N-Butylthiophosphoric triamide (NBPT, hereinafter referred to as "NBPT") is currently one of the most effective soil urease inhibitors. Agricultural fertilizers, mainly nitrogen fertilizers, are quickly decomposed by urease in the soil under normal use. This not only wastes a lot of nitrogen fertilizer resources, but also increases the cost of crop production, and brings a series of problems such as soil compaction and environmental pollution. The addition of urease inhibitor to nitrogen fertilizer is a new technology developed at the end of the last century. NBPT can suppress and release. On the one hand, it can effectively slow down the enzymatic hydrolysis process of nitrogen fertilizer decomposed into ammonia and reduce waste. At the same time, the diffusion time of nitrogen fertilizer at the fertilization point is prolonged, so that the need fertilizer of soil fertilization and the crop are synchronized, thereby increasing the effective utilization rate of nitrogen fertilizer by 30% to 40%. And the fertilizer efficiency can be increased from 50 days to 120 days. It covers almost the entire growth period of the crop. It is completely possible not to use secondary top dressing. NBPT is very effective for long-term crops such as trees and corn.
As a soil nitrogen fertilizer inhibitor, NBPT is highly efficient, non-toxic and has no side effects on the soil. Moreover, NBPT naturally degrades into ammonia and phosphorus in the soil, and can also be absorbed as fertilizer by the roots of the crop. NBPT reduces the toxic effect of ammonia on seed germination and seedling growth, and is an excellent soil nitrogen fertilizer inhibitor.
N-Butylthiophosphoric triamide (abbreviated as NBPT) is currently the most widely used nitrogen fertilizer slow release agent, which can greatly improve the utilization rate of nitrogen fertilizer. The traditional process route is to use dichloromethane as the solvent, and the phosphorus trichloride and n-butylamine are substituted. After ammonia gas is introduced, amination reaction is carried out, and crystallization is carried out to obtain a product. The residual liquid after the crystallization of the mother liquor through the recovery solvent is the waste mother liquor. The NBPT content is 3 wt% to 7 wt%, the dichloromethane content is 15 wt% to 20 wt%, and the thiophosphoric triamide derivative content is 73 wt% to 82 wt%.
Urease inhibitors are a class of chemical agents that inhibit urease activity in soil and delay urea hydrolysis. Soil urease is a specific hydrolase that catalyzes the hydrolysis of urea in soil. There are two main aspects to the mechanism of urease inhibitors controlling urea hydrolysis: One is due to the oxidation of SH to reduce urease activity; the second is to compete for ligands to reduce urease activity. Hydroquinone is mainly used in China. At present, several kinds of special fertilizers containing slow-release nitrogen fertilizers such as hydroquinone and dicyandiamide have been promoted and applied in a certain area. Urease inhibitors can also be used as feed additives for ruminants, which can effectively reduce the ammonia content in the air of poultry houses, improve the environment, and improve the efficiency of nitrogen utilization by animals.
Urease is an enzyme that hydrolyzes urea in the soil. When urea is applied to the soil, urease hydrolyzes it to ammonium nitrogen to be absorbed by the crop. Urease inhibitors can inhibit the hydrolysis rate of urea and reduce the volatilization and nitrification of ammonium nitrogen.
Its mechanism of action is:
- Urease inhibitors block the active site of soil urease on urea hydrolysis and reduce urease activity.
- The urease inhibitor itself is also a reducing agent, which can change the redox conditions of the micro-ecological environment in the soil and reduce the activity of soil urea.
- As a urease inhibitor, the hydrophobic substance can reduce the water solubility of urea and slow down the hydrolysis rate of urea.
- Antimetabolite-like urease inhibitors disrupt the metabolic pathways of microorganisms that produce urease, hinders the pathway for synthesizing urease, and reduces the density of urease distribution in the soil, thereby reducing the decomposition rate of urea.
- Urease inhibitors are themselves compounds that are similar in physical properties to urea. It moves synchronously with urea molecules in the soil to protect the urea molecules from urease-catalyzed decomposition. When urea is used to apply a certain amount of urease inhibitor, the activity of urease is limited, and the rate of decomposition of urea is slowed down, thereby reducing the inefficient degradation of urea.