When can nitrogen fertilization begin?

Council of Ministers Regulation of January 31, 2023. On the “Program of measures to reduce water pollution by nitrates from agricultural sources and prevent further pollution,” the so-called “Program of measures to reduce water pollution by nitrates from agricultural sources and prevent further pollution. nitrate program, sets deadlines for the application of fertilizers containing nitrogen in their composition. The period during which fertilizer application is allowed depends on the location, the condition of the land and the type of fertilizer, and begins on March 1 and ends between October 15 and November 30. Program update introduced on February 8, 2023. gives the opportunity to apply fertilizers earlier, i.e. from the first to the last day of February, if the right weather conditions occur.

Flexible timing of spring nitrogen fertilization

Earlier, compliant fertilizer application is possible if the average daily air temperature exceeds 3°C for autumn-sown crops, permanent or perennial crops and permanent grassland, and 5°C for other crops. Passing the threshold of a given temperature occurs when for 5 consecutive days the average daily air temperature exceeded the value mentioned in the nitrate program – these are 3°C or 5°C.

The five-day period adopted to determine the passage through the threshold of a given temperature is due to plant physiology (after this time, the processes that determine vegetation begin). In addition, such time is indicated, among others. in JRC(Joint Research Center) studies as a way to define the start of plant vegetation.

Nitrogen fertilization – where to find information

The list of counties where the average daily air temperature has passed the 3°C and 5°C thresholds is published every February on the website of the Institute of Meteorology and Water Management-State Research Institute in the AGROMETEO service. It is necessary to maintain these values at 95 percent. The area of the district in question. The appropriate time to begin fertilization when a farm is located in 2 or more counties is the date specified for the county with the largest percentage of the farm’s total area.

Where can nitrogen fertilizers already be applied?

According to information posted on the website of the Institute of Meteorology and Water Management-State Research Institute in the AGROMETEO service as of February 5, 2024. The use of fertilizers containing nitrogen in their composition is possible in the zachodniopomorskie, lubuskie and wielkopolskie provinces, and partially in the dolnoslaskie, kujawsko-pomorskie, opolskie, łódzkie, mazowieckie and pomorskie provinces. A detailed list is shown in the map below.

Prohibit the use of fertilizer on frozen, snow-covered or flooded soils

According to the provisions of the nitrate program, as well as Art. 20 para. 1 point 1 and paragraph. 3 Law of July 10, 2007. about fertilizers and fertilization, it is forbidden to apply fertilizers and digestion products on frozen, flooded or saturated soils, as well as on soils covered with snow. According to the Ministry of Infrastructure’s website, frozen soil is considered to be hardened soil that resists pressure and does not absorb water due to ice blocking its pores. If the soil thaws during the day, at least superficially, it is not considered frozen soil.

Flooded soils are those where stagnant water is visible (the definition does not include fish ponds). Water-saturated soils, on the other hand, are those that, despite the absence of stagnant water, do not absorb water and are slimy and plastic. A snow-covered field is one with at least 50 percent of its area covered with snow. The surface is covered by a layer of snow, from under which the soil is not visible.

What is the importance of the timing of nitrogen fertilization?

The proper timing of the start of nitrogen-containing fertilizers is an important factor in profits. This is especially crucial for farmers. On the one hand, it offers the possibility of high yields, and on the other, it does not lead to leaching of nutrients (which is associated with economic losses and environmental pollution). When nutrients are applied to the soil too early or too late relative to the time when plants can optimally utilize them, they will not be taken up from the soil and direct losses and nitrate pollution of surface water can occur.