Rome, 15 November 2022 – How much fertilizer is the right amount to use to ensure that crop yields are sufficient to guarantee local and global food security, but at the same time control environmental impacts?
Answering this question remains a huge challenge, but the latest reliable data from the FAO Statistical Database (FAOSTAT) can support a deeper exploration. This new information tool is the result of a joint effort between the Food and Agriculture Organization of the United Nations (FAO) and the International Fertilizer Association (IFA) and top scientists and experts from the Center for Environmental Sciences at the University of Maryland, the Swedish University of Agricultural Sciences, the Center for Agricultural and Environmental Risk Research at the Polytechnic University of Madrid, Wageningen University and Research Center, the University of Nebraska, and the African Plant Nutrition Institute.
The collaboration has succeeded in developing new data on on-farm nutrient gains and losses that can be used to measure the fertilizer inputs needed to support sustainable crop production and the potential environmental impacts.
Farm nutrient deficits are now the newest section of FAOSTAT, the world’s largest food and agriculture database. In this global public interest platform, FAO member countries and all stakeholders in the world’s agri-food system have access to harmonized data on yields, trade and consumption, with the latest panels providing information on the flow of the three main plant macronutrients (N, P and K) essential for crop growth.
As part of their international reporting obligations, countries provide basic crop and livestock production data to FAO. FAO combines the data with methods and models provided by the project’s scientific partners to generate a set of national common reference data for the period 1961-2020, which is updated annually. FAO Senior Statistician Francesco Tubiello explained that FAOSTAT is a solid set of data tools, based on top of basic national statistics, to help address intricate sustainable development challenges such as nutrient flows at national, regional and global levels.
On-farm nutrient gains and losses
On-farm nutrient surplus and deficit is an important indicator of nutrient flow, which can be used to determine whether agricultural inputs are in excess or deficit in terms of the dimensions of the three main nutrients required for plant growth, including mineral, chemical and organic fertilizers.
It is calculated by adding the amount of mineral, chemical and manure fertilizers applied to agricultural soils, as well as the effect of biological nitrogen fixation (legumes are strong nitrogen fixers) and atmospheric deposition, and subtracting the amount of nutrient runoff due to crop harvesting.
In principle, excess nutrients in the soil (recorded as surplus) pose environmental risks, such as leaching into water sources or volatilization in the form of greenhouse gas emissions. On the other hand, a nutrient deficit (denoted as deficit) often means lower crop yields or depletion of soil nutrients.
This can also be converted into a percentage efficiency, which is a measure of the efficiency of nutrient use by the crop (the ratio between nutrients consumed by the crop and total nutrient inputs). However, the results shown by the data also reflect some potential problems that need to be addressed with caution. For example, some utilization rates that appear impressive at first glance may actually imply excessive soil nutrient depletion, a situation that is often due to insufficient fertilizer inputs to support crop yield levels and therefore may lead to unsustainable yield shrinkage in the future.
In 2020, 85 million tons of nitrogen (N), 7 million tons of phosphorus (P) and 12 million tons of potassium (K) were applied to farmland globally, a fourfold increase from 1961, with an increasing share of synthetic fertilizers. The average application rates of N, P and K were 54 kg, 4 kg and 7 kg per hectare, respectively. Compared to the 1960s, nitrogen fertilizer application increased 3.4 times, phosphorus fertilizer application remained the same, and potassium fertilizer application decreased by 36%. The utilization rates of all three fertilizers have increased in recent decades, averaging between 50% and 62% over the entire cycle of record.
The values for nitrogen utilization in Africa clearly indicate that crop production here is generally dependent on nutrients found in natural soils.
China and India have the highest nitrogen surpluses in the world, with utilization rates below the world average of 50%. In Brazil and the United States, the nitrogen surpluses are much smaller, partly because both countries grow soybeans on a large scale and the legume family can supply natural biological nitrogen, so fertilizer inputs are lower in both countries.
Some countries have surpluses in one key nutrient and severe shortages in another, including major agricultural countries such as Argentina, Nigeria and Ukraine. Nathan Wanner, a project member of this new database build and an FAO statistician, explained that this may be because these countries have reoriented their strategies based on the prioritization of the selected species of crops and fertilizers.
Sustainable agriculture goals
A better understanding of on-farm nutrient gains and losses can help farmers and policy makers better select and evaluate practices to achieve more sustainable agriculture.
FAO is the regulator of SDG indicator 2.4.1, which monitors the proportion of agricultural areas engaged in productive and sustainable agriculture.
The newly introduced on-farm nutrient break-even data provides a different approach that goes beyond the basic standard of using fertilizer application as a simplified benchmark. While policymakers still disagree on how to weigh fertilizer inputs, food yield needs and environmental protection, the new data provide a more balanced and complete way to understand the interactions of each element in the nutrient flow process, enabling better identification of effective strategies.
To apply both basic statistics and complex data to promote and monitor the state of sustainable agriculture, FAO is active on multiple fronts, including recent initiatives to advance the PROSA (Monitoring Progress in Sustainable Agriculture) framework, host the Global Soil Partnership and, most recently, develop soil nutrient information maps.
Source: FAO microsignal
Post time: Nov-28-2022