The influence of weather on lucerne hay quality

There is still limited research available on the effects of weather on lucerne production in South Africa, This article, written by lucerne specialist Dr Gerrie Scholtz, agricultural economist Walter van Niekerk, and others, was published by the National Lucerne Trust and offers some insight on the matter, based on recent observations.

- Dr Gerrie Scholtz, Walter van Niekerk

In order to understand the factors that influence lucerne hay quality and yield, it is necessary to have a basic understanding of the biology of the lucerne plant. As the plant matures, the stems become more lignified in order to support the plant as it grows heavier during flowering. The stems, rather than the leaves, also begin to make up a greater proportion of the plant. This results in higher yield, but lower quality.

The lucerne also takes longer to dry due to the thicker stems, which in turn causes increased leaf loss due to shattering (lucerne leaves dry out three to five times faster than the stems). The main objective of lucerne hay production should therefore be to strive for the ideal balance between yield and quality.

RAIN DAMAGE

The extent of reduction in yield and quality of lucerne hay depends on heat, irrigation, cutting schedule, harvest management and weather patterns. Of these, harvest management has by far the greatest impact on forage quality. Moreover, it is under the direct control of the grower. Producing lucerne hay for maximum yield and quality requires an understanding of how environmental and management factors influence crop growth and development.

The smallest amount of untimely rain can postpone the harvesting process, causing rapidly maturing lucerne to decline in quality very rapidly. Rain just before cutting slows down drying after cutting, as the soil remains moist despite sunshine and low humidity. However, rain before harvesting is only one potential problem. Even larger difficulties can occur when it rains after cutting.