Abstract
Aim:
To study the combined effect of tillage and manure addition on bulk soil and
aggregate associated carbon and nitrogen in Vertisol.
Methodology: The study was conducted in a long-term tillage
experiment having two tillage treatments (reduced tillage and no-tillage)
together with100% NPK fertilizer without (T1) and with addition of
farm yard manure (T2) @ 2.0 ton C ha-1 to soybean in a
soybean-wheat cropping system in a Vertisol of Central India, with three
replicates in a split plot design. The parameters studied were aggregate size
distribution, mean weight diameter, water stable aggregates, bulk soil and
aggregate associated organic carbon, available nitrogen and rate of carbon
mineralization.
Results:
The results indicated significantly higher SOC in reduced tillage (0.87%)
than no-tillage (0.71%) under100% NPK fertilization in the bulk soil for 0-15
cm depth. However, 100% NPK + FYM showed a significant increase in the bulk
soil organic carbon in the no-tillage treatment only. Available nitrogen
content in the bulk soil and aggregate fractions were significantly lower
under no-tillage than the corresponding reduced tillage treatments. Manure
addition led to significantly higher available N content and proportion of
WSA in both the tillage practices. The carbon mineralization was
significantly higher by 1.4 to 1.6 times under reduced tillage than
no-tillage.
Interpretation: Long-term tillage study in Vertisol of
Central India indicated reduced tillage to be a better option than no-tillage
in maintaining organic carbon and nitrogen availability in soil.
Key
words:
Nitrogen, Soil aggregate carbon, Tillage, Vertisol, water stable aggregates
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