‘Smart fertiliser’ tablets created for slow release of nitrogen
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A team of biophysicists at Siberian Federal University has developed a tablet containing nitrogen fertiliser. Its bio-compatible materials break down in soil to provide a controlled release of nitrogen or other fertilisers.
Nitrogen is vital for the healthy growth and development of plants. When organic matter with high carbon content - such as waste sawdust - is added to soil, crops become increasingly susceptible to nitrogen deficiency. This can be countered by adding fertiliser to the soil.
The compounds of plant-available nitrogen are very mobile and can be easily “leached” from the soil. There is a need, therefore, for nitrogen fertilisers which could provide slow-release nitrogen to maintain a healthy, consistent concentration in the soil.
The team of researchers were able to create a slowly decaying structure which released nitrogen gradually, using a powdered, biodegradable polymer, poly-3-hydroxybutyrate. This was mixed with wood flour and ammonium nitrate: a typical nitrogen fertiliser.
The resulting mixture was pressed into tablets and coated with a biopolymer. These tablets could be simply added to soil, where they gradually disintegrate.
To test the tablets, the researchers grew wheat plants without fertilisers, with pure ammonium nitrate, and with the slow-release tablets. They found that the best results were achieved when the wheat was grown with a double-packed tablet (covered with a second, polymer film), which released the fertiliser to the soil over a period of two months.
“The key point for the development of such drugs is the presence of environmentally safe and bio-decomposable material,” said Professor Tatiana Volova of the Institute of Biophysics at Siberian Federal University.
“We have developed and implemented the technology for the synthesis of bio-decomposable polyesters of microbiological origin, effective as a material for products for biomedical applications, and also explored patterns of their decomposition in soil and other environments.”
The study of bio-decomposable materials, which break down under the influence of microflora, is a relatively new area of research in the field of agriculture, which could allow for waste products to be transformed into useful substances.