Saturday, March 5, 2016

Use of cover crops in soybean monoculture: effects on water and carbon balance

The cover crops (CC) is a good alternative to improve the lack of coverage and carbon balance in soils under no tillage with soybean (Glycine max L. Merr.) monoculture, predominant in the Pampean Region. In this study (2006-2011) the effect of winter cover crops -wheat (T), oats (A), vetch (V) and oats+vetch (A+V)- on water consumption, dry matter production and its impact on the of soil organic carbon contents (TOC) was evaluated. Biomass production of the CC was closely related to rainfall recorded between the months of June and October. In general, T and A treatments contributed greater amount of soil cover, on average, these grasses biomass were 24 and 91% higher compared with A+V and V. The water cost of including CC was 13-93 mm compared to traditional fallow (Ct). At the time of sowing of soybean, in general, Ct presented the highest water content. However, this treatment showed a loss of moisture by evaporation without biomass production, which is used by the CC to fix carbon between 18 and 303 kg C ha-1 depending on the year conditions. The use of CC -T, A and A+V- increased the TOC at 0-20 cm depth at rates of 597 to 98 kg C ha-1yr-1, while it decreased at 824 and 289 kg C ha-1 yr-1 without CC or using legumes (V), respectively. For conservation or increase the TOC, use of CC such as A, A+V and T would be a feasible option given that exceeds the minimum source C input of4,5 Mg C ha-1 necessary to maintain the TOC in soils south of Santa Fe.

Key words: Argiudoll; winter cover crops; available water; organic carbon
Duval M.E., J.E. Capurro, J.A. Galantini, J.M. Andriani. 2015. UtilizaciĆ³n de cultivos de cobertura en monocultivo de soja: Efectos sobre el balance de carbono. Ciencia del Suelo 32 (2) 247-261.
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