Soil Health
Overview
- Healthy soils can provide increased water-holding capacity, increased nutrient availability, and greater microbial activity, which can help reduce disease pressure and improve root growth.
- For Florida citrus soils, increasing soil organic matter and monitoring soil pH and nutrient concentrations are key to improving soil health.
Soil pH
- Soil pH should be tested at least annually and maintained between 5.8 - 6.5.
- It can take 6 to 24 months to adjust the soil pH to optimum depending on the soil buffer capacity, moisture, temperature, and aeration.
- Irrigation water in Florida is high in bicarbonates and increases soil pH over time.
- Irrigation water acidification, elemental sulfur application, or use of acidifying fertilizers are recommended to reduce soil pH.
- Soil pH reduction with acid injection into irrigation is faster compared to elemental sulfur soil application, but the effect of acid injection is short term versus elemental sulfur.
- Long-term use of ammoniacal fertilizers will also result in lowering the pH by nitrification.
- Low soil pH exacerbates nutrient leaching problems especially for calcium, magnesium, and potassium.
- High soil pH makes micronutrients unavailable while pH below 5 makes most micronutrients reach toxic levels for plants.
Learn more
Soil Organic Matter
- Organic matter is generally low in Florida citrus soils, so methods to increase organic matter content are important for improving soil health.
- Organic matter is created by microbial and chemical processes from decomposing plant and animal material.
- It is an important source of resources for soil microorganisms.
- Soil microorganisms assist in making nutrients available to the trees, deter pests and diseases, and improve root growth.
- Increased organic matter can also increase water and nutrient holding capacity, while reducing erosion and limiting weed growth.
- Common methods to increase soil organic matter are through the application of compost or the planting of cover crops.
- Composting can be done multiple times per year by broadcast application around the trees.
Cover Crop Management
- Can provide a continual source of organic matter to soils, as they can be planted year-round in Florida citrus.
- Current vegetation should be mowed before planting cover crops.
- Herbicide may be applied at least 2 weeks prior to planting cover crops to reduce germination competition.
- Annual cover crops should be planted at the beginning of the rainy season (June/July) and then again at the end of the rainy season (October/November) so growers do not need to irrigate cover crops.
- Mixing legumes with non-legumes in a cover crop mix can help increase microorganisms associated with nitrogen cycling.
- Planting can be done with a no-till seed drill to reduce impact to the citrus roots in the row middle, or by broadcasting the seeds.
- To build a seed bank, mowing and termination of the cover crops can wait until after they have flowered and formed seeds.
Learn more: Cover Crops for Florida Citrus: Practical Considerations and Their Impact on Soil Microbes
Resources
- Soil and Leaf Tissue Testing for Commercial Citrus Production
- Diagnostic Nutrient Testing for Commercial Citrus in Florida
- Flatwoods Citrus Best Management Practice: Soil Stabilization
- Soil Sampling Procedures
- Soil pH Management for Optimum Commercial Fruit Production in Florida
