L.J.C. Autrey, S. Ramasamy and K.F. Ng Kee Kwong describe the achievements in the process of introducing precision farming technologies in Mauritius, and the challenges ahead.
Sugar cane is vital to the economy of Mauritius. In 2004 it accounted for 19% of the value of exports and 5% of the country’s GDP. About 90% of the arable land, and 45% of the total area of the island is devoted to growing sugar cane. It also provides direct employment for 60,000 workers and small planters.
The island’s sugar industry urgently needs to strengthen its competitive position. The ACP-EU Sugar Protocol and the proposed 39% reduction in the price of sugar has accelerated the process of reform. The Mauritius Sugar Industry Research Institute (MSIRI) is now giving priority to precision farming research with an emphasis on intensifi ed mechanization. Cutting production costs by mechanizing all operations is seen as offering opportunities for optimizing the use of resources and for increasing the viability of this vital industry.
Introducing precision farming
Farm planning is an indispensable first step in introducing mechanization. However, in Mauritius most soils are very rocky and have developed on uneven topography, which complicates the development and adoption of appropriate tools and technologies. The very nature of the soil results in a spatial variability that hopefully can be addressed by precision farming.
In Mauritius, precision farming in the sugar cane sector is still at the experimental stage. Since 2001, the MSIRI has been evaluating the applicability and effectiveness of precision agriculture for the local industry. The research work has centred on testing an Australian prototype of a yield mapping system, the acquisition of spatial data on yields and soil, and assessing the signifi cance and causes of yield variations on two sugar estates, Médine and Beau Champ. The aim of the research is to facilitate the development of a totally mechanized industry - from soil preparation to harvest - on 55,000 of the 65,000 ha under sugar cane production. Steps have been taken to introduce special land use planning measures, including increased field sizes. These steps are in fact the beginning of the total mechanization of sugar cultivation in Mauritius.
Yield variability mapping
The cane yield maps produced so far have shown that yield variability is signifi cant. It can vary from 30 to 200 tonnes per hectare within a field, with distinctive patterns of low and high yields closely related to cane harvested in green or burned conditions. One immediate practical outcome of yield monitoring has been the improved management of cane loading operations, including measures to avoid overloading and over-spilling, improved transport scheduling of trucks and bins, and the verification of contractual work in terms of harvested area and tonnage.
Remote sensing, GIS and GPS
The resolution of satellite images has improved considerably. As images are now available in the range of 1-5 m, remote sensing is increasingly being used in studies of sugar cane precision farming. GIS and GPS have already become standard tools for building spatial databases and for geo-referencing fields and other spatial features.
In particular, 2.5 m resolution QuickBird satellite images of Mauritius have been used to identify spatial variability and corrrelations with other factors. In a natural colour composite image of the western part of Mauritius, for example, the spatial variability in cane canopy and the correlation with soil conditions can be seen very clearly. Patches of poor cane growth and low yields were associated with waterlogged areas (as indicated by soil conductivity surveys), and high-yield areas, indicated by dense canopy and high biomass, were also clearly visible on the image.
Over the past two decades significant progress has been made in applying precision farming techniques to crops such as maize, soy bean and wheat. In sugar cane, progress has been slow even in countries known to be at the forefront of precision farming research, such as Australia, South Africa, Brazil and Mauritius. Yield sensors combined with mapping soft ware for sugar cane are still not available as a commercial package. The first yield sensor - developed in 1996 for sugar cane in Australia - is still in prototype form.
Low world sugar prices, combined with other factors, have affected the availability of human and financial resources for research into sugar cane production using precision farming approaches and technology. Progress is also hampered by the fact that cultivation practices must be mechanized, and operators have to be well trained in the use of hightechnology equipment.
Despite these drawbacks, the outlook for precision farming remains firmly positive. For example, the continuing research on yield sensor systems means that they could soon be commercially available for use by farmers. On-the-go soil sensors are also being developed to facilitate the measurement of important plant and soil properties that directly aff ect crop yields. High-resolution satellite images are also becoming more accessible for mapping and thus contributing to our understanding of spatial variability.