Effect of cover crops on microbial community structure and its relationship with soil functionality and macronutrients availability.

DIEGO CHAVARRIA; ROMINA VERDENELLI; DANNAE SERRI; SILVINA RESTOVICH; ADRIAN ANDRIULO; JOSÉ MERILES; SILVINA VARGAS GIL

EUROPEAN JOURNAL OF SOIL BIOLOGY

ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER

Lugar: Paris; Año: 2016

1164-5563

Continuous monoculture inmajor agricultural regions has been characterized by the loss of fertility, increasedsoil erosion and surface runoff. Thus, the inclusion of cover crops (CC) is apromising option aimed at better preserving the sustainable production ofagricultural systems. The objective of this study was to assess the short-termeffect of CC on soil microbial community structure and relatedenzyme activities and macronutrient availability. Speciestested as CC were: oat (Avena sativaL.), vetch (Vicia sativa L.) andradish (Raphanus sativus L.), whichwere sown in two species mixtures, oat/radish (CC1) and oat/radish/vetch (CC2),with soybean monoculture and soybean/corn being the cash crops.The field trial wasperformed under no-tillage, and soil sampling was carried out in 2013 and 2014.The analysis of soil phospholipid fatty acid (PLFA) showed an increase of totalbacterial PLFA and Gram-positive PLFA under CC treatments, being on average 6.8%significantly higher in CC2 and CC1 than in the control treatment. In addition,soil enzyme activities (esterase activity, dehydrogenase activity and acid phosphataseactivity) were on average 20% higherin plots under CC in comparison to control treatments. The total N was significantly higher after CC2 treatment (0.31 mg g-1)than in either the CC1 (0.20 mg g-1) or control (0.22 mg g-1).This research revealed that theinclusion of CC mixtures in crop rotation produced an increase in bacterial PLFA,in particular Gram-positive bacteria, in the short term. These changes wererelated to soil enzyme activities and to the availability of the main macronutrientsN and P, with a CC mixture including oat/radish/vetch being highly recommendednot only to improve soil biological processes but also to provide additional Nto the cash crop.