Farm Table says:
What is the problem?
In recent years, lucerne (Medicago sativa) has been widely sown in productive livestock systems to provide nutritious feed to stock under dry summer conditions in southern Australia. While it is well known that lucerne has deep roots that are important for nutrient and moisture capture, little is known about the distribution of those roots in the soil under the Mediterranean environmental conditions experienced in southern Australia. In summer 2014-15, a field study was conducted to quantify the distribution of lucerne taproot.
What did the research involve?
This field study was conducted by sampling individual lucerne plants up to 50cm and all roots in soil cores up to 2m deep in two contrasting environments, Hamilton and Rutherglen, of Victoria, Australia.
What were the key findings?
The results showed that there was a significant (P < 0.01) exponential relationship between the biomass of lucerne taproots and soil depth. It was predicted that the majority of the taproots were present in the top 10 cm of the soil and over 90% in the top 30 cm of soil. There were also significant (P < 0.01) relationships between the biomass of all roots and soil depth for Hamilton and Rutherglen, respectively.
It is estimated that over 70% of the total root biomass was in the top 30 cm soil at both sites.