Agriculture Reference
In-Depth Information
P
r e C i is i o n
a
g r i C u L t u r e
Precision farming or precision agriculture is an agricultural concept that is becom-
ing popular in developed countries as a way to handle in-field variability. It uses
new technologies, such as global positioning systems (GPSs), sensors, satellites or
aerial images, and information management tools such as Geographic Information
Systems (GIS) to assess and understand field variability and precisely evaluate opti-
mum sowing density, fertilizer, and other input needs. It also allows the farmer to
more accurately predict crop yields earlier in the season and can help to better assess
disease or lodging problems. Farmers are using this technology to maximize profits
by spending money only in areas that need inputs, especially fertilizer. The farmer
can vary the rate of fertilizer applied across the field according to the need identi-
fied by GPS-guided grid sampling, thereby optimizing its use. This will become an
important farming practice in the future to help improve the efficiency of natural
resource use and improve productivity.
D
r y L a n D
a
g r i C u L t u r e
Sustainable food production for the future will continue to rely on favored agricultural
areas where water is not a limiting factor. Practices (such as those described) that
sustainably improve productivity in favored areas reduce the need to farm dryland,
sloping, or other marginal areas. However, more than half of the world's farmland
is still located in areas where rainfall is limiting either in quantity or in reliability.
These dryland areas are home to many of the world's poorest farmers.
It is often said that the GR bypassed these dryland areas. This is not entirely
accurate. GR-style genetic improvement has produced suitable materials with high-
yield potential and some drought tolerance (Harrington et al., 2008), but because of
lack of water, actual yields remain far below potential. Here, the key is higher water
productivity—higher output per unit of water depleted. Once this is achieved, nutri-
ent availability and improved biotic stress resistance become more important.
Water harvesting provides opportunities to improve productivity in dryland areas.
Water may be harvested by using contour bunds, slowing water flows, channeling
water to ponds and aquifers, and so on. Water harvesting is sometimes best intro-
duced at the community level, in which case community-level management is needed
to maintain water-harvesting structures and practices after development projects fin-
ish (Johnson et al., 2001). In India, there has been some success in improving farmer
livelihoods through watershed projects that have increased water harvest, filled
aquifers and soil profiles, and even made water available for partial irrigation. Crop
yields have increased and yield variability across years has decreased, and through
greater crop diversification and better markets, farmers have improved incomes.
CA will be as important in dryland as in favored production environments. No
till and permanent ground cover have been shown to increase rainwater infiltration
and improve water availability to plants. The challenge in dryland areas is to produce
enough crop residue biomass to allow some to be left as mulch on the ground while
still meeting animal feed requirements. Suitable seeding equipment is also needed
to place the seed into moisture in soils that have had no tillage.
