Scientist

Precision Farming Ð'- tool for efficient use of natural resources

2. Introduction

"Agriculture is the backbone of Indian economy" said Mahatma Gandhi five decades ago. Even today as we are in 21st millennium, the situation is still same, with almost the entire economy being sustained by agriculture. Land is precious natural resource for agriculture and per capita availability of land has decreased drastically from 0.46 ha in 1951 to 0.15 ha in 1996-97. This indicates need to increase productivity of existing land by increasing number of crops or improving the input utilization like fertilizer, herbicides, pesticides, irrigation etc. However, in post green-revolution agricultural growth became static.

Management technologies which are considered to be applied uniformly over larger areas may not help us to increase yield because of variation in micro-climate, socio-economics of farmers and soil variability at micro-level to apply input resources accordingly. In order to tackle these new challenges appropriate new technologies must be utilized in present day agronomic practices.

3. What is Precision Farming?

Precision Farming is the term used to describe the pursuit to increase efficiency in the management of agriculture. It is a developing technology that modifies existing techniques and incorporates new ones to produce a new set of tools for the manager to use. The electronics revolution of the last several decades has spawned two technologies that will impact agriculture in the next decade. These technologies are Geographic Information Systems (GIS) and Global Positioning System (GPS). Along with GIS and GPS there have appeared a wide range of sensors, monitors and controllers for agricultural equipment such as shaft monitors, pressure transducers and servo motors. Together they will enable farmers to use electronic guidance aids to direct equipment movements more accurately, provide precise positioning for all equipment actions and chemical applications and, analyze all of that data in association with other sources of data (agronomic, climatic, etc.). This will add up to a new and powerful tool box of management tools for the progressive farm manager.

Precision farming should not be thought of as only yield mapping and variable rate fertilizer application and evaluated on only one or the other. Precision farming technologies will affect the entire production function (and by extension, the management function) of the farm. A brief overview of the components in precision farming is presented in Fig. 1.

Yield monitoring

Instantaneous yield monitors are currently available from several manufacturers for all recent models. They provide a crop yield by time or distance (e.g. every second or every few meters). They also track other data such as distance and bushels per load, number of loads and fields.

Yield mapping

GPS receivers coupled with yield monitors provide spatial coordinates for the yield monitor data. This can be made into yield maps of each field.

Variable rate fertilizer

Variable rate controllers are available for granular, liquid and gaseous fertilizer application. Variable rates can either be manually controlled by the driver or automatically controlled by an on board computer with an electronic prescription map.

Weed mapping

A farmer can map weeds while combining, seeding, spraying or field scouting by using a key pad or buttons hooked up to a GPS receiver and data logger. These occurrences can then be mapped out on a computer and compared to yield maps, fertilizer maps and spray maps.

Variable spraying

By knowing weed locations from weed mapping spot control can be implemented. Controllers are available to electronically turn booms on and off, and alter the amount (and blend) of herbicide applied.

Topography and boundaries

Using high precision DGPS (Differential Global Positioning System), a very accurate topographic map can be made of any field. This is useful when interpreting yield maps and weed maps as well as planning for grassed waterways and field divisions. Field boundaries, roads, yards, tree stands and wetlands can all be accurately mapped to aid in farm planning.

Salinity mapping

GPS can be coupled to a salinity meter sled, which is picked across fields affected by salinity. Salinity mapping is valuable in interpreting yield maps and weed maps as well as tracking the change in salinity over time.

Guidance systems

Several manufacturers are currently producing guidance systems using high precision DGPS that can accurately position a moving vehicle within a foot or less. These guidance systems may replace conventional equipment markers for spraying or seeding and may be a valuable field scouting tool.

Records and analysis

Precision farming may produce an explosion in the amount of records available for farm management. Electronic sensors can collect a lot of data in a short period of time. Lots of disk space is needed to store all the data as well as the map graphics resulting from the data. Electronic controllers can also be designed to provide signals that are recorded electronically. It may be useful to record the fertilizer rates actually put down by the application equipment, not just what should have been put down according to a prescription map. A lot of new data is generated every year (yields, weeds etc.). Farmers will want to keep track of the yearly data to study trends in fertility, yields, salinity and numerous other parameters. This means a large data base is needed with the capability to achieve, and retrieve, data for future analyses.

4. Definitions

"Precision farming is the technology which involves the targetting of inputs to arable crop production according to crop requirement on the localized basis" (Stafford, 1996) "Doing the right thing, in the right place at the right time" Ð'.... For enhancing profitability and reducing environmental impact (Dr. Fran Pierce).

By these to classical definitions we can infer that Precision Farming is the careful tailoring of soil and crop management practices to different climatic conditions. Precision Farming also known as:

(1) Prescription Farming

(2) Site-specific Management

(3) Variable