Yuri Jacques Agra Bezerra da Silva

Atriplex nummularia Lindl. as alternative for improving salt-affected soils conditions in semiarid environments: a field experiment

3 CHILEAN JOURNAL OF AGRICULTURAL RESEARCH 76(1) JANUARY-MARCH 2016 3 ULY-SEPTEMBER Atriplex nummularia Lindl. represents a cost-effective alternative for improving salt-affected soils in arid and semiarid environments due to its high adaptability to salinity and water deficiency. This study aimed to investigate soil physical-chemical changes in response to A. nummularia cultivation under field condition. Additionally, we quantified its biomass yield and phytoextraction potential. Two treatments were evaluated: soil cultivated with Atriplex under two crop densities (1 × 1 and 2 × 2 m), and a control (bared soil) with four replicates. The samples were taken at three soil depths (0-5, 15-20, and 40-45 cm). In general, dry biomass yield for leaves, stems and roots, as well as the bulk density and the hydraulic conductivity of the soil were sensitive to crop densities. Thus, the use of A. nummularia can be recommended for phytoremediation of salt-affected soils, as well as to improve soil physical condition. When it comes to salt phytoextraction per area, we recommend planting A. nummularia at a 1 × 1 m crop density. The greater accumulation of salts was observed in leaves, as observed for Na (82% roughly). However, in order to improve soil physical conditions, we suggest the management of A. nummularia under 2 × 2 m crop density. Pruning was fundamental to increase the biomass yield and, consequently, the phytoextraction of specific ions, e.g., Na, Cl. It was responsible for 83% and 88% of the total dry biomass at 1 × 1 and 2 × 2 m crop density, respectively.

Soil fertility changes in vineyards of a semiarid region in Brazil

Cultivation can substantially change soil quality through improvement or degradation of the physical and chemical characteristics. Vineyard soils are sensitive to soil changes due to the intensive chemical input. This study assesses the soil fertility changes in vineyard soils of the São Francisco valley in Northeastern Brazil during different cultivation time spans (5, 6, 8, 10, 12, 15, and 16 years). An area with natural vegetation (Caatinga) was used as a reference area. We analyzed pH, exchangeable contents of Ca, Mg, Na, K, and Al, potential acidity (H+Al), available P, total organic matter, sum of bases, CEC, Al saturation, and base saturation at depths of 0-20 and 20-40 cm. Univariate and multivariate analyses were used for data evaluation. The results showed that soil fertility changes were closely related to cultivation time spans.

Bedload and Suspended Sediment of a Watershed Impacted by Dams

Sediment transport relates to suspended sediment and bedload. The suspended sedi‐ ment plays the most important role on the land-ocen sediment flux. On the other hand, the bedload should be considered in order to assess the impacts of dams on sediment transport and sediment yield. Recent effects of dam construction have been widely reported. The sediment load has been reduced by more than 75% for major rives, such as Nilo, Orange, Volta, Indus, Ebro, Kizil Irmark, Colorado, and Rio Grande and more than 40% of its lux is trapped within large dams. In addition, the multiple trapping through sequential dams has impacted the sediment transfer from terrestrial to coastal zone, triggering the coastal erosion. In terms of sediment reten‐ tion and transport, China stands out the most impacted country by dams, followed by United States, and continents such as Europe, Africa, and South America. Based on the foregoing, the impact of dams on sediment transport and yield of an important Brazilian watershed with multiple dams will be the focus of this chapter. Thus, a three years field sampling (2009-2011) was carried out to measure the sediment yield of Capibaribe Watershed, and also its contribution to coastal erosion. The ratio between QB and SSQ ranged from 0.12% to 27.3% with 76% of all values lower than 5%. Usual‐ ly, the bedload transport rate of a river is about 5–25% of the suspended sediment transport. This ranging sheds light on the lack of bedload reaching the coastal zone and it is likely one of the reasons to yield coastal erosion. The low rates can be attrib‐ uted to the presence of dams which have been admitted to have a strong effect on sediment transport. The sediment yield was equal to 3.69, 4.36, and 6.7 t km-2 ano-1 in 2009, 2010, and 2011, respectively. In comparison with bedload yield, the suspended sediment yield was higher than 95% for all studied years. Therefore, the limited bed‐ load supply – mainly responsible for construction of coastal landform – is likely con‐ tributing to the coastal erosion along part of the northeast region, Brazil. The multiple dams along the Capibaribe River watershed produce a deficit in sediment flux to

Implantação de Barragem Subterrânea e Avaliação da Qualidade da Água na Bacia Hidrográfica Semiárida do Riacho Jacu, Serra Talhada-PE

1 Doutor em Ciência do Solo, Professor Adjunto do Departamento de Tecnologia Rural da Universidade Federal Rural de Pernambuco (UFRPE), Rua Dom Manoel de Medeiros s/n, Recife, PE, CEP 52.171-900. Email: vcpiscoya@hotmail.com, Telefones:(0xx81)33206277/99125477/ 2 Doutor em Ciência do Solo, Professor Associado do Programa de Pos-Graduacao em Ciencia do Solo /UFRPE, email: cantalic@terra.com.br 3 Doutorando em Ciência do Solo, Departamento de Agronomia/UFRPE 4 Doutor em Ciência do Solo, Professor Associado do Programa de Pós-Graduação de Estatística Aplicada e Biometria/ UFRPE 5 Doutor em Engenharia Civil Tecnologia Ambiental e Recursos Hídricos, Professor Adjunto do Departamento de Tecnologia Rural/UFRPE Victor Casimiro Piscoya1, José Ramon Barros Cantalice2, Yuri Jacques Agra Bezerra da Silva3, Moacyr Cunha Filho4 & Vicente de Paula Silva5