Land evaluation Initial steps

When proposing a sugarcane project in a new area the first step is selection of the project site. Once the region has been identified, all potential districts should be visited to find the best site. The main criteria are:

Soils

Soil depth minimum 50 cm on heavier soils, 70 cm on sandy soils

Good natural drainage is important, or there should be potential for installation of drains Texture determines type of irrigation; soils with less than 6 % clay normally excluded Level of nutrition, salinity/sodicity

Sufficient area of reasonable soils for (say) 15 000 ha in one fairly contiguous block.

Climate

Rainfall, adequate length of dry season to allow long crushing season Sunshine hours, high is desirable

Temperatures, high but best with low night temperatures during the harvest season Latitude, elevation, effects on flowering and cane quality.

Irrigation water

Overall quantity as well as sufficient flow at the end of the dry season and at periods of crop peak demand; storage capacity available or potential

Water quality

Cost of accessing water from weir/canal Lift pumping from river

Subsurface water Flood protection.

Population density

Low density generally preferable as it minimizes problems of access to suitable land, but may cause problems in obtaining sufficient labor and labor housing costs may be high.

Local political issues and means of overcoming, e.g. local human resources expertise.

Location and infrastructure

Cost of moving sugar/ethanol to market Roads/railway

Power availability.

Topography

Flat to undulating preferable; note drainage in Chapter 2.1.

Availability of materials

Good quality rock for building aggregate Road gravel

Sand Coal Lime

Building timber.

The next steps

When the general site selection has been completed, the next steps are:

 Undertake a full climate suitability assessment to determine likely commercial yield potential (see Chapter 2.1).

 Obtain orthophotos and topographic maps that can be used to delineate the main rivers, topography, land form, vegetation type, existing land use and cover. Create a general map of area boundaries and demarcation of legal entitlement. This could be generated by satellite imagery, aerial photography or land survey and then verified by ground truthing in the case of satellite and aerial photography.

 Unless very detailed maps are available, it will be necessary to download satellite photography, carry out aerial photography or carry out land based surveys with a GPS to obtain contour mapping of at least 5 m (preferably 3 m) vertical interval (VI) which is required for general estate planning and layout.

 Establish rights to use the land (including environmental considerations).

 Visit leaders of local inhabitants and contact representative villagers to discuss the proposals in general terms, stressing employment opportunities in the future and acknowledging existing cultural sites, activities and especially women’s rights and activities. (See also Social section)

 Understand the legal requirements with regard to water usage – complying with all local and regional legal requirements. Obtain national/local regulations pertaining to water usage.

 If the project is to be irrigated it will be necessary to conduct a hydrological survey of the river and/or dam supplying water, assessing dry and wet season flow history and options for construction of off-river storage (refer to Chapter 6.8). For surface irrigation, further detailed topographic surveys will be required (either land based using GPS or aerial photography with LIDAR) to produce a contour map with 1 m VI.

 Conduct a reconnaissance soil survey to identify the main soil types and their distribution as well as their main physical and chemical properties.

 Conduct a pre-feasibility assessment to determine likely cane yield production and projections of costs for irrigation systems, infrastructure development, equipment, bush clearing and crop establishment.

Box 3.1 Survey and mapping for new irrigation projects

“A good detailed map is essential in the planning of any new irrigation project. Good drainage is as important as good irrigation, and very often more important. Good drainage of irrigation water is very often more critical in arid and semi-arid areas because of less complete leaching of salts out of the soil. Where overhead irrigation is planned, only enough land leveling needs to be done to ensure good runoff of surface water from the fields, although a master drainage system to take runoff away from the fields is essential. In the case of surface irrigation, i.e. furrow irrigation or, less commonly, flood irrigation, a high degree of accuracy is essential, not only to ensure free flow of water down the furrow, but also to ensure consistent application rates.

The survey and mapping should be carried out with two planning stages and a number of essential criteria in mind. The two planning stages are, first, the overall planning and bankable feasibility cost estimate stage and, second, the later detailed layouts of fields, drains, canals, roads, factory and housing areas. The map for overall planning can be small scale, e.g. 1:10 000, with, say, 2 m contours, but experience has shown that while moderately good detailed planning can be done using 1 m contours, 0.5 m contours allow for estimating cut and fill quantities to a very much higher degree of accuracy, and are also more cost effective in planning of field layouts, especially in the case of furrow irrigation.

Features that should be considered for inclusion in the mapping include:

 Natural drainage patterns.

 Routes for conveyance of water from source to the estate and to individual fields.

 Topography, in combination with the soil survey, whether suitable for furrow irrigation.

 Existing roads, rail, canals, power lines, buildings and other features.

 Suitable water storage areas.

 Density of vegetation.

 Potential factory, office and housing areas.

 In many countries a suitable area must be set aside for timber.

For mapping of large areas an aerial survey has many advantages over ground survey. In recent years Lidar (light detection and ranging) a technology that determines the distance to an object or surface using laser pulses, has increasingly been favored over traditional mapping from aerial photography.

Lidar has a number of advantages over traditional photography:

 Because images are digital and the camera is linked to a computerized GPS system in the aircraft, the images are corrected many times per second for the swing, tilt, yaw, bumps and dips of the aircraft flight. The data fed into the databank is what would be obtained from a smooth flight.

 Less ground control survey is needed.

 A bank of tens of thousands of digital images, with accurate x, y and z coordinates is built up which can be electronically thinned out to produce whatever scale and contour interval is required.

 The digital nature of the images allows for a factor to be applied that distinguishes between vegetation height and ground level. In all but the thickest forest, accurate ground contours to a high degree of accuracy can be generated.

 The digital databank results in rapid electronic generation of contours, saving hours of specialist time on traditional air photography plotters.

There are a number of other advantages to using Lidar, and these are developing rapidly in the market. Time spent with the mapping company discussing all the requirements and latest developments is time more than well spent.

Satellite imagery is developing rapidly and should not be dismissed, but at the time of writing the actual accuracies being achieved, especially vertical accuracies, are considerably below the generally perceived levels”

(N. Wilson, Tanzania, 2011, personal communication).

Climate suitability

There are certain climatic limits within which a sugarcane crop can be grown and a first requirement would be to ensure the land and the environment is suitable for cane growing. Ideally, for dryland cane the main growing season of four to five months should be warm with mean day temperatures around 30 °C and high incident solar radiation. The ripening and harvesting season of six to nine months should be cool, with mean day temperatures between 10 and 20 °C, but frost free, dry and with high incident radiation (see Chapter 1.4.1) for further details of climatic requirements). If the project is to be irrigated, lack of rainfall is unimportant; however excessive rainfall may result in a short harvesting season, flooding and associated low sunshine hours.

Reference to a crop atlas which maps the areas on the basis of climatic suitability for sugarcane production is a useful tool. Schulze (2008) has produced such an atlas for sugarcane production in South Africa. For this study, the daily time step conceptual-physical ACRU agrohydrological simulation model, was used to simulate sugarcane yields under dryland conditions for a range of season lengths in order to determine:

• areas suitable for sugarcane growth,

• optimum season lengths at different locations, and

• potential sugarcane yields.

In addition to this, the estimation of yield increments per 100 mm of irrigated water, using various modes of irrigation, can be calculated using the ACRU model.

In Brazil agroecological zoning (ZAE Cana) has been conducted taking into account national biodiversity and environmental conservation considerations (Unica 2010).t

–see www.unica.com.br/downloads/sugarcane-agroecological-zoning.pdf)

Box 3.2 Rules to guide the expansion of sugarcane production in Brazil

“To make the mapping of the national territory, the following guidelines have been set:

 Exclusion of areas with native vegetation

As the law is approved, it will be prohibited in the entire national territory to remove native

vegetation for the expansion of sugarcane cultivation. Areas in which native vegetation is dominant will be protected, as they are considered restricted areas, and sugarcane cultivation will not be permitted.

 Exclusion of areas for cultivation in the Amazon and Pantanal biomes, and in the Upper Paraguay River Basin

ZAE Cana prohibits the expansion of sugarcane production in the Amazon and Pantanal biomes, and in the Upper Paraguay River Basin. To protect the environment, preserve the biodiversity and make use of the natural resources in a rational manner, the installation of new units of ethanol production will not be permitted on these locations.

 Identification of areas with agricultural potential without need of full irrigation

ZAE Cana has considered weather and soil conditions, and cultivars of sugarcane to select areas in which sugarcane production uses the lowest volume of water possible.

 Identification of areas with slope below 12 %

Areas with slope up to 12 % allow the use of machinery on the harvesting. Therefore, an expansion of production environmentally adequate can be guaranteed, avoiding new burnings and CO2

emission. With mechanical harvesting, the expansion will happen with no need for sugarcane manual cutting.

 Respect for food security

The Bill provides that the Ministry of Agriculture will guide the expansion of sugarcane production so as to avoid any sort of risk to food production or to food security.

 Prioritization of degraded areas or pasture

ZAE Cana is an important tool to guide public policies and credit policies in a way to give priority to sugarcane expansion in areas already used as pasture. Over 34 million hectares of land currently underutilized or occupied by livestock or degraded pastures are identified in ZAE as suitable for sugarcane production. The increase in the livestock productivity in Brazil (head of cattle per hectare), which today is considered as being low, may provide new areas for sugarcane production”.

Summary table (adapted from Sugarcane Agroecological Zoning booklet –see www.unica.com.br/downloads/sugarcane-agroecological-zoning.pdf)

Description Area ha (millions) % of national territory

National territory 851.5 100

Environmentally restricted areas 694.1 81.5

Suitable areas currently used for

agriculture and livestock 64.7 7.5

Suitable areas currently used for

sugarcane (2008/2009) 7.8 0.9

Expansion of sugarcane areas

projected to 2017 6.7 0.8

Establish rights to use the land

This would involve permission to conduct pre-feasibility and feasibility assessments of a

development and usually will require an Environmental Impact Assessment (EIA)* as well as other conditions to be satisfied before the development will be allowed to proceed.

*Note: it is usual to include social assessments in such evaluations − Environmental and Social Impact Assessment (ESIA) − but in the context of this chapter we are concerned specifically with the environmental aspect, noting that the social aspect is also essential. It is important to involve local consultants in these activities.

National governments usually have some form of legislation which determines the land that can be considered for development and the criteria that require a detailed EIA to be performed. Brazil has developed a national map of agroecological zones, described above, which already precludes possible development in certain areas. South Africa has a National List of Threatened Ecosystems which needs to be taken into account in any EIA. In countries which do not have legislation in place to require EIAs it would still be considered Good Management Practice for a developer to voluntarily conduct sufficient investigation to ensure that no threatened biodiversity was affected. It could be considered good practice to at least adhere to international conventions on environmental issues such as the Convention on Biological Diversity (www.cbd.int) and the Ramsar Convention on Wetlands of International Importance (www.ramsar.org).

Legal requirements

All legal requirements for establishment and future management of a sugarcane production system need to be considered in the Land Use Plan (LUP). This includes economic, social and environmental legislation. A full assessment of all relevant national and regional legislation needs to be undertaken or accessed if already available. It is suggested here that all industries should provide a

comprehensive set of legal requirements for all participants in the industry. The International Sugar Organization has reported on a survey of all environmental laws affecting sugar production in each member country (ISO 2001). In South Africa a review of relevant international conventions and local legislation is included in the Standards and Guidelines for Conservation and Environmental

Management in the South African Sugar Industry (SASRI 2002).

Also relevant are international laws which are usually found in the form of Conventions. In regard to the environment there are laws which relate to assessment of new developments and expansions, and also laws which relate to the ongoing operation of sugarcane farming. This includes the management of impacts on biodiversity, water, soil and air (SASRI 2002; Maher 2007). Of great importance are international agreements on use of river water which flows through different countries, e.g. the Nile River Water Treaty.

Soil survey

Box 3.3 Main types of soil surveys

“There are two main types of soil surveys: reconnaissance and detailed.

A detailed soil survey has an observation intensity of one per four hectares (200 m grid) or less (150 m, 100 m grid, etc.). Any soil survey with an observation intensity of less than one per four hectares is deemed to be reconnaissance.

A reconnaissance soil survey has three main subdivisions: (i) fatal flaws (observation intensity of

< one per 100 ha), (ii) pre-feasibility (observation intensity of between one per 30 ha and one per 100 ha) and (iii) feasibility (observation intensity of > one observation per 30 ha). The level of intensity of observations has a direct influence on the accuracy of the maps and resulting

recommendations. The greater the number of observations for any given area, and the more accurate the maps and recommendations, the greater the cost to the client.

The above soil surveys can be conducted at any scale, but generally the following applies:

 A detailed soil survey is completed at 1:10 000 or 1:5 000 scale.

 A fatal flaws reconnaissance soil survey is conducted at scales ranging from 1:20 000 to 1:50 000.

 A pre-feasibility reconnaissance soil survey is normally conducted at 1:20 000 to 1:30 000 scale.

 A feasibility reconnaissance soil survey is often conducted at 1:10 000 to 1:20 000 scale.

The scale of mapping is also determined by the type, quality and resolution of the base map, which may be 1:50 000 topographic maps (which can be georeferenced into WGS84 ellipsoid), google earth imagery (this cannot be georeferenced) or georeferenced, contoured (0.5-10 m contours – contour intervals depend on the steepness/relief of the area – steep areas normally have 10 m contours, whereas flat/level areas have 0.5-1.0 m contours to pick up the micro topography), colored imagery that is clear at 1:1 000 scale (high resolution imagery).

Land use plans can be conducted using any of the above soil survey types, type of base map or scale of mapping. The larger the scale, the better/clearer the base map and the higher the imagery resolution and clarity, the more accurate the land use plan.”

(WZ Heathman, Hilton, 2011, personal communication).

The soil survey information is ultimately used in the land use planning process to support delineation of wetlands, watercourses, sacred sites, natural vegetation areas, sites for quarries, buildings, roads, dams, rubbish dumps, waste disposal sites, suitable areas for workshops and chemical stores.

Chemical disposal sites, non-crop land, recreational areas, and areas suitable for sugarcane fields should be delineated. Roads, waterways, contours, bridges, sediment traps, and recycling ponds for irrigation water containment should also be identified or sited and demarcated on the map. Knowing the predominant soil type in a particular field also forms the basis of management decisions with regard to the selection of tillage practices, planting techniques, cultivar selection, drainage and irrigation requirements, fertilizer requirements and harvesting schedules (see Chapter 2.7).

Soil development is very much affected by toposequence and an example of soil differences associated with topography is presented in Fig. 3.1.

Figure 3.1. Influence of slope on soil formation.

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