| dc.description.abstract | Conservation agriculture (CA) is becoming an important option for integrated land and water
resources management in most parts of the Sub-Saharan Africa region. Minimum soil
disturbance, maximum soil cover, and crop rotations are the cornerstones of CA. The popularity
of conservation agriculture is growing because, not only does it promise to improve yields, it
simultaneously improves the environment from which the food crops are being produced. The
former being important for Millennium Development Goal number one and the latter for goal
number seven. An attempt was made to contribute towards the advancement of the CA
technology, by defining the rainfall season quality in which CA would produce optimum yields
for maize. Implementing CA within this rainfall season quality would enhance efficient
utilization of rain water. Efficiency is one of the cornerstones for attaining integrated water
resources management, both at the catchment and basin level.
The Water Requirement Satisfaction Index, computed using the AgroMetShell, was used to
characterize rainfall seasonal quality. The characterization was in such a way that as the index
approaches 100, the quality of that season is considered very good and crop performance is
expected to be approaching its potential.
The average grain yield for maize and rainfall records for 34 farmers from 6 districts in Malawi,
namely, Balaka, Dowa, Machinga, Nkhotakota, Salima and Zomba were used. The rainfall
season quality at Extension Planning Area (EPA) and at farmer level was established for these 34
farmers. The interpretation that yield increases with an increase in the WRSI was tested both at
EPA and farmer level. The average grain yield from conservation agriculture was compared with
that from a conventional farmer’s practice at a given rainfall seasonal quality.
At EPA level, it was found that only in 1 district, Salima, did crop performance increase with an
increase in the WRSI. This increase however was not statistically significant. At farmer level,
10 out 26 crop performances followed the interpretation of the index. Out of the 10, only 1 crop
performance, for Dowa in 2009 was statistically significant at p=0.05.
There was no significant difference between the average grain yield obtained from conservation
agriculture and the average grain yield obtained from conventional farmers practice, at a given
rainfall season quality. However the yield gains from CA in relation to farmers’ conventional
practice increased with time.
The Water Requirement Satisfaction Index was thus found not to be the most suitable tool for
advising whether CA can be implemented in an area or not in Malawi. | en_ZW |
