Category Archives: Yield trial

Seepage irrigation

One fascinating thing about visiting Southwest Florida farms is seeing their distinctive seepage irrigation system. I had heard it described, but I didn’t really get it until I saw it in action.

Unique soils in Florida have allowed growers there to develop a an effective irrigation system that differs in many respects from what I have seen anywhere else. Sandy soils overlay a hardpan just below the maximum rooting zone. That situation allows lateral seepage of irrigation water over considerable distances with hardly any slope.

Main irrigation canals move water from water reserves in the abundant swampland to the fields. To irrigate a field, irrigation ditches are filled from those canals, then emptied when irrigation is done.

 

Irrigation water seeps sideways into the soil from the ditch. It reaches far enough that there are 12 beds between ditches. The water level is maintained precisely so that soil under the roots is wetted, but the roots are not drowned.

 

One of the significant advantages of this system is less disease. Because all the water stays underground,  it is rarer for the foliage to be wet and the humidity, while naturally high, is lower. Thus the conditions for fungal spores to germinate and for hyphae to grow are considerably less common.

A couple other unique features  make the system work. First, the land is very flat. Whole fields can be irrigated where the underground water table is maintained at an exact distance below the soil surface on the bed tops. In addition, field are interspersed with vast swamplands that serve as storage for irrigation water. Irrigation water can not only be drawn from these reservoirs, but it is also returned to them at the end of an irrigation cycle.

 

 

Broccoli potential in Southwest Florida

At the end of February, Project Director Thomas Björkman had a chance to visit Monica Ozores-Hampton’s trial site at the University of Florida’s Southwest Florida Research and Education Center and farmers in nearby Immokalee and Clewiston (between Lake Okeechobee and the Everglades).

The SWFREC has seven new faculty, which really adds energy. Like elsewhere in Florida, managing citrus greening is a big priority.

Monica Ozores-Hampton and her SWREC colleagues using infrared imaging to track crop growth by recording individual plants through the season.

The research station has recovered from Hurricane Maria last fall, with some new greenhouse facilities replacing ones lost. The fields at the station are set up to use the distinctive seepage irrigation system common in parts of Florida that have sandy soils with a hardpan. The crop in the Yield Trial is growing well and should produce good results for spring. The February days were 85°, so warmer spring weather will definitely test the adaptation of these hybrids.

Monica Ozores-Hampton’s yield trial at the UF Southwest Florida Research and Extension Center in Immokalee, Florida. The trial is on a sandy soil using a seepage irrigation system. This February day began at a balmy 70°F, which suited the students on spring break in nearby Ft. Myers just fine. But that night temperature is too high for broccoli reaching the most sensitive stage of development (and for winter-hardened Thomas Björkman, pictured). The grassy field edge runs along an irrigation ditch. In the morning, alligators like to come out of the ditch to sun themselves on the grass.

 

Vegetable farms in SW Florida are generally larger than elsewhere in the East. The smallest farm we visited raises a thousand acres of green beans and sweet corn. The land costs are moderate, and the sandy soil can be managed with appropriately scaled equipment. At this scale, vegetables reach large-scale buyers through the most prominent of eastern produce distributors.

The farms we visited all know very well how to raise broccoli efficiently. The bed system means that the plant populations are lower per gross acre than solid stands. Nevertheless, the yields have been good, pests are uncommon, and the labor has been available for harvest.

The main limitation has been access to markets. The growers noted some irony in being unable to interest south Florida buyers in local broccoli, but finding buyers in New York appreciated getting winter broccoli from closer by. A good relationship between buyers and sellers appears to allow many efficiencies that improve product quality and reduce costs.

Broccoli crowns forming in SC Yield trial

An Eastern Broccoli Yield trial in South Carolina will soon be ready to evaluate. Trial leaders Brian Ward and Powell Smith oversaw transplant of several broccoli cultivars on the farm of a commercial grower in Saluda County, SC.  The broccoli was transplanted onto plastic-mulched raised beds on 5-foot centers with 10-inch in-row spacing and 12 inch between-row spacing.  The photos below show small crowns forming in broccoli plants.

Earlier in the season, the same beds and plastic were used to produce peppers; planting broccoli following another crop on plastic lets growers spread the cost of the mulch over more than one crop and is a common practice in the southeast.

Eastern Broccoli Yield trial in Saluda County, SC