Seasonal growth, phosphate response, and drought tolerance of 11 perennial legume species grown in a hill‐country soil

Abstract

An experiment was conducted to evaluate 11 species (16 accessions) of herbaceous perennial legumes for their seasonal growth, response to added phosphate (P), and drought tolerance. Different species, and accessions of species, of the genii Adesmia, Medicago, and Trifolium were included. The plants were grown outdoors over 17 months in large (250 mm diameter) undisturbed hill‐country soil cores to provide full expression of their growth habit. Four rates of P were applied to the cores i.e. 0, 0.08, 0.24, and 0.48 g P/core. Herbage growth, stolon extension, and flowering patterns over 8 months were measured, after which the plants were subjected to a simulated summer drought and assessed for stress tolerance and recovery. The accessions showing the greatest growth rate throughout the year included two of T. pratense (Enterprise and a prostrate line); Huia white clover; and the South American legume Adesmia bicolor. The unnamed T. pratense line, and the Adesmia showed particular potential for strong growth, tolerance of low P fertility, and valuable morphological characteristics. However, both T. pratense lines were particularly susceptible to moisture stress. In contrast, the two T. semipilosum lines, and T. tumens tolerated and recovered from drought well. These four lines should be evaluated further under field conditions.

Keywords:

• Adesmia
• hill country
• Medicago
• perennial legumes
• phosphate
• drought
• soil cores
• Trifolium