• 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:
    • 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:
    • Lithourgidis, A.
    • Dordas, C.
  • Source: Crop Science
  • Volume: 50
  • Issue: 5
  • Year: 2010
  • Summary: Annual cool-season grain legumes like faba bean ( Vicia faba L.) grown in mixtures with winter cereals such as wheat ( Triticum aestivum L.), barley ( Hordeum vulgare L.), or rye ( Secale cereale L.) may offer advantages over cereal-alone crops grown for forage production. A 2-yr field study was conducted to evaluate the effects of intercropping faba bean with each of the above cereals in three seeding ratios (i.e., 75:25, 50:50, and 75:25) on growth rate, plant height, chlorophyll content, forage yield, and N uptake. Growth rate of faba bean and cereals was lower in the mixtures than in the monocultures, especially in the faba bean-barley mixtures because of the strong competitive ability of barley. Chlorophyll content was lower in faba bean compared with the cereals, and there was no difference among seeding ratios. Plant height of faba bean was higher in the intercrops compared with its monocrop at 3 wk after tillering (WAT), whereas at 6 WAT, the trend was different since faba bean plants in the monocrop were higher than in the intercrops. Rye monocrop and rye-faba bean intercrops provided the greatest forage yield. Although the three intercrops of faba bean with rye had lower crude protein (CP) content than the faba bean monocrop, they provided the highest CP yields per hectare because of their higher forage yield than the faba bean monocrop.
  • Authors:
    • Garcia, P. A.
    • Benitez, E.
    • Ramos, M. E.
    • Robles, A. B.
  • Source: Applied Soil Ecology
  • Volume: 44
  • Issue: 1
  • Year: 2010
  • Summary: Frequent tillage has been widely used in rainfed orchards in SE Spain in order to impede weed establishment and to increase water reposition in the soil profile. However, this practice may lead to soil degradation by decreasing structural stability, organic carbon content and microbial activity. This work examines the effect of different cover crop managements and frequent tillage on soil physical, chemical and biological properties in almond orchards in SE Spain. Two cover crops (oat - Avena sativa L. and oat-vetch - Vicia sativa L.) with two fertilization managements (mineral and organic) and three harvesting regimes (grazing in mid May, hay in early June, and grain-straw in mid July) were compared to a frequently tilled orchard system (three or four tillages per year). Most parameters were sensitive to soil management. Wet aggregate stability, total organic carbon, total nitrogen, carbon:nitrogen ratio, phosphatase, and beta-glucosidase activities increased with cover crops, whereas the soil-water content declined, especially for the grain-straw treatment. The kind of fertilizer affected the available P content, which was higher for mineral fertilizer, and influenced the beta-glucosidase activity, which augmented for the organic fertilizer. Livestock dejections depressed phosphatase activity, and increased WSC and available P. This study suggests that cover crops in semiarid environments improve soil quality compared to frequently tilled management, by increasing the organic matter content, improving the chemical and physical fertility of the soil, and enhancing the soil biological activity. Only higher water extraction by the plants could affect the orchard development and/or productivity; however, early cover crop removal would minimize possible yield losses.
  • Authors:
    • Carbonell, R.
    • Rodriguez-Lizana, A.
    • Gonzalez, P.
    • Ordonez, R.
  • Source: NUTRIENT CYCLING IN AGROECOSYSTEMS
  • Volume: 87
  • Issue: 2
  • Year: 2010
  • Summary: A common agricultural policy rule has banned the burning of wheat stubble. It might gradually increase the surface under no-till in Europe. The release dynamics of nutrients from the crop residues left on the soil surface has rarely been studied under Mediterranean climate conditions. As part of a long-term experiment started in 1982, a field study was carried out during the agricultural seasons 2001/2, 2002/3 and 2003/4, to determine the decomposition and nutrient release of above-ground residues deposited on a clayey soil in the south of Spain, in which a legume-cereal-sunflower rotation was followed. At the end of its decomposition cycle, the pea residue ( Pisum sativum L. cv. Ideal) had lost 60% of its initial mass, durum wheat ( Triticum durum L. cv. Amilcar) 35%, and sunflower ( Helianthus annus L. cv. Sanbro) 39%. The N release by the pea residue, wheat and sunflower was of 13.5, 6.7 and 8.5 kg ha -1, respectively. The P release was of 2.9 kg ha -1 (pea) and of 0.7 kg ha -1 (sunflower), and the highest content of released K was noted in the sunflower residue, 78 kg ha -1, compared to 22.5 kg ha -1 in wheat and 2.4 kg ha -1 in pea. In pea and sunflower, residue loss and N and P release in most cases followed simple linear and exponential functions, from which the specific decay rates were calculated. The decomposition rates of the different nutrients were higher than those of the residue in pea and sunflower, and the residue semi-decomposition periods, of 138 d in sunflower, and 191 d in pea, indicated a great persistence of the remains. The soil protection was acceptable in the case of wheat and sunflower, but not in pea. The application of the Douglas-Rickman model and the knowledge of the variation in the concentration of the nutrient in the crop remains permitted the estimation of the amount of N and P remaining in them over the intercropping period. In any case, in our climate and with soils rich in K, the release of nutrients from the residue, mainly N, is fairly scant and, in principle, does not seem to be of any interest in the fertilization programmes followed by the farmers in the area.
  • Authors:
    • Oad, S.
    • Abro, B.
    • Sohu, I.
  • Source: Pakistan Sugar Journal
  • Volume: 25
  • Issue: 3
  • Year: 2010
  • Summary: The study on intercropping of autumn planted sugarcane with onion, wheat, Lentil, Mustard and Safflower was carried out at the experimental Field of Sugarcane Research Station, QAARI Larkana during the year 2005-2006. The experiment was laid out in Randomized Complete Block with four replications with ultimate plot size of 8*8 m (64 m 2). The results obtained were analysed and reported briefly. The results were statistically non-significant for germination %age, number of tiller per stool and plant height. Maximum germination (59.98%) was recorded when sugarcane was planted sole followed by sugarcane+Lentil intercropping i.e. (58.00%). The same trend was noted for number of tillers stool -1, cane girth and internodes/cane. The cane yield ha -1 of sugarcane was maximum (120.97 m.t ha -1), when sugarcane planted alone, whereas all the intercrops reduced cane yield significantly. Smoothly and competitive effect was observed for all intercrops when sown with sugarcane.
  • Authors:
    • Mitchell, J. P.
    • Summers, C. G.
    • Stapleton, J. J.
    • Prather, T. S.
  • Source: PHYTOPARASITICA
  • Volume: 38
  • Issue: 1
  • Year: 2010
  • Summary: Experiments were conducted in laboratory bioreactors and in field plots to test effects of certain cultivated members of the grass family (Poaceae=Gramineae), including wheat ( Triticum aestivum cv. Yolo), barley ( Hordeum vulgare cv. UC337), oats ( Avena sativa cv. Montezuma), triticale ( X Triticosecale), and a sorghum-sudangrass hybrid ( Sorghum bicolor * S. sudanense="sudex", cv. Green Grazer V) for soil disinfestation potential. Soilborne pest organisms tested for effects on survival and activity included the phytopathogens Sclerotium rolfsii, Pythium ultimum and Meloidogyne incognita, and a variety of weed taxa. Following soil amendment, bioreactors were incubated for 7 days at ambient (23°C) or elevated, but sublethal (38°C day/27°C night), soil heating regimens. Addition of each of the poaceous amendments to soil at 23°C resulted in inconsistently reduced tomato root galling (49-97%) by M. incognita, or reduced recovery of S. rolfsii and P. ultimum (0-100%) fungi in soil, after 7 days' incubation ( P≤0.05). When the organisms were exposed to the poaceous soil amendments at the 38°/27° temperature regimen, nematode galling and recovery of active fungi were consistently and significantly reduced by 98-100%. These results demonstrated feasibility of soil disinfestation ("biofumigation") by activity of poaceous amendments, further aided by combining plant residues with soil heating (e.g. solarization). Results from three field experiments with sudex cover crops, conducted throughout the growing season, demonstrated biocidal activity on a range of weedy plants, including Amaranthus retroflexus, Calandrinia ciliata, Cerastium arvense, Digitaria sanguinalis, Echinochloa crus-galli and Poa annua. Both shoots and roots of sudex provided allelopathic weed biomass reductions of 35-100%, and for at least 106 days after shredding. Deleterious activity of shredded residues incorporated in soil was less persistent. These properties in poaceous crops can be useful for soil disinfestation; however, harmful phytotoxicity to subsequent crops may also result. In order to take full advantage of these low-input measures for controlling soilborne diseases and pests, further understanding of their properties must be gained, and user guidelines developed.
  • Authors:
    • Guiducci, M.
    • Tosti, G.
  • Source: European Journal of Agronomy
  • Volume: 33
  • Issue: 3
  • Year: 2010
  • Summary: Intercropping cereals and grain legumes is a common practice because of the advantages in N use, in pest and volunteer plant smothering, but when the grains need to be separated, there are several technical difficulties. These problems may be overcome by adopting a particular form of intercropping (termed "temporary intercropping") where the coexistence of the crops is limited to a portion of their life cycles. In a cereal-legume temporary row-intercropping, the legume component is ploughed into the soil before cereal shooting; thus the legume is used with a mere fertility purpose in order to improve N availability for the cereal component. The presence of such a positive effect, already confirmed in permanent intercropping, needs to be verified in temporary intercropping systems. In an organic farming system, a field experiment was carried out in two consecutive years (2005 and 2006) to evaluate the technical feasibility of a temporary intercropping between three varieties of durum wheat ( Triticum durum Desf.) and faba bean ( Vicia faba L. var. minor Beck.) and to test the effects on interspecific competition for light, N availability, cereal grain yield and quality. The species were temporarily intercropped following an additive design, and there was no fertilisation or crop protection. The N incorporated into the soil by the faba bean biomass was rather stable across years. The competitive effect of the legume reduced the biomass accumulation of the intercropped wheat, but the cereal N status was considerably improved. After the faba bean incorporation into the soil, the marked asymmetry of the temporary intercropped wheat (i.e. large inter-row space coupled with high plant density in the row) affected the radiation balance, nevertheless the yield was positively affected and the wheat grain protein content was increased to an excellent (from 12.0 to 13.9% in 2005) or a good (from 10.2 to 11.5% in 2006) level. Temporary intercropping was shown to be excellent method to improve the quality of organic durum wheat in the Mediterranean environmental conditions.
  • Authors:
    • Matic, T.
    • Todorovic, M.
    • Albrizio, R.
    • Stellacci, A.
  • Source: Field Crops Research
  • Volume: 115
  • Issue: 2
  • Year: 2010
  • Summary: The understanding of the interactive effect of water and N availability, associated with the ability of crops to efficiently use these resources, is a crucial issue for stabilizing cereal production in Mediterranean areas. A 3-year side by side experiment on durum wheat and barley, under different water regimes and nitrogen levels, was carried out in a typical Mediterranean environment of Southern Italy, to identify the outstanding features of these species that contribute to enhanced grain yield and improved water and nitrogen use efficiency. Wheat and barley response was assessed under three water supply regimes ( I100, I50, I0: full irrigation, 50% of full irrigation and rainfed) coupled with two N fertilizer levels (high N: 120 kg ha -1 and low N: not fertilized). In order to evaluate barley yield response under lower N rates, 60 kg ha -1 were applied in 2006. The occurrence of abundant rainfall during the experimental period determined only mild water stress during most of the growing season, especially in 2006 and 2007. Under these conditions, nitrogen fertilization was the main factor affecting crop response, and different crop traits in response to irrigation were primarily evident on tissue N concentrations. Grain number per unit land area explained a high proportion of grain yield and it was mainly influenced by N fertilization. Water availability enhanced N absorption: the response of both crops to N fertilization, in terms of N uptaken and grain N concentration, was higher in the year characterized by greater water availability during the most sensitive stages to drought stress. Under unfertilized conditions, the two crops showed similar response in terms of number of grains per unit land area; under N fertilization, barley exhibited a higher increase in number of grains per unit land area, but wheat achieved similar yields as consequence of the higher grain weight. In years characterized by similar average productivity of wheat, barley did not show further increase in number of seeds, even doubling the rate of N supplied. By increasing irrigation water supply, the two crops showed a similar yield response, but a different N partition, as confirmed by the lower nitrogen harvest index values for barley over 2007-2008. At similar total availability of N, barley reached higher N utilization efficiency than wheat, mainly because of a lower N concentration in the grain rather than a higher efficiency in using the available N.
  • Authors:
    • Riffkin, P.
    • MacEwan, R.
    • Clough, A.
  • Source: Proceedings of the 19th World Congress of Soil Science: Soil solutions for a changing world, Brisbane, Australia, 1-6 August 2010. Symposium 4.2.1 Soil, energy and food security
  • Year: 2010
  • Summary: Dryland cropping in the high rainfall zone (HRZ) of southern Australia has the potential to produce high yields of cereals, canola and pulses. However, actual yields often fall well short of the estimated potential. A survey of grain growers in the HRZ was conducted to gain a greater understanding of the factors which may prevent growers from achieving potential yields. The survey was developed in consultation with growers, soil scientists and agronomists and distributed nationally through an industry magazine. The survey captured grower perceptions of soil and crop management using multiple choice questions and free comment sections. This paper documents the section of the survey pertaining to soils. In this survey, growers throughout the HRZ provided common responses regarding their use of some forms of tillage, trafficking, chemical soil amelioration techniques and physical soil engineering techniques. Different responses were evident depending upon region and farm size for issues such as the use of conventional tillage, raised beds and lime. The perceived success of various types of soil management options is also discussed. This information is valuable for those who wish to identify which regions or grower audiences should be targeted for research and extension in soil management.