Long term growth rates and water extraction patterns of dryland chicory, lucerne and red clover

A 5-year experiment was conducted under dryland conditions (mean annual rainfall 660 mm) on a Wakanui silt loam at Lincoln University. The mean annual production of lucerne (20 t DM/ha) was greater than red clover and chicory (16 t DM/ha). The advantage of lucerne increased with time to 6 t DM/ ha in the final year, when the lucerne component of the sward was 94%, whereas chicory and red clover declined to 62 and 0% of their respective swards. The annual production advantage of lucerne was a result of higher growth rates in September and from December to May. The higher summer/autumn growth rates were attributed to a greater water extraction depth, giving lucerne access to more water during this time. The DM yield of all three species had a linear relationship with water use. These results are discussed in relation to the fitness of the three species for a dryland farming system, and how the performance of each would be expected to vary with differing soil type and rainfall situations.