Crop of the Week: Sesbania

• In Yuma, sesbania is grown as a cover crop or green manure during the summer months. Vegetable growers can achieve increased yields, pest suppression and reduced soil erosion and nutrient leaching by growing such a crop prior to planting winter crops.

• Cover crops suppress pests and fix the nitrogen in legumes which enhances plant development especially in organic crop production where synthetic pesticides and nitrogen fertilizers are not permitted. Cover crops can offer similar benefits in conventionally grown winter vegetables.

• A major benefit obtained from growing sesbania is the addition of organic matter to our desert soils. During the breakdown of organic matter by microorganisms, compounds are formed that are resistant to decomposition. These compounds help bind together soil particles as granules, or aggregates. A well-aggregated soil tills easily, is well aerated and has a high water infiltration rate.

• Sesbania is a genus of flowering plants in the pea family.

• Also known as the hummingbird tree in some areas, sesbania is a small tree believed to have originated either in India or Southeast Asia and grows primarily in hot and humid tropical areas of the world. When mature, the tree grows to between 6 and 15 feet in height. The leaves are regular and rounded and the flowers white and large.

• Unlike other legumes, sesbania does not need herbicide applications to be established in weedy fields and is considered an excellent cover crop in our hot Yuma climate. When planted in late spring, this crop can cover the ground in less than four weeks. In 50 days, sesbania can grow over 6 feet tall and produce more than 2 tons per acre of dry biomass.

• The plant sesbania captures nitrogen from the atmosphere.

• Typically, sesbania starts to flower in early September in the low deserts. The flowers of sesbania are eaten as a vegetable in Southeast Asia, particularly in Laos. The young pods are also eaten, along with the leaves.

Source: Kurt Nolte is an agriculture agent and Yuma County Cooperative Extension director. He can be reached at knolte@cals.arizona.edu or 726-3904.