AGRONOMY GUIDE
PURDUE
UNIVERSITY
Crownvetch Seed Production
AY - 178 Legumes
Maurice E. Heath, Agronomy Department
Introduction
For several years there has been considerable demand for crownvetch (Coronilia varia L.) seed for conservation and beautification purposes. Only recently has interest developed in crownvetch for forage purposes (see AY-177). There is interest among farmers in growing crownvetch for seed.
Weather and Seed Production
Pollination
Crownvetch is highly cross pollinated. The flowers provide a good source of pollen but produce little nectar.
Honey bees work the flowers reluctantly. Bumblebees and other wild bees and some insects will usually pollinate small acreages. However, two to three colonies of bees per acre are recommended.
Flower and Seed Characteristics
When weather is favorable, crownvetch produces an abundance of forage growth and regrowth between peak bloom and seed harvest. This abundant growth discourages seed pod development. Usually seed yields are best when summer rainfall is average or below and there are no prolonged damp wet periods during flowering and seed formation. Midsummer moisture stress, often found on low moisture retention soils or on southerly slopes, has been observed to stimulate crownvetch seed yields and discourage vegetative growth.
It is believed that many fragipan hill soils in southern Indiana where summer drought is common are practicularly well adapted to seed production of crownvetch. Avoid flat wet soils with poor surfact drainage.
Crownvetch has 10 to 15 violet to pinkish white florets per cluster. The weak hollow stems may grow to as much as five feet in length. Each compound leaf has six to 13 pairs of smooth leaflets. Crownvetch is heavy with bloom from late June to late July.
The cylindrical segmented seed pods may range from one to two inches in length. Each segment or capsule may contain a seed. There |s usually an average of four to eight segments per pod (Figure I). The pods turn brownish upon drying at maturity. The segments of the mature pods are easily broken apart. The hull adheres tightly to the seed and has to be removed with special equipment.
The elongated crownvetch seed are about twice the size of alfalfa seed (Figure 2).
Cooperative Extension Work in Agriculture and Home Economics, State of Indiana, Purdue University and U. S. Department of Agriculture Cooperating. H. G. Diesslin, Director, Lafayette, Ind. Issued in furtherance of the Acts of May 8 and June 30, 1914.