A new study published on 15 November in Frontiers in Sustainable Food Systems has presented a cheap and easy real-time method to measure nutrient levels in grassland (1). This rapid new technique will allow farmers to quickly monitor changes in pasture nutrients and adapt grazing methods based on the results. The researchers showed that overgrazing pastures to below 7 cm significantly reduces the amount protein in grassland and digestibility.
Grassland ecosystems cover 40% of the land on Earth and are mainly taken up by vegetation with little or no tree cover, and include meadows, steppes, and lands grazed by livestock. Nearly half of the European Union’s total land area is used for agriculture and this includes its grasslands associated with around 235 species that fall under the EU Habitats Directive, a directive set up by the European Commission to protect endangered and vulnerable species in the European Union. European grasslands are among the most species-rich vegetation types (up to 80 plant species/m2) on the continent. Thus, grasslands present important conservational value and can have a major impact on the sustainability of the environment and livestock systems.
Near-Infrared Spectroscopy (NIRS) is widely used in medical and physiological diagnostics and research, as well as pharmaceutical, food, and agrochemical quality control but traditionally requires the use of large specialized equipment in a laboratory. Samples are irradiated with near-infrared light and the resulting spectrum ― how much of each wavelength of light is reflected by the sample ― is measured. Bonds between different molecules (e.g. hydrogen, carbon, oxygen, nitrogen and sulphur) absorb the near-infrared light in different ways and so the spectrum contains important information about the sample’s composition.
Small and mobile NIRS devices with built-in data processing and storage now allow real-time analysis of farmland and can provide information on the nutritional composition of roughage and raw materials. The researchers, led by Dr Matt Bell and colleagues from the University of Nottingham, calibrated a handheld near-infrared spectroscopy (NIRS) device to measure nutrients in pastures. They collected samples from a nearby farm to assess changes in pasture nutrients and determine the potential factors leading to these changes.
The findings suggest that a decline in the height and cover of pastures is associated with lower digestibility and reduced concentrations of protein. They report, “Intensively grazed pastures should avoid going below a height of 7 cm, otherwise, nutrient intake by the animals will be limited. Below this height, the composition of the grass is more stem and residual plant material than vegetative plant material.” The next steps will be to look at variation in pasture nutrients such as botanical composition, differences between grazing animals, and variability within a single day.
According to the authors, the mismatch between nutrient supply and animal requirements reduces livestock performance, increases the demand for land, and reduces nutrient use efficiency. This new approach could greatly improve the sustainable management of grasslands, which is the main form of agriculture in many parts of the world.
The global population is expected to increase to 10 billion by 2050; therefore, to meet increasing global food demands, agricultural production will have to increase by nearly 60 per cent. Land resources are currently close to their limits, moreover, stagnant crop yields present a major challenge. This and other challenges ― such as supply chain issues, freshwater consumption by thirsty crops, and reducing greenhouse gas emissions while ensuring global food security ― can only be overcome by adopting novel approaches in precision agriculture and making use of technological innovation within the agricultural industry.
(1) Bell, M.J., Mereu, L., and Davis, J. The Use of Mobile Near-Infrared Spectroscopy for Real-Time Pasture Management. Frontiers in Sustainable Food Systems (2018). DOI: 10.3389/fsufs.2018.00076