The Perennial Peanut

The perennial peanut is a drought-tolerant, nitrogen-fixing ground cover that can be planted in existing orchards of all kinds, such as coffee, banana, cashew, cacao, mango, dragon fruit and papaya (see picture below). No land has to be set aside exclusively for its cultivation. It’s cultivated in just about all cities in Vietnam as an ornamental plant and weed suppressant. “It tolerates soils with 70% or greater Al saturation”. “It is not sensitive to low pH (4.6) coupled with high levels of soil Al” (Growth Responses of Perennial Forage Peanut and Two Barrel Medic Accessions to Soil pH and Aluminum Levels in an Andisol and an Ultisol). Once established, it never has to be replanted. The land on which it grows never has to be tilled. It eliminates soil erosion. It requires no nitrogen fertilizer, insecticides or fungicides. In fact, the rhizobia associated with the perennial peanut actually suppress many kinds of disease.

According to how it is managed, perennial peanut foliage has a crude protein content ranging from 13 to 32%, slightly higher than that of taro leaves which vary between 16 to 27%, and just about the same as water spinach which varies between 20 and 31%.

Leguminous plants such as the perennial peanut have a greater root volume than perennial trees, “allowing for a much greater absorption of mineral nutrients” (Influence of Cover Crop Cultivation). In acidic soils, phosphate ions might precipitate with Al and Fe cations. The perennial peanut produces organic anions that displace sorbed phosphate, making phosphorous more available to plants.  This is particularly important in Lam Dong province where most soils contain high levels of gibbsite. There’s enough phosphorous in some soils to sustain plant growth for the next 100 years. It’s only a question of making it available to plants.

When adequately shaded, the rhizoma perennial peanut can grow to a height of over 50 cm, making it is easy to cut and carry. Partial shade is essential in getting the perennial peanut to shift from reproductive to vegetative growth. Perennial peanut can be cut right down to rhizome level, as seen here.

It can be harvested every 45 days. The feed conversion ratio of rabbits fed perennial peanut is an astounding 2.6, lower than that of alfalfa and kudzu (Perennial Peanut: Developments in Animal Research).

The perennial peanut flowers throughout the year and “is a good source of nectar for bees”. Maintaining a healthy population of bees is vital for the pollination of many plants (U.S. Sets Plan to Save Honey Bees and Other Pollinators and Are Bees Back Up on Their Knees? and (Our Bees, Ourselves). Fresh perennial peanut foliage makes an excellent feed for certain insects destined for human consumption.

Perennial peanut is a good source of vitamins for pigs (Perennial Peanut). With perennial peanut as feed for sows, we definitely have a winner (Perennial Peanut: Developments in Animal Research):

Diets containing perennial peanut at 0, 40, 60, and 80% of the ration were fed to sows during gestation. Three separate parturition periods yielded similar results. Sows fed an 80% diet of perennial peanut farrowed more pigs than the other treatments and yielded an equivalent number of live weaned pigs compared to 100% corn/soybean ration. Body weight gain during gestation was greatest for sows fed 60% perennial peanut.  

Perhaps the best forage for a cow in a tropical setting is the perennial peanut. In the United States, it is often referred to as the “alfalfa of the south” (The Alfalfa of the South). In this paper (Perennial Peanut: Forage Nutritional Composition and Feeding Value), we see that for ruminant animals, the “perennial peanut is very nutritious and well liked. The nutritional quality of perennial peanut appears to be as good as alfalfa.” A bit further we read, “Perennial peanut is very nutritious, and in most cases, has more nutrition than what is needed by the animal.” Unlike many other legumes such as alfalfa, the perennial peanut does not cause bloating. Since the perennial peanut does not grow well in the last two months of dry season, it can be ensiled and stored for feeding throughout the year.

The perennial peanut is well accepted by cattle at all stages of growth. The feeding of perennial peanut increases milk production in dairy cows, and it improves stocking and calving rates. With regard to beef production, “steer gains average 1.7 lbs./head/day grazing perennial peanut as compared to 1.0 lbs./head/ day on bahiagrass (Perennial Peanut Uses). This represents an increase in growth of 70%. As previously noted, feeding high-quality forage such as the perennial peanut helps in reducing the production of enteric methane.

Fermenting the perennial peanut creates bypass protein: “Initially, on day zero of fermentation, the material presented a third of soluble protein, one third as bypass protein and the remaining as unavailable protein, whereas by effect of the fermentative process the content of soluble protein remained similar (33.05 %), the bypass protein increased to 51.38 % and unavailable protein reduced to 16.04 %. Perennial peanut silage can be used as feed for animals of high productive potential (milk and meat) starting ten days post-fermentation, since the system becomes stabilized and it presents a great proportion of bypass protein”. Perennial peanut can also be fed to sheep, goats and poultry.

Some large dairy companies in Vietnam have begun importing alfalfa from the US. Not only does this hurt the Vietnamese balance of trade and rob many small farmers of a potential livelihood, but it is also catastrophic for states such as California that export huge quantities of alfalfa. Alfalfa is grown on over 400,000 hectares in California, and this one crop “sucks up more water than any other crop in the state. And it has one primary destination: cattle” (Meat Makes the Planet Thirsty). While California was suffering one of its worst droughts on record, the alfalfa it produces sucks up almost 400 million cubic meters (100 billion gallons) of water each year. “Ridiculously unsustainable” is the only way to describe the export of alfalfa to Vietnam and other Asian countries (Watering California’s Farms).

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