Smart Nanofertilizers for Agriculture

Smart Nanofertilizers

Mineral nutrients  such as nitrogen, phosphorous potassium, calcium, magnesium, sulphur, and other micronutrients are essential for plant growth and crop production.  Presently, we face a glaring contrast of insufficient use of nutrients on one hand and excessive use on another. Nutrients Use efficiency (NUE) represents a key indicator to assess progress towards better nutrient management. Fertilizers are chemical compounds applied to promote plant growth. It is applied either through the soil or by foliar feeding. Artificial fertilizers are inorganic fertilizers formulated in approximate concentration to supply the nutrients. Nitrogen is an important source which is essential for the growth of plant. Urea is the most wildly used water soluble plant nitrogen source. Due to leaching the nitrogen content in the soil get decreased leading to low nitrogen utilization efficiency.

Nitrogen-use efficiency for most crops ranges from 30 to 50 percent, so researchers are developing intelligent nano-fertilizers to reduce the amount of nitrogen lost during the crop production.  The plant needs different amount of nitrogen depending on its growth stage. A new generation of fertilizers will increase this efficiency from 30 percent to upwards of 80 percent. The idea is to develop a product that will release nitrogen only when the plant needs it and in the amount the plant needs. The plants communicate their surroundings environment by producing all kinds of chemical signals. A plant synthesizes specific compounds to communicate with specific microbes. The microbes then go to work and free nitrogen that the plant uses to grow. Thus, roots send out signal that ask microbes to transform nitrogen in the soil into a chemical form the plant can use. Many chemical compounds that are associated  with nitrogen uptake have been identified. These compounds can be used to synchronize the release of fertilizer with nitrogen uptake by the crop. 

A biosensor is a device that combines a biological recognition element with a physical or chemical transducer to detect a biological product. In other words, it is a probe that integrates a biological one with an electronic component to yield a measurable signal. Several biosensors are being developed for different applications. Typically a biosensor consists of three components: the biological recognition element, the transducer and the signal processing electronics. Nano-biosensors that will bind to these compounds can be developed so as to control of the release of fertilizers. The polymers coatings that protects the fertilizers from the elements contains nano-sized biosensors which are made up of very specific chemical compounds that allow the fertilizers to be released into the soil when the plant needs it. These biosensors know when to release nitrogen because they are able to detect chemical signals released from the roots of the plant to the soil. Biosensors can detect when a plant requires more nitrogen and allow microbes access to the fertilizer-nitrogen inside the polymer protected particles. 

Each plant species sends out its own variety of chemical signals. Keeping this concept in mind, a smart nano-fertilizer product could be tailored to respond differently to the needs of different crops. For instance, the nitrogen particles could be designated to become available to wheat, but not to the canola growing in the same field because of different compounds emitted by different crops. We can prepare different biosensors using different compounds and tailor the fertilizers to each different crop for different climatic zones and soils. Dr. Carlos Montreal of Agriculture and Agri-Food Canada in Ottawa is one of the several research scientists developing a fertilizer that responds to organic compounds emitted by a plant’s roots. The research team is trying to make  intelligent fertilizers with the biodegradable three-dimensional polymer coating less than 100 nm  thick. Hence, in coming years farmers could have access to an intelligent nano-fertilizers  that synchronizes the release of nitrogen with crop uptake.