• Authors:
    • Basheer, A. M.
    • Mohamed, E. M.
    • Abukaf, N.
  • Source: Egyptian Journal of Biological Pest Control
  • Volume: 22
  • Issue: 1
  • Year: 2012
  • Summary: A study to survey parasitoid species associated with the citricola scale insect, Coccus pseudomagnoliarum (Kuwana) (Homoptera: Coccidae) was carried out in untreated citrus orchards, at 4 districts (Alrama-Ean Alaros-Hmaimimm and Albassa), at Lattakia, Syria, seasons 2010 and 2011. Weekly sampling was undertaken by collecting infested leaves and twigs. Rate of parasitism, population trend of the parasitoid complex and the role of each species was determined. The survey revealed the presence of 10 parasitoid species; 2 aphelinids ( Coccophagus lycimnia and Coccophagus sp.), 5 encyrtids ( Metaphycus sp., M. helvolus, Microterys nietneri, Baryscapus sp. and Encyrtus sp.), one pteromalid ( Prochiloneurus sp.) and 2 eulophids ( Abrostocetus sp. and Tetrastichus sp.).
  • Authors:
    • Oztekin, M. E.
  • Source: Journal of Food, Agriculture and Environment
  • Volume: 10
  • Issue: 2 part 3
  • Year: 2012
  • Summary: Land use is an important global issue in terms of preserving the soils, agricultural crop production and farmers' economy as well as the other usage purposes. There are many useful approaches and tools for efficient determination of the land use types. In this study, distribution of different field crops and citrus orchards were monitored and determined for land use types (LUTs) using the low cost ASTER satellite images and GIS in Akarsu Irrigation District of Lower Seyhan Plain (9495 ha) in southern Turkey. Prior to parceling in the field, study area maps of 1:5000 scale were digitized by using ArcGIS software. The enhanced satellite images were overlaid onto the digitized parcel map for ground observations. The images were printed and checked for all crops of the fields. Commonly grown different field crops and orchards were mapped during the field work. A database for this research was established after an intensive field work. The crop types and their coordinates were determined and recorded during the field works. Five LUTs were identified in the study area, and corn and citrus were the most planted LUTs. Furthermore, suitability of soil series for LUTs was investigated; Canakci and Mursel soil series in the study area were found to be highly suitable for all LUTs. It was concluded that cost effective ASTER images could be potentially used for the determination of different crops and orchards which have different reflection values. However, the images must be obtained during the appropriate time period.
  • Authors:
    • Conesa, M. R.
    • Domingo, R.
    • Perez-Pastor, A.
    • Pagan, E.
    • Caro, M.
  • Source: Agricultural Water Management
  • Volume: 111
  • Year: 2012
  • Summary: A two year experiment on Fortune mandarin trees (Clementina * mandarina Dancy ( Citrus clementina Hort. Ex. Tanaka * Citrus reticulata Blanco)) grafted onto Cleopatra mandarin ( Citrus reshni Hort. ex. Tanaka) rootstock was carried out with the aim of studying the suitability of midday stem water potential (psi stem) and trunk diameter reference baselines for irrigation scheduling. Plants were drip-irrigated with saline water during the second year (EC 25°C ~ 4 dS m -1). Measurements of psi stem, trunk daily growth rate (TGR) and maximum daily trunk shrinkage (MDS) were related with meteorological variables. Among them, MDS presented the best behavior. The mean temperature during the period 10.00-15.00 h solar time ( Tmd) was the environmental variable that best correlated with MDS, although there were no differences with other T-related variables (daily mean and daily maximum values). MDS data from stage III did not correlate with meteorological variables and fit-linear regressions became better with data from stages I and II (March-October), this being the period which covers 80% of total crop water requirements. Despite the different conditions that the trees were submitted to during the experimental period, i.e. irrigation water with different salinity and crop load, inter-annual differences were not observed in the reference baselines obtained.
  • Authors:
    • Huchche, A. D.
    • Srivastava, A. K.
    • Panigrahi, P.
  • Source: Agricultural Water Management
  • Volume: 104
  • Year: 2012
  • Summary: The scarcity of irrigation water is one of the major causes of low productivity and decline of citrus orchards. The present study was planned with a hypothesis that the drip irrigation (DI) could save a substantial amount of water over surface irrigation, besides improving the yield of citrus plants. The experiment was conducted for 3 seasons during 2006-2009, with 'Nagpur' mandarin ( Citrus reticulata Blanco) plants budded on rough lemon ( Citrus Jambhiri Lush) rootstock in central India. The effects of DI and basin irrigation (BI) on soil chemical properties and crop responses were studied. DI was scheduled every-other-day at 40%, 60%, 80% and 100% of the alternate day cumulative evaporation ( Ecp) measured in Class-A evaporation pan. DI except irrigation at 40% Ecp proved superior to BI, producing more growth and fruit yield of plants. The higher plant growth was recorded with higher regime of DI. The maximum fruit yield in DI at 80% Ecp, using 29% less irrigation water resulted in 111% improvement in irrigation water productivity under this treatment over BI. The heavier fruits, with lower acidity and higher total soluble solids, were harvested in DI at 80% Ecp compared with BI. The significant variation of soil water content at 0-0.2 m depth under DI indicated the confinement of effective root zone of the plants in top 0.2 m soil. The maximum rate of net-photosynthesis, stomatal conductance and transpiration in leafs was recorded in DI at 100% Ecp. However, the plants under DI at 80% Ecp exhibited the highest leaf water use efficiency. The maximum salinity build-up with highest decrease in pH was observed in 0-0.2 m soil under DI, whereas the salinity development was prominent in 0.4-0.6 m soil with an increase in pH under BI. The gain in available macronutrients (N, P and K) and loss of micronutrients (Fe, Mn, Cu and Zn) in soil followed the similar trend of EC. The leaf nutrient (N, P, K, Fe, Mn, Cu and Zn) analysis revealed that DI produced significantly ( P
  • Authors:
    • Huchche, A. D.
    • Srivastava, A. K.
    • Panigrahi, P.
    • Singh, S.
  • Source: Journal of Plant Nutrition
  • Volume: 35
  • Issue: 2
  • Year: 2012
  • Summary: Evaluation of drip irrigation treatments scheduled at 40, 60, 80, and 100% of alternate day cumulative pan evaporation (Ecp) against basin irrigation method was undertaken in 1-year-old 'Nagpur' mandarin ( Citrus reticulata Blanco) trees budded on rough lemon [ Citrus jambhiri (L)] rootstock on an alkaline Inceptisol soil type for three seasons during 2003-2005. Growth responses showed significantly ( P≤0.05) higher annual increase in tree height (0.44-0.50 m), scion girth (37-45 mm), and canopy volume (0.508-0.986 m 3) under drip-irrigation except irrigation at 40% Ecp, compared to tree height (0.40 m), scion girth (36 mm), and canopy volume (0.463 m 3) under basin irrigation. The highest magnitude of increase in different growth parameters was observed with drip irrigation at 80% Ecp, which produced the net water saving of 32% over basin irrigation method. Response on leaf nutrient composition under drip irrigation at 80% Ecp likewise produced the similar response, [2.27% nitrogen (N), 1.98% potassium (K), and 121.8 ppm iron (Fe)], significantly ( P≤0.05) higher than under basin irrigation (1.12% N, 1.04% K, and 98.3 ppm Fe), with other nutrients, e.g., phosphorus (P), manganese (Mn), copper (Cu), and zinc (Zn) remained unaffected.
  • Authors:
    • Alarcon, J. J.
    • Gil, M. I.
    • Allende, A.
    • Pedrero, F.
  • Source: Agricultural Water Management
  • Volume: 109
  • Year: 2012
  • Summary: The effects of applying different types of treated wastewater on citrus trees were studied in Murcia, in the south-east of Spain. Two treatments with wastewater effluents of different quality were applied for three consecutive years. In the first case, the wastewater received a secondary treatment (conventional activated sludge). In the second case, the irrigation water was a mix of well water and wastewater from a tertiary treatment plant (conventional activated sludge with ultraviolet tertiary treatment). The characteristics of the tertiary treated wastewater make it better for irrigation than the secondary treated wastewater. It was considered that high salinity, Cl and B concentration could be the main restrictions associated with treated wastewater irrigation in both cases, although leaf toxicity levels were not observed. The soil nitrate concentration increased over the experimental time period in both water irrigation treatments. The production was affected by the wastewater quality and the total crop yield was lower in the plots irrigated with secondary treated wastewater. However, in these plots, the fruit-quality indexes such as external colour, weight, peel thickness, firmness, soluble solids, pH, total acidity and maturity index were significantly better than those observed in the plots irrigated with tertiary treatment. The soil microbiological analysis revealed an absence of faecal coliforms, Escherichia coli and helminth eggs in the experimental plots irrigated with tertiary treated wastewater, but with secondary treated wastewater the soil accumulation of faecal coliforms exceeded health standards. In both cases, there was an absence of microbiological contamination on fruits.
  • Authors:
    • Montes, C. R.
    • Stoffella, P. J.
    • He, Z. L.
    • Pereira, B. F. F.
    • Melfi, A. J.
    • Baligar, V. C.
  • Source: Journal of Environmental Quality
  • Volume: 41
  • Issue: 3
  • Year: 2012
  • Summary: Irrigation of citrus ( Citrus aurantium L. * Citrus paradise Macf.) with urban reclaimed wastewater (RWW) can be economical and conserve fresh water. However, concerns remain regarding its deleterious effects on soil quality. We investigated the ionic speciation (ISP) of RWW and potential impacts of 11 yr of irrigation with RWW on soil quality, compared with well-water (WW) irrigation. Most of nutrients (~53-99%) in RWW are free ionic species and readily available for plant uptake, such as: NH 4+, NO 3-, K +, Ca 2+, Mg 2+, SO 42-, H 3BO 3, Cl -, Fe 2+, Mn 2+, Zn 2+, Co 2+, and Ni 2+, whereas more than about 80% of Cu, Cr, Pb, and Al are complexed with CO 3-, OH -, and/or organic matter. The RWW irrigation increased the availability and total concentrations of nutrients and nonessential elements, and soil salinity and sodicity by two to three times compared with WW-irrigated soils. Although RWW irrigation changed many soil parameters, no difference in citrus yield was observed. The risk of negative impacts from RWW irrigation on soil quality appears to be minimal because of: (i) adequate quality of RWW, according to USEPA limits; (ii) low concentrations of metals in soil after 11 yr of irrigation with RWW; and (iii) rapid leaching of salts in RWW-irrigated soil during the rainy season.
  • Authors:
    • Dodd, I. C.
    • Pérez-Pérez, J. G.
    • Botía, P.
  • Source: Functional Plant Biology
  • Volume: 39
  • Issue: 5
  • Year: 2012
  • Summary: To determine whether irrigation strategy altered the sensitivity of Citrus leaf gas exchange to soil, plant and atmospheric variables, mature (16-year-old) Fino 49 lemon trees ( Citrus limon (L.) Burm. fil. grafted on Citrus macrophylla Wester) were exposed to three irrigation treatments: control (irrigated with 100% of crop potential evapotranspiration, ET c), deficit irrigation (DI) and partial rootzone drying (PRD) treatments,which received 75% ET c during the period of highest evaporative demand and 50% ET c otherwise. Furthermore, to assess the physiological significance of root-to-shoot ABA signalling, the seasonal dynamics of leaf xylem ABA concentration ([X-ABA] leaf) were evaluated over two soil wetting-drying cycles during a 2-week period in summer. Although stomatal conductance ( gs) declined with increased leaf-to-air vapour pressure deficit (LAVPD), lower leaf water potential and soil water availability, [X-ABA] leaf was only related to stomatal closure in well irrigated trees under moderate (
  • Authors:
    • Espadaler, X.
    • Ribes, J.
    • Ribes, E.
    • Piñol, J.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 158
  • Year: 2012
  • Summary: The Heteroptera assemblage of a citrus grove and how it was affected by ant-exclusion was examined during transformation from conventional to organic agriculture. The results showed that the Heteroptera assemblage changed dramatically over the eight years of the study: at first, it mainly consisted of herbivorous lygaeids and predatory anthocorids but became dominated by predatory mirids in 2008-2009. The predator/herbivore ratio increased steadily over the eight years of the study. Ants can form mutualistic relationships with heteropteran pests. However, exclusion of ants from canopies did not affect the Heteroptera assemblage at the beginning of the study, but had a profound effect later on. In particular, ant-exclusion increased the abundance of most predatory Heteroptera, except for the myrmecomorphic mirid Pilophorus perplexus, which was approximately five times more abundant in control than in ant-excluded trees; the analyses showed that the only mimicked ant species was Lasius grandis.
  • Authors:
    • Santana, J. A. D. V.
    • Carvalho, G. C.
    • Machado, V. V.
    • Daniel, R.
    • Coelho, E. F.
    • Coelho Filho, M. A.
    • Sampaio, A. H. R.
    • Santana Junior, E. B.
  • Source: Acta Horticulturae
  • Issue: 928
  • Year: 2012
  • Summary: The management of irrigation using partial root drying (PRD) was tested in an orchard of 'Tahiti' lime in the semi-arid conditions of Iacu, BA. Six treatments were evaluated: T1, T2, T3 (50% ETc PRD) with plants irrigated by a microsprinklers with its position alternating every 7, 14 or 21 days, respectively, and wetting on opposite sides of the root system; T4 (DI 50% ETc) irrigation was fixed on one side using one emitter per plant, T5 (100% ETc) was the control treatment using two microsprinklers per plant in a fixed position. In T6, at each interval of 21 days, one and two micro-sprinklers were alternatively used per plant. Results demonstrated significant differences in fruit production by the Scott Knott test (p