AN EVALUATION OF THE PERFORMANCE OF 2 WHITE CLOVER VARIETIES AND A RESIDENT WHITE CLOVER ON AN ACID, PERMANENT GRASSLAND CLAY SOIL

A 3-year trial on an impermeable clay soil subject to seasonal waterlo gging compared the performance of a resident white clover with Grassla nds Huia and S184, in sown swards with perennial ryegrass. Treatments included nil fertilizer and a combined application of lime, phosphorus and potassium (CaPK). Assessments were made, under cutting intervals of 4 and 8 weeks, of herbage production and clover content. Mean annua l total dry matter (DM) harvested was 3.6 and 8.0 t/ha for nil fertili zer and CaPK treatments, respectively, and 5.0 and 6.6 t/ha for the 4- and 8-weekly cutting intervals. Differences in total DM between white clover varieties were small and not significant (Lit P<0.05) in any y ear, though DM from sowings of the resident clover increased from 94% of the mean of the commercial varieties in year I to 108% in year 3. M ean annual white clover DM yield was 0.24 and 1.72 t/ha for the nil fe rtilizer and CaPK treatments; 0.97 and 0.99 t/ha for the 4- and 8-week ly cutting intervals; and 0.97, 0.92 and 1.06 t/ha for Grasslands Huia , S184 and the resident clover, respectively. It is concluded that imp ermeable gley soils are capable of supporting grass/white clover sward s, but establishment is slow and white clover content is low unless lo w soil nutrient status is improved. Differences is DM yield between cl over varieties were small.