Wednesday, 5 August 2020

Why herbage testing?


New Zealand’s competitive advantage in pastoral farming is grounded in our ability to grow vigorous clover-based pastures. Spring is the time to ascertain whether nutrient supply by the soil and uptake by the herbage can support vigorous growth. Herbage testing complements soil testing by showcasing nutrient availability and is the better measure for trace elements. Together the two will provide a better overall picture of a farm’s nutrient status than either used alone.

Clover species have a poorer root system when compared with grasses and require higher soil nutrient levels, effectively being the ‘canary in the mine’. When one or more nutrients are in short supply, clover will be the first to suffer. For pasture, it is recommended that herbage testing is divided into mixed pasture and straight clover. This is designed to give you an indication of what the animal is ingesting, the metabolic energy (ME) of the pasture and separately how well the clover is provided with nutrients. The outcome will provide important information to determine fertiliser requirements along with monitoring the effectiveness of your fertiliser programme.

Clover species have a higher nutrient density and feed value than grasses along with the ability to fix nitrogen, from the atmosphere to supply to companion herbage species. Molybdenum is essential in the chemistry of fixing nitrogen with straight clover testing being the best way to measure availability. Although cobalt and selenium are not essential to plants but essential to animals, a herbage analysis is a standard method to determine whether animals are sufficiently supplied with these and other trace elements.

Plant testing can also be done on any crop to evaluate nutrient concentrations in the plant. Each individual crop type and growth stage can be selected to enable comparison of test results with optimum or typical nutrient requirements at various growth stages. In addition, plant testing can be carried out to ensure your nutrient levels are not reaching high levels or causing any imbalances for plant or animal health.

ARL has both the expertise and the equipment to meet your herbage testing requirements. Its full range of accredited herbage tests range from a basic plant analysis, to a combined pasture and feed analysis that covers ME and other feed parameters, macro nutrients and trace elements. Herbage testing, interpreted with seasonal knowledge, farm nutrient status and animal diet provide an important management tool to ensure optimal production and crop quality.