A tree native to India that produces oil-laden pods holds promise as an alternative crop for Florida growers who have lost groves to citrus greening disease. 

Fourth-generation citrus producer and FFVA member Peter McClure has been studying Pongamia pinnata for about 10 years and is bullish on its potential to part of be a new economically viable vegetable oil and protein industry in the Sunshine State. 

“Being in citrus where we have fought hard for 10 years, and we’re fighting a losing battle where we’re having to lay off people, I see a crop that will provide jobs for those same people,” said McClure, who at one time managed 12,000 acres of prime Indian River citrus and served on the Florida Citrus Production Research Advisory Council. “That’s a big deal. The economics of the interior counties in Florida that were dependent on citrus just dried up. These are good people. Being able to put them back to work is a good thing.”

McClure has joined TerViva, a California-based startup working to commercialize renewable energy and local food production, as its chief agriculture officer. TerViva has already established pilot pongamia groves in 12 locations in Florida.

TerViva also recently put in a pilot 30-acre planting on former Maui sugar cane ground and a 50-acre planting on the north shore of Oahu, said Tom Schenk, business development manager. The goal in Hawaii is to replace imported fuels with locally produced biodiesel and jet fuel.

Native to India, pongamia trees are members of the legume family and grow naturally from eastern Africa to northern Australia. The hardy trees produce nuts or pods with up to 40 percent high-quality oil content. In India, the oil is used for an array of products ranging from renewable fuels to cosmetics and paints. The oil also has bio-insecticidal properties similar to neem oil. TerViva has started the testing and regulatory work necessary to access those markets.

Drop-in replacement for citrus

McClure happened upon the potential for pongamia while conducting 300 acres of trials with 40 different alternative crops beginning about 10 years ago. At the time, he worked for a large citrus company whose leadership saw citrus greening as a major threat. The trial included everything from corn, cotton, soybeans and sugar beets to castor, chia and jatropha.

Citrus thrives in poor soils, whether it’s the sands of the ridge that runs through the center of Florida or flatwoods along both shores that have high water. Few other crops do well in those environs.

Much to McClure’s delight, pongamia excels in the same soils as citrus. In fact, one pongamia trial near Fort Pierce successfully survived standing water for two weeks after Hurricane Irma inundated the area, he said.

Using existing irrigation systems and citrus tree spacing practice of 100 to 140 trees per acre, McClure said pongamia is a true drop-in replacement for citrus groves lost to greening or other natural causes.

Initially, McClure experimented with pongamia seedlings. But the wild genetic background produced trees that were too variable. That’s where TerViva’s extensive collection of elite plant materials came in. They are still genetically diverse but with proven yield characteristics.

Much like citrus, he said, vegetative propagation will be the preferred approach because it produces high yields and quality. TerViva’s elite cultivars will be grafted onto seedlings. TerViva has a nursery operation and is contracting with several Florida nurseries to grow trees, which will sell for about $10 each. Tree sales will be handled through TerViva.

Because it’s a legume, pongamia has beneficial bacteria on its roots that form nodules and produce a portion of the tree’s seasonal nitrogen needs. Compared to citrus, pongamia trees will require much less nitrogen, if any, although they do require other nutrients to reach optimum yield. In the nursery, the trees are inoculated with beneficial Rhizobia bacteria, much like soybean growers inoculate soybean seed.

Because the trees have a broad genetic background, they are “jungle tough” and have few known pests, McClure said. Herbicides and mowing for orchard floor management will be two of the biggest inputs during the first three to four years after planting, he said. Growers must prune young trees to form a single trunk clear of branches from three feet down to allow harvesting with mechanical shakers. 

Trees come into production about the fourth year, ramping up until they peak at about year eight.

Pongamia are semi-deciduous, losing leaves in April and May during Florida’s dry season. The trees bloom in May and June when seasonal rains begin. Although one pongamia grove in Florida has never been irrigated and is doing well, Schenk said the trees grow better with supplemental water. The test plantings are three to five years old and have not received insecticide or fungicide applications. The tremendous genetic variation of TerViva’s elite cultivars should provide protection against a greening-like event hitting pongamia, McClure said.

Borrowing pistachio shakers

McClure has been working with Orchard Machinery Corp. of Ceres, CA, about using its Shockwave Catchall pistachio shakers to harvest pongamia. 

A set of machines, each with a deflector, surrounds the tree while a clamp shakes the trunk, loosening pods that fall onto the deflectors. A conveyor at the bottom then moves the pods into a bin or adjacent trailer.

Using pistachio shakers in Florida in May and June for pongamia makes the most of equipment that typically sits idle for about 10 months of the year, he said. The pongamia season complements the California pistachio season, which runs from late August through early fall.

As part of the trials, TerViva established a pilot oil press in an old Vero Beach citrus packing plant. Using a low-tech press calibrated for soybeans, they are processing pongamia nuts into oil and seedcake. 

“We just fed pongamia beans through it and it worked beautifully,” McClure said.

The nuts typically yield about 40 percent oil as well as a 36 percent protein seedcake. On a per-acre basis, pongamia yields about 400 gallons compared to 40 gallons for soybeans. Only palm oil outyields pongamia on a per-acre basis, he said.

Several petroleum companies already have tested pongamia oil and found its composition suitable for biofuel and bio jet fuel, Schenk said. With a 36 percent protein content, the seedcake also has several markets, including use as an organic fertilizer or as livestock feed.

Market potential

Once in full production, a grove can gross about $2,000 per acre annually, with net returns of about $1,000 per acre, McClure said. Ultimately, he sees potential for about 100,000 to 200,000 acres of pongamia in Florida.

“We had 800,000 acres of citrus when greening came in,” McClure said. “You can’t grow 800,000 acres of blueberries, peaches or pomegranates because the market isn’t big enough. With pongamia’s biological fit in Florida and the existing huge markets available for oil and protein, you can scale up and grow 100,000 to 200,000 acres or more without breaking the market.”