven tons per hectare. For the triple hybrids BRS 3046 and the simple BRS 1060, the productivity achieved was 6,5 to nine tons per hectare.

With the production of green ears, in the experiment conducted in Teresina, in 2018, planting densities of 2, 4, 6, 8 and 10 plants per square meter were observed. In this experiment, the triple corn hybrid BRS 3046, also from Embrapa, was used. Here, with a density of six plants per square meter, the answer was “adjusted to commercial standards” with 57.813 ears per hectare. “The results show that it is possible to adjust plant density to the sustainability of the corn production system in the regions studied”, highlighted Cardoso.

High density versus disease

The first conclusions of the project also prove that the imbalance in plant density in corn crops “increases foliar diseases”, such as white spot, bipolar spot and cercospore spot. In the study by researcher Cândido Athayde Sobrinho, in the municipality of Magalhães de Almeida, it was proven that diseases appear favored by “rain intensity, high relative air humidity and temperature and the effect of high plant densities”. 

The researcher's work also revealed the response of the difference in genotypes “to the severity of foliar diseases”. According to him, the BRS Assum Preto variety used in the experiment proved to be “much more susceptible to diseases” than the hybrids. The BRS 2020 double hybrid, according to the study, is the “most resistant genotype”.

Fertilization at the right time

As is already common knowledge in agriculture and research, correct fertilization is a determining factor in increasing productivity. In two experiments, also conducted in the municipality of Magalhães de Almeida, with the corn variety BRS Catingueiro and the simple transgenic hybrid PIONER30F53VYHR, both in 2019, researcher Francisco Brito was able to prove the efficiency of potassium and nitrogen through calibration with increasing doses of each of these nutrients.

The results of the experiments were encouraging. Let's see: with the transgenic simple hybrid, nitrogen doses of 145 and 104 kilos, respectively, per hectare, the highest grain yields were achieved, both for technical productivity (without considering the cost of fertilizer), which reached 8,3. 8,1 tons per hectare, as for economic productivity (which considers fertilization costs), which reached XNUMX tons per hectare. 

With the BRS Catingueiro variety, the researcher observed that doses of 117 and 54 kilos per hectare, respectively, were those that achieved the highest grain yields, both for technical productivity and economic productivity. The results were also impressive: in technical productivity, 3,9 tons per hectare were achieved; and in economic productivity it reached 2,8 tons per hectare.

Using potassium doses of 69 and 50 kilos per hectare, the experiment achieved a technical productivity of 3,4 tons per hectare and an economic productivity of dry grains of 2,9 tons per hectare.

The study also revealed that, in the case of the simple hybrid, for each kilogram of nitrogen applied, there was a production of 57 kilograms of dry corn grains, for technical productivity, and 77 kilograms of dry cereal grains for economic grain productivity. , which corresponds, respectively, to 66% and 61% increases, when compared to productivity without the use of nitrogen.

Indigenous people took the lead

Celebrated in the poem Prayer of Corn, by the poet Cora Coralina (Goiás, 1889-1985), in 1965, corn originates in Mexico and Guatemala, more than seven thousand years ago, according to specialized literature, and emerged from the grass Teosinte, through selection and domestication processes.

In Brazil, the cereal was already planted and consumed by the Indians, mainly the Guaranís, “even before the arrival of the Portuguese”. With the arrival of Europeans in the country, both the planting and consumption of corn gained strength. The cereal is rich in proteins, fats, carbohydrates, fiber, vitamins and minerals, such as potassium, phosphorus, magnesium, calcium and zinc.

Data from the Sector Notebook of the Technical Office of Economic Studies of the Northeast (ETENE), of Banco do Nordeste, from August this year, points to a production of 2020 million tons of corn grains in Brazil for the 21/96,3 harvest. . The Central-West is at the forefront of production with 51,6 million tons, followed by the South with 20,8 million tons. 

The largest Brazilian producers are the states of Mato Grosso, Paraná, Mato Grosso do Sul, Goiás and Minas Gerais. The United States, China and Brazil, together, are offering 1,12 billion tons to the market. The three countries account for more than 60% of world corn production.
Even though it is used in national cuisine all year round, the biggest demand for corn production is the animal feed industry: 53%. The cereal is also produced for the biofuels sector, both in Brazil (the country currently has 18 plants that produce ethanol from corn) and in other countries, particularly the United States and Germany.