What Is Fertilizer Use Efficiency? A Detailed Explanation of the Typical Use Efficiency of Different Types of Fertilizer
Fertilizer use efficiency refers to the percentage of a given nutrient absorbed by the crop in the current season out of the total amount of that nutrient in the applied fertilizer.
Under current cultivation management levels, the range of variation in crop use efficiency of chemical fertilizers is: 30%-60% for nitrogen fertilizer, 10%-25% for phosphate fertilizer, and 40%-70% for potassium fertilizer. The nitrogen use efficiency of organic fertilizers is relatively low; generally, well-decomposed barnyard manure or green manure is about 30%, compost is 20%, and mud fertilizer is less than 10%, while the use efficiency of phosphorus and potassium nutrients in organic fertilizers is somewhat higher than that of nitrogen. It can be seen that fertilizer use efficiency is not high.
Therefore, paying attention to scientific fertilization methods, applying fertilizer reasonably according to the weather, the soil and the crop, is one of the key measures for improving fertilizer effectiveness and reducing agricultural costs.
Appendix: China's fertilizer use efficiency reaches 33%
Fertilizer use efficiency is the main indicator for measuring the effect of fertilization. In order to comprehensively, accurately and objectively reflect the fertilizer use situation in China's agricultural production, the Ministry of Agriculture organized experts to complete the “Research Report on Fertilizer Use Efficiency of China's Three Major Grain Crops” and released the relevant research results recently.
The “Report” shows that at present, the average seasonal use efficiencies of nitrogen, phosphate and potassium fertilizers for China's three major grain crops, rice, corn and wheat, are 33%, 24% and 42% respectively. Among them, the nitrogen, phosphate and potassium fertilizer use efficiencies for wheat are 32%, 19% and 44% respectively; for rice they are 35%, 25% and 41% respectively; and for corn they are 32%, 25% and 43% respectively. At present, the fertilizer use efficiency level of China's main grain crops has entered the internationally recognized suitable range, but it is still at a relatively low level, and there is still considerable room for improvement.
Professor Zhang Fusuo of China Agricultural University, the main drafter of the “Report”, introduced that in recent years, the issue of fertilizer use efficiency has attracted increasing attention, but due to the lack of corresponding data, there had been no scientific research data on fertilizer use efficiency. In order to accurately measure fertilizer use efficiency, the researchers carried out a large amount of work in data selection, data organization, measurement methods, verification trials and other aspects, using soil analysis, field trials, field surveys and other data obtained from 9 years of soil testing and formulated fertilization, as well as fertilizer use efficiency verification trial data carried out by the National Agricultural Technology Extension Service Center, consulted a large number of domestic and foreign literature materials, and conducted tens of thousands of farmer household surveys, obtaining fertilizer use efficiency data that basically reflect the actual situation of fertilizer use for China's main grain crops at present.
Professor Zhang Fusuo said that there are misconceptions in the various statements about fertilizer use efficiency at present. Fertilizer use efficiency is not just a simple number; there are relatively large differences among different crops and different fertilizer varieties, and there are also differences between seasonal use efficiency and cumulative use efficiency. The currently widespread statement that “China's fertilizer use efficiency is about 30%, and 70% is wasted” is unscientific. Professor Zhang Fusuo explained that of the nutrients not absorbed and used by the current season's crop after fertilizer application, part will be stored in the soil for absorption and use by the next season's crop, and part will leave the farmland and enter the atmosphere and water bodies; only this part is called fertilizer loss. At present, fertilizer loss is mainly concentrated in nitrogen fertilizer, while most of the nutrients in phosphate fertilizer and potassium fertilizer will accumulate in the soil, and the cumulative use efficiency can reach more than 60%.
Director Li Rong of the Soil and Fertilizer Technology Division of the National Agricultural Technology Extension Service Center, a participant in the “Report”, introduced that the “fertilizer use efficiency” everyone cares about mainly refers to the seasonal nitrogen fertilizer use efficiency of grain crops. The fertilizer use efficiency of China's main grain crops has gone through a process of “first declining, then rebounding”. Since the 1990s, with the continuous increase in chemical fertilizer input, fertilizer use efficiency showed a downward trend. Taking nitrogen fertilizer as an example, the use efficiency dropped from 30-35% in the mid-1990s to 28% in the early this century (2005). In recent years, through the implementation of projects such as soil testing and formulated fertilization and soil organic matter improvement, and vigorous promotion of scientific fertilization techniques such as deep ploughing and deep loosening, deep application of chemical fertilizers, straw return to the field, and integrated water and fertilizer management, fertilizer use efficiency has been steadily rebounding. In particular, since the launch and implementation of the soil testing and formulated fertilization subsidy project in 2005, the transformation from traditional fertilization methods to scientific fertilization methods has been promoted, curbing the momentum of excessively rapid increase in chemical fertilizer use. According to calculations in the “Report”, the current seasonal nitrogen fertilizer use efficiency of the three major grain crops is 33%, an increase of 5 percentage points over the period before the implementation of the soil testing and formulated fertilization subsidy project (2005). The seasonal use efficiencies of phosphate fertilizer and potassium fertilizer increased by 12 and 10 percentage points respectively over 2005.
A relevant official of the Planting Industry Management Department of the Ministry of Agriculture stated that China is the world's largest producer and consumer of chemical fertilizers. Improving fertilizer use efficiency is an inevitable requirement for transforming the agricultural production mode and improving comprehensive agricultural production capacity. Next, agricultural departments at all levels will deepen the promotion of scientific fertilization work from five aspects, reduce unreasonable fertilizer input, and continuously improve fertilizer use efficiency: First, promote the application of formulated fertilizer to the fields. Continue to implement the soil testing and formulated fertilization subsidy project, carry out actions for cooperation between agricultural departments and enterprises to promote formulated fertilizer, increase the area where formulated fertilizer is applied, and solve the “last kilometer” problem of scientific fertilization technology. Second, promote the transformation of fertilization methods. Encourage the application of organic fertilizer and straw return to the field, vigorously promote scientific fertilization methods such as deep application of chemical fertilizers, integrated water and fertilizer management, and simultaneous sowing of seed and fertilizer, and develop new varieties that save fertilizer, increase efficiency, increase yield and increase income. Third, strengthen the integration and promotion of technology. Strengthen comprehensive management of nutrient resources, and in accordance with the requirements of high yield and high efficiency, assemble and match crop cultivation measures with efficient fertilization measures for large-area promotion and application. Fourth, strengthen publicity and training. Adopt various forms such as television, radio, plain-language leaflets, and mobile phone text messages to carry out technical training and publicity, so that farmers can truly master scientific fertilization technology and establish awareness of scientific fertilization.