• Authors:
    • Pires, L. F.
    • Nova, N. A. V.
    • Pereira, A. B.
    • Alfaro, A. T.
  • Source: Revista Brasileira de Meteorologia
  • Volume: 26
  • Issue: 2
  • Year: 2011
  • Summary: The uptake of water from the roots of crops comes to being a physiological response of the plant to the water loss process through its stomata. Getting to know the daily transpiration rates throughout the phenological cycle allows for the application of the ideal amount of irrigation water at the right moment to maximize production with environmental protection. Since transpiration direct measurements at the field, mainly for trees in general, are to be of operational difficulty and relatively high cost we came up with a methodology that allows one to calculate the daily transpiration rates of apple trees and citrus orchards from variables of both the physical environment and the crop. The input data of the proposed model are air temperature, air relative humidity, photoperiod duration, and leaf area. Estimated transpiration rates based on the water potential gradient between the air and leaf approach were comparable in apple trees and citrus orchards. Sap flow daily values were obtained by means of the heat balance method at Bordeaux, France, and Piracicaba, SP, Brazil. All the coefficients of determination of the regression equations obtained herein were higher than 0.93. This allows one to calculate the amount of irrigation water to be applied throughout the crop growing seasons with a high precision as a function of meteorological data and crop covering density at the sites in the study.
  • Authors:
    • Villar, H. L.
    • Sakai, E.
    • Bodine Junior, D.
    • Pires, R. C. de M.
    • Silva, T. J. A. da
    • Arruda, F. B.
  • Source: Engenharia Agrícola
  • Volume: 31
  • Issue: 6
  • Year: 2011
  • Summary: The aim of this study was to evaluate the effect of different microirrigation designs on root system distribution in wet bulb region, orange orchard yield and quality of orange fruits. The experiment was installed as random blocks with five treatments and four replicates in an orchard of 'Pera' orange trees grafted on 'Cleopatra' mandarin rootstock. The treatments consisted of: one drip line (T1), two drip lines (T2), four drip lines (T3) per planting row, microsprinkler irrigation (T4) and without irrigation (T5). Irrigation treatments favored yield and degreesBrix. The treatment with a single drip line (T1) showed the greatest quantity of roots in relation to the treatments T2 and T3.
  • Authors:
    • Ferrari, S.
    • Picoli, P.
    • Lazarini, E.
    • Barbosa, C.
  • Source: Cientifica (Jaboticabal)
  • Volume: 39
  • Issue: 1/2
  • Year: 2011
  • Summary: The objective of this study was to evaluate the straw effect of four cover crops [grain sorghum ( Sorghum bicolor L. Moench), sun hemp ( Crotalaria juncea L.), pearl millet ( Penisetum americanum L.), and brachiaria ( Brachiaria brizantha cv. Marandu)] sown at two different times and a fallow area and its effects on soybean cultivated in succession in a no tillage system. The study was carried out from march/08 to april/09 in the experimental farm of the College of Engineering, a unit of the Universidade Estadual Paulista (UNESP), located in Selviria, a county of the state of Mato Grosso do Sul, (51degrees22′W and 20degrees22′S, with 335 m altitude), Brazil, in an Oxisol. The treatments consisted in the sowing of the four cover crops on March 27 and April 23 of 2008 and in the use of a fallow area. The experiment was set in the field according to a randomized complete block design with eight repetitions. Forage crops (sunhemp and B. brizantha) sown in two seasons do not change the soybean yield. Soybean yield on sorghum and millet sown in March was higher than that observed for the same crops sown in April. The grasses used are shown as a viable option for the production of dry matter for soybean sown in March.
  • Authors:
    • Fiorin, J.
    • Nicoloso, R.
    • Tornquist, C.
    • Amado, T.
    • Campos, B.
  • Source: Revista Brasileira de Ciencia do Solo
  • Volume: 35
  • Issue: 3
  • Year: 2011
  • Summary: Soil C-CO 2 emissions are sensitive indicators of management system impacts on soil organic matter (SOM). The main soil C-CO 2 sources at the soil-plant interface are the decomposition of crop residues, SOM turnover, and respiration of roots and soil biota. The objectives of this study were to evaluate the impacts of tillage and cropping systems on long-term soil C-CO 2 emissions and their relationship with carbon (C) mineralization of crop residues. A long-term experiment was conducted in a Red Oxisol in Cruz Alta, RS, Brazil, with subtropical climate Cfa (Koppen classification), mean annual precipitation of 1,774 mm and mean annual temperature of 19.2degreesC. Treatments consisted of two tillage systems: (a) conventional tillage (CT) and (b) no tillage (NT) in combination with three cropping systems: (a) R0 - monoculture system (soybean/wheat), (b) R1 - winter crop rotation (soybean/wheat/soybean/black oat), and (c) R2 - intensive crop rotation (soybean/black oat/soybean/black oat+common vetch/maize/oilseed radish/wheat). The soil C-CO 2 efflux was measured every 14 days for two years (48 measurements), by trapping the CO 2 in an alkaline solution. The soil gravimetric moisture in the 0-0.05 m layer was determined concomitantly with the C-CO 2 efflux measurements. The crop residue C mineralization was evaluated with the mesh-bag method, with sampling 14, 28, 56, 84, 112, and 140 days after the beginning of the evaluation period for C measurements. Four C conservation indexes were used to assess the relation between C-CO 2 efflux and soil C stock and its compartments. The crop residue C mineralization fit an exponential model in time. For black oat, wheat and maize residues, C mineralization was higher in CT than NT, while for soybean it was similar. Soil moisture was higher in NT than CT, mainly in the second year of evaluation. There was no difference in tillage systems for annual average C-CO 2 emissions, but in some individual evaluations, differences between tillage systems were noticed for C-CO 2 evolution. Soil C-CO 2 effluxes followed a bi-modal pattern, with peaks in October/November and February/March. The highest emission was recorded in the summer and the lowest in the winter. The C-CO 2 effluxes were weakly correlated to air temperature and not correlated to soil moisture. Based on the soil C conservation indexes investigated, NT associated to intensive crop rotation was more C conserving than CT with monoculture.
  • Authors:
    • Castoldi, G.
    • Costa, L.
    • Steiner, F.
    • Costa, M.
    • Pivetta, L.
  • Source: Revista Ceres
  • Volume: 58
  • Issue: 2
  • Year: 2011
  • Summary: The use of animal manure combined with cover crops can provide sustainability to agricultural systems. Aiming to evaluate the effect of two farming systems and nutrient sources on the corn crop, an experiment was conducted on an Oxisol, in the municipality of Marechal Candido Rondon, Parana State, Brazil. The experiment was arranged in a randomized block design with treatments in a factorial scheme 2*3, consisting of two crop systems (succession wheat/corn and intercropping oat+vetch+turnip/corn) and three nutrient sources (mineral, organic and organic-mineral), with four replications. In June 2006, the wheat crop and the intercropping of cover crops were established. In October 2006, the corn was sowed on the two systems. Organic and organic-mineral fertilizations consisted of application of pig manure alone and combined with mineral fertilizer, respectively. Intercropping of oat, hairy vetch and wild radish produced adequate amount of biomass, showing its viability for providing soil cover during winter. Corn grown in rotation with wheat yielded the highest uptake of N and K and highest yield. Mineral fertilization gave higher N uptake and corn yield compared with the organic fertilizer and organic-mineral fertilizer based on pig manure.
  • Authors:
    • Perim, L.
    • Castro, G.
    • Crusciol, C.
    • Marques, R.
  • Source: REVISTA BRASILEIRA DE CIENCIA DO SOLO
  • Volume: 35
  • Issue: 2
  • Year: 2011
  • Summary: Lime and gypsum influence nutrient availability and uptake, as well as the content of organic acids in the aerial plant parts. These changes, quantified by plant analysis of soluble nutrients, may potentiate the effect of soil amendment, ensuring the sustainability of the no-tillage system. In this sense the effect of lime and gypsum surface application on the content of water-soluble nutrients in peanut and oat residues was evaluated. The experiment was conducted on an Oxisol in Botucatu (SP) in the growing seasons 2004/2005 and 2005/2006. It was arranged in a randomized block design in split plots with four replications, where lime rates represented the plots and presence or absence of gypsum application the subplots. Peanut was grown in summer and white oat in the winter in the entire experimental area. Gypsum applied to peanut increased soluble Ca only in the first season, due to the short period between product application and determination of soluble nutrient contents in the plant extract. Liming of peanut and oat increased soluble Ca, Mg, K contents, did not alter Cu content and reduced Zn, Mn and Fe contents in both years of cultivation. Gypsum on the other hand reduced the electrical conductivity of peanut (2004/2005 and 2005/2006) and white oat (2004/2005).
  • Authors:
    • Silva Junior, A.
    • Alves, M.
    • Muraishi, C.
    • Souza, Z.
  • Source: ACTA SCIENTIARUM-AGRONOMY
  • Volume: 33
  • Issue: 3
  • Year: 2011
  • Summary: This study was conducted at the Experimental Station belonging to UNESP Engineering University, Ilha Solteira Campus, based in Selviria, Mato Grosso do Sul State, Brazil, with the aim of evaluating chemical alterations in an Oxisol after being managed for two years with organic and/or chemical fertilization and different tillage systems during the agricultural years of 2004/2005 and 2005/2006. The treatments were: conventional-tillage; chisel tillage and no-tillage; the fertilization treatments were: control (no fertilization); chemical fertilization (300 kg ha -1 from the 20-00-20); organic fertilization (cattle manure - 20 Mg ha -1); organic+1/2 the recommended chemical fertilization for the used crop; 20 and 30 Mg ha -1 of sewage sludge. Soybean was used in the first year and sorghum in the next year, evaluating the soil chemical attributes in four layers. The soil chemical attributes were changed in the first year; the organic fertilization, sewage sludge and organic+chemical fertilization were efficient to change the chemical attributes; the sewage sludge was more efficient in soil P recuperation and, the no-tillage system contributed to soil K increase.
  • Authors:
    • Bergamaschine, A.
    • Ulian, N.
    • Araujo, F.
    • Andreotti, M.
    • Azenha, M.
    • Pariz, C.
  • Source: PESQUISA AGROPECUARIA BRASILEIRA
  • Volume: 46
  • Issue: 10
  • Year: 2011
  • Summary: The objective of this work was to evaluate the dry matter yield and chemical composition of forage in crop-livestock integration, according to different sowing dates. A randomized experimental block design in a 4*3 factorial scheme was used, with four forage plants (palisadegrass, Urochloa brizantha; fox millet, Setaria italica; pearl millet, Pennisetum glaucum; and sorghum, Sorghum bicolor) sowed on three dates, in two season (winter/spring and summer/autumn), in succession to soybean. The pearl millet and sorghum produced the highest amount of dry matter in all sowing dates, at both growing seasons and, contrary to palisadegrass and fox millet, it did not reduce the amount of total digestible nutrients. Crude protein levels decreased with the advancement of sowing dates in winter/spring and increased in summer/autumn, except for palisadegrass and pearl millet. Sorghum showed the lowest concentrations of neutral detergent fiber in the second and third sowing dates in winter/spring, and in the first sowing date in summer/autumn. In the second and third sowing dates in winter/spring, sorghum showed the lowest content of acid detergent fiber. In relation to the cell wall components, only the hemicellulose contents did not change in the forages due to sowing dates, at both seasons.
  • Authors:
    • Amarante, I.
    • Machado, J.
    • Fontaneli, R.
    • Santos, H.
  • Source: Pesquisa Agropecuaria Gaucha
  • Volume: 17
  • Issue: 1
  • Year: 2011
  • Summary: The effects of soil management systems and crop rotation on sorghum yield characteristics agronomic were evaluated during the period 2003/04 to 2010/11 at EmbrapaTrigo, Passo Fundo, RS, Brazil. Four soil management systems: (1) no tillage, (2) minimum tillage, conventional tillage using a disk plow and a disk harrow, and (4) conventional using a moldboard and a disk harrow; and three crop rotation system I (wheat/soybean), system II (wheat/soybean and common vetch/sorghum), and system III (wheat/soybean, white oats/soybean and common vetch/sorghum) were compared. An experimental design of blocks at random, with split-plots and three replications, was used. The main plot was formed by the soil management systems, while the split-plot constituted of the crop rotation systems. Minimum tillage and no-tillage presented higher yield of sorghum, while conventional tillage using a moldboard plow remained in intermediate position and tillage using disk plow the lowest yield of sorghum. The yield of sorghum grown after common vetch in system II was higher than yield obtained for sorghum after common vetch in system I. No significant differences were observed in sorghum characteristics agronomic as a result of soil management and crop rotation systems.
  • Authors:
    • Kawamura, O.
    • Mallmann, C.
    • Itano, E.
    • Ono, E.
    • Takabayashi, C.
    • Santos, J.
    • Hirooka, E.
  • Source: Food Additives and Contaminants Part A-Chemistry Analysis Control Exposure & Risk Assessment
  • Volume: 28
  • Issue: 8
  • Year: 2011
  • Summary: An indirect competitive enzyme-linked immunosorbent assay (ELISA) method using a monoclonal antibody for deoxynivalenol (DON) detection in wheat and flour was standardised and validated (detection limit - 177.1 g kg -1) and its performance was compared with LC-MS, (quantification limit=140 g kg -1). DON recovery ranged from 88.7% to 122.6% for wheat grain and from 70.6% to 139.3% for flour. Among the 38 wheat samples evaluated, DON was detected in 29 samples (76.3%) by ic-ELISA (281.6-12 291.4 g kg -1) and in 22 samples (57.9%) by LC-MS (155.3-9906.9 g kg -1). The 0.93 correlation coefficient between ic-ELISA and LC-MS data in 19 positive DON wheat samples demonstrated the reliability and efficiency of ic-ELISA. Results indicated that standardised ic-ELISA was suitable for DON screening in wheat samples and the need for continuous monitoring of mycotoxin levels in foodstuffs.