• Authors:
    • Przybylowicz, W.
    • Mesjasz-Przybylowicz, J.
    • Cramer, M.
    • Hawkins, H.
    • Louw, E.
    • O'Brien, C.
  • Source: Acta Horticulturae
  • Issue: 869
  • Year: 2010
  • Summary: Utilisation of previously cultivated land for Proteaceae crops is a viable alternative to using pristine land. However, cultivated lands have usually been fertilized and typically have soil [P] unsuitably high for Proteaceae, resulting in P toxicity. After establishing that the main effects of P toxicity on the shoot were increased leaf P and Mn, but reduced leaf Fe and Zn, it was hypothesized that binding soil P and providing additional Fe and Zn to leaves would ameliorate P toxicity. Various soil and leaf amendments were tested for their efficacy in reducing soil P in unplanted lands, or ameliorating or preventing P toxicity in lands or pots planted with Protea 'Sylvia'. In an unplanted field, deep ploughing to 50 cm reduced available P from 16213 to 8.82.6 mg P kg -1 soil, i.e. by 95%. Sowing two seasons of the cover crops oat and lupin also greatly reduced available P (80%) whilst Al 2(SO 4) 3 application (278 g m -2) reduced available soil P by 80-65% depending on initial soil [P]. Ploughing was associated with disadvantages such as reduced cations and possible disruption of microbial populations. Thus use of cover crops or, for more immediate reduction in available soil P, aluminium application may be preferable. Application of Al 2(SO 4) 3 was also shown to be effective in prevention and amelioration of P toxicity symptoms in Protea 'Sylvia' in the field, while a Fe-containing compound 'OX' and a Fe/Zn containing foliar spray were only effective in preventing P toxicity in a pot experiment. Calcium sulphate was not effective as a P-binder in the field. Different agents may be used for different requirements but Al 2(SO 4) 3 application was effective in both prevention and amelioration of P toxicity.
  • Authors:
    • Delatorre, C.
    • Federizzi, L.
    • Locatelli, A.
    • Martinelli, J.
    • Graichen, F.
    • Kulcheski, F.
  • Source: Euphytica
  • Volume: 175
  • Issue: 3
  • Year: 2010
  • Summary: Crown rust, which is caused by Puccinia coronata f. sp. avenae, P. Syd. & Syd., is the most destructive disease of cultivated oats ( Avena sativa L.) throughout the world. Resistance to the disease that is based on a single gene is often short-lived because of the extremely great genetic diversity of P. coronata, which suggests that there is a need to develop oat cultivars with several resistance genes. This study aimed to identify amplified fragment length polymorphism AFLP markers that are linked to the major resistance gene, Pc68, and to amplify the F 6 genetic map from Pc68/5*Starter * UFRGS8. Seventy-eight markers with normal segregation were discovered and distributed in 12 linkage groups. The map covered 409.4 cM of the Avena sativa genome. Two AFLP markers were linked in repulsion to Pc68: U8PM22 and U8PM25, which flank the gene at 18.60 and 18.83 centiMorgans (cM), respectively. The marker U8PM25 is located in the linkage group 4_12 in the Kanota * Ogle reference oat population. These markers should be useful for transferring Pc68 to genotypes with good agronomic characteristics and for pyramiding crown rust resistance genes.
  • Authors:
    • Lambrecht, S. C.
    • D'Amore, A.
  • Source: Ecological Restoration
  • Volume: 28
  • Issue: 4
  • Year: 2010
  • Summary: A study was conducted to gauge the relative efficacy of mowing twice, discing, and solarization in controlling invasive weeds. The two specific objectives were to test whether solarization could be used effectively for weed control in a cool, coastal region, and to compare this approach with other methods of weed control in terms of effectiveness, cost, and time required for implementation. The study was conducted in an area within a 1-ha fallow field in California, USA that had not been cultivated for ten years. Non-native annual grasses dominated the vegetation, primarily ryegrass ( Lolium perenne subsp. multiflorum), but also soft brome ( Bromus hordeaceus), oats ( Avena spp.), and foxtail barley ( Hordeum murinum). Mustard ( Brassica rapa) and radish ( Raphanus sativus) were also common non-native weeds. The site is about 7 km from the ocean, so it experiences a strong maritime influence. The solarization treatment was the most effective method for controlling weed cover at Triple M. All treatment areas had similar weed cover beforehand, and treatments differed in their effectiveness. Although all treatments were equally effective in reducing non-native annual grass cover, both the disking and mowing treatment areas were invaded by the annual/biennial bristly oxtongue ( Picris echioides) during the study. This species comprised 85% of the posttreatment weedy forb cover in the disked area and 98% in the mowed area, but was not found in the solar-treated area. This is the first study to demonstrate effective weed control using solarization in a cool coastal region.
  • Authors:
    • Lajeunesse, J.
    • Pageau, D.
    • Fregeau-Reid, J.
    • Collin, J.
    • Vanasse, A.
    • Lanoie, N.
    • Durand, J.
  • Source: Canadian Journal of Plant Science
  • Volume: 90
  • Issue: 3
  • Year: 2010
  • Summary: Naked oat ( Avena sativa L.) harvested in the province of Quebec, Canada, develops on average 10% covered grains and sometimes more. The objective of this study was to determine the effect of soil type, herbicides and their application stages on the proportion of covered grains in naked oat genotypes. Three genotypes were evaluated over 2 yr at two experimental sites. At each site, trials were seeded on two different soil types and each entry was treated with one of three types of herbicides: bromoxynil/MCPA, dicamba/MCPA and thifensulfuron methyl/tribenuron methyl, and compared with a weed-free check. The herbicides were applied at Zadoks 12-13 and 22-23. Results showed that dicamba/MCPA herbicide, applied at Zadoks 12-13, increased covered grains compared with the weed-free check and more covered grains were produced with the application made at Zadoks 22-23. However, differences in genotype reactions were observed. Few differences were found among the other weed control treatments. The application of dicamba/MCPA at Zadoks 22-23 decreased yield and test weight, but increased kernel weight. The other weed control treatments had no effect on agronomic characteristics.
  • Authors:
    • Lajeunesse, J.
    • Pageau, D.
    • Reid, J. F.
    • Collin, J.
    • Vanasse, A.
    • Lanoie, N.
    • Durand, J.
  • Source: CROP SCIENCE
  • Volume: 50
  • Issue: 5
  • Year: 2010
  • Summary: Naked oat ( Avena sativa L.) grown in Quebec, Canada, produces an average of 10% covered grains. The objectives of this study were to evaluate the effects of environment, herbicide, and genotype on the proportion of covered grains, to study the relation between the presence of awns and the proportion of covered grains, and to determine the location of covered grains on the plant (tiller) and on the panicle. Eight oat lines were evaluated over 2 yr at four experimental sites. Each line was treated with bromoxynil/MCPA, dicamba/MCPA, or thifensulfuron methyl/tribenuron methyl applied at Zadoks 12-13 and compared to a hand-weeded check. The highest percentages of covered grains, 5.5 and 6.9%, were found at different sites in 2006 and 2007. The application of dicamba/MCPA increased the percentage of covered grains in the lines normally producing a higher proportion of covered grains, but low producing lines were less affected. Minor differences were found among the other weed control treatments. No relation was found between the presence of awns and the proportion of naked grains. Covered grains were mostly produced on the main stem and their position on the panicle depended on genotype and weed control treatment.
  • Authors:
    • Jasso-Chaverria, C.
    • Martinez-Gamino, M.
  • Source: Proceedings of the 19th World Congress of Soil Science: Soil solutions for a changing world, Brisbane, Australia, 1-6 August 2010. Symposium 3.2.1 Highland agriculture and conservation of soil and water
  • Year: 2010
  • Summary: Among the main constraints to adopting conservation tillage in the semiarid zones in Mexico's north-central region are: low acceptance among farmers, need of specialized machinery, use of herbicides, and above all, the need to utilize stubble to feed animals. The objective of this study was to assess the effect of different tillage methods in an irrigated corn-oat rotation system on corn grain, stubble, and forage oat yield. Seven tillage methods were evaluated: (1) traditional plow and disk (P+D), (2) disturbing the upper 0-4 in layer (D), (3) without disturbing the upper 0-4 in layer (ND), (4) zero tillage with 0% soil cover (ZT+0%SC), (5) zero tillage with 33% soil cover (ZT+33%SC), (6) zero tillage with 66% soil cover (ZT+66%SC), and (7) zero tillage with 100% soil cover (ZT+100%SC). In each year from 1996 to 2007, corn was sowed on the spring while forage oat was grown during the fall-winter season. Corn grain yield results showed statistical differences among treatments (p≤0.05), where ZT+66%SC was the best treatment, surpassing by 90% the corn yield registered with P+D. The statistical analysis for corn stubble yield showed no differences (p≥0.05) among treatments. With ZT+66%SC, corn stubble production was increased 3.448 ton/ha compared with that of P+D, indicating that farmers can use 2.0 ton ha -1 to cover at least 33% of the soil surface. Forage oat yields within the seven treatments were not statistically different ( P≥0.05), but all ZT treatments were no-till seeded. Our conclusions are that corn and forage oat can be no-till seeded, increasing corn production and keeping stable production of forage oat. These results can be used to provide evidence to farmers of the benefits of adopting conservation tillage.
  • Authors:
    • Rocha, D.
    • Cano, M.
    • Patino, H.
    • Medeiros, F.
    • Gonzalez, F.
  • Source: Ciencia Rural
  • Volume: 40
  • Issue: 1
  • Year: 2010
  • Summary: The impact of energy supplementation on the performance and carcass characteristics of 24 Aberdeen-Angus * Charolais steers grazing an annual ryegrass ( Lolium multiflorum) and oat ( Avena strigosa [ Avena nuda]) pasture managed in order to avoid constrains to animal performance was evaluated. Treatments were levels of supplementation of 0, 0.4, 0.8 and 1.2% BW with a corn and mineral based supplement. Animals were slaughtered after reaching 4.5 mm of fat cover in the rump (P8) evaluated ultrasonography. No differences were observed in fat deposition, measured in live animals with ultrasound at the end of performance period, and in liveweight gain, which showed average values of 3.9 mm and 1.54 kg/day, respectively. Blood serum levels of urea were linearly decreased and cholesterol linearly increased by energy supplementation, with no differences in the serum levels of glucose and triglycerides. Energy supplementation linearly increased the killing-out proportion and carcass weight gain, but no differences were observed on the rib eye area, slaughter weight and hot carcass weight, which averaged 67.85 cm 2, 438.95 kg and 227.75 kg, respectively. Increasing the levels of supplementation resulted in higher killing-out proportion and higher carcass daily gains, without changes in performance and carcass parameters evaluated.
  • Authors:
    • Muchaonyerwa, P.
    • Chiduza, C.
    • Murungu, F. S.
  • Source: African Journal of Agricultural Research
  • Volume: 5
  • Issue: 13
  • Year: 2010
  • Summary: Production of large biomass yields and weed suppression from cover crops have been major constraints affecting success and uptake of conservation agriculture technologies by smallholder irrigation farmers. A field study was undertaken to evaluate biomass accumulation and N uptake by oats ( Avena sativa), grazing vetch ( Vicia dasycarpa), faba bean ( Vicia faba), forage peas ( Pisum sativum) and Lupin ( Lupinus angustifolius) and their winter weed suppression efficacy in the 2007 and 2008 winter seasons. Cover crops were grown at two fertiliser levels: no fertiliser and fertilized. Control plots were included where no cover crop was grown. At the end of each winter season, glyphosate was applied to kill the cover crops and maize planted. Oats, grazing vetch and forage pea's cover crops produced mean dry weights of 13873, 8945.5 and 11073 kg ha -1 respectively while lupin had the lowest dry weight of 1226 kg ha -1. Oats responded to fertilisation while, there was little or no response from the other cover crops. Oats and grazing vetch also reduced weed density by 90 and 80% respectively while lupin only reduced weed density by 23% compared with the control plots. Grazing vetch fixed a mean of 112 kg N ha -1. The results suggest that legumes such as grazing vetch and forage peas may be grown to maximise biomass yields with minimal fertilizer inputs. Amount of biomass produced was a major factor in controlling winter weeds, while there was a progressive decline in the winter weed burden from the first to the second season. The low C:N ratio of grazing vetch (
  • Authors:
    • Sakai, R. H.
    • Ambrosano, E. J.
    • Melo, P. C. T. de
    • Negrini, A. C. A.
    • Schammass, E. A.
    • Rossi, F.
  • Source: HORTICULTURA BRASILEIRA
  • Volume: 28
  • Issue: 1
  • Year: 2010
  • Summary: The performance of lettuce in sole and intercropped with green manures was assessed under different establishment times. The lettuce fresh and dry weight, number of leaves per plant, diameter and length of head, and fresh and dry weight of green manure were evaluated. The intercropping design was additive and both cash and cover crops were planted in rows. The experimental design was of randomized complete blocks in split plot scheme, with six replicates. The plots represented the green manure sowing days (0, 20, 40 and 60 before transplanting of lettuce), and the sub-plots were assigned by cropping systems (lettuce in sole crop and intercropped with black oat, cowpea or white lupin). Simultaneous planting in the intercropping did not affect the lettuce performance. However, when the green manures were sown before lettuce, they influenced it in a negative way. Among the green manures, cowpea increased biomass and had a higher negative effect on lettuce performance compared to white lupin, which appeared to produce less competition. The sole crop and the intercropping with simultaneous planting of the green manures resulted in a better lettuce performance.
  • Authors:
    • Marangon, R.
    • Mondardo, J.
    • Martin, T.
    • Pavinato, P.
  • Source: Proceedings of the 19th World Congress of Soil Science: Soil solutions for a changing world, Brisbane, Australia, 1-6 August 2010. Division Symposium 3.2 Nutrient best management practices
  • Year: 2010
  • Summary: The use of phosphate fertilizer has promoted changes in phosphorus fractions and availability in soil, that highlights the requirement of more studies to understand phosphorus dynamics in soil, and to develop cultivation strategies to increase crop grain yield under phosphate fertilization. The work aimed to evaluate changes in soil phosphorus availability in sequential crop seasons, under effects of phosphate fertilizer sources and cover crop plants. The experiment was carried at Technological Federal University of Parana, Dois Vizinhos, PR, Brazil. The soil is a Ferralsol, with high level of available P. Experimental design was a factorial 3*8, in randomized blocks, with three replicates and 5*5 m plots. Treatments were composed of natural phosphate and soluble phosphate, and a control. During winter season, the seven cover crops were: vetch, white lupin, radish, ryegrass, black oat, clover and pigeon pea, and a witness with no cover crop. Brazilian Ferralsol, with high level of available P, does not increase plant grain yield with sources of phosphate fertilization. Available P in soil changes markedly with phosphate fertilization, especially in the surface layer (0-5 cm). Important results are expected in soil P availability after winter cover crops.