• Authors:
    • Kremer, R. J.
    • Kussman, R.
  • Source: Agroforestry comes of age: putting science into practice. Proceedings of the 11th North American Agroforestry Conference, Columbia, Missouri, USA, 31 May - 3 June, 2009
  • Year: 2009
  • Summary: Intercropping alleys of agroforestry systems provides an income source until the tree crop produces harvestable yields. However, cultivation of annual crops soil organic matter and increases soil erosion, especially on sloping landscapes. Perennial crops maintain a continuous soil cover, maximize water infiltration, minimize soil erosion, and improve overall soil quality. The objective of this on-farm study was to assess the effects of a perennial legume, kura clover ( Trifolium ambiguum), on various soil quality parameters in a recently established pecan ( Carya illinoinensis) orchard. The pecan-kura clover agroforestry system was established on deep loess soils of the Missouri River hills. These silt loams are on 3 to 10% slopes and can be highly erosive. Kura clover, intercropped eight years after pecan planting, was selected based on its perennial growth habit, nitrogen-fixing ability, winter hardiness, high forage quality, and soil conservation properties. Kura clover was seeded in 2002 and harvested for hay annually beginning 2003. During this period soil organic matter and activities of selected soil enzymes have steadily increased compared with cultivated and grass pasture control soils. Water-stable aggregation improved by 50%. Results illustrate that kura clover as the interplanted component improved soil fertility and biological activity through increased organic matter and improved soil structure, and yielded high quality forage valuable for the cattle-feeding operation. Pecan trees thrive in this system partly because soil quality is maintained or improved and, unlike other "living mulch" systems in which cover crops may suppress the main crop, kura clover does not compete with tree growth.
  • Authors:
    • Bernards, M. L.
    • Wilson, R. G.
    • Jordan, D. L.
    • Wilcut, J. W.
    • Shaw, D. R.
    • Owen, M. D. K.
    • Weller, S. C.
    • Johnson, W. G.
    • Kruger, G. R.
    • Young, B. G.
  • Source: Weed Technology
  • Volume: 23
  • Issue: 1
  • Year: 2009
  • Summary: Corn and soybean growers in Illinois, Indiana, Iowa, Mississippi, Nebraska, and North Carolina, as well as cotton growers in Mississippi and North Carolina, were surveyed about their views on changes in problematic weeds and weed pressure in cropping systems based on a glyphosate-resistant (GR) crop. No growers using a GR cropping system for more than 5 yr reported heavy weed pressure. Over all cropping systems investigated (continuous GR soybean, continuous GR cotton, GR corn/GR soybean, GR soybean/non-GR crop, and GR corn/non-GR crop), 0 to 7% of survey respondents reported greater weed pressure after implementing rotations using GR crops, whereas 31 to 57% felt weed pressure was similar and 36 to 70% indicated that weed pressure was less. Pigweed, morningglory, johnsongrass, ragweed, foxtail, and velvetleaf were mentioned as their most problematic weeds, depending on the state and cropping system. Systems using GR crops improved weed management compared with the technologies used before the adoption of GR crops. However, the long-term success of managing problematic weeds in GR cropping systems will require the development of multifaceted integrated weed management programs that include glyphosate as well as other weed management tactics.
  • Authors:
    • Rizzo, I.
    • Sarandón, S. J.
    • Sisterna, M. N.
    • Lori, G. A.
    • Chidichimo, H.
  • Source: Crop Protection
  • Volume: 28
  • Issue: 6
  • Year: 2009
  • Summary: Fusarium head blight (FHB) is a destructive disease of the world's wheat-growing areas. In Argentina, the area under reduced tillage has increased due to soil erosion that threatened productivity. The effect of conventional and no tillage systems on FHB combined with other agronomic practices such as nitrogen fertilization, and the influence of the environmental conditions was analysed under natural infection on different cultivars. Wheat trials were conducted in three consecutive years; maize was the previous crop in the first and wheat the previous crop in the subsequent two years of the study. The experimental design was a split plot, with tillage treatments (conventional tillage and no-till) as the main plots. Fertilizer treatments were applied as a range of urea concentrations. Fusarium head blight was observed in all three experimental years. Differences of disease expression among trials were associated with the environmental factors prevailing during the experiments. In the first year, with moderate weather conditions, the only interactions for FHB incidence were between no-till and urea split doses. Seedling emergence, seed health, thousand kernel weight and deoxynivalenol (DON) concentration did not differ suggesting that the fertilizers and genotypes did not affect disease susceptibility. Climatic conditions prevailing in the second year were more conducive to disease development and severe FHB infection was observed. Tillage and fertilization treatments did not affect the variables analysed. Only cultivars showed significant differences and DON values were high. In the third year, unfavourable conditions for disease development resulted in low disease levels and no effect or interaction among variables was observed. The results obtained would suggest that favourable weather conditions are likely to be more important than tillage practice and fertilizer treatments. Since soil conservation practices have been widely adopted in most areas of Argentina, an integrated used of all the available strategies should be considered to decrease FHB damage.
  • Authors:
    • Fernandes, C.
    • Cora, J. E.
    • Marcelo, A. V.
    • Martins, M. dos R.
    • Jorge, R. F.
  • Source: Revista Brasileira de Ciência do Solo
  • Volume: 33
  • Issue: 2
  • Year: 2009
  • Summary: Decomposing crop residues in no-tillage system can alter soil chemical properties, which may consequently influence the productivity of succession crops. The objective of this study was to evaluate soil chemical properties and soyabean, maize and rice yield, grown in the summer, after winter crops in a no-tillage system. The experiment was carried out in Jaboticabal, Sao Paulo, Brazil on a Red Latosol (Oxisol), in a completely randomized block design, in strip plots with three replications. The treatments consisted of four summer crop sequences (maize monocrop, soyabean monocrop, soyabean/maize rotation and rice/bean/cotton rotation) combined with seven winter crops (maize, sunflower, oilseed radish, pearl millet, pigeon pea, grain sorghum and sunn hemp). The experiment began in September 2002. After the winter crops in the 2005/2006 growing season and before the sowing of summer crops in the 2006/2007 season, soil samples were collected in the layers 0-2.5; 2.5-5.0; 5-10; 10-20; and 20-30 cm. Organic matter, pH, P, K +, Ca 2+, Mg 2+, and H+Al were determined in each soil sample. In the summer soyabean/maize rotation and in maize the organic matter contents and P levels were lower, in the layers 0-10 cm and 0-20 cm, respectively. Summer rice/bean/cotton rotation increased soil K levels at 0-10 cm depth when sunn hemp and oilseed radish had previously been grown in the winter, and in the 0-2.5 cm layer for millet. Sunn hemp, millet, oilseed radish and sorghum grown in the winter increased organic matter contents in the soil down to 30 cm. Higher P levels were found at the depths 0-2.5 cm and 0-5 cm, respectively, when sunn hemp and oilseed radish were grown in the winter. Highest grain yields for soyabean in monoculture were obtained in succession to winter oilseed radish and sunn hemp and in rotation with maize, after oilseed radish, sunn hemp and millet. Maize yields were highest in succession to winter oilseed radish, millet and pigeon pea. Rice yields were lowest when grown after sorghum.
  • Authors:
    • Jorge, R. F.
    • Cora, J. E.
    • Martins, M. dos R.
    • Marcelo, A. V.
  • Source: Soil & Tillage Research
  • Volume: 104
  • Issue: 1
  • Year: 2009
  • Summary: The adaptation of no-tillage system in tropical regions depends on the suitable choice of summer and winter crops which should contribute to improvement of soil properties. The aim of the present study was to determine the effect of crop sequences on soil aggregation and contents of organic C and polysaccharides in aggregates of a Rhodic Eutrudox under no-tillage. The treatments consisted of the combination of four summer crop sequences and seven winter crop sequences. The summer crop sequences were: maize monocrop ( Zea mays L.) (MM); soybean monocrop ( Glycine max (L.) Merrill) (SS); crop sequence of soybean/maize/soybean/maize (SM); crop sequence of rice ( Oryza sativa L.)/bean ( Phaseolus vulgaris L.)/cotton ( Gossypium hirsutum L.)/bean (RB). The winter crops were: maize, sunflower ( Helianthus annuus L.), radish ( Raphanus sativus L.), pearl millet ( Pennisetum americanum (L.) Leeke), pigeon pea ( Cajanus cajan (L.) Millsp), grain sorghum ( Sorghum bicolor (L.) Moench) and sunn hemp ( Crotalaria juncea L.). The highest total organic C, total polysaccharides and dilute acid-extracted polysaccharides contents were found in 2.00-1.00 mm water-stable aggregates and the lowest contents were found in
  • Authors:
    • Ray, J.
    • Smith, R.
    • Castlebury, L.
    • Mengistu, A.
    • Bellaloui, N.
  • Source: Plant Disease
  • Volume: 93
  • Issue: 10
  • Year: 2009
  • Summary: Phomopsis longicolla is a major seed pathogen of soybean ( Glycine max) in hot, humid environments. The objective of this study was to monitor the infection and development of P. longicolla on vegetative and reproductive tissues of six cultivars and to determine the relationship between this infection and subsequent seed infection and seed germination. Cultivars were grown for 3 years (2002 to 2004) without irrigation or with irrigation applied at pre- plus postflowering or at postflowering growth stages. P. longicolla was isolated most frequently from leaf, stem, pod, root, and seed. Diaporthe phaseolorum and three unidentified Phomopsis sp. were also isolated. Diaporthe aspalathi, which previously has not been reported on soybean, was also recovered from leaf samples. These isolates, however, were recovered very infrequently. Recovery of P. longicolla from roots was much lower than from leaves, stems, and pods in all years and irrigation environments. The recovery of P. longicolla from seed was affected by irrigation environments. Seed from irrigated plots had more P. longicolla than that from nonirrigated plots. Isolation of P. longicolla from seed was negatively correlated with percentage of seed germination in irrigated environments but not in the nonirrigated environment. Pod infection was correlated with seed infection in all three irrigation environments. Even though infection of leaves and stems increased with increasing moisture availability, such infection did not consistently correlate with seed infection. Seed germination and seed infection were negatively correlated with percent hard seed. This study provided the first demonstration of the seasonal progression of P. longicolla on soybean cultivars grown under three irrigation environments.
  • Authors:
    • Monteiro, J. E. B. A.
  • Source: Agrometeorologia dos cultivos: o fator meteorológico na produção agrícola
  • Year: 2009
  • Summary: This book brings together a broad base of information on 32 major Brazilian agricultural crops and their relations with climate. The focus of the book is not on the methodologies and applications of agrometeorology per se, but rather restricts its focus to crops and traits that determine yield as a function of the environment. The crops included are rice, castor oil, sunflowers, pineapples, soyabeans, triticale, maize, potatoes, barley, peanuts, oats, onions, canola, wheat, cotton, beans, sugarcane, Pinus, black wattle ( Acacia mearnsii), tropical and temperate grapes, coconuts, citrus, bananas, sisal, cocoa, coffee, apples, Jatropha, Eucalyptus and the fodder plants Cynodon, Brachiaria and Panicum. The contents of the book are divided into three main parts, I. Introduction, II. Temporary crops and III. Permanent crops, with each chapter within parts II and III dedicated to a particular crop, and covering: (1) the main features of farming and phenology; (2) agrometeorological productivity constraints - water availability, temperature, solar radiation, photoperiod and wind; and (3) adverse events - hail and rainstorms, droughts and dry spells, winds and gales, frost, and too much rain and over-prolonged drought. The book was organized by the National Institute of Meteorology and had the collaboration of 105 researchers from 37 Brazilian institutions (federal and state), research centres, institutes and universities.
  • Authors:
    • Ferreira, R. S.
    • Moraes, J. C.
    • Costa, R. R.
  • Source: Ciência e Agrotecnologia
  • Volume: 33
  • Issue: 5
  • Year: 2009
  • Summary: Studies were conducted to evaluate the effect of the application of inducers on the resistance of 2 soyabean cultivars to the whitefly Bemisia tabaci Biotype B. The seeds of the soyabean cultivars IAC-19 and MONSOY-8001 were previously treated with captan. The following treatments were tested: irrigating the soil around the plants of each pot with 250 ml solution of 1.0% silicic acid (T1); spraying of the plants, to the 'point of dripping', with a solution of 0.3% acibenzolar-S-methyl (T2); spraying of the plants, to the 'point of dripping', with a solution of 0.24% pyraclostrobin+epoxiconazole (T3); and control (T4). The plants were infested with 100 adult whiteflies that were released 8 days after applying the treatments. The number of ova on the abaxial face of each leaf, which was marked for further evaluation of nymphs, tannin and lignin contents and dry weight of the aerial parts and roots. There was no difference for the number of ova and nymphs among the soyabean cultivars. Nevertheless, the average survival rate of B. tabaci was lower on cultivar IAC-19. The application of silicon or acibenzolar-s-methyl induced an increase in lignin content in the soyabean cultivar IAC-19.
  • Authors:
    • Haller, W. T.
    • Mudge, C. R.
  • Source: Weed Technology
  • Volume: 23
  • Issue: 1
  • Year: 2009
  • Summary: The effects of flumioxazin in irrigation water were evaluated on four row crop species (corn, cotton, soybean, and wheat) and three ornamental species (begonia, impatiens, and snapdragon). Plants were overhead irrigated one time with flumioxazin at concentrations of 0, 10, 25, 50, 100, 200, 400, 800, 1,600, and 3,200 g ai/L in water equivalent to 1.27 cm. Ornamental plant tolerances on the basis of a 10% reduction in dry weight (effective concentration 10 [EC 10]) were as follows: impatiens (40)
  • Authors:
    • Silva, S. A. da
    • Bastos, E. C.
    • Fadul, M. J. do A.
    • Prado, R. B.
    • Fidalgo, E. C. C.
    • Pedreira, B. da C. C. G.
    • Zainer, N. G.
    • Peluzo, J.
    • do A. Fadul, M. J.
    • da Silva, S. A.
  • Source: Boletim de Pesquisa e Desenvolvimento - Embrapa Solos
  • Issue: 136
  • Year: 2009
  • Summary: The basins of rivers Guapi-Macacu Caceribu are located east of the basin of the Bay of Guanabara, in Rio de Janeiro and their watercourses supply water to more than two million people. Their water resources are considered of good quality, but factors such as the removal of riparian vegetation, inappropriate use of land, rectification and siltation of rivers, erosion, urban sprawl, lack of treatment of sewage and the establishment of industries, including the Rio de Janeiro's Complex Petrochemical Rio de Janeiro (COMPERJ) modify the water quality and the storage capacity of these basins. The occurrence of continuous spatial and temporal changes of use and land cover in catchment areas of rivers Guapi-Macacu Caceribu and without the support of adequate funding has caused changes in the structure of the landscape of the region and may bring undesirable consequences for the environment as for the activities of man. Thus, it is necessary to gather information and meet this dynamic process of use and coverage to support the planning of actions in the short, medium and long term, to adequate land use and improving environmental quality in river basins question. Thus, this study aimed to map the spatial-temporal use and land cover in a period previous to the installation of COMPERJ, for the years 1997 and 2007 to record the current scenario and create a starting point for monitoring region's future post-deployment of this enterprise. Mappings were performed for space-time (1997-2007) of use and land coverage using images from Landsat satellite, aerial photographs, survey of secondary data and field work. In addition, this study also aimed to analyze the effect of atmospheric correction on the multitemporal images of the region, using the method of subtraction of the gray levels in the environment ENVI 4.5. The results indicated that this method was not effective in reducing the atmospheric effects of images, and have continued to have a significant influence on the spectral response of the targets. The analysis of the dynamics of land use, the results showed that in 10 years, in terms of absolute values, changes in land cover were occasional and not very responsive. However, individually, changes occurred in some classes of use, among which can be highlighted, for example: The class vegetation in the intermediate stage of regeneration has only reduction in area (12.5 ha), which turned into pasture. Distributed throughout the study region were observed areas of suppression of vegetation in initial stage of regeneration, and noticed an increase in concentration saw Soarinho. These areas began to be occupied by pasture (275 ha), exposed soil (3 ha), water (4.8 ha) and urbanized area of low density (22.7 ha). On the other hand, there was also an increase of vegetation in initial stage of regeneration observed in the vicinity of the Mountain area, north of Macacu and southern Caceribu that was once pasture and agriculture. Was also a small increase in area of mangrove class (127.48 ha) of the APA Guapimirim. The agriculture class, the observed changes relate mainly to the areas of temporary crops. The standing crops due to its sparse distribution on the ground and are made up of small plots and/or located in the shaded, could not be identified clearly in the images. There was so much increased (701.71 ha) and reduction in class agriculture. The areas that have changed their grazing area to agricultural area totaled 891.4 ha and the reverse conversion totaled 178.4 ha. The pasture was a class that suffered the greatest reduction in area (1934.01 ha). However, it should be noted that some areas suffer seasonal changes between the pasture and agriculture, thus changing the use observed in the use class grazing were probably due to soil management and the seasonal farming activities. Moreover, in 2007 it was observed that one of the areas of pasture in 1997 became exposed soil, which is related to increased mining activities in the city of Niteroi, and partly turned into lots for development. The class exposed soil showed a significant increase in area, but that does not qualify on the change of land use, because this class were inserted the areas prepared for farming or grazing reform, which eventually may present as exposed soil. Classes urbanized area and urbanized area of low density experienced expansion in the period between 1997 and 2007, there was intensification of settlements and new areas were added from the conversion of areas previously occupied by pasture and vegetation at an early stage of regeneration. There was an increase in this period of new urban lots, predominantly in the river basin Caceribu, where there is an increasing trend of urbanization due to the installation of the Petrochemical Complex of Rio de Janeiro.Together these classes showed an increase of 504.69 ha, predominantly observed along the roads. The processes of urbanization are occurring mainly in the municipalities of Itaborai and Sao Goncalo. The class water showed an increase in area of 104.11 ha. The greatest change observed with regard to dam the beverage industry Schincariol in Waterfalls Macacu built to retain water. Part of the new areas of water are in areas occupied by mining, especially near the rivers Caceribu. It also observed an increase of small lakes in rural areas have been trained in fish farming and/or leisure activities. With respect to classes of use and coverage included in protected areas, the results indicated that there was more regeneration than removal of natural vegetation between 1997 and 2007. The best-preserved natural vegetation found in areas protected by conservation areas which inhibit the clearing of the remaining areas of Atlantic and help to maintain the quality and quantity of water in river, but does not prevent that they are progressively degraded, a factor that can be accentuated with the installation of COMPERJ.