121. Sensibility of cotton crops to mepiquat chloride under saline conditions.

• Authors:
  • de Oliveira, F. R. A.
  • de Medeiros, J. F.
  • de Oliveira, F. de A.
  • de A. de Oliveira, F.
  • Freire, A. G.
  • Oliveira, M. K. T. de
  • Oliveira, F. R. A. de
  • Medeiros, J. F. de
  • Oliveira, F. de A. de
  • de Oliveira, M. K. T.
• Source: Revista Ciência Agronômica
• Volume: 43
• Issue: 3
• Year: 2012
• Summary: This work was carried out to evaluate the effect of irrigation water at different salinity levels, and of seed treatment with plant growth regulator, on the development of the cotton plant. The experimental design used was completely randomized, arranged in a 5*2 factorial scheme with four replications. The treatments resulted from the combinations of five levels of salinity of the irrigation water (S 1-0.5, S 2-2.0, S 3-3.5, S 4-5.0 and 6.5 dS m -1) on seeds, both treated and not treated with growth regulator. The evaluated characteristics were: number of leaves, leaf area, height, dry mass of stems, leaves and vegetative parts, specific leaf area and leaf area ratio. There was an interaction between salinity and seed treatments with mepiquat chloride, but only for leaf area and leaf area ratio. All other characteristics decreased with the increasing salinity of the irrigation water, with greater reductions in leaf area (mean of 65.8%) and dry mass of vegetative parts (64%). Seed treatment with mepiquat chloride affected plant development, independent of salinity.

122. Advances of hydroponics in Latin America.

• Authors:
  • Rodriguez-Delfin, A.
• Source: Acta Horticulturae
• Issue: 947
• Year: 2012
• Summary: Hydroponics has been used during years for research in the field of plant mineral nutrition and related topics. Today the soilless culture method is the most intensive horticulture production and is being applied with success in developed countries for commercial purposes. The growing and future of hydroponics in Latin America will much depend of the developing and adaptation of less sophisticated commercial systems. These have to be cost competitive with respect to the high sophisticated technology generated and used in developed countries, using natural and local substrates, developing native or endemic crops of the Region with economical potential for its high feed or medicinal value, among others. Meanwhile, as there is a considerable decreasing of agricultural soils in the world, soilless culture would be an important production alternative in urban and peri-urban areas, mainly in undeveloped countries. Inside the context of urban agriculture, hydroponics could be applied in the cities with more simple and low cost of technologies, mainly in extreme poverty areas, as a way to spread vegetables for self-consumption and to support the family or community income. Also to create micro-companies that will generate employments. There are no official statistics on the evolution of the state of the hydroponic cultures in Latin America. The main hydroponic systems used are the drip irrigation and NFT system. According with their profits, the main hydroponic crops are lettuce, tomato, pepper and strawberry. In Andean countries like Peru, Bolivia, Colombia and Ecuador, aeroponics is being developing to obtain basic potato tuber seed, free of virus. In relation to the media used in soilless culture, there is no ideal or optimum substrate, because a great diversity in media could be used, as pure or as mix form. Among the inorganic substrates it is possible to use quarry, river and quartz sand, gravel, pumice and tezontle. Husk rice, coco fiber, peat moss and sawdust are used as organic media. The use of rock wool is not generalized in the Region, but in countries like Mexico and Chile it is mainly used in tomato crop with drip irrigation system. Brazil and Mexico are the more representative hydroponic countries in Latin America. The area of soilless culture is increasing in the Region and every day there is much interest to learn and to dominate this technique of plants production without using soil. A great number of international courses, seminaries, congresses and symposia organized in countries like Peru, Mexico, Brazil, Costa Rica and Chile demonstrate this affirmation. Finally, it is necessary to obtain a hydroponic certification, as well as the organic products, to support the hydroponic growers in our countries.

123. Partial root drying as strategy for water use optimization in a 'Tahiti' lime orchard under the semi-arid of Bahia State.

• Authors:
  • Santana, J. A. D. V.
  • Carvalho, G. C.
  • Machado, V. V.
  • Daniel, R.
  • Coelho, E. F.
  • Coelho Filho, M. A.
  • Sampaio, A. H. R.
  • Santana Junior, E. B.
• Source: Acta Horticulturae
• Issue: 928
• Year: 2012
• Summary: The management of irrigation using partial root drying (PRD) was tested in an orchard of 'Tahiti' lime in the semi-arid conditions of Iacu, BA. Six treatments were evaluated: T1, T2, T3 (50% ETc PRD) with plants irrigated by a microsprinklers with its position alternating every 7, 14 or 21 days, respectively, and wetting on opposite sides of the root system; T4 (DI 50% ETc) irrigation was fixed on one side using one emitter per plant, T5 (100% ETc) was the control treatment using two microsprinklers per plant in a fixed position. In T6, at each interval of 21 days, one and two micro-sprinklers were alternatively used per plant. Results demonstrated significant differences in fruit production by the Scott Knott test (p

124. Chemical properties of a Humic Dystrudept after 12 years under conventional and no tillage with crop succession and rotation.; Atributos quimicos de um Cambissolo Humico apos 12 anos sob preparo convencional e semeadura direta em rotacao e sucessao de culturas.

• Authors:
  • Albuquerque, J.
  • Picolla, C.
  • Mafra, A.
  • Andrade, A.
  • Bertol, I.
• Source: Ciencia Rural
• Volume: 42
• Issue: 5
• Year: 2012
• Summary: Suitable soil management is one of the bases for sustainability in agricultural systems. The study aimed to evaluate chemical properties of a Humic Dystrudept for 12 years under two tillage systems, with crops rotation and succession. The experiment was carried out in Lages, SC, under conventional tillage (CT) and no-till (NT), with rotation (r) and succession (s) cropping systems, using crop sequences of beans-fallow-maize-fallow-soybean in CTr; maize-fallow in CTs; beans-oats-maize-fodder radish-soybean-vetch in NTr; and maize-vetch in NTs. The experimental design was completely randomized with four replicates. The soil samples were collected in the layers 0-2.5, 2.5-5, 5-10 and 10-20 cm. The variables assessed were total organic carbon (TOC), calcium, magnesium, exchangeable aluminum, phosphorus, potassium, total nitrogen (TN) and water pH. The no-tillage system increased TOC and nutrient levels in comparison with conventional tillage, especially in the surface soil layer. Maize and vetch crop succession had higher TOC and TN contents in the surface soil layer compared to crop rotation under no-tillage.

125. Forage yield in three pearl millet genotypes submitted to different chicken manure rates.; Produtividade de forragem em tres genotipos de milheto em diferentes doses de cama de aviario.

• Authors:
  • Hanisch, A.
  • Balbinot Junior, A.
  • Vogt, G.
• Source: Revista de Ciencias Agroveterinarias
• Volume: 11
• Issue: 1
• Year: 2012
• Summary: The objectives of this work were to evaluate the forage yield of three pearl millet genotypes under different chicken manure rates and to verify the residual effect of this organic fertilizer on soil. An experiment was carried out in Papanduva, Santa Catarina, Brazil, during the 2008/09 and 2009/10 crop seasons. In the first crop season, three pearl millet genotypes were evaluated: a common genotype and two hybrids (ADR 500 and LAB 733), which were cultivated under four chicken manure rates (0, 4, 8 and 12 t ha -1). In succession, the multicropping (black oat+common vetch) and pearl millet were cultivated to evaluated the residual effect of this organic fertilizer. The experimental design was a randomized blocks, with four replications. The pearl millet production was evaluated by cuts, while in multicropping between black oat+common vetch was evaluated the total dry mass. There was interaction between pearl millet genotypes and manure rates in relation to total shoot dry mass. The hybrid genotypes showed the higher performance due to increase manure rate. There was residual effect of this organic fertilizer on the multicroping of black oat+common vetch and pearl millet.

126. Soil microbial biomass under different tillage and levels of applied pig slurry.

• Authors:
  • Matos, M.
  • Machineski, O.
  • Balota, E.
• Source: REVISTA BRASILEIRA DE ENGENHARIA AGRICOLA E AMBIENTAL
• Volume: 16
• Issue: 5
• Year: 2012
• Summary: The objective of this work was to evaluate the changes in microbial biomass C, N and P due to the application of pig slurry under different soil tillage systems. The experiment was established in a clayey Oxisol, Eutrophic Red Latossol in Palotina, PR. Different quantities of pig slurry (0, 30, 60 and 120 m 3 ha -1 year -1) were applied to the soil prior to the summer and winter crop season under conventional tillage (CT) and no tillage (NT), in three replicates. The area was cultivated with soybean ( Glycine max L.) or maize ( Zea mays L.) in the summer and wheat ( Triticum sativum Lam.) or oat ( Avena sativa L.) in the winter. The soil samples were collected in March and October of 1998 and 1999 at depths of 0-5, 5-10 and 10-20 cm. The soil tillage and pig slurry application influenced the microbial biomass C, N and P. The microbial biomass and the microbial activity presented high sensibility to detect changes in the soil due to tillage and the application of pig slurry. The soil microbial biomass and C mic/C org relation increased as the quantity of applied pig slurry increased. The metabolic quotient under CT increased with depth while under NT it decreased. The soil microbial biomass was enriched in N and P under NT and as the quantity of applied pig slurry increased.

127. Soil quality indicators at the Riberao Extrema watershed, Distrito Federal: Part II.; Indicadores de qualidade dos solos na microbacia do Ribeirao Extrema, Distrito Federal: Parte II.

• Authors:
  • Neumann, M.
  • Lacerda, M.
  • Lago, W.
• Source: REVISTA BRASILEIRA DE ENGENHARIA AGRICOLA E AMBIENTAL
• Volume: 16
• Issue: 7
• Year: 2012
• Summary: The intensively increasing agricultural use of Distrito Federal soils may compromise their quality and trigger environmental problems in the region. Given this fact, the objective of this work was to study the soil quality (SQ) indicators, in areas under no tillage (PD), with diversified managements (corn-soybean rotation and bean-sorghum succession), at the Riberao Extrema watershed, Distrito Federal. Soil bulk density (Ds), flocculation index (GF), organic matter (MO), cation exchange capacity (CTC), microbial respiration (Rmic) and microbial biomass carbon (Cmic) were the attributes of SQ evaluated. Statistical analysis was performed using the statistical software Statistics Analysis System (SAS) and consisted of analysis of variance (ANOVA) followed by Tukey test for comparison of means. Results show that some of the evaluated SQ indicators were affected by different types of soil management under evaluation (Ds, Cmic and MO), while others were not sensitive to them (GF, CTC and Rmic). Positive correlation was found between MO and CTC of the soils in both investigated treatments, highlighting the importance of no tillage system on the chemical properties of soil.

128. Productivity of double-purpose winter cereals in the Depressao Central region of Rio Grande do Sul state.; Produtividade de cereais de inverno de duplo proposito na depressao Central do Rio Grande do Sul.

• Authors:
  • Bem, C.
  • Horst, T.
  • Agnolin, C.
  • Fontaneli, R.
  • Olivo, C.
  • Meinerz, G.
• Source: REVISTA BRASILEIRA DE ZOOTECNIA-BRAZILIAN JOURNAL OF ANIMAL SCIENCE
• Volume: 41
• Issue: 4
• Year: 2012
• Summary: The objective of this research was to evaluate early growth, yield and canopy characteristics of 12 genotypes of six species of winter cereals with double purpose (forage and grains) submitted to harvest at Depressao Central region of Rio Grande do Sul state, South Region of Brazil. Species and genotypes tested were: BRS 277, BRS Guatambu, BRS Taruma and BRS Umbu wheat; Agro Zebu, UPFA 21 - Moreninha and Commom black-oat; UPF 18 white-oat; BR 1 and BRS Serrano rye; BRS Marciana barley; and BRS 148 triticale. The genotypes were distributed in 36 experimental plots, in a completely randomized design with 12 treatments, three replications and repeated measure. Studied variables were herbage mass, botanical and structural composition, forage and grains production. The earliest genotypes for forage production were BR 1 rye and BRS 148 triticale. BRS Taruma wheat presented higher forage and leaf blade production. BRS Umbu wheat presented higher grains yield and hectoliter weight. Among the genotypes evaluated, BRS Taruma wheat is the most suitable for double purpose in Depressao Central region of Rio Grande do Sul state.

129. Conservation agriculture, increased organic carbon in the top-soil macro-aggregates and reduced soil CO2 emissions

• Authors:
  • Govaerts, B.
  • Verhulst, N.
  • Dendooven, L.
  • Guerrero, A.
  • De Leon, F.
  • Etchevers, J.
  • Hidalgo, C.
  • Fuentes, M.
• Source: PLANT AND SOIL Volume: 355 Issue: 1-2 Pages:
• Volume: 355
• Issue: 1-2
• Year: 2012
• Summary: Conservation agriculture, the combination of minimal soil movement (zero or reduced tillage), crop residue retention and crop rotation, might have the potential to increase soil organic C content and reduce emissions of CO2. Three management factors were analyzed: (1) tillage (zero tillage (ZT) or conventional tillage (CT)), (2) crop rotation (wheat monoculture (W), maize monoculture (M) and maize-wheat rotation (R)), and (3) residue management (with (+r), or without (-r) crop residues). Samples were taken from the 0-5 and 5-10 cm soil layers and separated in micro-aggregates (< 0.25 mm), small macro-aggregates (0.25 to 1 mm) and large macro-aggregates (1 to 8 mm). The carbon content of each aggregate fraction was determined. Zero tillage combined with crop rotation and crop residues retention resulted in a higher proportion of macro-aggregates. In the 0-5 cm layer, plots with a crop rotation and monoculture of maize and wheat in ZT+r had the greatest proportion of large stable macro-aggregates (40%) and highest mean weighted diameter (MWD) (1.7 mm). The plots with CT had the largest proportion of micro-aggregates (27%). In the 5-10 cm layer, plots with residue retention in both CT and ZT (maize 1 mm and wheat 1.5 mm) or with monoculture of wheat in plots under ZT without residues (1.4 mm) had the greatest MWD. The 0-10 cm soil layer had a greater proportion of small macroaggregates compared to large macro-aggregates and micro-aggregates. In the 0-10 cm layer of soil with residues retention and maize or wheat, the greatest C content was found in the small and large macro-aggregates. The small macro-aggregates contributed most C to the organic C of the sample. For soil cultivated with maize, the CT treatments had significantly higher CO2 emissions than the ZT treatments. For soil cultivated with wheat, CTR-r had significantly higher CO2 emissions than all other treatments. Reduction in soil disturbance combined with residue retention increased the C retained in the small and large macro-aggregates of the top soil due to greater aggregate stability and reduced the emissions of CO2 compared with conventional tillage without residues retention and maize monoculture (a cultivation system normally used in the central highlands of Mexico).

130. Exploring the climate problems of Brazil's Nordeste: a review

• Authors:
  • Hastenrath, S.
• Source: CLIMATIC CHANGE
• Volume: 112
• Issue: 2
• Year: 2012
• Summary: This article reviews the exploration of the climate dynamics of Brazil's Nordeste in the course of a century. The drought-prone and semi-arid northern Nordeste of Brazil experiences a short rainy season around March-April, when the interhemispheric gradient of sea surface temperature (SST) in the tropical Atlantic is weakest and the Intertropical Convergence Zone (ITCZ) reaches its southernmost position in the course of the annual cycle. The recurrent Secas (droughts) have a severe socio-economic impact. During drought years, the interhemispheric SST gradient in the tropical Atlantic is steep and the ITCZ stays far North, while the waters of the eastern equatorial Pacific tend to be anomalously warm. Based on the extensive diagnostic exploration of the circulation mechanisms of interannual climate variability, empirical methods have been developed for the forecasting of the Nordeste rainy season. These have been applied in the real-time prediction of seasonal rainfall anomalies throughout the last decade of the 20th century.