Agriculture Reference
In-Depth Information
7 billion, with growth still rapid in the less developed countries of Asia, Africa,
and the Middle East. Thus, while arable land has essentially reached the limits
of expansion, pressures on the land resource base continue to increase with ever-
greater demands for food production. The need for producing higher amounts of
food on the same amount of land has fuelled agricultural intensification. The Green
Revolution of the post-World War II era enabled many advanced nations to dra-
matically increase crop yields and food production through the use of inorganic
fertilizers and improved crop varieties. However, by the end of the 20th century,
the impacts of intensified production systems, which relied heavily on man-made
chemical fertilizers and pesticides, on the environment, as well as soil biophysi-
cal quality degradation, erosion, and fertility decline, could no longer be ignored
(Thomas et al. 1956). As the nutritive requirements of a growing world population
will only increase into the foreseeable future, sustainable agricultural intensifica-
tion practices and technologies are indispensable. The development and adoption of
such options will require concerted efforts on the parts of scientists, governments,
and local farming communities merged through contextual knowledge systems.
The application of integrated nutrient management has shown that optimum combi-
nations of farmyard manure and inorganic fertilizers increased yields by 16%-35%
in the mid-hills of Nepal. Similarly, a combination of compost and fertilizer gave
significantly higher yields of wheat and potato crops over conventional farming.
Combinations of different crops, such as pigeon pea and groundnut, have been
shown to result in yield increases of maize of >100%, while leading to improved soil
properties. Inoculation of seeds with
Rhizobium
strains have also been found to lead
to yield increases of 40%-67% compared with noninoculated seeds for a variety of
crops, such as soybean, lentils, black gram, groundnuts, and broad beans. Apart
from crop and seed improvements, soil and water management options, such as
conservation tillage, mulching, and microirrigation, are equally important in ensur-
ing sustainable intensive production. Studies in the mid-hill region of the Himalaya
have demonstrated that mulching and reduced tillage could lead to a reduction in
soil and nutrient losses from upland farms by 46% to >100%, while increasing water
retention and providing comparable crop yields. Thus, successful implementation
of sustainable agricultural intensification to meet the growing global food demand
will involve simultaneously addressing soil and land management, water use effi-
ciency, crop and agrobiodiversity, and adequate policy and institutional support.
Soil and land resources have been the backbone of human civilization ever since
prehistoric communities of people established permanent settlements and began set-
tled agriculture some 10 thousand or more years ago (Darlington 1969). Past civiliza-
tions, such as the ancient settlements of the Tigris-Euphrates and Nile River valleys,
flourished as a direct consequence of having access to fertile soils, and likewise,
declined as a result of degradation and loss of fertility of agricultural lands (Hillel
1992). Through the course of history, previous human communities learned to man-
age their soils and successfully cultivate their lands, even under rather harsh climates
and terrains such as the arid region of Egypt and the mountainous regions of South
Asia (Hillel 2007).
Over the centuries, and particularly since the beginning of the Industrial Rev-
olution in the 1800s, the human population has seen a tremendous increase in growth
