Proven Method To Reduce Fertilization and Increase Economic and Environmental Benefits

(February 3, 2023) - A method that determines the ideal fertilizer application for wheat crops – without sacrificing yield or protein content – has been proven to reduce fertilizer input requirement, decrease greenhouse gas emissions and increase net income for grain growers.

The Director of The University of Western Australia’s Institute of Agriculture Hackett Professor Kadambot Siddique contributed to the seven-year research project, which was led by scientists from Northwest A&F University in China.

The study, recently published in the journal Field Crops Research, aimed to produce high grain yield and protein content for wheat production in China using a High Nutrient-Use Efficiency Based Fertilizer Recommendation (High NUFER) method.

According to the Bankwest Curtin Economics Centre, Western Australian farmers increased their use of fertilizer fourfold between 1990 and 2018.

Fertilizer was also the main source of WA farm costs at approximately 18%.

Similarly in China, fertilizer use increased 511% from 1978 to 2019, with grain production increasing by only 118% in the same period.

China is the world’s largest producer and user of fertilizers, with numerous reports of fertilizer overuse.

Although chemical fertilizer application is key to ensuring high and stable crop production, Siddique said excessive fertilization reduced fertilizer efficiency and farm economic benefits and caused various environmental problems.

“Over-applied fertilization has been shown to cause excessive nitrate-N in water, eutrophication and greenhouse gas emissions that threaten drinking water quality and environmental safety,” he said. "This study provides scientific guidance for saving costs, increasing farm income and improving sustainable agricultural development in China and other countries in similar situations, such as Australia."

For the study, the research team conducted farm surveys covering 1,575 fields in 17 of China’s major wheat production provinces from 2015 to 2019.

The on-farm information included wheat planting area, varieties, field management, soil nutrient status and fertilization status.

Wheat plant and soil samples were also collected from farmers' fields for measurement and analysis.

From 2020 to 2021, the researchers verified the High NUFER method in 46 sites across seven major wheat production provinces.

Professor Siddique said the validation experiments in the final year of the study proved that fertilizers were over-applied and often imbalanced.

"It revealed that the recommended fertilizer application based on High NUFER reduced nitrogen and phosphorus fertilizer use without affecting grain yield and protein content, relative to the farmer’s previous fertilization application," he said.

"The reduced fertilizer improved the partial productivity of nitrogen and phosphorous fertilizer and alleviated soil available potassium depletion.

“With the High NUFER method, grain growers can reduce their fertilizer input, thereby increasing economic benefits and decreasing greenhouse gas emissions. Similar studies are urgently needed in Australia and other wheat-growing countries, with the involvement of relevant farmer groups.”