The effect of lime on the growth and nodulation of lucerne (Medicago sativa L.): A dissertation submitted in partial fulfilment of the requirements for the degree of Bachelor of Agricultural Science with Honours in the University of Canterbury

Abstract

The effect of lime on the growth and nodulation of lucerne (Medicago sativa L. cv. AS13R) was studied on a Templeton silt loam at Lincoln. Measurements were made of the shoot dry matter yield, root dry weight, and the number of nodules. Shoot nitrogen percentage at the second harvest was analysed. Increasing rates of lime gave increased shoot dry matter yields generally, but the size of the response depended on the time of sampling during growth.Yield increases from 0 t ha⁻¹ to 8 t ha⁻¹ lime (pH 5.3 - 5.4 to 6.1 - 6.2) were 35 - 37% over the first two harvests. Lime did not significantly increase root dry weight to a depth of 20 cm. Lime increased the total number of nodules at all samples. The number of small (< 2 mm) nodules increased significantly with lime at all samples. During the first harvest, lime gave a response with the number of medium (2 - 4 mm) and large (> 4 mm} nodules, but there was no response to lime during the second harvest. The total number of nodules increased with time at all lime rates . Lime did not affect shoot N % at the second harvest, but gave a highly significant increase in N yield.