Ideal nitrogen fertilizers in the corn belt have been climbing for decades, the study shows

The amount of nitrogen fertilizer needed to maximize the profitability of corn production in the Middle West is increasing by about 1.2% per year in the last three decades, according to the New Iow State University.

Study, published Last month in Nature communicationThey analyzed data from the previous long -term and short -term studies of the State of Iowa and the University of Illinois to calculate the optimal nitrogen nitrogen rates, which researchers considered to be static despite the fluctuations from year to year over time. The authors of the study primarily attributed the increase in optimal nitrogen rates from 1991 to 2021 to increased loss during moist spring and nutrient needs of larger yields, which also increased about 1.2% per year in the same period of time.

“As surprised as we were, it was really no surprise when you sat down and thought about it,” said study co -author Michael Castellano, professor of agronomy and professor William T. Frankenberger of Science Science. “It’s like a bank account. If you pull out money, you have to deposit more money to continue your account.”

Analysis is accompanied by an Iowa farmer’s surveys, whose login is reported nitrogen fertilizer The corn has also increased in recent decades.

“Seeing this study going out, I’m sure some of them would say, ‘I knew! “, Said the co-author of the study by Sothirios Archontoulis, pioneer hi-Brend agronomy professor.

Improvement of efficiency

A certificate of foam nitrogen based on data should be repeated the importance of continuous improvement of the efficiency of the use of fertilizers, which is necessary to limit the effect on the quality of water and greenhouse gas emissions. Knowledge of science is more in synchronization with the experiences of farmers can help build confidence in professional recommendations for effectively applying nitrogen fertilizer, said agricultural and biosuviation professor, and Brenta and Professor Cindy Hart Matthew Helmers, director of the Nutritional Substance Center in Iowa.

“Farmers hear information from many different sources. There is some uncertainty,” said Helmers, also a co -author of the study. “But the more I can accurately adjust their nitrogen management, the greater the return to see their investment in the field and the more we will reduce the losses in the environment.”

Although there is still room for growth, farmers have become more effective in applying nitrogen fertilizer. Using 0.7 pounds of nitrogen or less per corn bushes is a common goal for the last years for Iowa farmers, but the recommendation of the Iowa state was 1 kilogram per shrub 20 years ago and 1.2 kilograms per shrub 30 years ago, Castellano said. Increasing optimal nitrogen rates in the last 30 years would be even greater if improved efficiency did not slow down increase.

Rotation of crops, improved drainage and fertilizers’ spring use are the greatest influence to increase the efficiency of nitrogen use, according to Jes’s extension and reach that many of the same researchers who contributed to the new study last year.

The application of the right amount of nitrogen is also crucial, and farmers have more resources than ever to set up rates especially adapted to individual fields. The Iowa Nitrogen Initiative conducts tests on private farms throughout the country, using the modeling of data and crop system to offer corn farmers IOWA more accurate nitrogen.

Public-private partnerships-Koje was led by Castellano and Archontoulis, supported by the Ministry of Agriculture and Land Management in Iowa and numerous commodity groups-Najješće has published an initial version of his digital decision support. N-Fact (nitrogen consultation tool) recommends adapted rates in location, time, nitrogen in the soil, planting date, pruning system and market prices.

“Farmers knew that optimal rates were increasing before we did it, and now through our partnership with farmers, the research would be closer to match the real production realities on the farms,” ​​Castellano said.

A trend that is likely to continue

Efficiency has a greater impact on environmental sustainability of nitrogen fertilizer than the speed at which it is applied. This is good news because optimal rates are likely to continue to increase, said Mitchell Baum, an associate of postdoctoral research in the Agronomy Department and the first author of the study.

“As long as yields will increase, unless there is a massive increase in efficiency, we do not see the signs of this slowdown,” Baum said.

The analysis listed in the study focused on three different types of optimal nitrogen rates: economic, agronomic and environmental. The economic optimum is based on the maximization of farmers’ profits, the agronomic optimum point is a point where additional nitrogen has no effect on yield, and the optimal environment involves the estimated financial cost of the nitrogen oxide emissions and the flushing of nitrate into groundwater.

The economic optimum is always lower than the agronomic optimal and larger than the optimal environment, but the gaps between the rates change. The difference between agronomic optimal optimal and maximum-prinos and economic optimal optimal optimal decreased by 79% over 30 years studied, while the difference between economic and environmental rates increased by 34%.

The reduction of nitrogen fertilization rates to the optimal environment would cause a drop in a yield of about 6%, and only a slight reduction in nitrogen loss, an unfavorable compromise, Archontoulis said.

“If you want to reduce nitrogen fertilizers under the necessary optimal and also maintain yields, well, we can’t have everything. If you reduce nitrogen, reduce yield,” he said.