The effect of spray volume on spray partitioning between plant and soil

Applications of chlorsulfuron (11.25 g ai ha⁻¹) were made to wheat, flax, canola and lentils at spray volumes of 48, 108 and 2171 ha⁻¹, and with metsulfuron methyl (6.00 g ai ha⁻¹) at spray volumes of 48 and 2171 ha⁻¹. Applications were made to the shoot only, the soil only and to the plant plus soil. Spectrofluorometric analysis was used to determine spray partitioning within the plant-soil system and foliar retention was related to efficacy. Fresh and dry weights of shoot material were determined 3 weeks after treatment. Flax and wheat were more tolerant of restricted-foliar applications than those made to the soil, the converse being true to canola and lentils. Applications made to the plant and soil were always the most deleterious. Foliar retention and efficacy did not correlate directly. Applications in 2171 ha⁻¹ were generally more efficacious than those at 481 ha⁻¹.