Questions Remain on Cover Crops and Compost

Josh McGillSoil Health

Cover crops and compost can impact soil microbes in citrus groves, and that’s generally considered a good sign, soil microbiologist Sarah Strauss said in a virtual May 24 seminar. Microbes are critical components of soil health through their contributions to soil organic matter, nutrient cycling and plant defenses.

Cover crops and compost

But the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) researcher said she still has questions on the long-term impact of cover crops and compost on trees. She added that researchers have not yet seen big yield differences as a result of cover crops planted in groves with older trees. She also noted that some practices, like the use of cover crops, can take years to demonstrate whether they are working.

One reason there are questions is that most soil health indicators have not been evaluated on subtropical crops like citrus, Strauss said. She reported that the U.S. Department of Agriculture lists a total of 31 soil health indicators, including general microbial activity and carbon food source.

Strauss noted that cover crops are planted to benefit the soil and are generally not harvested for profit.

In cover crop trials, Strauss and fellow researchers have planted the legumes sunn hemp and cowpea in both summer and winter, as well as white clover and crimson clover in winter.

Their non-legume cover crops have been buckwheat in summer and winter. Other summer non-legume plantings have been browntop millet, dove millet, Egyptian wheat and sorghum sudangrass. Other winter non-legume cover crops have been daikon radish, oats and rye.

Strauss said the cover crops in trials were planted in May at the start of the rainy season and in November at the end of the rainy season. The cover crops are planted in row middles, not trunk to trunk, but Strauss said citrus roots grow into the row middles.

Learn more from Strauss and others about cover crops in citrus here.

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About the Author

Ernie Neff

Senior Correspondent at Large

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