Energy balance model applied to pasture experimental areas in São Paulo State, Brazil.

The Simple Algorithm for Evapotranspiration Retrieving (SAFER) was used to estimate biophysical parameters and theenergy balance components in two different pasture experimental areas, in the São Paulo state, Brazil. The experimentalpastures consist in six rotational (RGS) and three continuous grazing systems (CGS) paddocks. Landsat-8 images from2013 and 2015 dry and rainy seasons were used, as these presented similar hydrological cycle, with 1,600 mm and 1,613mm of annual precipitation, resulting in 19 cloud-free images. Bands 1 to 7 and thermal bands 10 and 11 were used withweather data from a station located nearthe experimental area. NDVI, biomass, evapotranspiration and latent heat flux(λE) temporal values statistically differ CGS from RGS areas. Grazing systems influences the energy partition and theseresults indicate that RGS benefits biomass production, evapotranspiration and the microclimate, due higher LE values.SAFER is a feasible tool to estimate biophysical parameters and energy balance components in pasture and has potentialto discriminate continuous and rotation grazing systems in a temporal analysis.

Development of alternative methods for determining soil organic matter.

Soil organic matter (SOM) is important to fertility, since it performs several functions such as cycling, water and nutrient retention and soil aggregation, in addition to being an energy requirement for biological activity. This study proposes new trends to the Embrapa, Walkley-Black, and Mebius methods that allowed the determination of SOM by spectrophotometry, increasing functionality. The mass of 500 mg was reduced to 200 mg, generating a mean of 60 % saving of reagents and a decrease of 91 % in the volume of residue generated for the three methods without compromising accuracy and precision. We were able to optimize conditions for the Mebius method and establish the digestion time of maximum recovery of SOM by factorial design and response surface. The methods were validated by the estimate of figures of merits. Between the methods investigated, the optimized Mebius method was best suited for determining SOM, showing near 100 % recovery.