Pathways for recent Cerrado soybean expansion : extending the soy moratorium and implementing integrated crop livestock systems with soybeans.

The Brazilian Soy Moratorium has effectively reduced forest conversion for soybeans in Amazonia. This has come at the expense of the region?s pasturelands, which have increasingly ceded space for compliant soy expansion. The question of extending the policy to the Cerrado, where recent soy expansion has come at the cost of ecologically valuable vegetation, plugs into a wider discussion on how to reconcile competing commodities on finite amounts of cleared area. Innovative management strategies that allow different land uses to coexist are urgently needed. Integrated crop-livestock systems with soybeans(ICLS)rotates beef and soy on the same area, and shows promise as a means to improve production, farmer benefit, and environmental impacts. Here we reconstruct historical land use maps to estimate Cerrado Soy Moratorium outcomes with benchmark years in 2008 and 2014, we then estimate additional production afforded by ICLS implementation between 2008 and 2014. We find that if a 2008 Cerrado Soy Moratorium were in place, 0.7 Mha of 2014 Cerrado soy area would currently be in violation of the policy. Roughly 96% of this acreage is found in Matopiba (82%) and Mato Grosso (14%)states, suggesting that adoption may have slowed recent production in these rapidly transforming soy centers, in contrast to central and southwestern Cerrado where there is more concentrated eligible expansion area. Changing the benchmark to 2014 could have added 0.7 Mha of eligible expansion area, though over 80% of these additions would be in states with the most 2008 eligible area (Distrito Federal, Mato Grosso, Maranh?o, Minas Gerais, Mato Grosso do Sul). Meanwhile, ICLS adoption could have added between 4.0 and 32 Mha of new soy land to the study area without additional clearing between 2008 and 2014, though this would depend on rigorous accompanying land zoning policy to guide implementation. The roughly 5 Mha of Cerrado soybean expansion that actually occurred between 2008 and 2014 could have been accommodated on 2008 suitable pasture area given an ICLS rotation frequency of every 6 years or less. Conservation estimates presented here represent the upper limit of what is possible, as our scenario modeling does not account for variables such as leakage, laundering, or rebound effects

What drives the seasonality of photosynthesis across the Amazon basin? A cross-site analysis of eddy flux tower measurements from the Brasil flux network

We investigated the seasonal patterns of Amazonian forest photosynthetic activity, and the effects thereon of variations in climate and land-use, by integrating data from a network of ground-based eddy flux towers in Brazil established as part of the ‘Large-Scale Biosphere Atmosphere Experiment in Amazonia’ project. We found that degree of water limitation, as indicated by the seasonality of the ratio of sensible to latent heat flux (Bowen ratio) predicts seasonal patterns of photosynthesis. In equatorial Amazonian forests (5◦ N–5◦ S), water limitation is absent, and photosynthetic fluxes (or gross ecosystem productivity, GEP) exhibit high or increasing levels of photosynthetic activity as the dry season progresses, likely a consequence of allocation to growth of new leaves. In contrast, forests along the southern flank of the Amazon, pastures converted from forest, and mixed forest-grass savanna, exhibit dry-season declines in GEP, consistent with increasing degrees of water limitation. Although previous work showed tropical ecosystem evapotranspiration (ET) is driven by incoming radiation, GEP observations reported here surprisingly show no or negative relationships with photosynthetically active radiation (PAR). Instead, GEP fluxes largely followed the phenology of canopy photosynthetic capacity (Pc), with only deviations from this primary pattern driven by variations in PAR. Estimates of leaf flush at thre