There is an ancient tree species that is catching some growers’ attention as a potential new alternative crop in Florida. Native to India, the pongamia tree has grown wild there and used by people for thousands of years.
Pongamia produces a legume, which looks similar to a butter bean. It can be crushed to extract oil and used as a fertilizer.
“Most people in India collect the beans and crush them for lamp oil or to make medicines with it,” says Peter McClure, Chief Agriculture Officer for Terviva. “They would use what was leftover to make fertilizer to use on their small farms.”
The tree has never been domesticated by humans, so it is very genetically diverse. That diversity makes for a pretty robust tree that has a number advantages for agronomic cultivation. Terviva is looking to promote growing of the tree in hopes of scaling up acreage to play in oil, feed, and fertilizer markets. The company is still in its start-up phase, but interest is growing in the crop. The company targets areas where major agricultural sectors are challenged like former sugarcane and pineapple production areas in Hawaii and citrus in Florida.
McClure had grown citrus all his life prior to joining the company and knows all too well the challenges brought on by greening. He says pongamia is a good drop-in crop on groves overtaken by greening. It can be grown on existing beds and utilize existing irrigation infrastructure.
“As a citrus grower in the world of greening, we know citrus has a very narrow gene pool because of our domestication of the tree,” McClure says. “The different varieties are all very similar [genetically], so it is much easier for one little bug and disease to come along create huge problems. Pongamia is much more diverse and robust and much less likely to be taken out by just one thing.”
Soybeans on a Tree
Like any other orchard tree, there is a wait period before commercial production becomes viable. McClure says pongamia trees take about five years to start producing and six to eight years to reach full production potential.
“Pongamia will produce about 400 to 500 gallons of oil per acre,” he says. “They are like soybeans on tree, but they will yield about 10 times as much oil per acre as soybeans once they get into full production. They also will produce about 3 tons per acre of seed cake, which is what is leftover after you squeeze the oil out of the bean. We will turn that cake into feed for cattle, poultry, and other livestock.”
While oil and protein is the ultimate market they hope to supply with pongamia, before acreage scales up, there will be a focus on higher-value markets. The oil can be converted into biopesticide similar to neem oil and the cake can be converted into organic fertilizer.
Another characteristic of the tree that fits well with Florida is it has a high tolerance to salt. In its native state, the trees grow near mangroves and riverbanks, so it can naturally withstand salinity.
“We have some pongamia planted in Florida in areas with real salty water that had already been taken out of citrus because of salt, not because of greening,” McClure says. “The pongamia is doing beautifully there.”
The tree also seems pretty tolerant of various soil types. McClure says it seems to do fine in higher to lower pH ranges.
“We have it growing in about 10 locations in Florida, and it looks good on the Ridge, Flatwoods, and East and West coasts,” he says. “There is a cold limit with the tree like citrus, so we are not sure how far north of I-4 it will go, but there is plenty of land in South Florida to scale this crop up.”
According to McClure, the cost of managing pongamia will be similar to citrus before greening and canker in the $500 to $600 per acre range. Because it is a legume, it produces its own nitrogen, so it will require less fertilizer. And, it is pretty robust against pests and diseases.
“I can’t say that it will not need any nitrogen applied, because it is a new crop and we are still learning how it acts in this climate,” McClure says. “But, we have some crops that are five years old and have had only 100 pounds total of nitrogen applied per acre on those trees, and they look great. They are going to need some phosphorus and potassium and minors applied to them, so it will need some farming to grow them. We have some five-year-old crops that have not been sprayed with pesticides that look great as well.”
The trees also are drought hardy and should require less irrigation.
“The pongamia will bloom in May and June, which is good timing because we are past worrying about freezes at that point and it is still in rainy season,” McClure adds. “If you think about citrus bloom in the dry season, we are irrigating heavily in March and early May. This tree will be setting a crop in the rainy season, so we don’t think we will need to be irrigating as much.”
The trees will be harvested with a mechanical pistachio harvester. McClure says Orchard Machinery Corporation will be shipping harvesters from California because the windows of harvest are complementary. Pistachios are harvested in the fall and pongamia harvest in Florida is during April and May.
“With the labor shortages and problems growers are having with it, the ability to harvest these trees mechanically is a big plus,” he adds.
The crop will require an infrastructure to press the oil and process the seed cake. Currently, the company is utilizing a small, mobile processing machine to work with crops and use for demonstration purposes for growers.
“We also are working with the Hardee County Economic Development Council to establish a permanent processing facility in Wachula,” McClure says. “The good news is the technology is very simple and not nearly as costly as an ethanol or juice processing plant. If we successfully scale up acreage, we might expect to have four or five plants around the state.”
Catching a Wave
McClure believes another factor making pongamia an attractive alternative crop is the growing demand for oil and protein around the globe, especially in developing countries. And, the growing demand for organic foods in developed countries like the U.S.”
“The citrus industry caught a wave after World War II,” he says. “We had a great product in frozen concentrate orange juice; we were becoming more affluent; and refrigeration spread across the country. So, we caught the wave of demand for orange juice.
“We are hoping to catch a wave with pongamia as places like India and China become more affluent and want to improve their diets with more protein. Pongamia can provide the feed for those protein source and help meet the growing demand for oil in those places.
“Another wave we can catch is the growing demand for organic food. Pongamia can be converted into a nice 4-4-1 organic fertilizer.”