Seasonal growth, flowering patterns, and phosphate response of 18 annual legume species grown in a hill‐country soil

Abstract

An experiment was conducted to evaluate 18 herbaceous annual legume species for growth in a low‐fertility, low‐pH, hill soil, and for their response to added phosphate (P) fertiliser. Lotus, Ornithopus, Medicago, and Trifolium species were included. The plants were grown outdoors in large (250 mm diameter) undisturbed soil cores to provide for full expression of their growth habit. Two P treatments were applied to the cores, a zero rate and a high rate equivalent to 100 kg P/ha. Herbage growth, flowering pattern, and seed production over 8 months were measured. Ornithopus compressus and O. sativus had the highest growth rates and seed production, followed by Lotus subbiflorus and L. angustissimus. These four lines should be evaluated further under field conditions. A number of other species were unable to express full reproductive development under the harvesting regime imposed. A wide range in response to added P was recorded, Trifolium tembense having the greatest proportional increase in growth.

Keywords:

• annual legumes
• hill country
• Lotus
• Medicago
• Ornithopus
• Trifolium
• phosphate
• response
• soil cores