Chemistry Reference
In-Depth Information
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Figure 3
Maize grain yield as affected by application of compound fertiliser (NPK, 17 :
17 : 17) at 100 kg ha
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and the crop grown in the preceding season (maize,
climbing beans [CB] or soybean [SB]) in South Kivu, DR Congo. SED 5
standard error of difference; * 5 significant at P ,0.05; ** 5 significant at P
,0.01. There was no significant fertiliser 6 preceding crop interaction. CB:
climbing bean (Phaseolus vulgaris L.); SB: soybean (Glycine max L.).
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interactions, originate in organic input-driven alleviation of other growth-
limiting factors besides N. Consequently they rather influence the demand for
plant-available N and lead to higher N uptake. They do not necessarily,
however, improve synchrony as the timing of such improved demand may not
have changed drastically. Through a meta-analysis, fertiliser N-AE values were
observed to be significantly higher for the treatments where fertiliser was
combined with manure or compost [38 kg (kg N)
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], but all other organic
resources did not significantly affect N-AE values compared to the sole
fertiliser treatment [25 kg (kg N)
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].
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However, when performing the
statistical analysis on the data with maximum organic N application rates of
30 or 60 kg N ha
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, organic inputs belonging to Class II and manure/compost
had significantly higher N-AE values than the sole fertiliser treatment or the
Classes I and III/IV organic inputs (Figure 4). At higher organic N application
rates, only the treatment with manure/compost gave significantly higher N-AE
values than the sole fertiliser treatment (Figure 4). This confirms that higher
quality organic inputs are mainly a source of nutrients while Class II or
manure/compost alleviated other constraints to plant growth besides N, thus
improving the uptake of fertiliser N by maize.
An important issue related to organic inputs and ISFM is concerned with
the question whether fertiliser application can generate the required crop
