Comparative agriculture methods capture distinct production practices across a broadacre Australian landscape

Myrtille Lacoste,Roger Lawes,Olivier Ducourtieux,Ken Flower

doi:10.1016/j.agee.2016.09.020

Abstract

In farming systems research the link between farm resources, management and performances is often described, but rarely confirmed or quantified. Problems arise in formalising such linkages because substantial spatial and longitudinal whole-farm data are difficult to acquire. This study used the integrative discipline of comparative agriculture to collect such information and address a wide range of related farming system questions. The mixed method procedure included a landscape analysis, a historical investigation, and the collection of current farm information from 36 farms, representing half the farming businesses of a 4 000km2 area in a region of the Western Australian wheatbelt (≈300mm/year) with highly variable soils.Land types influenced management, including cropping specialisation, and explained some of the regional variability in grain yield and enterprise mix. Rotations varied by soil type and farm type. On average their duration was 3–4 years, typically starting with a 2–3 years of wheat, resulting in overall composition of 64% cereals, 20% break crops and 16% pastures/fallows. Break crops were grown more on light sandy soils than on heavier fine-textured soils. Lights soils were managed similarly by all farmers but distinctions occurred on heavier soils between mixed crop-livestock farmers and cropping specialists. This divergence in farming production was explained by farm soil composition: whilst cropping appears more profitable in the region, mixed farmers retained animals and pastures as a strategy to cope with having greater proportions of land less suited to crop production. Typical farm grain yields were indeed found to vary in relation to farm soil composition. The location of the original family farm in the landscape is likely to explain these differences in farm land resources, and subsequently current farm performance, production strategies and trajectories.This study highlighted the potential of a method that deserves wider application: comparative agriculture helped identify and establish complex relationships within the farming system, some of which challenge common assumptions. Further applications to define typical farms, monitor practices, and contribute meaningful divisions of agricultural landscapes are also discussed.

Highlights

The importance of soil type on agronomic performance is widely recognised, the impacts of soil variability at the farm level are more difficult to assess
This study highlighted the potential of a method that deserves wider application: comparative agriculture helped identify and establish complex relationships within the farming system, some of which challenge common assumptions
The rotation strategies of farmers were found to vary across the agricultural landscape according to distinct patterns; mixed models showed differences in rotation duration and enterprise composition between farm types and across soil types

Summary

Introduction

The importance of soil type on agronomic performance is widely recognised, the impacts of soil variability at the farm level are more difficult to assess. Assumptions are commonly made about farming practices that are not validated, prompting questions as to what extent the farmers’ objectives and the criteria that influence their management are integrated. Farmers are known to manage soils differently, the impact of soil heterogeneity on their practices is rarely quantified. In low rainfall southern Australia, where winter cereals and mixed crop-livestock farming systems dominate, controlled experiments, field surveys and simulation modelling regularly demonstrate that soil types have a major influence on crop production and resource use efficiency.

Methods

Results

Discussion

Conclusion