Horticultural Sciences Department

You are here

Issue No. 602

The Vegetarian Newsletter 

A Horticultural Sciences Department Extension Publication on 
Vegetable and Fruit Crops 

Eat your Veggies and Fruits!!!!!

Publish Date: 
June 2015

RATOONING SUNN HEMP APPROPRIATELY TO MAXIMIZE BENEFITS

Qingren Wang, Extension Agent for commercial vegetables and pesticide licensing, UF/IFAS Miami-Dade County Extension

In the subtropical region of south Florida, especially in Miami-Dade County, the annual rainfall is usually about 60 inches and almost 80% of which falls between June and October. However, for most vegetable growers in this region, this period of the year is the off-season because of higher production costs, difficulty to control pests and inability to compete with producers in northern states. Keeping land fallow during this high rainfall period definitely results in a substantial loss of water and nutrients through leaching, especially in the sandy or gravelly soils.

Summer cover crops, especially sunn hemp, can tolerate drought during the late spring and flooding during the rainy summer. It grows very well and covers the land surface quickly and densely (Fig. 1). Since last year, the acreage of sunn hemp has amazingly reached up to 3,000 acres each year in Miami-Dade County because of the abundant sources of seed and the acceptable price – about $1.50 per lb and the seeding rate ranging 30-40 lbs per acre. This translates to about $45-$60 per acre and it is affordable for most vegetable growers.

Appropriate ratooning of sunn hemp can substantially improve the biomass production and its quality because the plant has a capability to regrow. Being a fiber crop, if cut too late the fibrous stems (Fig. 2) decompose slowly by microbial activities in the soil. Cutting the main stem of sunn hemp, which destroys the dominance of the apical bud, increases the number of primary and secondary branches, and concomitantly induces more leaves on the newly formed branches.

Typically, sunn hemp is seeded in May, ratooned in July to produce more biomass, consequently flail mowed and incorporated into the soil in August or early September in this region. However, most growers sowed sunn hemp in early April this year, and some of them started as early as in March, right after the final harvest of their vegetables. Seeding too early or too late can limit the biomass production because sunn hemp is a short-day length crop, and the plant size reaches the maximum when it flowers. Most of time, sunn hemp starts blooming at the end of July through August but some appeared in May (Fig. 3) this year because of early planting. Therefore, it is necessary to remind growers that, to maximize the benefits they should ratoon their sunn hemp plants at the right time with the right approach.

A field trial demonstrated that ratooning sunn hemp at about 30 inches above the ground (after 2-months of growth) with a sickle bar or other appropriate equipment mounted on a tractor almost doubled the amount of biomass production, producing very high quality biomass with only a small amount of fibrous stem material (Fig. 4). Therefore, for early planting growers, it is worthwhile to consider ratooning in June to optimize the quantity and quality of cover crop biomass production.   

601.1.1_0.jpg

Fig. 1. Sunn hemp covering the land completely within a month after seeding. Credit: Qingren Wang

601.1.2_0.jpg

Fig. 2. Cutting too late, resulting in production of fibrous stems. Credit: Qingren Wang

601.1.3.jpg

Fig. 3. Plants blooming at the end of May due to early planting. Credit: Qingren Wang

601.1.4.jpg

Fig. 4. Ratooning at appropriate time and method for maximum biomass production. Credit: Qingren Wang


Article #13 – Unfortunate and Preventable Accidents

Two unfortunate accidents occurred during February of 2015. If you are a farm labor supervisor, please read and check your operational procedures to ensure these accidents do not occur on our farms.  

On February 3, 2015, a migrant worker thought he was helping out his crew leader by moving a bus to the front of a restaurant. In the process the worker crashed the bus through a fence and pinned two other workers between the bus and the restaurant.   One worker died and the other was seriously injured.   The worker who drove the bus was not a licensed farm labor contractor, and further, did not have the proper license to operate a farm labor bus.

Two important lessons from this accident.   First, no one should move labor buses other than people licensed and authorized to drive them, and second, authorized drivers should be the ONLY people with keys.   The keys should never be accessible to workers.  It is important that companies create a security policy for keys, let employees know how important it is, and check it periodically by asking workers if they know where the keys are.    (Thanks to Wes Wurth, CHAPP Insurance.)

On February 17, 2015, Esteban Manuel Ernesto was accidentally run over by a field truck in Hendry County as it was backing up to make a tight turn.   Manuel was crouched down picking bell peppers on an outside row directly behind the truck.  The truck did not have a back-up beeper.  Manuel died before the ambulance arrived. 

During harvest periods, workers are focused on their work.  This is when they make the most money and they often don’t even want to stop to use the bathroom or drink water.   In row crop operations, they prefer to pick rows that are closest to the truck road, as these plants tend to be higher yielding, and the workers do not have to spend extra time crossing rows to dump their buckets. Their proximity to the field truck puts them at higher risks for accidents when the truck moves.

An added complication comes with crop height.   Backing up in the fields is more dangerous when dealing with crops like bell peppers versus, for example, tomatoes, which are usually staked.   A field truck, with an overhang of 10 – 12 feet, can back up farther over peppers because peppers are not staked and the plants are lower.  Therefore, workers who are in the 3rd and 4th rows from the truck road are at risk, not just those closest to the truck.   (Thanks to Noe Leal, Leal Harvesting.)

There is no mandatory standard in agriculture for a backup signal, but best practices indicate that all vehicles in the fields should have one.  And if your vehicle comes with a signal, it needs to be working.   (Thanks Cesar Asuaje, UF/IFAS Palm Beach County). 

Whether you have a backup signal or not, before the truck moves ---- STOP all work!  CHECK both sides of the field truck to be sure all the people are out of the way.   LOOK at the people to make sure they stop work and are paying attention, not texting or chatting or otherwise distracted.  

DO YOU HAVE QUESTIONS RELATED TO FARM LABOR MANAGEMENT?   Please call or email Fritz Roka (fmroka@ufl.edu) and Carlene Thissen carlene@ufl.edu and we will try to get your questions answered.  

Also, you can educate yourself, crew leaders, and farm or grove supervisory management by taking classes for Farm Labor Supervisors developed by SWFREC/IFAS Immokalee.   Take a total of 8 classes and earn the CERTIFICATE OF FARM LABOR MANAGEMENT, offered since 2014.    The next set of public trainings will be held in various locations in fall, 2015.   Between now and then, on-site grower trainings are available and also we can arrange trainings with a minimum of 15 guaranteed attendees.    Contact Carlene Thissen, carlene@ufl.edu, 239-658-3449.