• Authors:
    • Ben-Hammouda, M.
    • Errouissi, F.
    • Moussa-Machraoui, S. B.
    • Nouira, S.
  • Source: Soil & Tillage Research
  • Volume: 106
  • Issue: 2
  • Year: 2010
  • Summary: No-tillage (NT) is becoming increasingly attractive to farmers worldwide because it clearly reduces production costs relative to conventional tillage (CT) and improves soil properties and crop yield. Currently, under semi-arid conditions in North Africa, modern no-tillage techniques are being practiced on several hectares of land. The effect of NT and CT management and crop rotation on soil properties under semi-arid Mediterranean conditions was studied, over a 4-year period at two locations in northern Tunisia. Data from a short-term (2000-2004) use of both no-tillage (NT) and conventional tillage (CT) at the ESAK (Tunisia) were used to evaluate the influence of the tillage systems on the physicochemical properties of soil at the 0-20 cm depth layers. Trial was set up in 2000, where the two tillage systems (CT and NT), and four crop types (durum wheat, barley, pea and oats) were implemented in two distinct sites close to two governorates: Kef (silt/clayey) and Siliana (sand/clay) in northwestern Tunisia. Four years after implementing the two different tillage systems, soil parameters (N, NO(3)(2-), NH(4)(+) P, P(2)O(5), K, K(2)O, SOC, SOM and CEC) were determined and comparison between the two tillage systems was made. Our results showed that after 4 years the contents of some parameters for most crop types were greater under NT than under CT at 0-20 cm depth layers, the results varied depending on crop type and site. NT significantly improved soil content especially for K, K(2)O, P(2)O(5) and N. Under NT system SOM and SOC were enhanced, but without significant results. These enhancements were accompanied by the enhancement of the CEC and the decrease of the C/N ratio. Thus the mineralization process was slightly quicker under NT. Our results also indicate that residue cover combined with no-tillage appears to improve some agronomic parameters and biomass production (grain yield). Multivariate analyses indicate that the improvement of soil properties was dependant on tillage management, sites (climate and soil type) and crop succession (species and cover residue). It must be pointed Out that a 4-year period was not sufficient to clearly establish some parameters used in the effects of the NT system on soil properties under semi-arid conditions in northwestern Tunisia. (C) 2009 Elsevier B.V. All rights reserved.
  • Authors:
    • Brennan, J. P.
    • Murray, G. M.
  • Source: Australasian Plant Pathology
  • Volume: 39
  • Issue: 1
  • Year: 2010
  • Summary: The incidence, severity and yield loss caused by 40 pathogens associated with 41 diseases of barley were assessed from a survey of 15 barley pathologists covering the winter cereal growing areas of Australia. The survey provided data on the frequency of years that each pathogen developed to its maximum extent, the proportion of the crop then affected in each growing area, and the yield loss that resulted in the affected crops with and without current control measures. These data were combined with crop production and grain quality data to estimate the value of the losses aggregated to the Northern, Southern and Western production regions. Pathogens were estimated to cause a current average loss of $252 x 10(6)/year or 19.6% of the average annual value of the barley crop in the decade 1998-99 to 2007-08. Nationally, the three most important pathogens are Pyrenophora teres f. maculata, Blumeria graminis f. sp. hordei and Heterodera avenae with current average annual losses of $43 x 10(6), $39 x 10(6) and $26 x 10(6), respectively. If current controls were not used, losses would be far higher with potential average annual losses from the three most important pathogens, P. teres f. maculata, H. avenae and P. teres f. teres, being $192 x 10(6), $153 x 10(6) and $117 x 10(6), respectively. The average value of control practices exceeded $50 x 10(6)/year for nine pathogens. Cultural methods (rotation, field preparation) were the only controls used for 14 pathogens and contributed more than 50% of the control for a further 13 pathogens. Breeding and the use of resistant cultivars contributed more than 50% of control for five pathogens and pesticides for four pathogens. The relative importance of pathogens varied between regions and zones.
  • Authors:
    • Riravololona, M.
    • Pardo, G.
    • Munier-Jolain, N. M.
  • Source: European Journal of Agronomy
  • Volume: 33
  • Issue: 1
  • Year: 2010
  • Summary: This study extends into the economic domain the analysis of a trial comparing cropping system prototypes based on the principles of Integrated Weed Management (IWM), which demonstrated their potential for managing weed infestations. A farm simulation model was used to analyse the consequences of implementing such IWM-based cropping systems at the farm scale. The labour requirement for field operations and their distribution over the year were compared to the amount of time when field conditions were suitable for the corresponding equipments. In the simulated IWM-based virtual farms, repeated shallow soil cultivations for promoting pre-sowing weed emergence and mechanical weeding could both be accommodated during suitable periods, but the rule of late cereal sowings for escaping periods of peak weed emergence generated possible labour bottlenecks. Machinery costs were calculated from the farm simulations so that the economic profitability of the virtual farms could be compared. In the economic context of 2006, the saving of input costs did not offset low yields of spring crops introduced in the crop sequence for diversifying sowing dates as required by IWM principles. The method of farm simulations could be used with other data sets from cropping system experiments to provide the required knowledge for supporting future policy development in Europe. (C) 2010 Elsevier B.V. All rights reserved.
  • Authors:
    • Saulas, P.
    • Ghiloufi, M.
    • Picard, D.
    • de Tourdonnet, S.
  • Source: Field Crops Research
  • Volume: 115
  • Issue: 1
  • Year: 2010
  • Summary: The sustainability of cropping systems can be increased by introducing a cover crop, provided that the cover crop does not reduce the cash crop yield through competition. The cover crop may be sown at the same time as a cash crop in the crop rotation. We carried out an experiment in 1999-2000 and 2000-2001 in the Paris Basin, to analyze the effects of simultaneously sowing winter wheat (Triticum aestivum L.) and red fescue (Festuca rubra L.), a turf grass. Competition between wheat and fescue was analyzed with one variety of red fescue, Sunset, and two varieties of wheat, Isengrain and Scipion, each sown at a density of 150 plants m(-2). In this study, we evaluated the effect of undersown fescue on wheat yield and analyzed the competition between the two species in detail. The undersown red fescue decreased wheat yield by about 12% for Isengrain (8.7 t ha(-1) for undersown Isengrain versus 9.8 t ha(-1) for Isengrain alone) and 7% for Scipion (7.4 t ha(-1) for undersown Scipion versus 8.0 t ha(-1) for Scipion alone). During the early stages of wheat growth (up to the '1 cm ear' stage, corresponding to stage 30 on Zadoks' scale), undersown fescue and fescue sown alone grew similarly. However, fescue biomass levels were much lower (5.6 and 4.7 g m(-2) for fescue grown alone and undersown fescue) than wheat biomass levels on the undersown plots (1120 g m(-2) for Isengrain and 111 g m(-2) for Scipion). From the e1 stage onwards, the wheat canopy rapidly extended, whereas that of red fescue remained sparse. The time lag between the beginning of the rapid increase in LAI and PAR interception by wheat grown alone and that for fescue grown alone was 590 dd in the second year. This resulted in much slower growth rates for undersown fescue than for undersown wheat. Biomass production rate was therefore low for undersown fescue (12% those of fescue grown alone, on average, at the time of wheat harvest), as were levels of water and nitrogen use. Neither the water deficit that occurred during the second experiment nor the nitrogen nutrition status of the wheat on plots with undersown fescue significantly affected wheat biomass production after anthesis. The global interception efficiency index IG epsilon(i) indicated that the fraction of the PAR(o) intercepted by the wheat during its growth (255 days) was 0.35. (C) 2009 Elsevier B.V. All rights reserved.
  • Authors:
    • Portz, G.
    • Chagas, J. P.
    • Bagatini, T.
    • Cogo, Neroli P.
    • Portela, J. C.
  • Source: Revista Brasileira de Ciência do Solo
  • Volume: 34
  • Issue: 4
  • Year: 2010
  • Summary: Soil structure plays a prominent role in plant growth and erosion control, and consequently in food production and soil and water conservation. This research was developed with the objective of implementing and accompanying the restoration process of the structure of a degraded soil, by planting crop sequences under no-tillage (autumn-winter and spring-summer, grass and legume, in single and intercropped systems), and later verifying the relations with water and soil losses caused by rainfall erosion, under distinct surface physical conditions (untitled soil, with and without crust; freshly-tilled soil by chiseling and by chiseling followed by disking after one month, and crop residue covering 100, 18, and 0 %). The field study was developed under simulated rainfall, at the Agriculture Experimental Station of the Federal University of Rio Grande do Sul (EEA/UFRGS), in Rio Grande do Sul State, Brazil, from May 2004 to Decembe, 2007. The six erosion tests, in intervals of about a week, were performed from October to December, 2007. The soil used is an Ultisol, with a sandy clay loam texture in the surface layer and 0.115 in m(-1) average slope steepness, and an advanced degree of degradation. The rains were applied with a rotating-boom rainfall simulator, at a constant intensity of 64 mm h(-1), for 1-3 h. For this study, water and soil loss data were adjusted to a rainfall duration of 1.5 h. Properties of soil and plants were measured in the experimental plots and water erosion in the surface runoff The crop sequences and erosion tests influenced the results of the study significantly, with greater differences in the latter than in the former. The erosive process was more influenced by the external or soil surface than the internal or subsurface physical conditions. In general, all crop sequences were effective in restoring the soil structure in the experimental period. The sequence involving teosinte controlled the rainfall erosion process most effectively with regard to soil and water loss and the one involving corn+cowpea and pearl millet with regard to soil loss. The highest soil and water losses in the study were observed from the soil surface with no mobilization and little crop residue cover, regardless of the presence or type of crust, but especially when this latter was slightly cracked prior to rainfall application. The soil surface entirely covered by crop residue, be it untilled or freshly chiseled, controlled runoff effectively and impeded erosion completely. Soil and water losses from the freshly-disked soil surface chiseled a month earlier, although the soil was the most mobilized of all and bare, were practically zero, opposite to what was expected.
  • Authors:
    • Arriaga, F. J.
    • Rogers, H. H.
    • Runion, G. B.
    • Prior, S. A.
  • Source: Journal of Environmental Quality
  • Volume: 39
  • Issue: 2
  • Year: 2010
  • Summary: Increasing atmospheric CO(2) concentration has led to concerns about potential effects on production agriculture. In the fall of 1997, a study was initiated to compare the response of two crop management systems (conventional tillage and no-tillage) to elevated CO(2). The study used a split-plot design replicated three times with two management systems as main plots and two atmospheric CO(2) levels (ambient and twice ambient) as split plots using open-top chambers on a Decatur silt learn soil (clayey, kaolinitic, thermic Rhodic Paleudults). The conventional system was a grain sorghum [Sorghum bicolor (L.) Moench.] and soybean (Glycine max (L.) Merr.] rotation with winter fallow and spring tillage practices. In the no-tillage system, sorghum and soybean were rotated, and three cover crops were used [crimson clover (Trifolium incarnatum L.), sunn hemp (Crotalaria juncea L.), and wheat (Triticum aestivum L.)]. Over multiple growing seasons, the effect of management and CO(2) concentration on leaf-level gas exchange during row crop (soybean in 1999, 2001, and 2003; sorghum in 2000, 2002, and 2004) reproductive growth were evaluated. Treatment effects were fairly consistent across years. In general, higher photosynthetic races were observed under CO(2) enrichment (more so with soybean) regardless of residue management practice. Elevated CO(2) led to decreases in stomatal conductance and transpiration, which resulted in increased water use efficiency. The effects of management system on gas exchange measurements were infrequently significant, as were interactions of CO(2) and management. These results Suggest that better soil moisture conservation and high rates of photosynthesis can occur in both tillage systems in CO(2)-enriched environments during reproductive growth.
  • Authors:
    • Razafimpamoa, L. H.
    • Randrianaivoarivony, J. M.
    • Rahetlah, V. B.
    • Ramalanjaona, V. L.
  • Source: African Journal of Food, Agriculture, Nutrition and Development
  • Volume: 10
  • Issue: 10
  • Year: 2010
  • Summary: Forage availability and quality during the dry and cool season is a major constraint to dairy development in the Highlands of Madagascar. The objective of the present study was to determine optimal seeding of oat and common vetch mixtures for increased production and quality of forage. The study was conducted under irrigated conditions in two agro-ecological zones of the Vakinankaratra region in the Highlands of Madagascar. Seed proportions studied were oat-vetch 100:0; 0:100; 50:50 and 50:75. Pure stands of oat and vetch were seeded at the rate of 100 and 60 kg ha -1, respectively. Standard fertilization for forage oat production was uniformly applied on each plot. Pure stands and mixtures were given two successive cuts at flag leaf stage of oat. For both sites and their average, dry matter (DM), feed unit for lactation (UFL), crude protein (CP), and protein digested in the small intestine (PDI) yields were not significantly (p>0.05) different among mixtures and pure stands. The highest yields were obtained from the 50:50 mixture at the first site and from the 50:75 mixture at the second site. According to the two sites' results' average, the highest DM (7.71 t ha -1), UFL (6.08*103 units ha -1), CP (1.64 t ha -1) and PDI (597.1 kg ha -1) yields were obtained from 50:50 mixture. There were no significant differences (p>0.05) in forage quality characteristics except for CP and protein digested in the small intestine when rumen-fermentable nitrogen is limiting (PDIN). Mean CP concentration varied from 15.20% for pure stand of oat to 27.01% for pure stand of vetch. The highest value (178.8 g/kg DM) and the lowest value (103.5 g/kg DM) in PDIN content were obtained from pure stand of oat and pure stand of vetch, respectively. Mixtures had 4.6 to 6.3% more CP content and 15.6 to 39.1% more PDIN content than pure stand of oat. Combined land equivalent ratio values exceeded unity in both mixtures which showed an advantage of intercropping over sole system in terms of the use of environmental resources. As intercropping of oat with vetch at 50:50 (50:30 kg ha -1) mixture achieved maximum yield advantage and forage quality, it could be used as alternative practice of oat sole cropping for high forage and protein production in the Vakinankaratra region.
  • Authors:
    • Nepomuceno, A. L.
    • Oliveira, G. M. de
    • Neumaier, N.
    • Rakocevic, M.
    • Farias, J. R. B.
  • Source: Pesquisa Agropecuária Brasileira
  • Volume: 45
  • Issue: 7
  • Year: 2010
  • Summary: The objectives of this work were to determine the heliotropic movements of the upper trifoliates for two soybean cultivars, BR 16 and Embrapa 48, during a daily cycle, in three phenological stages and two water regimes, and to estimate the impact of irrigation and daily leaflet movements on agronomic characteristics and grain yield. Heliotropic movements were studied in three phenological stages: V4-V6, V7-V10, and R5 in irrigated and non-irrigated plots. For each stage, the leaflet elevation and azimuth were measured hourly. Under a low (V4-V6 stage) and mid (V7-V10 stage) leaf area index (LAI) the diaheliotropism was slightly more frequent and intensive in non-irrigated than in irrigated plants, only at early morning and late afternoon hours. At R5 stage (high LAI) the paraheliotropism of superior trifoliates was predominant and more intensive in non-irrigated plants. The heliotropic movements are correlated to carbon gain, but not to environment (light intensity or temperature), for measurements at 11 h. 'Embrapa 48' expresses greater paraheliotropism than 'BR 16' at high LAI, while 'BR 16' displays lower heliotropic plasticity under irrigation. In spite of significant heliotropic differences, genotype and water availability treatments did not influence the final grain yield.
  • Authors:
    • Srivastva, A. K.
    • Mina, B. L.
    • Kundu, S.
    • Bhattacharyya, R.
    • Chandra, S.
    • Pandey, S. C.
    • Gupta, S.
    • Saha, S.
  • Source: Nutrient Cycling in Agroecosystems
  • Volume: 86
  • Issue: 2
  • Year: 2010
  • Summary: To date, the sustainability of wheat ( Triticum aestivum)-soybean ( Glycine max) cropping systems has not been well assessed, especially under Indian Himalayas. Research was conducted in 1995-1996 to 2004 at Hawalbagh, India to study the effects of fertilization on yield sustainability of irrigated wheat-soybean system and on selected soil properties. The mean wheat yield under NPK+FYM (farmyard manure) treated plots was ~27% higher than NPK (2.4 Mg ha -1). The residual effect of NPK+FYM caused ~14% increase in soybean yield over NPK (2.18 Mg ha -1). Sustainable yield index values of wheat and the wheat-soybean system were greater with annual fertilizer N or NPK plots 10 Mg ha -1 FYM than NPK alone. However, benefit:cost ratio of fertilization, agronomic efficiency and partial factor productivity of applied nutrients were higher with NPK+FYM than NPK, if FYM nutrients were not considered. Soils under NPK+FYM contained higher soil organic C (SOC), total soil N, total P and Olsen-P by ~10, 42, 52 and 71%, respectively, in the 0-30 cm soil layers, compared with NPK. Non-exchangeable K decreased with time under all treatments except NPK. Total SOC in the 0-30 cm soil layer increased in all fertilized plots. Application of NPK+FYM also improved selected soil physical properties over NPK. The NPK+FYM application had better soil productivity than NPK but was not as economical as NPK if farmers had to purchase manure.
  • Authors:
    • Dalal, R. C.
    • Blamey, F. P. C.
    • Rao, A. S.
    • Rao, D. L. N.
    • Mohanty, M.
    • Reddy, K. S.
    • Dixit, S. K.
    • Pandey, M.
    • Menzies, N. W.
  • Source: Proceedings of the 19th World Congress of Soil Science, Soil Solutions for a Changing World, 1–6 August 2010, Brisbane, Australia
  • Year: 2010
  • Summary: The Mother Baby Trial (MBT) approach is an on-farm participatory mechanism to introduce and test technology options suited to a heterogeneous community. In this study, the MBT concept was followed with integrated nutrient management (INM) technology in a soybean-wheat system. Seven treatments were tested in Mother trials in 2005-06 and 2006-07 on farmers' fields in the Rajgarh and Bhopal districts of Central India. In 2007-08, 100 Baby trials were conducted by farmers in 10 surrounding villages to demonstrate and test the INM technology. The Baby trials were based on the results of Mother trials which showed that INM using 50% of the recommended NPKS fertilizer+5 t FYM/ha+ Rhizobium to soybean and 75% of the recommended NPKS fertilizer+P-solubilizing bacteria to wheat produced higher soybean yield by 46% and higher wheat yield by 24% over the farmers' practice. In the Baby trials, there was a wide variation in soybean yield obtained with INM, balanced fertilization (BF) using inorganic fertilizers, and farmers' practice; in poorer yielding trials, some problems were evident in the control of weeds and insect pests. Wheat responded well to BF and INM in trials irrigated 3-4 times. The MBT approach proved valuable in demonstrating higher productivity of the soybean-wheat system, and the value of INM and BF technologies, but only with proper weed and pest management in soybean, and adequate irrigation in wheat, as a package of practices.