ISBN 9781498706148 – CAT# K24813

Entre os pinus tropicais, Pinus caribaea var. hondurensis é uma variedade
natural, oriunda de região com clima tropical na América Central. A espécie se aclimatou
bem em várias partes do mundo, em regiões com alta pluviosidade e temperaturas elevadas.
Embora não tolere geadas severas, pode ser plantada em partes da região Sul do Brasil
onde o clima é mais quente e a frequência de geadas é menor e é indicado para plantio em
boa parte do Brasil, em mais de 3,5 milhões de km2. Essa é uma variedade que apresenta
alto rendimento em madeira de boa qualidade, além de possibilitar a exploração da resina.
Neste trabalho, são apresentadas as regiões no Brasil que apresentam potencial para
cultivo dessa variedade em regime de silvicultura intensiva, tomando como base sua
região de origem no mundo. São indicadas para plantio comercial as zonas com os menores
riscos de geada nos estados da região Sul, no Estado de São Paulo e nas demais regiões
que oferecem condições climáticas favoráveis, principalmente de disponibilidade hídrica
para o desenvolvimento dessa variedade de pinus.

Previous numerical simulations have suggested that the area adjacent to Itaipu Lake in Southern Brazil is significantly affecting the local thermal regime through development of a lake breeze. This has led to concerns that soybean growth and development, and consequently yield, has been affected by the creation of the artificial lake in this important agricultural region, but a systematic climatological study of the thermal effects of Itaipu Lake has not been conducted. The objectives of this study were to assess the spatial pattern of minimum and maximum air temperatures in a 10-km-wide area adjacent to Itaipu Lake as affected by distance from the water. Measurements were conducted over 3 years in seven transects along the shore of Itaipu Lake, with five weather stations placed in each transect. Phenological observations in soybean fields surrounding the weather stations were also conducted. Generalized additive models for location, scale, and shape (GAMLSS) analysis indicated no difference in the temperature time series as distance from water increased. Semivariograms showed that the random components in the air temperature were predominant and that there was no spatial structure to the signal. Wind direction measured over the three growing seasons demonstrated that, on average, the development of a lake breeze is limited to a few locations and a few hours of the day, supporting the temporal and spatial analysis. Phenological observations did not show differences in the timing of critical soybean stages. We suggest that the concerns that soybean development is potentially affected by the presence of Itaipu Lake are not supported by the thermal environment observed.

While a number of papers have shown that subway systems have an impact on the air quality through the release of particulate matters, no information about the impact of such particles on tree attributes is available. Tree leaves from three different species from the exit side of a subway station in Rio de Janeiro, Brazil, were more asymmetrical than leaves from the entrance side. This leaves also presenting changes in leaves cuticle and chlorophyll content.

Oilseed-derived biochar, a by-product of pyrolysis for biodiesel production, is richer in aliphatic compounds than the commonly studied wood-derived biochar, affecting both its mineralization in soil and its interaction with native soil organic carbon (nSOC). Here, we investigated the soil C sequestration potential of three different oilseed biochars derived from C3 plant material: soyabean, castor bean and jatropha cake. The chemical composition of these biochars was determined by elemental analysis (CHN) and 13C NMR spectroscopy. The cumulative CO2 efflux from 30-day laboratory incubations of biochar mixed with a sandy soil containing nSOC from C4 plants was measured as a proxy for mineralization rate. The relative contribution of each source to CO2 production was calculated based on the 13C-signatures of total CO2 efflux and the source materials (soil and biochars). Our results showed that: (i) castor bean biochar contained relatively large amounts of aliphatic compounds, resulting in a greater mineralization rate than soyabean and jatropha biochars; (ii) CO2 efflux from the soil-biochar mixtures originated mostly from the biochars, suggesting that these biochars contain rapidly decomposable compounds; and (iii) all three oilseed biochars decelerated nSOC mineralization. This negative priming effect appeared to be caused by different factors. We conclude that oilseed biochars have the potential to increase soil C stocks directly and increase soil C sequestration indirectly in the short term through negative priming of nSOC mineralization.

The objective in this research was to identify photosynthetic responses of three leaf age groups measured in three portions of the leaf blade of two morphologically contrasting genotypes of Panicum maximum. Photosynthetic rate (PR) varied across leaf age groups and among leaf portions. Highest PR (20.6 μmol CO2 m−2 s−1) was recorded on the youngest fully expanded leaf, followed by the oldest green leaf and the expanding leaf. The middle and apical portions of the leaf had, on average, the highest PR (24.2 and 26.3 μmol CO2 m−2 s−1, respectively). In both ‘Massai’ and ‘Tobiatã’ cultivars the photosynthetic response was dependent upon leaf age groups and portions of the blade, with highest rates measured on the middle portion of the youngest fully expanded leaf. The P. maximum had similar parameters for the light response curve suggesting similar photosynthetic light response to light intensity across genotypes.

EMISSION OF NITROUS OXIDE AND METHANE IN SOIL FROM PASTURE RECOVERY AREAS IN THE AMAZON
MATOGROSSENSE. This study evaluates the chemical processes responsible for the nitrous oxide (N2O) and methane (CH4) fluxes
in the managed pasture (PM) and unmanaged pasture (PNM). In addition, the impact of nitrogen fertilization on the N2O and CH4
fluxes was assessed. The experiments were conducted on three farms in Alta Floresta city in the state of Mato Grosso. Both regular
and intensive samples were collected from PM, PNM, and forest areas for each of the properties. The gases were sampled using static
chambers in the morning. Higher N2O fluxes were recorded in the PMs, whereas the CH4 fluxes showed no influence of nitrogen
fertilization in both regular and intensive samples. Low fertilizer levels resulted in low N2O emissions

The low natural fertility of Oxisols in the Cerrado region makes some crops in this region very dependent on high rates of synthetic N-fertilizers, which are of growing environmental concern as a major source of N2O emissions in agriculture. In a field experiment, we quantified direct N2O emissions and NH3 volatilization (a source of indirect N2O emissions) from surface-applied N fertilizer on a no-till maize (Zea mays L.) crop in Cerrado biome. We used four fertilizers at the rate of 120 kg N ha−1 as topdress-N (V4–V6 growth stage), which were regular urea, urea + zeolite, calcium nitrate and ammonium sulfate, and a non-topdressed control. The total N losses as volatilized NH3 ranged from 2.2% (calcium nitrate) to 4.5% (urea + zeolite). The N loss as volatilized NH3 from urea was very low (3.2%), with no significant difference between urea + zeolite, ammonium sulfate and calcium nitrate. Significantly, higher cumulated N2O emissions were observed with ammonium sulfate than with the control. No significant differences among fertilizers were found for emission factor (EF), which was 0.20% on average (0.14–0.26%), indicating that use of IPCC default EF (1.00%) would substantially overestimate N2O emission. Free drainage and acidity of Oxisols and occurrence of dry spells, known as ‘veranicos’, are characteristics of Cerrado biome that may naturally mitigate N2O emissions.

Epigeous termite mounds are frequently observed in pasture areas, but the processes regulating their population dynamics are poorly known. This study evaluated epigeous termite mounds in cultivated grasslands used as pastures, assessing their spatial distribution by means of geostatistics and evaluating their vitality. The study was conducted in the Cerrado biome in the municipality of Rio Brilhante, Mato Grosso do Sul, Brazil. In two pasture areas (Pasture 1 and Pasture 2), epigeous mounds (nests) were georeferenced and analyzed for height, circumference and vitality (inhabited or not). The area occupied by the mounds was calculated and termite specimens were collected for taxonomic identification. The spatial distribution pattern of the mounds was analyzed with geostatistical procedures. In both pasture areas, all epigeous mounds were built by the same species, Cornitermes cumulans. The mean number of mounds per hectare was 68 in Pasture 1 and 127 in Pasture 2, representing 0.4 and 1 % of the entire area, respectively. A large majority of the mounds were active (vitality), 91 % in Pasture 1 and 84 % in Pasture 2. A “pure nugget effect” was observed in the semivariograms of height and nest circumference in both pastures reflecting randomized spatial distribution and confirming that the distribution of termite mounds in pastures had a non-standard distribution.

Potassium (K) is an important limiting factor of tree growth, but little is known of the effects of K supply on the long-distance transport of photosynthetic carbon (C) in the phloem and of the interaction between K fertilization and drought. We pulse-labelled 2-year-old Eucalyptus grandis L. trees grown in a field trial combining K fertilization (+K and −K) and throughfall exclusion (+W and −W), and we estimated the velocity of C transfer by comparing time lags between the uptake of 13CO2 and its recovery in trunk CO2 efflux recorded at different heights. We also analysed the dynamics of the labelled photosynthates recovered in the foliage and in the phloem sap (inner bark extract). The mean residence time of labelled C in the foliage was short (21–31 h). The time series of 13C in excess in the foliage was affected by the level of fertilization, whereas the effect of throughfall exclusion was not significant. The velocity of C transfer in the trunk (0.20–0.82 m h−1) was twice as high in +K trees than in −K trees, with no significant effect of throughfall exclusion except for one +K −W tree labelled in the middle of the drought season that was exposed to a more pronounced water stress (midday leaf water potential of −2.2 MPa). Our results suggest that besides reductions in photosynthetic C supply and in C demand by sink organs, the lower velocity under K deficiency is due to a lower cross-sectional area of the sieve tubes, whereas an increase in phloem sap viscosity is more likely limiting phloem transport under drought. In all treatments, 10 times less 13C was recovered in inner bark extracts at the bottom of the trunk when compared with the base of the crown, suggesting that a large part of the labelled assimilates has been exported out of the phloem and replaced by unlabelled C. This supports the ‘leakage-retrieval mechanism’ that may play a role in maintaining the pressure gradient between source and sink organs required to sustain high velocity of phloem transport in tall trees.

O PLANO Setorial de Mitigação e de Adaptação às Mudanças Climáticas para a Consolidação de uma Economia de Baixa Emissão de Carbono na Agricultura, conhecido como Plano ABC, tem o objetivo de garantir o aperfeiçoamento contínuo das práticas agropecuárias que reduzam a emissão de gases do efeito estufa (GEEs). O Plano ABC foi delineado em 2009, no contexto da Conferência do Clima da ONU em Copenhague, a COP-15.