Sustainable Soil Management Is More than What and How Crops Are Grown - Principles of Sustainable Soil Management in Agroecosystems - page 372

indigenous acacia species Faidherbia albida into maize-based conservation agri-
culture in Zambia on a large scale is a noteworthy example. These programs have
demonstrated the practical opportunities for combining fertilizer trees with CA in
both small-scale and commercial-scale farming systems.
Shifting agriculture, also referred to as “swidden” or “slash and burn,” entails
the clearing of land to prepare a cultivation plot and subsequently returning this
to regrowth and eventual natural reforestation, during which damaged soil struc-
ture and depleted “indigenous” plant nutrients are restored. Shifting cultivation has
acquired a negative connotation, particularly because of the burning of vegetation.
However, for sustainable intensification, such systems can be adapted to follow CA
principles, changing from slash-and-burn systems into slash-and-mulch systems
with diversified cropping (including legumes and perennial crops) that reduce the
need for extra land clearing.
The System of Rice Intensification (SRI) has taken root on an international scale
in more than 40 countries across all developing regions, including China, India,
Indonesia, and Vietnam, moving beyond its origins in Madagascar (De Laulanié
1993). Trained farmers have shown SRI to offer higher income and productivities
(use efficiencies) of inputs of labor, nutrients, and water, and to require less seeds,
water, energy, fertilizer, and labor compared with conventional irrigated or rainfed
flooded rice production systems. SRI advantages have been shown to apply to tra-
ditional as well as modern cultivars. As with crops in CA systems, SRI phenotypes
are widely reported by farmers to be less susceptible to pest and disease damage.
The SRI production concept has been defined on the basis of a set of practices (i.e.,
seedlings 10 days of age for transplanting, or direct seeding; single plant; wide spac-
ing; mainly moist, not saturated and flooded, soil water regimes; regular weeding to
also facilitate soil aeration; and liberal use of organic fertilizers) (Uphoff et al. 2011;
Kassam et al. 2011c; Uphoff and Kassam 2011). An SRI system based on CA prin-
ciples is being practiced on permanent nontilled raised beds as well as in unpuddled
paddies in Asian countries, thus eliminating puddling and the soil-disturbing ways
of weeding (Sharif 2011). The wheat-rice cropping system in the Indo-Gangetic
Plains involves the production of no-till wheat over some 3 million ha with residues
from the previous rice crop providing soil cover. It would now seem appropriate to
introduce no-till SRI rice in the wheat-rice cropping system and manage the crop-
ping system based on the CA principles.
14.6.1 c roP m anagement P racticeS anD S uStainaBle S oil m anagement
Standard agronomic crop management practices comprise crop and cultivar choice,
crop establishment and yield response to water, crop genetic improvement, pest man-
agement, fertilizer and nutrient management, and crop rotation and intensification.
Individual crop management practices that form a constituent part of good integrated
production systems are often interrelated. The interactions among practices can work
synergistically to produce outcomes in terms of productivity via improvements in
conditions of the soil as a rooting medium, enabling the better expression of plants'
genetic and epigenetic potentials. For example, for a given amount of rainfall, soil
moisture availability to plants depends on how the soil surface, SOM, soil structure,