Degree: PhD

Year Colin Holmes' Scholarship awarded: 2017, 2018

Project description: Urinary nitrogen (N) is the main source of N loss (leaching) from grazing systems. When milk production is increased through feeding more supplements (‘importing’ N into the farm system) then N excretion, and N loss, is also likely to increase.

Martin is comparing two spring-calving systems to explore N utilization efficiency (ENU) and N losses of cows. System 1 has once-a-day (OAD) milking with minimal supplements to reduce nitrate leaching and achieve target environmental outcomes. System 2 has twice-a-day milking with more supplement fed per cow.

These systems are being run on two research farms, with cow performance measures and calculated efficiencies being used to adapt a computer model to simulate these systems. Martin can then change variables in the model, such as stocking rate, fertiliser use, and feeding level, to determine the impact on environmental, productivity and profitability outcomes. 

Comments on the scholarship: I am immensely grateful to the contribution of this scholarship allowing me to undertake this important personal and professional stage of my career, but I must say that the support was not only monetary. The DairyNZ Academic Committee gave me the intellectual support and encouraged me on this challenge so I can be confident that I will accomplish my project thesis in time.

Future plans: After completing my doctoral project I plan to continue working towards the development and refinement of sustainable pastoral models for dairy industries around the world, with a particular focus on the Australasian and Latin American contexts. My professional commitment is to produce research that bears a significant contribution to our current worldwide imperative to reduce environmental impact on food production. I plan to continue my research as a postdoctoral fellow aiming to contribute on sustainable grazing food production systems.