Francisco Sandro Rodrigues Holanda

Influence of crop rotations and tillage systems on phosphorus and potassium stratification and root distribution in the soil profile

Abstract The combination of cropping rotation and tillaging for several years have altered the distribution of nutrients such as phosphorus (P) and potassium (K) in the soil profile. These long‐term changes have led researchers to investigate the distribution of nutrients and the distribution of roots in alternate cropping and tillage systems. The purpose of this study was to clarify if and how interactions between tillage systems and crop rotation, in long‐term plots, affected P and K distribution and root development, in the soil profile. This continuous long‐term tillage study consisted of 8 treatments arranged in a randomized split‐plot design and replicated three times. It consisted of one rotation treatment, corn (Zea mays L.) And soybean [Glycine max (L.) Merr.] and of continuous corn as the main plot. Three primary tillage operations (fall moldboard plow, fall chisel, and no tillage) were tested as subplot. We found a greater concentration of P in the upper layers of the soil regardless of the til...

Estabilização de taludes marginais com técnicas de bioengenharia de solos no Baixo São Francisco

The river banks of the Lower Sao Francisco River, which mostly present low cohesion soils, have suffered with the increase in erosion, leading to margin retreat and sedimentation. The purpose of this work was to study the application of a soil bioengineering technique in order to control the riverbank erosion by its stabilization aiming toward the riparian vegetation recovery. The experimental area was divided in two different assays, with three replications. The test assay (without the soil bioengineering technique) was installed upstream, and the assay with soil bioengineering was installed downsteam. The soil bioengineering technique was characterized by the association of the biotextile screen under the trade name Fibrax® 400BF, associated with Brachiaria decumbens grass and sediment retainers under the trade name Bermalonga®, installed along the river bank base. In order to evaluate the riverbank changes, direct topographic measures was used. The data was collected 30, 180, 360 and 540 days after the beginning of the study. At the assay without soil bioengineering protection, strong slope soil mass movement occurred. The opposite behavior occurred in the assay with soil bioengineering, with a very little soil movement.

Riparian vegetation affected by bank erosion in the Lower São Francisco River, Northeastern Brazil

Changes in the hydrological regime of the Lower Sao Francisco River, located in Northeastern Brazil have brought negative environmental impacts, jeopardizing the flora and fauna of a global biodiversity hotspot, due to implementation of hydroelectric power dams and surface water withdrawal for irrigation in public and private perimeters. Remnants of the riparian stratum associated to the riverbank destabilization in six fragments were studied by surveying trees, shrubs, herbs, and aquatic species. The calculation of the Factor of Safety (FS) was performed in order to understand the riverbanks stability related to soil texture and vegetation cover. An overall number of 51 botanic families distributed in 71 genera and 79 species were recorded, predominantly from the families Mimosaceae, Myrtaceae, and Fabaceae. The fragmented riparian vegetation is mostly covered by secondary species under a strong anthropogenic impact such as deforestation, mining and irrigation, with an advanced erosion process in the river margins. Strong species that withstand the waves present in the river flow are needed to reduce the constant landslides that are mainly responsible for the river sedimentation and loss of productive lands. A lack of preservation attitude among the local landholders was identified, and constitutes a continuing threat to the riparian ecosystem biodiversity.

Environmental Perception of the São Francisco Riverine Population in Regards to Flood Impact

Abstract The São Francisco river discharge regularization, which regulates floods on the riverine population land, has promoted changes in land use associated to the implementation of irrigated areas, leading to a destruction of natural riverbank vegetation and an increase in soil and bank erosion. Past river and land use involved fishermen and landholders in a complex relationship which provided for the practice of both activities: fishing and agriculture, without any constraint. The objective of this work was to understand and analytically interpret the perception of the riverine population regarding the natural or artificial floods caused by the operation of dams in the São Francisco River Basin, in its lower course. A survey related to the perception of the riverine population concerning to flood occurrences at the lower Sao Francisco river municipalities was carried out, especially in regards to the 2004 flood, with the evaluation of the produced externalities through intentional and non-probabilistic questionnaires. To the riverine population, natural floods were always historically recognized as being positive, with the practice of agriculture on the flooded lands possible and also working as a nursery area for fish, promoting the local biodiversity conservation. With the river discharge regularization throughout the year, a decrease of fish quantity, biodiversity, and waterlogged land farming (marginal lagoon) was reported. The social and environmental costs resulting from the policies of development in the São Francisco River Basin were not considered by the policymakers.

Rendimento e qualidade da fruta do maracujazeiro-amarelo adubado com potássio, esterco de frango e de ovino

The majority of soils grown with passion fruit plants in Sergipe State present low natural fertility and this has caused reduced productivity of this plant. Thus, the aim of this work was to evaluate the combination of organic fertilization sources from poultry and sheep manure, with potassium doses on yield and quality of yellow passion fruits. This experiment was carried out in the Research Station of the Universidade Federal de Sergipe. The experiment design was in a 2x5 randomized blocks (organic fertilizer x potassium doses) +1 factorial scheme. The treatments were constituted by 2 sources of organic fertilizers (T1=10 L of poultry manure and T2 = 20 L of sheep manure) and five potassium doses (0, 27, 54, 81 e 108 g plants-1) and an additional treatment (2.5 L of poultry manure + 7.5 L of sheep manure). The variables studied were: total soluble solid concentration (SST), total acidity by titration (ATT), cortex thickness (ESPC) (mm), number of fruit per plant (NFPLM) and yield (REND) (t ha-1), in the first year. Yellow passion fruits presents adequate attributes for consumption in natura and for the industry, when fertilized with poultry and sheep manure combined with potassium doses, promoting SST between 10.8 and 14.02%, ATT of 8.48 to 7.57 g 100 mL-1 of juice, ESPC between 6.52 and 7.12 mm, REND between 27.5 and 30.24 t ha-1 and NFPLM of 28 to 29 fruits, respectively.

Effect of liming on sweet sorghum yields in two Brazilian oxisols

Abstract An experiment was conducted in order to verify the effect of liming on sweet sorghum yields in two oxisols (Red‐Yellow Latosol and Dark Red Latosol). The treatments consisted of four rates of lime: 0, 2, 4, and 6 ton#lbha‐1 and 0, 4, 8, and 12 ton#lbha‐1 of lime in the Red Yellow Latosol (Tres Pontas County) and in the Dark Red Latosol (Felixlândia County), respectively. The experimental design was a randomized block with three replications. The experiments were conducted during two years. For sweet sorghum growing at Tres Pontas, stalk yields were increased by liming, the positive effect of the lime due to calcium (Ca) and magnesium (Mg) fertilization. At Felixlândia, the stalk and grain yields were increased by liming, and in this case, liming reduced aluminum (Al) saturation and furnished Ca and Mg. At both locations, higher yields of sorghum were obtained with rates of lime greater than those necessary to neutralize Al toxicity.

Propagation through cutting technique of species ocurring in the Lower São Francisco River in Sergipe State with different concentrations of indolbutiric acid

The objective of this work was to evaluate the feasibility of vegetative propagation through cutting technique of seven tree species with strong occurrence in the riparian forest of the Lower Sao Francisco River in Sergipe State, under different concentrations of indolbutiric acid at 0, 2500, and 5000 mg.L -1 , for potentialization of its use in soil bioengineering technique. It was used a complete random block design with three replicates, and a total of twenty-one treatments. The evaluation period was 120 days for each species, and the data collection was made in intervals of fifteen days, in a total of eight evaluations for each species. The evaluated parameters were: Survival Rate, callus formation, and Root Dry matter Weight. Among the studied species, Schinus terebinthifolius Raddi presented the best results related to cutting technique mainly under the indolbutiric acid concentration of 2500 mg.L -1 .

Streambank Soil Bioengineering Approach to Erosion Control

Rivers in tropical regions have been submitted to strong environmental impacts through changes in the hydrologic and sedimentological regime, and also to the ongoing destruction of their riparian vegetation, despite the important role of riparian vegetation in riverbank protection through root systems and plant cover, which improve soil particle aggregation in a low cohesion situation, reducing runoff and resulting in a lower erosion rate and sedimentation of the river channel. Rivers are in effect often referred to as dynamic systems which means they are in a constant state of change. Techniques of stream bank and bed stabilization are needed and can be accomplished in several ways, such as the use of rockfill, which, though efficient, is quite expensive, precluding its use extensively along the river banks. In an attempt to solve the problem, riverine populations have resorted to various empirical solutions that, in addition to not producing the desired effect, cause problems for riparian vegetation recovery besides degrading the landscape (Holanda et al., 2010). The function of riverbank protection is to avoid bank erosion, that could cause movement of the river channel, which can be of vertical and horizontal direction, arise meandering, braiding, or moving and changing the river s path. As an alternative to the empirical practices of the riverines and to expensive bordering and rockfill techniques, the use of abundant raw material has been tested and used, providing a way of mitigating the problem that can be economically viable and with proven technical efficiency. This chapter intends to discuss soil bioengineering as a biotechnology that consists of the use of living materials or inert plant substances, biotextiles, associated or not with rocks, concrete, or metals that present themselves to be environmentally sustainable to riverbank erosion control at the various conditions of slope and soil texture along their water systems like reservoirs, irrigation canals, and rivers. Soil bioengineering can be applied in the mitigation of watershed disasters and protection and restoration of ecology. In soil bioengineering, plants assume an important ecological contribution (providing multiple ecological services), as well as an economic, and especially structural, contribution in contrast to other technologies in which plants are merely an aesthetic component of design. Also, a discussion will be developed on the vegetation component, which has a great importance in these biotechnologies, recognized not only for its landscaping qualities, but also for its beneficial hydromechanical effects and protection against soil erosion.

FUNGOS MICORRÍZICOS ARBUSCULARES E ENDOFÍTIOS “DARK SEPTATE” NO DESENVOLVIMENTO DA BIOMASSA DO CAPIM VETIVER

Vetiver grass is a member of the grass family Poaceae. Its fast development is probably due to the interaction with native microbiota, whose influence has not been studied yet. The objective of this work was to evaluate the colonization and development of the vetiver grass (Chrysopogon zizanioides (L.) Roberty) inoculated with arbuscular mycorrhizal fungi and dark septate endophytic fungi. The experimental design was a completely randomized design with six treatments (control, without mycorrhizal fungi, native inoculants, UFLA05 – Gigaspora albida, UFLA351 – Rhizoglomus clarum, UFLA372 – Claroideoglomus etunicatum, and UFLA401 – Acaulospora morrowiae), with three replicates each. Vetiver grass tillers as well as the native microbial inoculum were obtained from the Lower São Francisco river experimental area, located in Sergipe state, Northeastern Brazil. There was a negative interaction between all tested UFLAs mycorrhizal isolates and the native microbiota (mycorrhizal and endophytic fungi) in the treatments, especially when taking into consideration plant height and volume of roots. The effects of inoculation with UFLA isolates may have been influenced by the presence of the native mycorrhizal fungi and the dark septate endophytic fungi. Vetiver grass was responsive to the native inoculant. The mycorrhizal colonization of the vetiver grass was vesicular, but the formation of the arbuscules can be influenced by the interaction between the fungus, plant, and the environment.

Mangrove Soil in Physiographic Zones in the Sao Francisco River Estuary

Mangrove ecosystem dynamics and diverse human activities have led to a need for studies that give us a better understanding of the peculiarities of their soils. The objective of this study was to evaluate the physical and chemical soil attributes of mangrove forests located in the São Francisco River estuary, related to local ecological conditions. Two stations, divided into three forest types (fringe, basin and transition) were selected and five composite soil samples were collected from each forest type. Soil samples were submitted for chemical and physical analysis. The soil presented a sandy texture, with high organic matter and element content in the following order: Mg2+>Na+>Ca2+>H+>K+>P>Al3+ and Fe2+>Zn2+>Cu2+>Mn2+, respectively, with variations between the forests and stations. In general, the mangrove forests presented high fertility, especially in the basin forest, provided by vegetation development, showing a zoning trend for species in relation to soil fertility.