Precision agriculture - AbsoluteAstronomy.com

Precision farming or precision agriculture is a farming management concept based on observing and responding to intra-field variations.
It relies on new technologies like satellite imagery

Imagery

Imagery is used in literature to refer to descriptive language that evokes emotional responses. It is useful as it allows an author to add depth and understanding to his work, like a sculptor adding layer and layer to his statue, building it up into a beautiful work of art.-Forms of imagery :Visual...

, information technology

Information technology

Information technology is the acquisition, processing, storage and dissemination of vocal, pictorial, textual and numerical information by a microelectronics-based combination of computing and telecommunications...

, and geospatial tools. It is also aided by farmers’ ability to locate their precise position in a field using satellite positioning system like GPS.

Precision agriculture issues

Precision agriculture aims to optimize field-level management with regard to:

crop science: by matching farming practices more closely to crop needs (e.g. fertilizer inputs);
environmental protection
Environmental protection
Environmental protection is a practice of protecting the environment, on individual, organizational or governmental level, for the benefit of the natural environment and humans. Due to the pressures of population and our technology the biophysical environment is being degraded, sometimes permanently...

: by reducing environmental risks and footprint of farming (e.g. limiting leaching of nitrogen);
economics
Economics
Economics is the social science that analyzes the production, distribution, and consumption of goods and services. The term economics comes from the Ancient Greek from + , hence "rules of the house"...

: by boosting competitiveness through more efficient practices (e.g. improved management of fertilizer usage and other inputs).

Precision agriculture also provides farmers with a wealth of information to:

build up a record
Document
The term document has multiple meanings in ordinary language and in scholarship. WordNet 3.1. lists four meanings :* document, written document, papers...

of their farm;
improve decision-making;
foster greater traceability
Traceability
Traceability refers to the completeness of the information about every step in a process chain.The formal definition: Traceability is the ability to chronologically interrelate uniquely identifiable entities in a way that is verifiable....
enhance marketing of farm products
improve lease arrangements and relationship with landlords
enhance the inherent quality of farm products (e.g. protein level in bread-flour wheat)

Stages and tools

Precision agriculture is a four-stage process using techniques to observe spatial variability:

Geolocation of data

Geolocating a field enables the farmer to overlay information gathered from analysis of soils and residual nitrogen, and information on previous crops and soil resistivity. Geolocation is done in two ways:

The field is delineated using an in-vehicle GPS receiver as the farmer drives a * The field is delineated on a basemap derived from aerial or satellite imagery. The base images must have the right level of resolution and geometric quality to ensure that geolocation is sufficiently accurate.

Characterizing variability

Intra- and inter-field variability may result from a number of factors. These include climatic conditions (hail

Hail

Hail is a form of solid precipitation. It consists of balls or irregular lumps of ice, each of which is referred to as a hail stone. Hail stones on Earth consist mostly of water ice and measure between and in diameter, with the larger stones coming from severe thunderstorms...

, drought, rain, etc. ), soils (texture, depth, nitrogen levels), cropping practices (no-till farming), weed

Weed

A weed in a general sense is a plant that is considered by the user of the term to be a nuisance, and normally applied to unwanted plants in human-controlled settings, especially farm fields and gardens, but also lawns, parks, woods, and other areas. More specifically, the term is often used to...

s and disease.
Permanent indicators—chiefly soil indicators—provide farmers with information about the main environmental constants.
Point indicators allow them to track a crop’s status, i.e., to see whether diseases are developing, if the crop is suffering from water stress

Water stress

Researchers define water stress and water scarcity in different ways. For example, some have presented maps showing the physical existence of water in nature to show nations with lower or higher volumes of water available for use. Others have related water availability to population...

, nitrogen stress, or lodging, whether it has been damaged by ice and so on.
This information may come from weather stations and other sensors (soil electrical resistivity

Resistivity

Electrical resistivity is a measure of how strongly a material opposes the flow of electric current. A low resistivity indicates a material that readily allows the movement of electric charge. The SI unit of electrical resistivity is the ohm metre...

, detection with the naked eye, satellite imagery, etc.).
Soil resistivity measurements combined with soil analysis make it possible to precisely map agro-pedological conditions.

Decision-making – two strategies for dealing with variability

Using soil maps, farmers can pursue two strategies to adjust field inputs:

Predictive approach: based on analysis of static indicators (soil, resistivity, field history, etc.) during the crop cycle.
Control approach: information from static indicators is regularly updated during the crop cycle by:
- sampling: weighing biomass, measuring leaf chlorophyll content, weighing fruit, etc.
- remote sensing: measuring parameters like temperature (air/soil), humidity (air/soil/leaf), wind or stem diameter is possible thanks to Wireless Sensor Networks
- proxy-detection: in-vehicle sensors measure leaf status; this requires the farmer to drive around the entire field.
- aerial or satellite remote sensing: multispectral imagery is acquired and processed to derive maps of crop biophysical parameters.

Decisions

Decision making

Decision making can be regarded as the mental processes resulting in the selection of a course of action among several alternative scenarios. Every decision making process produces a final choice. The output can be an action or an opinion of choice.- Overview :Human performance in decision terms...

may be based on decision-support model

Conceptual model

In the most general sense, a model is anything used in any way to represent anything else. Some models are physical objects, for instance, a toy model which may be assembled, and may even be made to work like the object it represents. They are used to help us know and understand the subject matter...

s (crop simulation models and recommendation models), but in the final analysis it is up to the farmer to decide in terms of business value and impacts on the environment

Natural environment

The natural environment encompasses all living and non-living things occurring naturally on Earth or some region thereof. It is an environment that encompasses the interaction of all living species....

Implementing practices to remedy variability

New information and communication technologies (NICT) make field-level crop management more operational and easier to achieve for farmers.
Application of crop management decisions calls for farming equipment that supports variable-rate technology (VRT), for example varying seed

Seed

A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...

density along with variable-rate application (VRA) of nitrogen

Nitrogen

Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...

and phytosanitary products.

Precision agriculture uses special equipment on board the farmer’s tractor:

positioning system
Positioning system
A positioning system is a mechanism for determining the location of an object in space. Technologies for this task exist ranging from worldwide coverage with meter accuracy to workspace coverage with sub-millimetre accuracy.- Interplanetary systems :...

(e.g. GPS receivers that use satellite signals to precisely determine a position on the globe);
geographic information systems (GIS), i.e., software that makes sense of all the available data;
variable-rate farming equipment (seeder
Seeder
A seeder is a stamp-type leatherworking tool used in leather carving. It is predominantly used in floral designs to represent the seeds in the center of a flower, hence the name. Similar to other stamp-type tools, it is held vertically over the leather and struck with a wooden or rawhide mallet...

, spreader).

Precision agriculture around the world

The concept of precision agriculture first emerged in the United States in the early 1980s.
In 1985, researchers at the University of Minnesota varied lime inputs in crop fields. It was also at this time that the practice of grid sampling appeared (applying a fixed grid of one sample per hectare). Towards the end of the 1980s, this technique was used to derive the first input recommendation maps for fertilizers and pH corrections. The use of yield sensors developed from new technologies, combined with the advent of GPS receivers, has been gaining ground ever since. Today, such systems cover several million hectares.
In the American Midwest (US) it is associated not with sustainable agriculture but with mainstream farmers who are trying to maximize profits by spending money only in areas that require fertilizer. This practice allows the farmer to vary the rate of fertilizer across the field according to the need identified by GPS guided Grid or Zone Sampling. Fertilizer that would have been spread in areas that don't need it can be placed in areas that do, thereby optimizing its use.
Around the world, precision agriculture developed at a varying pace. Precursor nations were the United States, Canada and Australia. In Europe, the United Kingdom was the first to go down this path, followed closely by France.
In France, precision agriculture first appeared in 1997-1998. The development of GPS and variable-rate spreading techniques helped to anchor precision farming management practices. Today, less than 10% of France’s farmers are equipped with variable-rate systems. Uptake of GPS is more widespread. But this hasn’t stopped them using precision agriculture services, which supplies field-level recommendation maps.

Economic and environmental impacts

Precision agriculture management practices can significantly reduce the amount of nutrient and other crop inputs used while boosting yields. Farmers thus obtain a return on their investment by saving on phytosanitary and fertilizer costs.
The second, larger-scale benefit of targeting inputs—in spatial, temporal and quantitative terms—concerns environmental impacts. Applying the right amount of inputs in the right place and at the right time benefits crops, soils and groundwater, and thus the entire crop cycle.
Consequently, precision agriculture has become a cornerstone of sustainable agriculture

Sustainable agriculture

Sustainable agriculture is the practice of farming using principles of ecology, the study of relationships between organisms and their environment...

, since it respects crops, soils and farmers. Sustainable agriculture seeks to assure a continued supply of food within the ecological, economic and social limits required to sustain production in the long term.
Precision agriculture therefore seeks to use high-tech systems in pursuit of this respectable and worthy goal.

External links

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