AgNet DEMO

Category: Soil

  • Soil Sampling: Management Practice Key for Upcoming Season

    Photo by Mike Riffle/Shows supplies needed to take soil sample.

    One of the most overlooked management practices for vegetable and specialty crop producers is also one of the most essential this time of year.

    Soil sampling can save producers money by providing valuable information about the nutrient content in their soils. It is a more efficient means of preparing for the upcoming season instead of just guessing, said Joe Kemble, Alabama Extension vegetable specialist.

    “Right now, fertilizer costs are high. You really don’t need to use anymore than you have to. That’s the key of getting a soil test done,” Kemble said. “Plus, it will also give you a lime recommendation. Ideally, we try to lime a few months ahead of time before we put a crop out. Some lime is better than no lime, even if it’s not timely. Adjusting your soil’s pH, getting out your fertilizers, based on your soils test, I think that’s an excellent thing to do while you’re waiting for your fields to dry off.”

    Sample Boxes Available

    Kemble said there are sample boxes available in Alabama and provides instructions on how to properly take a sample. Producers can also search Alabama Extension for additional information that specify what is needed to take a soil sample.

    “It is easily the most overlooked agronomic practice that I run into. The reason I know that is because I see it on the other side. A grower calls me up and says, ‘I’ve got a problem.’ Normally, the very first thing I ask them for is a copy of their soil test because that’s going to help me rule out some things,” Kemble said.

    “Unfortunately, in Alabama, a lot of soils tend to become more acidic over time. The pH keeps going down and down and down. You can get into a situation where you’re not getting the yields you used to get, and you keep putting more and more fertilizer out and not getting the yields you think you should get. It could be tied to soil pH.”

    Multiple Crops

    Growers can also request multiple results for the same acre if they want to grow different crops. The sample will yield data relevant to growing tomatoes and a cucurbit, for example.

    It is a cheap method to utilize compared to the high cost of fertilizers and takes the guesswork out of the equation.

    “Normally, you’re going to be sampling, based on the size of the field; from a handful of samples to a couple of dozen depending on how big your area is. You mark it based on the area and the crop that you want to grow. The sample goes off to the lab, and it gets analyzed,” Kemble said.

    “You’ll get the results based on the particular crop you want to grow. It’ll say where your nutrients are at in the soil based on the availability within the soil for the specific crops that you want to grow.”

  • Building Better Soil

    A cover crop mix of sorghum and sunn hemp produces positive results for Honeyside Farms.

    By Tiffany Bailey and Ida Vandamme

    It was about 18 months ago when we began planning our first crop to be planted on our newly certified organic field at Honeyside Farms in Parrish, Florida. The field was previously used for pastureland. It was easy to see that we would be starting from a soil structure that is common in our area: very sandy with low amounts of existing organic matter. We quickly learned that building these soils would need to become a priority.

    It can be common for issues to surface during the first few months of converting from perennial pastureland to vegetable production, and that is exactly what we experienced. Our first major problem was due to the microbe populations living in the soil. We were tilling the land for the first time in possibly decades, and we believe that practice turned the existing microbial ecosystem on its head.

    Without the introduction of good bacteria and fungi suited for vegetable farming, our organic crops were especially vulnerable to disease pathogens coming from infected seeds, neighboring farms and even on our equipment and shoes. It was a huge challenge! But, over time, we began to build up the proper microbe population for our farm. Planting cover crops proved to be an important part of building healthy soil.

    COVER CROPS OFFER BIG BENEFITS

    Cover crops are a very helpful tool in aiding and maintaining this transition. Unlike perennial pastureland, cover crops for vegetable farming are annual, covering the ground for a few months at a time (very convenient for your off season when it’s not practical to grow your main crop). Cover crops grow very fast, covering and protecting the soil from erosion.

    Root mass grows down, infiltrating, breaking up compaction, improving structure and excreting exudates that condition the soil and attract good bacteria. Above ground, leaf matter adds literally tons of biomass that contributes to organic matter when broken down and attracts all kinds of beneficial insects and wildlife. There are so many more benefits to cover crops; these are just the main ones.

    COVER CROP OPTIONS

    Honeyside Farms has grown sorghum-sudangrass, sunn hemp, buckwheat and cowpeas for cover crops. As an organic farm, we preferably use organic seed. However, organic cover crop seed is not always widely available. Most certifying agencies will make exceptions when certified organic seed is not available.

    Sunn hemp is probably our favorite cover crop. According to a Sustainable Agriculture Research and Education publication, sunn hemp can produce 5,000 pounds of dry matter per acre and 120 pounds of nitrogen per acre. That’s enough slowly available nitrogen to feed some crops from start to finish without needing to add any extra nitrogen.

    Sorghum is also very beneficial. The sorghum-sundangrass hybrid is more productive in biomass and leaf matter, which is more beneficial as a cover crop than grain sorghum. Sorghum-sudangrass has been recorded to produce up to 18,000 pounds of dry matter per acre. The roots are perfect for scavenging any leached nutrients from the previous crop and putting them within reach of the next crop, thus minimizing pollution and making effective use of nutrition. Sorghum is also known to suppress diseases and nematodes by breaking up their life cycle and producing compounds toxic to them.

    Cowpea is a legume. As a climber, it can be a nice addition to any tall cover crop mix like sunn hemp and sorghum. We have seen that cowpeas and buckwheat can provide significant sources of nectar and food for beneficial insects that we want to attract to the farm. Buckwheat acts as a great short-term cover and easily breaks down. It’s perfect for the 40- to 50-day gap between crops when other covers would take too long.

    COVER CROP MANAGEMENT

    When planting, it’s important to broadcast the proper amount of seed per acre. If the seed is planted too thin, one can miss out on biomass production. But there is no need to waste seed and money planting too thick. Before applying any fertilizer to the cover crops, we take samples and follow what the soil report recommends at planting.

    The best time to knock down the cover crop is when the biomass is optimized, but before the carbon-to-nitrogen ratio gets too high and before seed set to prevent weeds. We allow a few weeks to let the cover crop break down enough so that it is not tying up nitrogen that should be available for our main crop. Sometimes before planting a cover crop, we can tell that this timing will not match when we need the field ready to grow a crop. But we find it better to still plant cover crops and gain some of the benefits rather than let the land sit bare and gain nothing or possibly even lose valuable soil due to erosion. Allow a few weeks to let the cover crop break down enough that it is not tying up nitrogen that should be for your main crop.

    Most challenges come from what is limited by resources, time and practicality. Nothing will be gained if no time is taken to plan for cover crop management. But with proper intention and planning, planting cover crops will provide long-term benefits for many seasons to come.

  • Soil Sample for Nematodes Now

    UGA Extension photo/Stubby root-knot nematode on onion plants in 2017.

    The time is now to soil sample for nematodes, says Pablo Navia, Adama Technical Development Leader for East Region.

    “This is the best time since populations of nematodes are really high right now in the soil. There’s still some roots that they are feeding on. This is the best time to sample,” Navia said. “It’s a good way to know what enemy you’re dealing with next season.”

    Navia said growers need to coordinate with the Extension agents in their county to take samples and arrange to take their samples to the appropriate lab.

    “Each state’s Extension agent will know where to send the sample. Each university will have their lab and you can send the sample to their lab,” Navia said.

    Navia recommends that producers take between 4 and 8 samples in a field, which will provide growers a good representation of the entire field.

    There are different types of nematodes that impact vegetables, with root-knot nematodes being the most widespread and can cause the most damage. Nematodes are especially troubling because of the wide range of potential hosts. In addition to vegetables, nematodes cause problems in cotton, peanut and tobacco plants.

    “It’s one of the most damaging pests out there,” Navia said. “It’s as important as a soil-borne disease or a foliar disease. There are many diseases that can affect a particular crop. But nematodes will make everything worse. If you have nematodes, then you have high chances of losing your crop.”

    Soil sampling better prepares growers for the following season and will help them know if numbers are beyond threshold and if further action is warranted.

    “If you have root-knot nematode and you find one nematode in your sample, that means you may be in trouble next season. Nematodes, like stubby root for example, the threshold is 200. Depending on the crop, like the citrus nematode, the threshold is 1,000,” Navia said. “It really depends on the species.”

  • Soil Moisture Sensors Benefit Florida Farmers

    By Ashley Robinson

    File photo shows soil moisture sensors.

    Florida’s sandy soils mean that water management is a key component of producing crops in the Sunshine State. According to Charles Barrett, University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) regional specialized Extension agent for water resources, irrigation scheduling tools like soil moisture sensors can help producers maximize their water efficiency and crop yields.

    Technology Packed with Benefits

    Soil moisture sensors are key irrigation tools for growers. If used correctly, they can be very beneficial.

    Whether growers have an irrigation schedule in place or not, the soil moisture sensor can be checked for trends to determine the efficacy of current irrigation practices. With the sensors, the grower can see if the soil is drying out or if the soil moisture is increasing over time. The sensor can also monitor the crop’s root zone, which can be helpful in fine-tuning an irrigation schedule.

    “I’d say that the number one benefit of soil moisture sensors is that you are able to manage your water more efficiently by supplying the right amount of water at the right time,” Barrett says. “By managing your water better, you’re also managing your nutrients better since water and nutrients cannot be separated in the state of Florida because of our sandy soils.”

    According to Barrett, the sensors are stationed in different locations in the field to allow growers to view the moisture and nutrients in the crop. This helps to avoid over-irrigation and loss of plant nutrients from leaching.

    “Soil moistures have come a long way. Before, growers used tensiometers, an older form of the technology which is much inferior to the technology we have now. Now, they have a graph, a history in time they can watch trends occur and see when they need to irrigate. Tensiometers required you to drive up to them and take a look. You only got a snapshot in time,” Barrett says. “With this technology we have the ability to watch whole movie versus before when they only had a small snapshot.”

    Funding Available

    To encourage the use of this technology, UF/IFAS Extension Northeast District introduced a pilot program in 2017, installing the sensors free of charge to allow growers to view and understand the data provided before they commit to the investment. Funding from the Florida Department of Agriculture and Consumer Sciences (FDACS) helped launch the program.

    In addition, cost-share programs are also available to growers. Growers who are enrolled in the Best Management Practices program can get cost-share anywhere within the state through FDACS or through their water management district.

    According to Barrett, the adoption of soil moisture sensors has been rapidly expanding. He believes it will continue to grow as more growers get to experience the technology for themselves. He hopes to expand the program statewide so that agents across the state can get their hands on the sensors.