Integrated crop and environmental management for improved productivity and food security

Abstract

Improved productivity requires informed decisions on a number of issues including crop, water, soil and financial risk management. In this paper, we use some case-study examples to illustrate how crop simulation models can be used to analyze the threats and opportunities arising from climate variability, climate change, and market variation for a focus crop at selected locations. We then demonstrate how this analysis can be coupled with site-specific soil information to inform soil and crop management strategies so that crop yield potential can be realised. Two sites in eastern Australia, Dalby (27 degrees S) and Corowa (36 degrees S) were used as a case study to analyse wheat growing conditions at two contrasting locations. Average annual rainfall ranged from 540 mm in Corowa to 675 mm in Dalby, with rainfall summer dominant in the north and winter (growing season) dominant in the south. Simulated crop growth parameters were assessed using APSIM (Agricultural Production Systems Simulator) and the data set was split into two time periods (1957-1983 and 1984-2011) to allow comparison. Dalby in the north showed a shift to decreasing simulated grain yield in the later period. For example the median grain yield at Dalby was reduced from 4000 kg/ha to a little over 3000 kg/ha. The decreased yield probabilities were accompanied by increased water stress during critical growth stages at Dalby. APSIM simulations highlight the climate change/ variability at Dalby with current 80 percentile yield of about 4000 kg/ha whereas at Corowa, there is no evidence of climate change/ variability and the 80 percentile yield is about 6000 kg/ha. The soil at the Dalby location is a Vertisol, while that at Corowa is a Solonetz. We used the paper-based DSS (Decision-Support Systems) called SCAMP (Soil Constraints and Management Package). Management strategies for ameliorating production constraints are identified, including the use of amendments such as gypsum and soil analyses to give fertiliser recommendations. Fertiliser management (fertilizer rate, timing and placement) can then be optimised using the CD-based DSS SafeGauge for Nutrients to maximise nutrient use efficiency and to minimise the environmental risk associated with off-site nutrient movement. Climate variability and economic return considerations indicate Corowa is the better choice for long term food security and economic returns than Dalby. SCAMP and SafeGauge for Nutrients indicate that different soil management practices would be needed at the two sites to realise yield potential. This case study thus demonstrates the principles of our new research project, funded by the Qatar National Research Fund (QNRF) through its National Research Priority Program, in that the climate of a site of interest is analysed using a crop growth model to firstly indicate if the crop can grow there, what would be the likely yield, and what would be the likely effects of climate change on yield potential. Economics then dictate if the yield is high enough and stable enough to warrant development. SCAMP and other relevant models are then used to identify soil constraints that will need to be mitigated to maintain productivity.