Indigenous Practices for Soil and Water Conservation - Agropedia

The Use of Crop Combinations in Reducing
Soil Erosion and Degradation
K.G.Kshirsagar
In the face of rapid degradation of soil and natural resources, many farmers
adopt constructive measures that integrate conservation w i t h their agric
u l t u r a l practices. G r o w i n g crops in combinations is one such means of reducing
soil erosion and degradation. This paper focuses on crop combinations, in
an attempt to review their effectiveness and future prospects. The study is
based on 10 years of data collected f r o m farmers' plots in semi-arid districts of
Maharashtra and Andhra Pradesh.
Results and Discussion
R a i n f a l l is t h e m a i n cause of soil erosion in these areas. Crop combinations are
a safeguard against the highly variable rainfall, and they reduce soil losses
during high rainfall years. In general, the farmer is successful in managing
soil erosion on smaller plots. On the larger plots, farmers grow different crop
combinations in order to check erosion and maintain soil fertility.
A major advantage of growing crops of different durations together is control
of soil erosion. This is because the soil is protected by leaf cover and root mass
for long periods. Splash erosion by raindrops may be reduced by as much as
90%. The roots of various species in crop combinations feed at different depths
in the soil, thereby helping to reduce rill and gully erosion.
Such combinations are employed more in Andhra Pradesh than in Maharashtra,
perhaps to protect the erosion-prone Alfisols found in Andhra
Pradesh.
Legume crops play an important role in crop combinations, due to their
ability to fix atmospheric nitrogen and increase the soil organic matter cont
e n t , thereby i m p r o v i n g the s t r u c t u r e o f the soil. This i n t u r n enhances i n t e r -
nal aeration and drainage, and improves the storage of soil moisture and
nutrients, thus favoring plant root growth and, indirectly, limiting soil erosion.
These practices illustrate the farmers' awareness of the correlations between
soil, environment, and physical resources, and how they can be used
complementarily to reduce degradation.
However, in recent years, some of the complex crop combinations have become
less profitable, and the number of crops grown in combinations has been
reduced. Important crop components that help maintain the natural resource
base are vanishing from the combinations. These practices evolved in the context
of a low-population, subsistence-oriented farming system in which crop
combinations were by nature resource extensive. In today's changed circumstances,
the same systems cannot remain effective.
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