Crop Performance and Management

Key Areas

This programme develops models and better management practices to sustain and enhance sugarcane production within the following broad areas:

Research in this Key Area focuses on the gathering of crop physiological data and the use thereof to facilitate modelling, with a view to:

  • Developing high throughput phenotyping tools to assist Commercial Breeding under current and predicted future climatic conditions;
  • Refining the accuracy of crop models and crop yield forecasting. The resources and technologies developed will ultimately enhance the quest for improved efficiencies in Commercial Breeding; and
  • Refinement of harvest age and associated variety management recommendations to growers.

Research in this Key Area focuses on the development of knowledge, technologies and resources to further enhance the accuracy of fertiliser recommendations to the grower community, including:

  • Accurate quantification of soil and leaf nutrient concentrations and the determination of improved leaf nutrient threshold values;
  • Development of near and mid infra-red spectral libraries for rapid, routine diagnostics and analysis of soil fertility
  • Assessment of the efficacy of various sources of nutrients, fertiliser formulations and application rates; and
  • Grower decisions support to optimise whole-farm fertiliser use.

Research in this Key Area focuses on the development of knowledge, technologies and resources to enable the maintenance of, and where necessary, the restoration of soil health. In progress are studies to develop:

  • Knowledge on how soil acidity related processes affect management practices used in sugarcane;
  • Demonstration of the value of best management practices for soil and crop health in partnership with growers; and
  • A labile carbon measure for use in a commercial laboratory to assess impacts of changes in sugarcane management practices on soil health.

Research in this Key Performance Area focuses on the development of knowledge, technologies and resources to enable effective and beneficial Crop Residue Management practices in the industry.

Particular emphasis is placed on the long-term effects of residue retention on crop productivity and soil health so that specific recommendations to growers may be formulated.

Research in this Key Area focuses on the development of knowledge, technologies and resources to enable and demonstrate effective sugarcane chemical cane quality management practices in the industry. Under development are technologies and models that will assist the grower community with chemical ripener decision-making. Proof-of-concept studies are also underway to assess the feasibility of using multi-spectral imagery from unmanned aerial vehicles (UAVs) for precision sugarcane quality management.

Research in this Key Area focuses on the assessment of potential impacts of climate change on the industry and exploration of ways in which field management might be modified to adapt to the projected changed climate.

Dr Riekert van Heerden

Programme Manager: Crop Performance & Management


Programme Manager: Crop Performance & Management

Tel: 031 508 7400 (Switchboard)
Tel: 031 508 7439 (Direct)

Role & Overall Purpose

As programme manager, I am responsible for the coordination and management of research within the Crop Performance and Management Research Programme at SASRI. This role involves development of the annual programme of work through encouraging focus, innovation and collaboration in research. As senior scientist, my role is to initiate and conduct research leading to best management practices for sugarcane cultivation in South Africa.

A key outcome of my research is to promote the responsible use of chemical ripeners in the sugar industry. Chemical ripeners enhance the sucrose content of sugarcane during certain parts of the milling season. My research conducted under statistically-designed experimental conditions, and on a much larger commercial scale in participation with sugarcane farmers, has shown that increases in sucrose yields up to 3 tons per hectare can be achieved with chemical ripeners. Success stories, and advice on the use of ripeners, are often shared with farmers at knowledge exchange events and in the form of popular articles, which drives the ongoing adoption of this important crop management practice.

My contribution to farmer sustainability in the South African sugarcane industry was acknowledged when I received the Agriculturist of the Year (KwaZulu-Natal) Award from Agricultural Writers SA in 2011. I am currently also a National Research Foundation (NRF)-rated scientist.

  • Physiological and biochemical basis of stress tolerance in plants.
  • Sugarcane quality management, with emphasis on the responsible use of chemical ripeners.
  • Participatory on-farm research and knowledge exchange to promote adoption of best management practices by sugarcane farmers.
Research Interests
  • The use of chemical ripeners for sugarcane quality management focusing on cultivar responses and climatic influences on chemical efficacy.
  • Innovations facilitating on-farm sugarcane quality management decisions to enable the responsible and informed use of chemical ripeners.
  • Participatory on-farm research and knowledge exchange with sugarcane farmers.
Key Outcomes
  • Ensuring the responsible use of chemical ripeners in the South African sugar industry.
  • Conversion of peer-reviewed research findings to best management practices for profitable and sustainable sugarcane production in South Africa.
Key Publications

van Heerden PDR (2019). Response of selected South African coastal sugarcane varieties to chemical ripeners: Active ingredient effectiveness and associated impacts on grower and miller sustainability. International Sugar Journal 121: 902 – 904.

Van Antwerpen R, van Heerden PDR, Tweddle P, Cheong RN & Riviere V (2018). Advances in harvesting and transport of sugarcane. In: Achieving sustainable cultivation of sugarcane Volume 1: Cultivation techniques, quality and sustainability, Rott P (Ed.), pp. 203 – 234, Burleigh Dodds Science Publishing Limited, Cambridge, UK, ISBN: 978-1-78676-144-6.

van Heerden PDR, Adendorff MW, Lagerwall G, Botha P, Cronjé CPR, van der Merwe J, Nel N, Smith P, Höll E, Hyslop G, Smith V, Harris A., Harris W, Mhlongo JB, Harris DM & Dheopursad J (2015). Grower – Extensionist – Researcher partnerships: On-farm demonstration trials to facilitate adoption of chemical ripening. International Sugar Journal 117: 500-506.

van Heerden PDR, Mbatha TP & Ngxaliwe S (2015). Chemical ripening of sugarcane with trinexapac-ethyl (Moddus®) – Mode of action and comparative efficacy. Field Crops Research 181: 69-75.

van Heerden PDR, Singels A, Paraskevopoulos A & Rossler R (2015). Negative effects of lodging on irrigated sugarcane productivity – an experimental and crop modelling assessment. Field Crops Research 180: 135-142.

van Heerden PDR (2014). Differential acclimation capacity to frost in sugarcane varieties grown under field conditions. Plant Growth Regulation 72: 181 – 187.

van Heerden PDR (2014). Evaluation of Trinexapac-ethyl (Moddus®) as a new chemical ripener for the South African sugarcane industry. Sugar Tech 16(3): 295-299.

van Heerden PDR, Eggleston G & Donaldson RA (2014). Ripening and Post-harvest deterioration. In: Sugarcane Physiology, Biochemistry, and Functional Biology, Botha FC and Moore PH (Eds.), pp. 55 – 84, Wiley-Blackwell, USA, ISBN: 978-0-8138-2121-4.

Lopes MS, Araus JL, van Heerden PDR & Foyer CH (2011). Enhancing drought tolerance in C4 crops. Journal of Experimental Botany 62: 3135-3153.

van Heerden PDR, Donaldson RA, Watt DA & Singels A (2010). Biomass accumulation in sugarcane – unravelling the factors underpinning reduced growth phenomena. Journal of Experimental Botany 61, 2877-2887.

International Consultancy & Training

Over seven years of international consultancy work and training (related to sugarcane quality management) for sugar industries in Chad, Cameroon, Congo, Côte d’Ivoire, Gabon, Central African Republic, Zimbabwe, Eswatini and Guatemala.

  • M.Sc. – Plant Physiology (Stellenbosch University).
  • Ph.D. – Plant Physiology (North-West University – Potchefstroom campus).

Current Projects

Midlands variety management
Developing P calibration response curves for sugarcane using multiple extractants
Improving Si uptake in sugarcane under field conditions
Modelling leaf nutrient concentrations in sugarcane using in situ hyperspectral data
The development and linking of soil management units (SMUs) to better management practices (BMPs) in the Northern Irrigated Regions
Long-term burning and mulching project
Ripener x varieties evaluation project
Feasibility assessment of using aerial multi-spectral imagery from unmanned aerial vehicles (UAVs) for precision sugarcane quality management
Phased investigation of the usefulness of SAR images for sugarcane crop assessment
Characterising past climate change and its impacts on yield
Upgrades to the StalkGro DSP
A plant and soil spectral library for the SA sugar industry