• Authors:
    • Sungur, S.
    • Sangün, M. K.
  • Source: Food Chemistry
  • Volume: 126
  • Issue: 1
  • Year: 2011
  • Summary: Recently, the exposure to perchlorate was emphasised as an important risk factor for human and especially newborn health. A number of studies were focused on this matter. In this study, samples of soil, vegetable (cabbage, spinach, lettuce, carrot, tomato, red cabbage), fruit (orange, mandarin, lemon, grapefruit), water, milk and fish were taken from 8 different regions of Hatay (Samandag, Krkhan, Reyhanl, Amik Plain, Dortyol, Yayladag, Altnozu, Erzin). An ion chromatography system (Shimadzu C196-E039A model) was used to determine the concentrations of perchlorate in the samples. 2.5 mM Phthalic acid and 2.4 mM tris (hydroxymethyl)aminomethane solutions (pH=4) were used as the mobile phase. A flow rate of 1.5 ml min -1 and oven temperature of 40°C were used during the analysis. The foods had perchlorate concentrations in the range of 0.236-1.218 g kg -1. The perchlorate concentration varied from 0.300.01 to 0.940.02 g l -1 in milk samples. Perchlorate concentrations were determined to be lower in the drinking waters (0.440.03 g l -1) compared to irrigation waters (0.590.03 g l -1). Perchlorate concentrations of the fish samples were ranged from 0.380.01 to 0.610.01 g kg -1.
  • Authors:
    • Ichinokiyama, H.
    • Suzaki, N.
    • Okuda, H.
  • Source: Agricultural Information Research
  • Volume: 20
  • Issue: 3
  • Year: 2011
  • Summary: In commercial orchards of satsuma mandarin in Japan, mulching cultivation has been developed to produce high quality fruit. It is, however, difficult to manage irrigation to produce consistent characteristics such as high fruit quality, fruit productivity, and tree vigor. The principal reason for this is that no simple, easy, and reliable indicator has been developed to evaluate tree water deficits. In this study, we demonstrated that the morning maximum leaf water potential could be estimated using the fruit hardness in the evening of the previous day. To assist farmers in estimating fruit hardness, we developed a set of three silicone rubber balls with different degrees of hardness as a reference tool, and verified their effectiveness. The experiment was performed in 2008 and 2009, and revealed that irrigation management during July and August using the silicone rubber reference balls gave good results, with high fruit quality and high fruit productivity. Fruit hardness estimated using the silicone rubber balls therefore appears to be a good indicator of irrigation management during July and August for mulched citrus orchards.
  • Authors:
    • Yang, G. H.
    • Li, Q.
    • Yang, L. T.
    • Jiang, H. X.
    • Tang, N.
    • Chen, L. S.
  • Source: Biologia Plantarum
  • Volume: 55
  • Issue: 4
  • Year: 2011
  • Summary: Sour pummelo ( Citrus grandis) seedlings were irrigated with nutrient solution containing four boron concentrations ( i.e., 2.5, 10, 25 and 50 M H 3BO 3) and two aluminum concentrations [ i.e., 0 (-Al) and 1.2 mM AlCl 3 . 6 H 2O (+Al)]. It was found that B did not affect, but Al increased, the Al content in the roots. The Al and citrate contents in the -Al leaves either did not change or slightly increased with increasing B concentration. On the other hand, the Al and citrate contents in the +Al leaves rapidly decreased as B concentration increased from 2.5 to 50 M, then decreased at the highest B concentration. The Al and citrate contents were higher in the +Al than in the -Al leaves, except for at 25 M B when they were similar. The leaf malate content did not change in response to B or Al, except for an increase in the +Al leaves and a decrease in the -Al leaves at 2.5 M B. Similarly, the root malate and citrate contents did not change in response to B with or without Al, except for a decrease in the malate and citrate contents in the +Al roots at 50 M B and an increase in the citrate content in the -Al roots at 50 M B. The activities of acid-metabolizing enzymes were less affected by B-Al interactions in the roots than in the leaves.
  • Authors:
    • Hashimoto, A.
    • Ito, R.
    • Togami, T.
    • Kameoka, T.
  • Source: Agricultural Information Research
  • Volume: 20
  • Issue: 3
  • Year: 2011
  • Summary: In Nanki, Mie Prefecture, Japan, the mulching and drip irrigation system produces high-quality fruit despite large variations in the weather. For this cultivation system, we developed a small, stationary agricultural robot, "Field Server", which measures environmental and growing conditions in real time in the orchard. Our goals were to solve the problem of loss of the skills developed by experienced farmers due to a lack of new agricultural workers and aging of farmers, and to cultivate mandarin oranges with the required quality under occasionally severe and highly variable climate conditions. In this research, we demonstrated the ability of Field Server to monitor the agro-environmental conditions that affect plant physiology and the farmer's attitude towards their work and demonstrated the eKo wireless sensor network that was designed for agricultural use. To accomplish our goals, we installed a sensor network to support long-term, stable operation, including optimal placement of sensor nodes, optimal installation of the sensors and modification of network connections with Internet, and developed user-friendly Field Server and eKo data browsing software to help agricultural workers. Long-term data acquisition for a 1-ha agricultural site became possible due to improvements of the eKo system's hardware and software. In addition, the development of databases and related software permitted comparisons of the acquired data with data obtained from nearby AMeDAS stations. The comparison revealed the importance of agro-environmental monitoring (especially for rainfall) close to the production area and of soil moisture measurement to guide irrigation and produce high-quality mandarin oranges.
  • Authors:
    • Merwe, S. van der
    • Verreynne, S.
  • Source: SA Fruit Journal
  • Volume: 10
  • Issue: 2
  • Year: 2011
  • Summary: Sunburn is a major problem on early maturing mandarins such as 'Miho Wase' Satsuma. Currently, optimal irrigation during critical periods and shade nets are the only measures to reduce losses due to sunburn. Previous work using particle film technology (kaolin) on citrus to reduce sunburn was very effective, but the formulation used resulted in insect repercussions. The objective of the study was to determine if products such as Screen TM, Vapor Gard, Silicon and Raynox TM can reduce tree canopy temperature and thereby reduce sunburn on 'Miho Wase' Satsuma mandarins. All treatments were applied three times between December 2009 and January 2010. Screen TM reduced the sunburn incidence (fruit per tree) by 50%, possibly due to reductions in leaf temperature by 2.53C and fruit temperature by 1.73C, without a negative effect on fruit quality. Screen TM increased the sugar content of fruit. Vapor Gard increased fruit temperature, reduced the sugar content of the fruit, and increased sunburn incidence by 16%. Raynox TM, Silicon, and the combination of Screen TM and Vapor Gard had no effect on sunburn incidence.
  • Authors:
    • McClymont, L.
    • McAllister, A.
    • O'Connell, M. G.
    • Whitfield, D. M.
    • Abuzar, M.
    • Sheffield, K.
  • Source: Acta Horticulturae
  • Issue: 922
  • Year: 2011
  • Summary: The METRIC algorithm (Allen et al., 2007) was applied to a Landsat 5 image to assess the range of vegetation cover (measured as Normalised Difference Vegetation Index; NDVI), and rates of evapotranspiration (ET), of major horticultural crops grown in the Sunraysia Irrigation Region of SE Australia. The image represented the period of maximum foliage cover of horticultural crops grown in the Region. The range in mid-season NDVI of almond, grape and citrus crops almost matched the whole-of-season range reported for broad-acre irrigated annual crops grown in Idaho, USA. Alfalfa reference ET (ETr) constituted the upper limit to ET rate seen in Sunraysia crops. The range of ET and NDVI observations in this study therefore complied with limits on ET and NDVI seen in irrigated crops in Idaho, USA. ET-NDVI relationships seen in USA crops appear to provide a useful reference framework for well-watered irrigated crops in cases where ETr is the upper limit on ET. ET rates in Sunraysia crops were strongly related to NDVI. The dependence of ET rates on NDVI, combined with the large range in NDVI, meant that irrigation water requirement varied widely within and between crop types in the Sunraysia region: results support the use of NDVI measures to account for site-specific differences in crop water requirement attributable to vegetation cover. Findings suggest that satellite-based METRIC methods of ET estimation may be used to formulate region- and crop-specific estimates of the crop coefficients (Kcb, Ke, and Kc) required for optimal irrigation water management of horticultural crops.
  • Authors:
    • Chen, J. C.
    • Baez, I.
    • Takeuchi, Y.
    • Sequeira, R. A.
    • Ouyang, G. C.
    • Xia, Y. L.
  • Source: Plant Health Progress - Peer-Reviewed Journal of Appied Plant Health
  • Issue: October
  • Year: 2011
  • Summary: The Asian form of huanglongbing (HLB) is caused by ' Candidatus Liberibacter asiaticus (Las),' a phloem-limited bacterium transmitted by the Asian citrus psyllid, Diaphorina citri Kuwayama. Nutrient management, together with other cultural practices such as pruning and irrigation, for mitigation of the disease has been practiced in China for many years. Our literature review, field survey, and interviews with Chinese scientists and growers indicate that these cultural practices were generally ineffective for the disease management. However, a nutritional approach in conjunction with other cultural practices such as irrigation can maintain grove productivity for a certain time depending on the type of citrus species/cultivars, the age of the trees, the propagation method of the plants, the Asian citrus psyllid (ACP) ( Diaphorina citri Kuwayama) population, and other factors. Symptomatic mature pommelo ( Citrus maxima Merr) and sweet orange ( C. sinensis L. Osbeck) plants can commonly survive and maintain a certain level of productivity for an additional 4 to 5 years, even longer assuming vigorous ACP control.
  • Authors:
    • Siebert, S.
    • Portmann, F. T.
    • Doll, P.
  • Source: Global Biogeochemical Cycles
  • Volume: 24
  • Issue: 1
  • Year: 2010
  • Summary: To support global-scale assessments that are sensitive to agricultural land use, we developed the global data set of monthly irrigated and rainfed crop areas around the year 2000 (MIRCA2000). With a spatial resolution of 5 arc min (about 9.2 km at the equator), MIRCA2000 provides both irrigated and rainfed crop areas of 26 crop classes for each month of the year. The data set covers all major food crops as well as cotton. Other crops are grouped into categories (perennial, annual, and fodder grasses). It represents multicropping systems and maximizes consistency with census-based national and subnational statistics. According to MIRCA2000, 25% of the global harvested areas are irrigated, with a cropping intensity (including fallow land) of 1.12, as compared to 0.84 for the sum of rainfed and irrigated harvested crops. For the dominant crops (rice (1.7 million km 2 harvested area), wheat (2.1 million km 2), and maize (1.5 million km 2)), roughly 60%, 30%, and 20% of the harvested areas are irrigated, respectively, and half of the citrus, sugar cane, and cotton areas. While wheat and maize are the crops with the largest rainfed harvested areas (1.5 million km 2 and 1.2 million km 2, respectively), rice is clearly the crop with the largest irrigated harvested area (1.0 million km 2), followed by wheat (0.7 million km 2) and maize (0.3 million km 2). Using MIRCA2000, 33% of global crop production and 44% of total cereal production were determined to come from irrigated agriculture.
  • Authors:
    • Döll, P.
    • Siebert, S.
  • Source: Journal of Hydrology
  • Volume: 384
  • Issue: 3-4
  • Year: 2010
  • Summary: Crop production requires large amounts of green and blue water. We developed the new global crop water model GCWM to compute consumptive water use (evapotranspiration) and virtual water content (evapotranspiration per harvested biomass) of crops at a spatial resolution of 5′ by 5′, distinguishing 26 crop classes, and blue versus green water. GCWM is based on the global land use data set MIRCA2000 that provides monthly growing areas for 26 crop classes under rainfed and irrigated conditions for the period 1998-2002 and represents multi-cropping. By computing daily soil water balances, GCWM determines evapotranspiration of blue and green water for each crop and grid cell. Cell-specific crop production under both rainfed and irrigated conditions is computed by downscaling average crop yields reported for 402 national and sub-national statistical units, relating rainfed and irrigated crop yields reported in census statistics to simulated ratios of actual to potential crop evapotranspiration for rainfed crops. By restricting water use of irrigated crops to green water only, the potential production loss without any irrigation was computed. For the period 1998-2002, the global value of total crop water use was 6685 km 3 yr -1, of which blue water use was 1180 km 3 yr -1, green water use of irrigated crops was 919 km 3 yr -1 and green water use of rainfed crops was 4586 km 3 yr -1. Total crop water use was largest for rice (941 km 3 yr -1), wheat (858 km 3 yr -1) and maize (722 km 3 yr -1). The largest amounts of blue water were used for rice (307 km 3 yr -1) and wheat (208 km 3 yr -1). Blue water use as percentage of total crop water use was highest for date palms (85%), cotton (39%), citrus fruits (33%), rice (33%) and sugar beets (32%), while for cassava, oil palm and cocoa, almost no blue water was used. Average crop yield of irrigated cereals was 442 Mg km -2 while average yield of rainfed cereals was only 266 Mg km -2. Average virtual water content of cereal crops was 1109 m 3 Mg -1 of green water and 291 m 3 Mg -1 of blue water, while average crop water productivity of cereal crops was 714 g m -3. If currently irrigated crops were not irrigated, global production of dates, rice, cotton, citrus and sugar cane would decrease by 60%, 39%, 38%, 32% and 31%, respectively. Forty-three per cent of cereal production was on irrigated land, and without irrigation, cereal production on irrigated land would decrease by 47%, corresponding to a 20% loss of total cereal production. The largest cereal production losses would occur in Northern Africa (66%) and Southern Asia (45%) while losses would be very low for Northern Europe (0.001%), Western Europe (1.2%), Eastern Europe (1.5%) and Middle Africa (1.6%). Uncertainties and limitations are discussed in the manuscript, and a comparison of GCWM results to statistics or results of other studies shows good agreement at the regional scale, but larger differences for specific countries.
  • Authors:
    • listed as anonymous
  • Source: Egyptian Journal of Plant Breeding
  • Volume: 11
  • Issue: 1
  • Year: 2007
  • Summary: These proceedings contain 30 papers on the various aspects of plant breeding including heterosis, combining ability and inheritance studies, characterization of cultivars, performance evaluation and genetic improvement of field crops (including wheat, cotton, soyabean, maize, rice, barley, rape, sorghum and faba bean) and horticultural crops (e.g. mango, tomato, pepper and grape).