For those interested in cover crops for citrus groves, the end of harvest and the upcoming start of the rainy season is a great time to start planning.
Cover crops can have a variety of benefits to soil health. These include increasing soil organic matter and microbial diversity and activity as well as reducing weed growth. While research is still ongoing, improving soil health may also provide benefits to citrus management and production. However, before planting cover crops, there are a few items that should be considered.
There is a wide variety of cover crops that can be planted in citrus groves. Planting legumes — such as perennial peanut, sunn hemp or cowpeas — can help contribute nitrogen to the soil. Nonlegumes can also provide important soil carbon inputs, which can assist with improving microbial activity and nutrient cycling.
Both annuals and perennials can be used as cover crops. For annuals, planting often occurs at the beginning of the rainy season. These summer season crops can continue to grow until the end of the rainy season. To ensure adequate moisture for a winter season of crops, the summer season crops can be terminated at the end of the rainy season (October/November) so that the winter season crops can be planted while there is still some rain.
In tree crops, cover crops are generally planted in the row middles, and the area underneath the tree canopy is kept clean through herbicide application. However, cover crops can be planted trunk-to-trunk so that they are also under the canopy. Standard seed drills may not be applicable for planting under the canopy, so additional preparations might be needed to broadcast the seed.
To optimize conditions for germination, row middles need to be prepared prior to planting cover crops. Herbicides can be applied to row middles before planting depending on the density of weeds currently in the row middles. Seeds can then be planted using a variety of seed drills.
After seeds are planted, mowing the dead weeds can help the soil retain moisture and possibly enhance germination of the cover crops. In general, cover crops in citrus are not irrigated, so timing your planting with the start of the rainy season is critical to enhance cover crop germination and growth.
See the following University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) articles for more information on cover crops that have had positive results in Florida:
Sarah Strauss is an assistant professor at the UF/IFAS Southwest Florida Research and Education Center in Immokalee.