19862015
  • Authors:
    • Wallender, W. W.
    • Burger, M.
    • Horwath, W. R.
    • Mailapalli, D. R.
  • Source: Agricultural Water Management
  • Volume: 98
  • Issue: 1
  • Year: 2010
  • Summary: Farming practices, including tillage, cover cropping and residue management can have profound effects on the efficiency of irrigation practices. The effects of three field management practices (FMPs) standard tillage and winter-fallow (ST), standard tillage and winter-cover crop (STCC), and no-till and winter-fallow (NT) and two field lengths (122 and 366 m) on runoff and export of dissolved organic carbon (DOC) were investigated in a furrow-irrigated cropping system over two years. The residue cover was 40, 32 and 11% in 2007, and 58, 61 and 11% in 2008 for STCC, NT and ST, respectively. Furrow irrigation experiments were conducted prior to crop planting following the cover crop. The inflow was kept constant across all treatments, and infiltration and runoff were estimated using a volume balance model (VBM). The DOC concentration tended to increase with increasing field length, but did not differ among the FMPs. A threefold increase in field length increased infiltration by 40%, and decreased runoff by 60-90% and DOC export by 65-83%. In both years, infiltration was highest in STCC. In NT, infiltration was lowest in 2007, which was likely due to soil sealing, and intermediate among the three FMPs in 2008 perhaps due to the increase in residue cover in the second year. The DOC budget analysis showed that fields and FMPs acted as DOC sinks exporting less DOC than was applied in the irrigation water. The results suggest that longer furrows and STCC were greater DOC sinks compared to ST and shorter field practices. The VBM, as applied in this study to estimate infiltration and runoff, could be used to predict optimal field length to minimize runoff and promote DOC adsorption to soil within the constraints of water quality and availability and soil conditions.
  • Authors:
    • Encide-Olibone,A. P.
    • Olibone,D.
    • Rosolem,C. A.
  • Source: Soil Use and Management
  • Volume: 26
  • Issue: 4
  • Year: 2010
  • Summary: Crop rotation and the maintenance of plant residues over the soil can increase soil water storage capacity. Root access to water and nutrients depends on soil physical characteristics that may be expressed in the Least Limiting Water Range (LLWR) concept. In this work, the effects of crop rotation and chiselling on the soil LLWR to a depth of 0.1 m and crop yields under no-till were studied on a tropical Alfisol in Sao Paulo state, Brazil, for 3 yr. Soybean and corn were grown in the summer in rotation with pearl millet (Pennisetum glaucum, Linneu, cv. ADR 300), grain sorghum (Sorghum bicolor, L., Moench), congo grass (Brachiaria ruziziensis, Germain et Evrard) and castor bean (Ricinus comunis, Linneu) during fall/winter and spring, under no-till or chiselling. The LLWR was determined right after the desiccation of the cover crops and before soybean planting. Soil physico-hydraulic conditions were improved in the uppermost soil layers by crop rotations under zero tillage, without initial chiselling, from the second year and on, resulting in soil quality similar to that obtained with chiselling. In seasons without severe water shortage, crop yields were not limited by soil compaction, however, in a drier season, the rotation with congo grass alone or intercropped with castor resulted in the greatest cover crop dry matter yield. Soybean yields did not respond to modifications in the LLWR.
  • Authors:
    • Poffenbarger, H.
  • Source: Natural Sciences Education
  • Volume: 39
  • Year: 2010
  • Summary: Integrating livestock into a cropping system by allowing ruminant animals to graze cover crops may yield economic and environmental benefits. The effects of grazing on soil physical properties, soil organic matter, nitrogen cycling and agricultural production are presented in this literature review. The review found that grazing cover crops generally led to increased bulk density, especially in no-till systems. On the other hand, the negative effects of grazing on penetration resistance and aggregate stability were more prominent under conventional tillage than no-till. The deleterious effects of grazing on soil physical properties were most severe when grazing was implemented at high intensity and on wet soils. Microbial biomass C was higher under grazed conditions than ungrazed conditions. Nitrogen was found to be higher when cover crops were grazed than not grazed; however, this was only true for conventional tillage systems. Generally, grazing cover crops did not negatively affect primary crop yields. Cover crops provided nutritious forage for cattle and reduced feed costs by offsetting the use of hay or other pasture.
  • Authors:
    • Boykin, D.
    • Balkcom, K.
    • Arriaga, F.
    • Balkcom, K.
  • Source: Agronomy Journal
  • Volume: 102
  • Issue: 2
  • Year: 2010
  • Summary: Increased production costs and potential benefits of maintaining surface residue has renewed interest in conservation tillage systems for peanut ( Arachis hypogaea L.) production. We determined surface residue cover from rye ( Secale cereale L.) or oat ( Avena sativa L.) cover crops after two strip tillage systems (narrow vs. wide) and planting operations with different row configurations (single vs. twin). We also compared plant populations, yields, and total sound mature kernels for three peanut cultivars ('ANorden', 'AP-3', and 'Georgia-02C') across each treatment combination. Seven site-years were examined across similar soil types in Alabama and northern Florida during the 2004 to 2006 growing seasons. The highest surface residue counts were for the narrow tillage system planted in single rows. Final plant stands were influenced by an interaction between cultivar and row configuration, with 'ANorden' planted in single rows below recommended rates. Peanut yields were affected by strip tillage system and row configuration, but differences among cultivars were also observed. Twin-row peanut yields were 5% greater than single-row peanut yields in the narrow strip tillage system but were similar across strip tillage systems. Cultivars 'AP-3' and 'Georgia-02C' yielded 20% higher than 'ANorden'. Total sound mature kernels were only affected by peanut cultivar, with the cultivar 'Georgia-02C' producing the highest-quality peanut, followed by 'ANorden' and 'AP-3'. These results indicate that growers interested in using twin rows for peanut production can also take advantage of a narrow strip tillage system that maximizes surface residue coverage and subsequent benefits.
  • Authors:
    • Molnar, L. J.
    • Blackshaw, R. E.
    • Moyer, J. R.
  • Source: Canadian Journal of Plant Science
  • Volume: 90
  • Issue: 4
  • Year: 2010
  • Summary: Farmers on the Canadian prairies are interested in including legume cover crops in their cropping systems to reduce fertilizer inputs and improve farm sustainability. A field study was conducted to determine the merits of establishing alfalfa ( Medicago sativa L.), red clover ( Trifolium pratense L.) or Austrian winter pea ( Pisum sativum L.) cover crops in fall or in spring with winter wheat ( Triticum aestivum L.). Spring-planted legumes emerged well within the winter wheat crop, but their growth was limited under these semi-arid conditions. Fall-planted red clover had low plant densities following winter in two of three experiments and fall-planted winter pea reduced winter wheat yield by 23 to 37% compared with the no cover crop control. In contrast, fall-planted alfalfa exhibited good winterhardiness, provided some weed suppression without reducing winter wheat yield, caused only a slight reduction in soil water content, and contributed an extra 18 to 20 kg ha -1 of available soil N at the time of seeding the following spring crop. Additionally, fall-planted alfalfa increased the yield of succeeding canola ( Brassica napus L.) in unfertilized plots in two of three experiments. Further research is warranted to better understand the agronomic and economic benefits of alfalfa-winter wheat intercrops under a wider range of environmental conditions.
  • Authors:
    • Inomoto, M. M.
    • Machado, A. C. Z.
    • Borges, D. C.
  • Source: Tropical Plant Pathology
  • Volume: 35
  • Issue: 3
  • Year: 2010
  • Summary: Black oat ( Avena strigosa), white oat ( A. sativa) and Algerian oat ( A. byzantina) are extensively cultivated in the south of Brazil for grain, forage, hay and silage production, or as cover crop in no-tillage and crop-pasture integration systems. In both systems, the genotypes of oat used as cover crop must be nonhosts or poor hosts of damaging nematodes for summer cash crops. Taking into account the relevance of Pratylenchus brachyurus as a pathogen for many cash crops in Brazil, two experiments were carried out in a glasshouse in order to evaluate the host suitability of selected oat cultivars to this nematode. The initial population inoculated (Pi) were 92 specimens/plot in experiment 1, and 270 in experiment 2. At the end of experimental periods (86 days after inoculation in experiment 1 and 67 days in experiment 2), the final population (Pf) of P. brachyurus was estimated and the reproductive factor (RF=Pf/Pi) was calculated. The results demonstrated that black oat (RF=0.04-1.03) is more valuable than Algerian oat (RF=2.63-2.88) or white oat (RF=1.37-1.93) for the management of P. brachyurus.
  • Authors:
    • Oliveira, O. L. P. de
    • Melo, G. W. B. de
    • Botton, M.
    • Onzi, I.
  • Source: ACTA SCIENTIARUM-AGRONOMY
  • Volume: 32
  • Issue: 4
  • Year: 2010
  • Summary: The use of cover crops is an important strategy to reduce erosion and improve chemical and physical soil properties. In this work, we evaluate the effect of cover crops to reduce Brazilian ground pearl Eurhizococcus brasiliensis (Hemiptera: Margarodidae) infestation in vineyards. In the first experiment, glyphosate was sprayed each three months to avoid cover crops. This treatment was compared with naturally occurring vegetation during the year and the use of Avena sativa in the winter. In a second experiment, Stizolobium aterrimum was cultivated during the summer compared with naturally occurring vegetation. Brazilian ground pearl population was higher in glyphosate sprayed areas than where cover crops were maintained during the year. No differences in inssect infestation were observed between naturally occurring vegetation and A. sativa during the winter. Scale infestation where S. aterrimum was cultivated during the summer was similar to naturally occurring vegetation. S. aterrimum is registered for the first time as a host of E. brasiliensis.
  • Authors:
    • Alda, L.
    • Baluta, D.
    • Manea, D.
    • Alda, S.
    • Lazureanu, A.
    • Caciu, G.
    • Circiu, L.
  • Source: Journal of Horticulture, Forestry and Biotechnology
  • Volume: 14
  • Issue: 2
  • Year: 2010
  • Summary: The research was conducted in 2008-2009 and followed the influence of six plants run on the cover of plants with weeds plants culture and production of winter wheat. Predominant weeds were Veronica hederifolia, Viola arvensis, Polygonum Convolvulus, Convolvulus arvensis and Stellaria media. The degree of reduction of weeds, depending on pre-plant fluctuated between 17,84 and 28%, 43% in 2008 and between 20.49% and 29.58% in 2009. Production is directly proportional to the absolute level of covering plants with weeds plants, beings from 38.05 q/ha and 43.26 q/ha in 2008 and between 44.72 q/ha and 52.08 q/ha in 2009.
  • Authors:
    • Singer, J.
    • Moorman, T.
    • Cambardella, C.
  • Source: Nutrient Cycling in Agroecosystems
  • Volume: 87
  • Issue: 3
  • Year: 2010
  • Summary: Coupling winter small grain cover crops (CC) with manure (M) application may increase retention of manure nitrogen (N) in corn ( Zea mays L.), -soybean [ Glycine max (L.) Merr], cropping systems. The objective of this research was to quantify soil N changes after application of liquid swine M ( Sus scrofa L.) at target N rates of 112, 224, and 336 kg N ha -1 with and without a CC. A winter rye ( Secale cereale L.)-oat ( Avena sativa L.) CC was established prior to fall M injection. Surface soil (0-20 cm) inorganic N concentrations were quantified every week for up to 6 weeks after M application in 2005 and 2006. Soil profile (0-120 cm in 5, 20-cm depth increments) inorganic N, total N, total organic carbon and bulk density were quantified for each depth increment in the fall before M application and before the CC was killed the following spring. Surface soil inorganic N on the day of application averaged 318 mg N kg -1soil in 2005 and 186 mg N kg -1soil in 2006 and stabilized at 150 mg N kg -1soil in both years by mid-November. Surface soil NO 3-N concentrations in the M band were more than 30 times higher in the fall of 2005 than in 2006. The CC reduced surface soil NO 3-N concentrations after manure application by 32% and 67% in mid- November 2005 and 2006, respectively. Manure applied at 224 kg N ha -1 without a CC had significantly more soil profile inorganic-N (480 kg N ha -1) in the spring after M application than manured soils with a CC for the 112 (298 kg N ha -1) and 224 (281 kg N ha -1) N rates, and equivalent inorganic N to the 336 (433 kg N ha -1) N rate. These results quantify the potential for cover crops to enhance manure N retention and reduce N leaching potential in farming systems utilizing manure.
  • Authors:
    • Radicetti, E.
    • Mancinelli, R.
    • Campiglia, E.
    • Caporali, F.
  • Source: Crop Protection
  • Volume: 29
  • Issue: 4
  • Year: 2010
  • Summary: Cover crops and mulches are a suitable choice for sustainable agriculture because they improve weed control and crop performance. The aim of this research was to investigate weed control and nitrogen supply by using different winter cover crop species which were converted into mulches in spring. We carried out a 2-year field experiment where a tomato crop was transplanted into four different types of mulches coming from winter cover crops [(hairy vetch ( Vicia villosa Roth.), subclover ( Trifolium subterraneum L.), oat ( Avena sativa L.), and a mixture of hairy vetch/oat)] and in conventional treatment (tilled soil without mulch). The mixture of hairy vetch/oat cover crop produced the highest aboveground biomass (7.9 t ha -1 of DM), while the hairy vetch accumulated the highest N in the aboveground biomass (258 kg N ha -1). The oat cover crop was the most effective cover crop for suppressing weeds (on average -93% of weed aboveground biomass compared to other cover crops). After mowing the cover crop aboveground biomass was placed in strips as dead mulch into which the tomato was transplanted in paired rows. Weed density and total weed aboveground biomass were assessed at 15 and 30 days after tomato transplanting to evaluate the effect of mulches on weed control. All mulches suppressed weeds in density and aboveground biomass compared to the conventional system (on average -80% and -35%, respectively). The oat was the best mulch for weed control but also had a negative effect on the marketable tomato yield (-15% compared to the conventional treatment). Amaranthus retroflexus L. and Chenopodium album L. were typical weeds associated with the conventional treatment while a more heterogeneous weed composition was found in mulched tomato. Legume mulches, in particular hairy vetch, gave the best marketable tomato yield 28% higher than the conventional system both with and without nitrogen fertilization. This research shows that winter cover crops converted into dead mulch in spring could be used successfully in integrated weed management programs to reduce weed infestation in tomato crops.