Winter grazing and dead material effects on early spring pasture production

Spring pasture production in New Zealand hill country has come under increasing pressure due to increased demand through improved performances of the national ewe flock and the displacement of finishing farms into hill country where spring pasture growth is lower relative to traditional finishing farms. Increasing spring pasture production to cope with this increased demand is considered one of the main areas of improvement needed in hill country farming. Current knowledge of the impact of winter dead material and grazing intensity on spring pasture production is limited. A trial set up on two sites in the South Island of New Zealand was conducted to measure the response of spring pasture production to two winter grazing intensities across three levels of sward dead matter. Total spring pasture production was unaffected by winter grazing intensity. However, winter dead matter levels significantly affected total spring pasture production. Plots with high dead matter levels (>60%) grew 657kg DM/ha less than plots with low dead matter levels (<30%) over the spring period. This difference in production can potentially be explained by the shading of tillers by the large amount of dead material during autumn and winter. Reducing the amount of dead material in the sward is therefore recommended as this will increase both pasture quantity and quality of spring swards.