Systems In Cerrado Research Articles

Effects of tree species and planting density on the total yield of an agroforestry system in the Brazilian Cerrado

ABSTRACT This study aimed to evaluate the effects of spacing and population density of three tree species on the primary yield of an agroforestry system in the Cerrado. The experiment was conducted in the experimental area of the State University of Goiás, São Luís de Montes Belos, Brazil. The experiment was designed to assess the effects of tree species, density, and spacing in a factorial scheme of 3 × 2 × 3, totaling 18 treatments with two tree rows each. The tree species assessed were Corymbia citriodora (seedlings), Eucalyptus cloeziana (seedlings), and an Eucalyptus urophylla clone. The trees were planted in single and triple rows (Trees planted in single and triple rows, varying density). In the first year of the experiment, maize (Zea mays) and Crotalaria juncea were sown, maize and Marandu palisadegrass (Uroclhoa brizantha cv. Marandu) in the second year, and a monoculture of Marandu palisadegrass during the third and fourth years. Due to the larger tree-covered area, the arrangement in triple rows reduced maize yield by 36% in the first year, silage yield by 40% in the second year, and pasture yield by approximately 30%. Reducing tree density is crucial to ensure the functionality of the agroforestry system.

Nitrogen response of two corn cultivars grown alone or intercropped in a soybean succession system in the Brazilian cerrado

The most widely used production systems in the Cerrado region are soybean (Glycine max)-corn (Zea mays) and soybean-corn intercropped with ruzigrass [Urochloa ruziziensis (Syn. Brachiaria ruziziensis)]. Thus, these systems may require a higher supply of mineral nitrogen (N) fertilizer. Therefore, the objective of this study was to evaluate the agronomic traits of two corn cultivars grow in the second-crop harvest in different environments, production systems, and N application rates in an Oxisol in the Cerrado region of Mato Grosso do Sul. The experimental design was a randomized block arranged in a split-split plot with three replicates. Plots consisted of two environments (UFMS 1 and UFMS 2), subplots consisted of two production systems [corn alone (monoculture) or corn intercropped with U. ruziziensis, and sub-subplots of five N application rates in topdressing (0, 40, 80, 120, or 160 kg N/ha). Urea was used as the source of N (45% N), and it was applied 30 days after emergence (DAE). Two corn cultivars (NS50 and Invictus Viptera 3) were used. During the flowering period of corn (i.e., after the emergence of female inflorescence), the relative chlorophyll index, leaf N concentration, plant height, and ear insertion height were recorded. At physiological maturity, the ear insertion height, ear length, number of grain rows per ear, number of grains per row, ear diameter, mass of one thousand grains, and grain yield were measured. The corn grain yield is lower in the system intercropped with U. ruziziensis when compared to the cultivation of corn alone (monoculture). In addition, the environment with greater soil base saturation and N availability (UFMS 2) results in a distinct response for the corn cultivar used; thus, a greater grain yield is expected from cultivar Viptera 3 in this environment. The maximum agronomic efficiency for corn grain yield is obtained with 102 to 123 kg N/ha for the Viptera 3 and NS50 PRO cultivars, respectively.

Production and quality of forage under intercropping systems in the Cerrado/Pantanal ecotone

The aims of this study were to evaluate forage production and nutritional quality of the elephant grass, leucaena and pigeon pea beans, grown in monocrop or in intercropping systems in Cerrado / Pantanal ecotones in both, dry and rainy, seasons. Experimental design was completely randomized with five treatments and five repetitions. The treatments were: elephant grass, leucaena and pigeon pea all of these in monocrop; intercropping elephant grass with Leucaena; intercropping elephant grass with pigeon pea. During the rainy season, it was carried out three cuts at intervals of 60 days, and in the dry season a single cut with 180 days. In the rainy season, the biomass produced of the forages elephant grass, leucaena and pigeon pea corresponded respectively to 72, 64, 76% of the annual production. Under intercropping system, fodder behaves similarly, with the average of 72% of annual production. During this period, the nutritional quality of the forages was also higher than the dry season. In the dry period, there was decreased the production of biomass and a reduction in the proportion of leaves in all the forage, regardless of cultivation system. In both seasons (rainy and dry), the forage grown under intercropping system showed higher dry matter production in relation to monocrop system, with most of this production coming of elephant grass. The intercropping elephant grass with the pigeon pea has the highest production of dry matter, while the intercropping elephant grass with Leucaena has better nutritional quality.

Assessment and kinetics of soil phosphatase in Brazilian Savanna systems.

The activity and kinetics of soil phosphatases are important indicators to evaluate soil quality in specific sites such as the Cerrado (Brazilian Savanna). This study aimed to determine the activity and kinetic parameters of soil phosphatase in Cerrado systems. Soil phosphatase activity was assessed in samples of native Cerrado (NC), no-tillage (NT), conventional tillage (CT) and pasture with Brachiaria brizantha (PBb) and evaluated with acetate buffer (AB), tris-HCl buffer (TB), modified universal buffer (MUB) and low MUB. The Michaelis-Menten equation and Eadie-Hofstee model were applied to obtain the kinetic parameters of soil phosphatase using different concentrations of p-nitrophenol phosphate (p-NPP). MUB showed the lowest soil phosphatase activity in all soils whereas AB in NC and NT presented the highest. Low MUB decreased interferences in the assessment of soil phosphatase activity when compared to MUB, suggesting that organic acids interfere on the soil phosphatase activity. In NC and NT, soil phosphatase activity performed with TB was similar to AB and low MUB. Km values from the Michaels-Menten equation were higher in NC than in NT, which indicate a lower affinity of phosphatase activity for the substrate in NC. Vmax values were also higher in NC than in NT. The Eadie-Hofstee model suggests that NC had more phosphatase isoforms than NT. The study showed that buffer type is of fundamental importance when assessing soil phosphatase activity in Cerrado soils.

Distribuição vertical dos sistemas de polinização bióticos em áreas de cerrado sentido restrito no Triângulo Mineiro, MG, Brasil

Alguns fatores podem influenciar a distribuição dos recursos florais e sistemas de polinização bióticos nos ecossistemas, como por exemplo, o clima, a altitude, a região geográfica, fragmentação de áreas naturais e as diferenças na composição florística na estratificação vertical. Este estudo teve por objetivo avaliar a distribuição dos sistemas de polinização bióticos na estratificação vertical em fragmentos de cerrado sentido restrito no Triângulo Mineiro. Não houve diferença significativa (χ²0,05,9 =14,17; p = 0,12) na riqueza florística geral entre os fragmentos, nem quando comparada em separado para cada estrato (arbóreo, arbustivo, herbáceo e liana), estando o estrato arbustivo mais bem representado. Da mesma forma, não houve diferenças significativas entre fragmentos quanto aos sistemas de polinização (χ²0,05,21 =13,80; p = 0,8778), sendo a polinização por abelhas mais comum, correspondendo ao menos 85% das espécies de plantas em cada fragmento. Em termos relativos, as plantas polinizadas por abelhas foram dominantes em todos os estratos, chegando a 100% das lianas e herbáceas em alguns fragmentos. Neste estudo, com base na composição florística e distribuição dos sistemas de polinização na estratificação vertical, podemos caracterizar um mosaico vertical no cerrado sentido restrito, que tem implicações na sustentabilidade das comunidades no cerrado, assim como os mosaicos horizontais de fitofisionomias.

Life cycle assessment of sugarcane ethanol and palm oil biodiesel joint production

Abstract Sugarcane (Saccharum spp.) and palm tree (Elaeis guianeensis) are crops with high biofuel yields, 7.6 m3 ha−1 y−1 of ethanol and 4 Mg ha−1 y−1 of oil, respectively. The joint production of these crops enhances the sustainability of ethanol. The objective of this work was comparing a traditional sugarcane ethanol production system (TSES) with a joint production system (JSEB), in which ethanol and biodiesel are produced at the same biorefinery but only ethanol is traded. The comparison is based on ISO 14.040:2006 and ISO 14044:2006, and appropriate indicators. Production systems in Cerrado (typical savannah), Cerradao (woody savannah) and pastureland ecosystems were considered. Energy and carbon balances, and land use change impacts were evaluated. The joint system includes 100% substitution of biodiesel for diesel, which is all consumed in different cropping stages. Data were collected by direct field observation methods, and questionnaires applied to Brazilian facilities. Three sugarcane mills situated in Sao Paulo State and one palm oil refinery located in Para State were surveyed. The information was supplemented by secondary sources. Results demonstrated that fossil fuel use and greenhouse gas emissions decreased, whereas energy efficiency increased when JSEB was compared to TSES. In comparison with TSES, the energy balance of JSEB was 1.7 greater. In addition, JSEB released 23% fewer GHG emissions than TSES. The ecosystem carbon payback time for Cerrado, Cerradao, and Degraded Grassland of JSEB was respectively 4, 7.7 and −7.6 years. These are typical land use types of the Brazilian Cerrado region for which JSEB was conceived.

Particulate organic matter in soil under different management systems in the Brazilian Cerrado

The combination of the no-till planting system (NTS) and pasture (e.g. brachiaria grass, Urochloa sp.) for livestock production constitutes a crop–livestock integration (CLI) system. CLI systems significantly increase the total organic carbon (TOC) content of soil and the particulate organic carbon (POC) of soil organic matter (SOM). The present study evaluated TOC and the granulometric fractions of SOM under different management systems in a Cerrado area in the state of Goiás. Two areas applying crop rotation were evaluated, one using CLI (corn/brachiaria grass/bean/cotton/soybean planted sequentially) and the other NTS (sunflower/pearl millet/soybean/corn planted sequentially). A third area covered with natural Cerrado vegetation (Cerradão) served as a reference to determine original soil conditions. Soil was randomly sampled at 0–5, 5–10, 10–20, and 20–40 cm. The TOC, POC, and mineral-associated organic carbon (MOC) were assessed, and POC and MOC stocks calculated. The CLI system resulted in greater TOC levels than NTS (0–5, 5–10, and 10–20 cm). Compared with the Cerradão, CLI areas exhibited higher stocks of TOC (at 5–10 and 10–20 cm) and POC (at 0–40 cm). Results obtained for TOC and POC fractions show that land management with CLI was more efficient in increasing SOM than NTS. Moreover, when compared with NTS, the CLI system provided better POC stratification.

Production, decomposition and half-life of the straw of grass under different levels of manure for no-tillage system in cerrado

In the conditions of cerrado (savannah), the climate is favorable in the increase and acceleration of the straw decomposition, thus, hindering the permanence and the maintenance of the residue in the surface of the soil. This work aimed at evaluating the production, decomposition and half-life of straw mixture with grass about the anticipation of levels of the culture successor’s manure in no-tillage system, in the savannah, in the Southwest area of Tocantins. The production of dry mass and the decomposition rate were appraised in an experiment with fifteen types of vegetable covering: millet (Pennisetum americanum), brachiaria (Brachiaria brizantha), forage sorghum (Sorghum vugares pers), bluestem (Gayanus kunth), in single and in mixed plantation, and with 0% and 40% of chemical manure recommended for the culture successor (soy), in savannah soil, in Alvorada, south area of Tocantins. In a Latossolo Vermelho Distrofico, submitted to 13 years of cultivation, which were: 8 years under conventional system with the use of harrow disc and disking; 2 years under minimum cultivation with the use of disking and later subsolador and 3 years under no-tillage system. The obtained results demonstrate that the consortium use of grass increases the straw production in no-tillage system. The increase of the amount of chemical fertilizer promotes increment in the fitomass production, being the most significant effect in the mixed plantation that involved grass. The throwing seeding of the bluestem grass in the soil surface promotes a better exploration of the area which produces straw. However, that grass did not contribute to the increase of the productivity in the mixed plantation to which it was involved. The presence of millet, brachiaria and sorghum grass in mixed plantation increases the production and volume of remaining straw for the system of no-tillage system in both levels of chemical manure.