• Authors:
    • White, C. M.
    • Weil, R. R.
  • Source: Soil Science Society of America Journal
  • Volume: 75
  • Issue: 1
  • Year: 2011
  • Summary: Cover crops can influence nutrient cycling in the agroecosystem. Forage radish (FR) (Raphanus sativus L. var. longipinnatus) is unique in terms of P cycling because of its high tissue P concentration, rapid growth in the fall, and rapid decomposition in winter and spring. In addition, FR produces a taproot that decays during the winter and leaves distinct holes in the surface soil. This study measured P uptake by FR and cereal rye (CR) (Secale cereale L.) cover crops; the Mehlich 3 P concentration (M3P) in bulk soil following FR, CR, and no cover crop (NC); and M3P in soil within 3 cm of FR taproot holes. Cover crop treatments of FR, CR, and NC were established at two sites each fall for three subsequent years in a cover crop-corn (Zea mays L.) silage rotation. Cover crop shoot P uptake ranged from 5.9 to 25 kg P ha(-1) for FR measured in the fall and from 3.0 to 26 kg P ha(-1) for CR measured in the spring. The greatest cover crop effect on bulk soil M3P was observed at the 0- to 2.5-cm depth aft er 3 yr of cover crops, with M3P values of 101, 82, and 79 mg P kg(-1) aft er FR, CR, and NC, respectively. Soil within 3 cm of FR taproot holes had greater M3P than FR and NC bulk soil. Further studies should be conducted to determine if FR could increase P removal rates in excessively high P soils or increase P availability in low P soils.
  • Authors:
    • Radicetti, E.
    • Mancinelli, R.
    • Campiglia, E.
    • Marinari, S.
  • Source: Nutrient Cycling in Agroecosystems
  • Volume: 89
  • Issue: 3
  • Year: 2011
  • Summary: There is not sufficient knowledge concerning the risks involved in NO 3-N leaching in relation to the use of cover crops and mulches. A 2 year field experiment was carried out in a pepper ( Capsicum annuum L.) crop transplanted into different soil management treatments which involved the addition of mulch of three different types of winter cover crops (CC) [hairy vetch ( Vicia villosa Roth.), subclover ( Trifolium subterraneum L.), and a mixture of hairy vetch/oat ( Avena sativa L.)], and an un-mulched plot. At the time of CC conversion into mulch, the hairy vetch/oat mixture accumulated the highest aboveground biomass (5.30 t ha -1 of DM), while hairy vetch in pure stand accumulated the highest quantity of N (177 kg ha -1) and showed the lowest C/N ratio (12). The marketable pepper yield was higher in mulched than in conventional (on average 33.5, 28.9, 27.7 and 22.2 t ha -1 of FM for hairy vetch, subclover, hairy vetch/oat mixture, and conventional, respectively). Generally, the NO 3-N content of the soil was minimum at CC sowing, slightly higher at pepper transplanting and maximum at pepper harvesting (on average 15.2, 16.8, and 23.3 mg NO 3-N kg -1 of dry soil, respectively). The cumulative leachate was higher during the CC period (from October to April) than the pepper crop period (from April to September), on average 102.1 vs 66.1 mm over the years, respectively. The cumulative NO 3-N leached greatly depended on the type of mulch and it was 102.3, 95.3, 94.7, and 48.2 kg ha -1 in hairy vetch, subclover, hairy vetch/oat mixture, and conventional, respectively. A positive linear correlation was found between the N accumulated in the CC aboveground biomass and the NO 3-N leached during pepper cultivation ( R2=0.87). This research shows that winter legume cover crops, especially hairy vetch in pure stand, converted into dead mulch in spring could be used successfully for adding N to the soil and increasing the yield of the following pepper crop although the risks of N losses via leaching could be increased compared to an un-mulched soil. Therefore when leguminous mulches are used in the cultivation of a summer crop, appropriate management practices of the system, such as a better control of the amount of irrigation water and the cultivation of a graminaceous or a cruciferous catch crop after the harvesting of the summer crop, should be adopted in order to avoid an increase in NO 3-N leaching.
  • Authors:
    • Leap, J.
    • Klonsky, K. M.
    • Shennan, C.
    • Smith, R. F.
    • Muramoto, J.
    • Ruiz, M. S.
    • Gliessman, S. R.
  • Source: HortScience
  • Volume: 46
  • Issue: 8
  • Year: 2011
  • Summary: Legume/cereal mixed winter cover crops are commonly used by organic growers on the central coast of California, but they are unable to provide sufficient nitrogen (N) for a high N-demanding vegetable crop such as broccoli and supplemental fertilizer application may be necessary. The goals of this project were to evaluate the contribution of N from a mixed legume/cereal cover crop (CC) and feather meal and blood meal as organic fertilizers (OF) to an organic broccoli crop and to evaluate economic benefits of CC and OF to the subsequent organic broccoli crop. Trials were conducted at two sites (A and B) with different management histories. Cover crops were grown over the winter and incorporated into the soil in the spring and subsequently broccoli [ Brassica oleracea L. (Italica group)] was grown in 2006 at both sites and in 2007 at B only. Cover crop and no CC treatments were grown with supplemental organic fertilizers at four fertility levels (0, 84, 168, and 252 kg N/ha of OF) with four replicates. Generally broccoli head yields at A (14.9 to 26.3 Mg.ha -1) were higher than at B (0.7 to 17.4 Mg.ha -1 in 2006 and 5.5 to 17.9 Mg.ha -1 in 2007). Yield and aboveground biomass N were significantly increased by OF at rates up to 168 kg N/ha at A and to 252 kg N/ha at B and by CC in 2006 at both sites but not in 2007 at B. Although N content of the CC was similarly low at A (2006) and at B (2007), immobilization of soil mineral N occurred only at B. This suggests that the addition of a low N content CC was offset by high N mineralization from the soil at A with a long organic management history (greater than 33 years). Supplemental fertilizer applications may be necessary to achieve optimal yields, but the amount needed can be reduced by cover cropping in fields with a long history of cover crop-based organic management (A) or when cover crop N content is sufficiently high to prevent immobilization (B, 2006). Soil NO 3-N patterns suggest a pre-side dress nitrate test may also be useful for N management in organic broccoli. Use of cover crops increased net return above harvest and fertility costs when the yield reduction by N immobilization did not take place. However, the net return increase by the use of cover crops tended to diminish as the rate of OF application increased.
  • Authors:
    • Maniutiu, D.
    • Indrea, D.
    • Muresan, A. O.
    • Sima, R.
  • Source: Journal of Horticulture, Forestry and Biotechnology
  • Volume: 15
  • Issue: 1
  • Year: 2011
  • Summary: In comparative stationary field experiments performed in Apahida, Cluj County, during four years (2005-2008), cabbage, sweet corn, carrot and garden bean crops have been followed on two different tillage systems: a conventional system - 5-6 tillage works including deep ploughing (25-28 cm deep) and 2-3 weeding, and the minimum tillage system: the strip-tillage cover crop system (spring fodder=oat+vetch) that was treated with Glyphosat herbicide (2 l/ha) and remained on the ground as mulch on which 10-15 cm wide sowing strips were split open. With the minimum tillage a 3-5 day delay in plant sprouting was noticed and vegetation was prolonged for few days in sweet corn, carrot and bean. Yield decreases by the minimum tillage vary between 7.7% and 16.7% in carrot and 5.0% and 10.9% in garden bean. In cabbage and sweet corn yield decrease was stated only during the first 2 years, while during the last 2 years the crop would balance on the two tillage methods. There was some product quality decrease with the minimum tillage, especially in carrots and beans.
  • Authors:
    • Ponizil, A.
    • Henriksen, B.
    • Pozdisek, J.
    • Loes, A. K.
  • Source: Agronomy Research
  • Volume: 9
  • Issue: 1/2
  • Year: 2011
  • Summary: In 2009, controlled field trials were conducted on three certified organic farms with field pea (leaf type), spring barley and spring wheat in monocultures and mixtures (pea:cereal ratio 60:40) to study the possibility of producing fodder for monogastric animals under Czech conditions. By grain harvest time, seed samples were collected and analysed for dry matter, ash, crude protein, fat and crude fiber, and content of organic matter and nitrogen-free extracts (NFE) were determined. Weed harrowing at various pea heights were included at one farm. Samples for analysis of tannins and trypsin-inhibitor activity (TIA) were taken from treatments with no weed harrowing (H0) and harrowings at 5 and 10 cm pea height (H2). Analyses of amino acids were conducted from H0-samples. To complement the data from the farm trials, samples of grains from treatments with the same pea and cereal varieties in plot trials conducted in 2008 and 2009 studying the effect of pea:cereal seed ratio and weed harrowing at various pea heights, were analysed. In cereals, the crude protein content increased by intercropping with pea. This increase was compensated for by a decrease in NFE. Wheat and barley grown in mixtures with peas seemed to contain more methionine than cereals in monoculture, and there tends to be higher threonine content in intercropped barley compared with barley monoculture. This is positive for the nutrition of monogastric animals. There were no pronounced effects of intercropping on tannins or TIA or on the content of other analysed nutrients in the cereals. The chemical composition of peas was not significantly impacted by intercropping.
  • Authors:
    • Liu, M.
    • Zhai, H.
    • Shi, C.
    • Dong, B.
    • Ruan, F.
    • Qiao, Y.
  • Source: Chinese Journal of Eco-Agriculture
  • Volume: 19
  • Issue: 5
  • Year: 2011
  • Summary: Ridge planting and intercropping of winter wheat ( Triticum aestivum L.) are important cropping systems in the North China Plain (NCP), in which there exists an acute shortage of water resources especially for crop production. This study analyzed water use efficiency ( WUE) of winter wheat in wheat||spinach-tomato cropping system using both traditional and ridge cultivation as the control practices. Traditional cultivated spinach ( Spinacia oleracea L.) and tomato ( Lycopersicon esculentum Miller) system was the control cropping practice for the spinach||tomato intercropping system. The results showed that wheat grain yield under ridge planting and intercropping was 11% less than under traditional cultivation (401 kg.667 m -2). The reduction in grain yield was attributed to low tiller number as ridge-edge effect was not fully exploited. Tiller numbers of ridge-planted ridge-intercropped wheat were 13.2% and 8.2% less than traditional cultivated wheat system. Row tiller number was much less in either ridge-planted or ridge-intercropped systems than in traditional cultivation system. Comparisons among the three cropping systems suggested that traditional wheat cropping had the highest WUE (1.039 kg.667 m -2.mm -1), and that intercropping had the lowest WUE (0.868 kg 667 m -2.mm -1). Ridge cultivation had a smaller WUE (0.944 kg.666.7 m -2.mm -1) than traditional cultivation system because between-ridge water was not fully utilized. Yield of spinach was, however, not affected by wheat. Yields of intercropped and traditional cultivation spinach systems were 826 kg.667 m -2 and 851 kg.667 m -2, respectively, with a difference not statistically significant. However, tomato growth was greatly hampered under the intercropping system. Stem diameter and biomass per plant under intercropped tomato was respectively 27% and 37% less than that under traditional cultivation system. This suggested that after spinach harvest, tomato transplanting should be postponed as long as possible so as to shorten crop symbiosis and make the cropping system more manageable. It was therefore concluded that wheat||spinach-tomato cropping system facilitated di-season vegetable and food production, provided that the wheat and vegetable cultivars were properly selected and cultivated.
  • Authors:
    • Zwirtes, A. L.
    • Baronio, C. A.
    • Rigon, J. P. G.
    • Capuani, S.
  • Source: Revista Verde de Agroecologia e Desenvolvimento Sustentavel
  • Volume: 6
  • Issue: 4
  • Year: 2011
  • Summary: The objective of this study was to evaluate the influences of different plants covering on the agronomic characteristics of beans. The experiment was conducted on Red Latossol alumino-ferric, using randomized block design with four repetitions, being the data submitted to the Tukey test and compared by orthogonal contrasts. Treatments consisted of covering plants, carrying its growth in single system, as well as some consortia, across species: Flaxseed ( Linum usitatissimum); Ryegrass ( Lollium multiflorum), Black and White Oats ( Avena stringosa and A. sativa), vetch ( Vicia sativa), wild radish ( Raphanus sativus) and Triticale ( Triticum secale). The agronomic attributes evaluated of bean were: the 1000 seeds per pod, length and number of pods per plant and plot, plant population and yield. Direct and different influence was verified on the components yield of beans, vegetables and the number of the larger relationship with productivity beans. Among the plants used predecessor, the Vetch and Turnip provided larger productive increment, differently of Ryegrass, as well as flaxseed, which resulted in lower yields beans.
  • Authors:
    • Nelson, D.
    • Hopkins, A.
    • Barker, A.
    • Brown, A.
  • Source: IOBC/WPRS Bulletin
  • Volume: 64
  • Year: 2011
  • Summary: The mollusc specific parasitic nematode Phasmarhabditis hermaphrodita (Nematoda: Rhabditida) has been shown to infect and kill a number of economically important pest slug and snail species. This beneficial nematode is available commercially under the trade name Nemaslug (Becker Underwood Ltd., Littlehampton, UK). Use of this biological control agent by large commercial growers is increasing. This increase in use also includes expanding from its traditional markets in higher value salads, to broad acre vegetables such as potatoes. Use of P. hermaphrodita has increased in recent years on outdoor crops due to a number of factors. Firstly additional products are often needed to compliment the available chemicals (e.g. Methiocarb, Metaldehyde and Ferric phosphate) in sub-terranian environments where they are often not as effective. Secondly there is a drive for more environmentally sensitive farming practices of which biological control, as part of an integrated pest management program, is an important component. This expansion into new markets, such as potatoes, has presented a number of challenges in applying these microscopic worms. Application of these soft bodied nematodes now needs to be carried out to large areas over long periods of time. To enable a grower to be able to do this, nematode specific application equipment has been developed. The Wroot water Nemaslug Xtra applicator is an injection unit which, whilst being able to inject nematodes into irrigation water for a boom or gun, can keep the nematode solution constantly agitated and supplied with oxygen. This system has been shown to be able to keep the nematodes alive and mixed in suspension for over 24 hours. This equipment allows a grower the increased flexibility of no longer having to wait for rain to apply and reduced application labour costs by not having to spend time spraying P. hermaphrodita onto the crop with a tractor mounted boom. The Wroot water Nemaslug Xtra applicator is the first ever piece of nematode specific application equipment developed. This equipment has been designed, built and made available for commercial growers, specifically for use of applying the biocontrol agent P. hermaphrodita (Nemaslug Xtra) to broad acre vegetable crops.
  • Authors:
    • Eryigit,T.
  • Source: Yuzuncu Yil Universitesi Journal of Agricultural Sciences
  • Volume: 21
  • Issue: 1
  • Year: 2011
  • Summary: The industrial crops with contribution to national income and industrial sector in terms of providing raw materials have a significant place in our crop production. Agricultural industry in our country has a large capacity, but due to lack of raw materials and financing a significant portion of the installed capacity can not be benefited. Especially in recent years, increasing of population and production decrease in some industrial plants due to the resulting vegetable oil deficit. Our country pays the highest foreign currency to imports of the oil and oil seed crops for closure of this gap after the oil imports. Therefore, the priority should be given to the oil plants within the groups of industrial plants. Igdr has its own microclimate characteristics. The diversity of product design is greater due to the climate and irrigation conditions in the plain. Grains constitute the main products of the region. All kinds of vegetables, olives and citrus fruit except that all the fruits can be grown. Sugar beet and cotton plants of industrial crop and the alfalfa plants of the forage crops have great importance in the development of animal husbandry. However, in recent years, changes in the climate regime, increases in the cultivation of sugar beet, sunflower and rapeseed gave rise to a decrease in the number of the small farmers who planted cotton. Igdr has high agricultural potential, so the alternative species of industrial crops and their varieties will be integrated to the present cultivation of plain by the scientific studies which will be held on industrial crops in the province.
  • Authors:
    • Virendra, K.
    • Gorantiwar, S. D.
    • Gadge, S. B.
    • Mahesh, K.
  • Source: Journal of Agrometeorology
  • Volume: 13
  • Issue: 1
  • Year: 2011
  • Summary: A study was carried out to estimate crop evapotranspiration (ETc) for different crops growing under surface (SI) and microirrigation (MI) methods in the command area of Mula Irrigation Project in Maharashtra, India. A spreadsheet-based computer model was developed to estimate the ETc values and compute the water requirement. The climatological data obtained from the meteorological observatory located at All India Co-ordinated Research Project on Water Management, Rahuri (Maharashtra), from 1975 to 2005 was used. The crop water requirement under MI methods was less than that under SI methods. The saving in water for MI method was maximum under pomegranate and lime (88%) and minimum for summer groundnut (38%) when compared to the SI method. Similar saving in water was also observed for other crops under MI methods. The percentage saving in MI methods was 75, 62, 64, 73, 68, 61, 43, 51, 65, 48, 53, 70, 63, 65, 63, 40, 52 and 63% for pawpaw, banana, sugarcane, grapes, kharif soyabean, rabi tomato, kharif groundnut, rabi onion, cotton, gram, potato, kharif brinjal [aubergine], cabbage, summer brinjal, summer cucumber, summer onion, summer okra and summer chilli, respectively, when compared to the water requirement under SI method. Thus, there is a saving of at least 50% of water if drip irrigation method is used instead of SI method. This indicates that in the case of water scarcity there is possibility of bringing additional area under irrigation by using the saved amount of water.