Management Strategies for Improving Manure Nutrient Use Efficiency and Productivity of Subsistent Farmers in Enset-based Farming Systems of Southern Ethiopia
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Date
2012-06
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Addis Ababa University
Abstract
The overall objective of this study was to evaluate enset clones for nitrogen use
efficiency and identify best manure management practices minimizing losses and
maximizing nitrogen use efficiency by the crop. The study consisted of i) evaluation of
manure nitrogen mineralization and nitrification potential ii) effects of rate of manure
nitrogen supply on growth and nitrogen use efficiency of enset clones iii) manure
placement effects on growth and nutrient recovery efficiency of enset iv) the effect of
traditional methods and duration of manure storage on manure chemical composition and
quality.
The results of laboratory incubation study on manure mineralization and nitrification
revealed that addition of manure significantly (P<0.001) increased the amount of
inorganic nitrogen released compared to that of the control soil. Moreover, net
mineralization and nitrification of manure organic nitrogen was observed throughout the
incubation period. The net rates of mineralization varied between 0.04 to 0.33 mg N kg-1
of soil /day with mean value of 0.21 mg N kg-1 soil/ day. On the other hand, the net rates
of nitrification range from 0.058-0.57 mg kg-1 soil/ day with mean nitrification rate value
of 0.28 mg kg-1 soil/ day.
iv
In relation to the effect of rate of manure nitrogen supply, it was observed that the rate of
manure nitrogen supply significantly (P<0.001) influenced nitrogen use efficiency of
enset clones. In the study, the highest nitrogen use efficiency was obtained at application
rate of 300 kg of total manure nitrogen per hectare. Of the enset clones studied, clone Ado
showed the highest nitrogen use efficiency.
In relation to methods of manure application, a significant (P<0.001) manure placement
effects on growth and nitrogen recovery efficiency of enset were observed. In the study,
placement of manure at 20 cm depth and split application of half above and half at 20 cm
depth induced better growth and nitrogen recovery efficiency than to surface application.
On the other hand, the existing traditional practice of manure storage in open air was
found to be in efficient. It not only reduces the carbon and nitrogen content of manure but
also increases the C/N ratio. The duration of manure storage had also significant
influence on chemical composition and manure quality. In general, based on the results of
the present study it can be concluded that the growth and yield of enset plants in
smallholder farms could substantially be increased with planting nitrogen efficient clones
along with improved management practices.
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Biology