Is it true that intercropping cereal-legume favors higher microbial diversity and activity compared to cereal-legume rotation? What might be the reasons? Any publications on the same?
this is a very intelligently placed question . I think , cereal -legume rotation will have much higher rhizospere microbial diversity than either cereals alone or legumes alone. Probabaly , this is the legume-cereal combination sustains much better than either of the two alone..
Dear Anoop and Hesam, Thanks for your superbly put responses. Just to add more, the dense rooting network in the cereal-legume combination also favors secretion of exudates alongside improving soil structure, thus occasioning proliferation of microbes compared to legume-cereal rotations
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As stated earlier by Dr. Anoop, I think, cereal-legume rotation will provide a higher rhizosperic microbial diversity than Cereal-legume intercrop or mono-cereal / mono-legumes. However, field studies on this cropping system will provide a definite answer.
I am sure that inter-cropping with cereal/legume or any crop sps with legume enhances microbial diversity, It is all depends on the quality and quantam of exudates releasing by crop species. If it is inter-crop obviously diversity of exudates will be more and microbial diversity also be more.
To add to the cereal legume system, my experience is we find more microbial diversity in the arid ecosystems when we have both shallow and deep rooted plants together. May be agro-forestry system where you have shallow rooted crops ( may be cereal or legumes) and deep-rooted trees (may be leguminous or cereal). We also observed that Agri-horti system influences more AM diversity. For example, in the clusterbear-Acacia nilotica system there were 37 different species of AM fungal population. A similar observation was also noticed with Neem -clusterbean system.
Great contributions friends!Very interesting.
Dr. Tarafdar and Dr. Sachin, would you kindly share some of these publications...Would really appreciate.
Diversification of any soil microbes is mainly governed by types and kind of root exudates released from root rhizopheric zone which is also governed by the specific ratio of soil Carbon to nitrogen and phosphorus. In rotation due to a temporary lag period between the first and second crop this sorts of diversification may be less while in inter-cropping due to variations in extent and rate of release of exudates, there arises a sort of competition among the microbes and thus the wide diversification.
Interesting discussion indeed.. Please find enclosed some interesting facts in favor of on-going discussion...
SOIL MICROBIAL DIVERSITY AND COMMUNITY STRUCTURE UNDER WHEAT AS INFLUENCED BY TILLAGE AND CROP ROTATION ( Source :Soil Biol. Biochem. Vol. 30, No. 13, pp. 1733±1741, 1998)
SummaryÐSoil microbial diversity is important to sustainable agriculture because microbes mediate many processes that support agricultural production. The BIOLOG2 system for detection of specific patterns of substrate utilization by bacteria was used to investigate the effects of tillage and crop rotation on the diversity and community structure of soil bacteria. In each of 2 yr, soil was sampled (0± 7.5 cm) in the wheat phase of different cropping rotations which had been established under zero tillage or conventional tillage on a Gray Luvisol in northern Alberta. Soil was collected from bulk soil at planting time and from bulk soil and wheat rhizosphere at ¯ag-leaf stage of wheat growth. Tillage significantly (P < 0.05) reduced the diversity of bacteria by reducing both substrate richness and evenness. The infuence of tillage on microbial diversity was more prominent at the ¯ag-leaf stage than at planting time and more prominent in bulk soil than in the rhizosphere at the ¯ag-leaf stage. Microbial diversity was significantly higher under wheat preceded by red clover green manure or field peas than under wheat following wheat (continuous wheat) or summer fallow. The substrate utilization patterns of the bacterial communities also revealed that the bacterial community assemblages under conventional tillage had more similar structures than those under zero tillage. These results indicate that conservation tillage and legume-based crop rotations support diversity of soil microbial communities and may affect the sustainability of agricultural ecosystems.
PDF enclosed for further reading....
Another very interesting review article entitled Methods of studying soil microbial diversity..PDF enclosed fro further reference ...
Very nice pdfs. Also considering the resource use efficiency, legume-cereal dual intercrops have high resource use efficiency indices compared to sole cropping, and this translates to the better growth, yields and above ground biomass in intercroped crops compared to sole crops
This is the reason intercropping of legumes favors much better microbial diversity than cereal -legume rotation ...soil is biologically more alive with such practices...
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