For Agrositio. 14/05/2021 | 16:05
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Last May 12, in the first virtual day of the Fertility Symposium 2021, the agronomist Andrs Grasso, technical coordinator Fertilizar AC, spoke about the availability of nutrients and responses in production and quality. It must be known that our great production reservoir is the nutrients that are in the soil, that these nutrients are limiting and that the bridge to be able to reconcile the production of grains with those limitations is fertilization. Thus opened his exhibition Grasso, who provided the data that, in the Pampean region, fertilization contributes 23% to grain production.
Grasso stressed the importance of doing soil analysis to obtain a diagnosis, interpret the results, and then design the nutrition strategy. This is the basis for managing balanced crop nutrition. It is necessary to move from the vision of the lot to that of the environment, he pointed out.
Since 2010, Fertilizar AC has been working with INTA and other institutions in trials in 9 localities and 12 representative sites, evaluating four fertilization strategies: a control (without fertilizing); a medium fertilization (only nitrogen and phosphorus); an average recommended fertilization (with soil analysis); and a balanced nutrition aiming for high yields.
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The results of this network show that the wheat producer who fertilized with an average recommendation obtained 27% more yields, but would have gained 20% more with a balanced fertilization. In barley, the gap between what was obtained and what was achievable was 22% (more than 1,300 kg / ha). In corn, the producer who fertilized gained 22%, but could have reached 1,700 kg more with adjusted management.
In the case of soybeans, Grasso stated that the belief that the oilseed does not respond to fertilization began to be reversed, although little nutrient input is still made: only a phosphorus starter is applied. Grasso assured that with sulfur and micronutrients 15% can be gained, around 630 kg of soybeans per ha.
He summarized that balanced fertilization increases yields by up to 26% on average. Under conditions not limited in nutrition, crop yields are up to 16% higher than those achieved with current practices. “While, in most crops with average fertilization recommendations, making adjustments with N, P , S and micronutrients the difference is reduced by half.
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Grasso showed the nutrient availability maps, according to a 2018 INTA-Fertilizar AC survey. There is a restrictive situation, but it is management because we already know that nutrients are lacking: nitrogen from organic matter along with zinc and phosphorus. Phosphorus deficiency occurs in 60% of soils. And the loss of zinc Zn- has been widespread in recent years, limiting production, he warned.
The Fertilizar AC technician indicated that it is necessary to move towards good fertilization practices, summarized in establishing the doses and the type of nutrients depending on the diagnosis; the expectation of achievable returns (from the average yield of the last campaigns) and the time and place where they will be applied.
Crop nutrition and yield gaps
At the close of the first virtual session of the Fertility Symposium 2021, Juan Pablo Monzn, a researcher at the University of Nebraska-Lincoln, United States and CONICET, and who also works in the Integrated Unit of INTA Balcarce and the University of Mar del Plata, lectured on crop nutrition to narrow the yield gap.
The analyzes indicate that the current nutrient applications are not sufficient to close the current yield gap and, in most cases, the balances indicate that there is nutrient mining (deficient application). He noted that this issue explains the advance of agriculture over marginal and unproductive systems.
These factors combined produce a strong pressure on the current crop area, therefore, if future demand for food is to be satisfied without an expansion of the already cultivated area, a (sustainable) intensification of crop production will be required so that each hectare produces close to its potential, minimizing environmental impact and preserving the soil resource.
With data from the ReTAA network of the Buenos Aires Cereal Exchange, Monzn listed that corn currently has a negative nutrient balance of 35 kg / ha of nitrogen; 9 kg / ha of phosphorus and also 9 kg / ha of sulfur. Adding N to corn is highly profitable, he said.
In wheat, the negative balance of mineral nutrition is 7 kg / ha in the case of N; 0 in P and 5 in Z. It is the only crop that, for current yields, in some regions of the country presents a positive phosphorus balance.
Soybeans, meanwhile, present a negative balance of P of 11 kg / ha and lack of S per 7 kg / ha. In order to close that yield gap without compromising the quality of the soil, we will require a substantial increase in the use of nutrients, said Monzn. And he reinforced that current applications are not enough to close the performance gap.
While he warned that these greater contributions carry a greater risk of losses if the nutrients are not applied properly and at the same time other limiting factors also appear, such as an inadequate choice of sowing date or plant density, cycle length, or a poor weed, insect and disease control.
Any program that aims to increase yields in a sustainable way will require an explicit recognition of the need for greater and better use of nutrients in Argentina, he concluded.
All this information arises from an initiative to diagnose nutrient gaps in Argentina, in which experts from the University of Nebraska-Lincoln, ReTAA, University of Buenos Aires, CONICET, Fertilizar AC, UMdeMP, INTA, IICA, Bayer, Universidad Kansas and private advisers.
New virtual days
The next virtual meetings of the Fertility Symposium 2021 will be held on May 19 and June 2, from 8.30 a.m. to 10.30 a.m. through the Agroconsultas platform.
The event is supported by the following companies: Yara, Bunge, Amauta, Profertil, Stoller, Timac Agro, Nutrien Ag Solutions, ACA, COFCO, EuroChem-EMERGER Fertilizantes, SR Industria Metalrgica SA, Microessentials, Fertec, YPF Agro, Compo Argentina, LCD -Macro Frtil, Rizobacter, Kioshi, Bertotto Boglione, Spraytec Fertilizers, FertiGlobal, Cargill, Recuperar, Soil Frtil and Metalfor.
The Fertility Symposium 2021 is aimed at producers, students, professionals and technicians, from the public and private activity of the country and the region. It is free and open access and requires pre-registration, since it has limited places.
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