THE USE OF IT IN AGRICULTURE RESOURCES
By DR AMANULLAH CHAUDHRY
Feb 14 - 20, 2005
Satellite data and computers can be used to monitor the state of Pakistan's agricultural resources. The use of electronic information technology for agricultural resources management is gaining interest. It makes agriculture management less tedious and costly, by collecting a wider spectrum of data in a much shorter span of time. This is far departure from labour and time-intensive traditional on-site surveys and monitoring approaches. Now exciting opportunities are emerging in precision agriculture, GIS-based mapping and modelling of soil erosion — using satellites to monitor changes in land use and disseminating the information.
As the world's population continues to grow, humankind is faced with the onerous task of meeting the world's food demand. This can only be accomplished with sustainable agriculture. Sustainable agriculture requires a delicate balance between crop production, natural resources use, environmental impacts and economics. The goal of sustainable agriculture is to optimize food production while maintaining economic stability, minimizing the use of natural resources and minimizing impacts on the environment. The use of electronic information technology for agricultural resources management is gaining interest among researchers throughout the world. It is one of the tools that can be used by Pakistan in its bid to use its natural resources sustainably.
Some countries including Japan are already making advanced use of this technology. Other countries are still in the process of evolving a baseline data, while building their human resources to strengthen their technology capability in the future.
Both group of countries need to continue exploring the merits of this technology, with the aim of counteracting the negative effects of development, such as soil erosion, soil salinity, soil pollution and flooding. Unless these can be reversed, they will cumulatively reduce the carrying capacity of land and soil resources over the years. Electronic information technology is a significant tool to help countries manage their land and agricultural resource sustainably, restoring their productivity for future generations. Some of the uses of this technology are:
Precision agriculture (or site-specific agriculture) utilizes rapidly evolving electronic information technologies to modify land management in a site-specific manner as conditions change spatially and temporally. The intent of precision agriculture is to optimize crop production while minimizing detrimental environmental effects. First conceived in the mid-1980s, the technological pieces needed to bring precision agriculture into its own fell into place in the mid 1990s with the maturation of global positioning system (GPS) and geographic information systems (GIS). As such, precision agriculture is technology driven system. The future of precision agriculture rests on the reliability, reproducibility, and understanding of the technological developments on which it is based.
WHAT IS PRECISION FARMING?
The term "precision farming" or "precision agriculture" is capturing the imagination of many people concerned with production of food, feed and fiber. It offers the promise of increased productivity, while decreasing production costs and minimizing the environmental impact of farming. Precision farming was originally developed for large farming units, such as those found in the United States. More recently, it has been adapted to the needs of small-scale farms in Asia, which in some countries have average size of only one hectare (2.6 acres).
ELEMENTS OF THE TECHNOLOGY
There are three fundamental elements in this technology.
(A) DESCRIBING VARIABILITY
Describing variability is the key concept. Variability should be understood in at least three aspects; spatial, temporal and predictive. This variability includes both the range of variation in individual fields, and the variation found between fields in the area or region where the system is being applied.
(a) Real-Time Soil Sensing: Japan has recently developed automated ways to know the variability within the fields, using a real time soil sensing. Portable soil organic matter sensor with photodiodes using a single wavelength is developed. It gave good results in predicting soil organic matter in the range 1.5-6 percent. The feasibility of spectral reflectance to sense soil organic matter is also investigated.
A potable NIR spectrophotometer was designed to evaluate soil organic matter, cation exchange capacity and moisture content in a ploughed soil at a depth of 3.5-5 cm. This approach can be useful to get information about the field surface, but they still need in situ soil sensing in the zone of root development for practical use in crop management. They have developed a real-time soil spectrophotometer with an RTK-GPS to sense underground soil parameters at a depth of 15-40 cm.
The objective of this work is to use the soil spectrophotometer to generate soil maps of field, for the implementation of precision farming. The sensor system is composed of three main units — the external housing, the soil penetration and probes, and the external sensing and monitoring devices. Data scanning time is just over four microseconds. Integration of scanned data is carried out for each individual scan to get average values. A video data recorder on the tractor displays images of the soil surface. Satellites are used to collect the data.
(b) Use of soil electrical conductivity in precision agriculture: From a global perspective, irrigated agriculture make an essential contribution to the food needs of the world. While only 15 percent of the world's farmland is irrigated, roughly 35 to 40 percent of the total supply of food and fiber comes from irrigated agriculture. However, vast areas of irrigated land are threatened by salinization. Although accurate worldwide data are not available, it is estimated that roughly salinity and water logging affect half of all existing irrigation systems. Salinity within irrigated soils clearly limits productivity in vast areas of the Pakistan and other parts of the world. It is generally accepted that the extent of salt-affected soil is increasing. In spite of the fact that salinity buildup on irrigated lands is responsible for the declining resources base for agriculture. We do not know the exact extent to which soils in our country are salinized, the degree to which productivity is reduced by salinity, the increasing or decreasing trend in soil salinity development, and the location of contributing sources of salt loading to ground and drainage waters. Suitable soil inventories do not exist, and until recently, neither did practical techniques to monitor salinity or assess the impact of changes in management on soil salinity and salt loading. A mean of assessing soil salinity across the landscape is essential to management of soil salinity. Because of the influence of soil salinity on crop productivity and the dynamic spatio-temporal nature of salinity, real-time measurement and monitoring of the spatial and temporal distribution of soil salinity is a crucial piece of information for precision agriculture application on irrigated agricultural soils. Soil EC is determined by standardizing measures of soil conductance by volume of soil through which current travels. Traditionally, soil paste EC has been used to assess soil conductivity, but commercial devices are now available that can be used to rapidly map bulk soil EC across agricultural field through direct contact or induction techniques.
(B) VARIABLE-RATE TECHNOLOGY (VRT)
This is used to adjust the agricultural inputs according to the site-specific requirements in each part of the field. If machines are used, this requires variable-rate machinery. On small farms, inputs can be applied manually. Variable-rate applications need:
— Correct positioning in the field;
— Correct information at the location; and
— Timely operations at the site concerned.
Variable-rate technology not only increases productivity by re-organizing the three factors of technology, plants and fields, but also creates better linkage with regional infrastructures, e.g. by following environmental regulations.
(C) DECISION-SUPPORT SYSTEM (DSS)
Decision support system offer a range of choices to farmers with respect to trade-off problems where conflicting demands must be taken into account, such as productivity and protection of the environment. This approach helps to optimize the whole farming system. A decision support system provides the best technology, taking into account the aims and motivation of farmers as well as environmental factors. In other words, precision farming brings about an innovation in the whole system of agriculture. It is possible to apply precision farming to small as well as large farms, and make it part of rural development programs.
This technology is now being developed to help small -scale rice farmers in Taiwan to improve their fertilizer applications. Although Taiwan has a strong island-wide soil testing service, some rice farmers in Taiwan do not know the nutrient status of their soils, particularly with regard to nitrogen, phosphorus and potassium. Decision support systems are being developed which will be able to provide site-specific fertilizer recommendations.
A number of agricultural organizations in Taiwan, including agricultural universities, and government research institutes have established various systems. They are web-based GIS system which attempt to share and disseminate information and soil properties to potential users particularly agronomists, extension staff and leading farmers.
GIS-BASED MAPPING AND MODELLING OF SOIL EROSION
Conventional surveys of soil erosion in the field are costly in time and labor. All soil survey are labor-intensive, but surveys of erosion usually have to cover several years, to get a reliable estimate of the rate of soil erosion and the main factors influencing it. GIS-assisted physical model are now available which can predict where erosion "hot-spots" are likely to occur. The model could thus be used to identify sites, which were very vulnerable to erosion, and where conservation measures were urgently needed.
GIS could also be used to predict the effects of surface cover on the discharge of water and soil sediments from the catchments area.
USING SATELLITES TO MONITOR CHANGES IN LAND USE
All governments have legal restrictions concerning the use of public land, especially the cutting of forest, and the conversion of forest to arable land. In practice, it is difficult to monitor what are usually remote areas, and detect changes in land use at an early stage before environmental damage has become serious. Satellite remote sensing is an effective way of monitoring resource management and changes occurring over large areas. This type of analysis is also very useful for showing the sustainability of different agricultural systems Policy makers can only promote sustainable land use systems if they know which ones they are. GIS facilitates the classification of land into different land use classes, and can monitor the long-term impact of different kinds of land use. In this way, policy maker's can be helped to distinguish land where agriculture can be intensified or expanded, from land where rehabilitation and diversification are needed. The information from GIS is now becoming detailed enough to show which areas are suitable for specific crops.
Farmers and electronic technology
In discussion of sustainable land use, there is often a conflict between the wishes of policy makers and needs of farmers. Policy makers wish to make their nation's use of resources sustainable, and take a broad view of the country's economic development. Farmers have an immediate need to support their families. Farmer's response to this technology is more positive if they are consulted during the development of GIS-based programs. Participatory consultation is now becoming an important part of GIS programs.
Farmers can also be a key source of information. Often the local knowledge of farmers is more relevant and useful than the academic knowledge of scientists. GIS can also show gaps in infrastructure, such as scarcity of roads or marketing centers, that may cause agricultural development programs to fail in an area which otherwise seems suitable. The great benefit of GIS and DSS is that they can provide site-specific information, including recommended practices. This also a challenge, in that it is difficult to disseminate detailed information of this kind to specific farmers.
Korea and Taiwan are pioneering the use of information technology in environmental management for agriculture. Sources of data are land use surveys, aerial photographs, detailed soil survey maps etc. Maps are generated from these sources and encoded in central computers. The system is linked to related institutes and centers throughout Korea and Taiwan, and is then made available on the Internet.
Internet users, including farmers or extension staff, can easily find information at a provincial, county or district level. Information includes land use, drainage, soil type, soil depth, and soil chemical properties. Recommendations for each type of land use are also being provided for farmers and other clients.
1. Many agricultural producers are currently facing low crop prices. These are likely to fall even lower because Pakistan has joined WTO. Site-specific nutrient management is new approach to productions, which may replace current uniform rate technology. It offers the promise of increasing productivity, while decreasing production costs and minimizing the environmental impact of farming. It is important to develop and use this technology in Pakistan, because this is feasible for both large and small farms.
2. From the point of view of development in rural areas which includes small farms and local companies, precision farming offers the possibility of developing of a new kind of industry, by fusing agriculture to various kinds of industrial activity. If these multi-functions of agriculture are re-evaluated using information-added fields, value-added space of this kind can be seen as providing new sources, such as biological materials, open-air classrooms and eco-tourism.
3. In adopting electronic information technology, it is necessary to identify the specific clientele whom it will be serving. These may be small or large-scale farmers, extension staff, or institutions that will be adopting this technology. Will these be the small or large-scale farmers, the extension worker or an institution?
4. Crop or soil management based on this technology should have the marketing aspect and risk management factored in.
5. The benefit of participatory development of this technology should be explored.
6. In developing an electronic information technology based system, a decision needs to be taken about the best mode of information dissemination, based on the country's present situation. This might be a decision support system (DSS), stand-alone or web pages.
7. In Pakistan SUPPARCO may take a leading role for development of infrastructure for the use of this technology.
8. Our private sector or government organizations should develop joint venture with other leading countries in this technology.
The author is from Department of Agronomy, University of Agriculture, Faisalabad. E-mail: firstname.lastname@example.org