Influence of boron in organic red clover (Trifolium pratense L.) seed production. (Special Issue: Forage legumes.)

摘要

The effect of boron (B) on flower development, nectar production, seed yield and germination in organic red clover was investigated in soils with <1 mg B kg-1. Different techniques for application of a liquid B product were studied in four field experiments in 2009-2011. The treatments were as follows: control (no B); three rates of B application to the soil at sowing; and three rates of B as foliar application in the harvest year. The effects of B application varied between the fields and included increased seed yield, seed weight of fifty inflorescences (IFs), number of florets IF-1 and nectar volume IF-1. The greatest effects on seed yield were found in treatments with low B rates. Boron application increased seed B concentration in only one experiment and had no effect on shoot B concentration. The percentage of seeds with normal germination increased with increasing seed B concentration (R2=0.73). Seed weight of fifty IFs and number of IFs m-2 increased with increasing shoot B concentration. Boron is therefore an important element for red clover seed production. Further knowledge on improving the B uptake of red clover plants is required to improve seed yield and quality.