Consider Precision Agriculture Practices

Precision agriculture, as the name implies, means application of precise and correct amount of inputs like water, fertilizer, pesticides etc. at the correct time to the crop for increasing its productivity and maximizing its yields.

• 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 water, pesticide, 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, 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 goal.

Precision agriculture aims to optimize field-level management about:

• Crop science: by matching farming practices more closely to crop needs (e.g. fertilizer inputs).
• Environmental protection: by reducing environmental risks and footprint of farming (e.g. limiting leaching of nitrogen).
• Economics: 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 of their farm;
• Improve decision-making;
• Foster greater traceability
• 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)

The Process

Precision agriculture is usually done as a four-stage process to observe spatial variability:

Data Collection

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

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

Variables

Intra and inter-field variability may result from several factors. These include:

• Climatic conditions (hail, drought, rain, etc.)
• Soils (texture, depth, nitrogen levels)
• Cropping practices (no-till farming)
• Weeds and disease

Permanent indicators (mainly 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, 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, detection with the naked eye, satellite imagery, etc.). Soil resistivity measurements combined with soil analysis make it possible to measure moisture content. Soil resistivity is also a relatively simple and cheap measurement.

Strategies

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. Airborne instruments are able to measure the amount of plant cover and to distinguish between crops and weeds.

Decisions may be based on decision-support models (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.

Implementing Practices

New Information and Communication Technologies (NICT) make field-level crop management more operational and easier to achieve for farmers. The application of crop management decisions calls for agricultural equipment that supports variable-rate technology (VRT), for example, varying seed density along with variable-rate application (VRA) of nitrogen and phytosanitary products.

Precision agriculture uses technology on agricultural equipment (e.g. tractors, sprayers, harvesters, etc.):

• Positioning system (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, spreader).

Click here to view a video that explains the future of farming.