• Authors:
    • Zhou, Y.
    • Zhang, X.
    • Chen, X.
    • Zhao, Q.
    • Lei, J.
    • Zhang, H.
    • Qiao, X.
  • Source: Xinjiang Agricultural Sciences
  • Volume: 48
  • Issue: 10
  • Year: 2011
  • Summary: Objective: The purpose of this project was to clarify shade condition's effect on the formation of kernel number per spike and analyze yield components of wheat under shade condition so as to take an effective growth measurement on fruit tree-crop intercropping models (Jujube-wheat, Apricot-wheat and Walnut-wheat intercropping). Method: In the present paper, the effects of shading on kernel number per spike were studied and analysis of yield components of wheat under the artificial shade condition was carried out. Result: The results showed that, under the artificial shade condition, the fertile florets, plant weight, grains per spike, grains weight per spike, spike number per hectare and yield were obviously reduced in the course of the wheat growth period. Conclusion: The results indicated that improving the kernel number per spike should be focused on the differentiation, growth and development, degeneration and grain courses of florets. Improving the yield should be focused on the growth and development, spike number per hectare and grain-filling characteristic courses of plants.
  • 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:
    • Goulart, R. Z.
    • Rocha, P. V. da
    • Santos, M. S. dos
    • Eltz, F. L. F.
    • Rocha, M. R. da
  • Source: REVISTA BRASILEIRA DE CIENCIA DO SOLO
  • Volume: 35
  • Issue: 4
  • Year: 2011
  • Summary: The watermelon is cultivated mainly by small producers, in sandy soils under conventional tillage, with occurrence of high erosion taxes, since the crop doesn't form canopy capable to cover the soil entirely. Watermelon ( Citrullus lanatus L.) was evaluated under different cultivation systems on an Ultisol in the Central Depression of RS, Brazil, in an experiment in the 2008/2009 growing season. On 48 m 2 plots in a randomized block design with four repetitions, the following cultivation systems were tested: conventional tillage (CT), no-tillage (NT), NT chiseled with one chisel shank (NT1S), NT chiseled with two shanks (NT2S), NT chiseled with three shanks (NT3S), NT chiseled with four shanks (NT4S), NT chiseled with five shanks (NT5S); the distance between chisel shanks was 0.35 m. Data were analyzed by the Duncan test (p6 kg), the root surface area and root system distribution in the soil profile perpendicular to the sowing line were determined 30 and 60 d after sowing. Besides, some soil physical properties (soil density and resistance to penetration) were determined after the watermelon cycle. The yield was highest under CT (126 t ha -1), differing statistically from the other treatments. The total root area increased with intensity and area of soil mobilization, except in the NT4S treatment. In the CT treatment, no difference in depth was observed, but in the other treatments the 0-5 cm layer differed from the deeper layers. Resistance to penetration in the 0-10 cm layer was lower, which may be related to the higher root concentration in that layer.
  • Authors:
    • [Anonymous]
  • Source: Agricultural Information Research
  • Volume: 20
  • Issue: 3
  • Year: 2011
  • Summary: This special section contains four papers dealing with the establishment of the field server applications for high-quality mandarin orange production in Japan. It covers soil moisture measurement to support production of high-quality oranges for information and communication technology application, field datalogger system using mobile phones and a web-based interface, a new tool utilizing silicone rubber balls for fruit hardness determination, and agro-environmental monitoring using wireless sensor network.
  • Authors:
    • Intrigliolo, D.
    • Castel, J.
    • Ballester, C.
    • Castel, J.
  • Source: Agricultural Water Management
  • Volume: 98
  • Issue: 6
  • Year: 2011
  • Summary: The effects of mid-summer regulated deficit irrigation (RDI) treatments were investigated on Clementina de Nules citrus trees over three seasons. Water restrictions applied from July, once the June physiological fruit drop had finished, until mid September were compared with a Control treatment irrigated during all the season to match full crop evapotranspiration (ET c). Two degrees of water restrictions were imposed based on previous results also obtained in Clementina de Nules trees ([Ginestar and Castel, 1996] and [Gonzalez-Altozano and Castel, 1999]). During the RDI period, deficit irrigation was applied based on given reductions over the ET c, but also taking into account threshold values of midday stem water potential (psi s) of -1.3 to -1.5 MPa for RDI-1 and of -1.5 to -1.7 MPa for RDI-2. Results showed that water savings achieved in the RDI-2 treatment impaired yield by reducing fruit size. On the contrary, the RDI-1 strategy allowed for 20% water savings, with a reduction in tree growth but without any significant reduction in yield, fruit size nor in the economic return when irrigation was resumed to normal dose about three months before harvest. Water use efficiency (WUE) in the RDI trees was similar or even higher than in Control trees. RDI improved fruit quality increasing total soluble solids (TSS) and titratable acidity (TA). In conclusion, we suggest that the RDI-1 strategy here evaluated can be applied in commercial orchards not only in case of water scarcity, but also as a tool to control vegetative growth improving fruit composition and reducing costs associated with the crop management.
  • Authors:
    • Benchabane, M.
  • Source: IOBC/WPRS Bulletin
  • Volume: 62
  • Year: 2011
  • Summary: After studies (2006-2009) of the states of fading of citrus fruits in the Mitidja (Algeria), we noted a troubling epidemic evolution in some orchards where the death rates reached proportions of 5 to 10%. The symptomatologic diagnosis indicates the presence of a strong likeness between the different biotic reasons possible without the presence of symptoms typical and/or of revealing signs of the known diseases (bacteria and virus). The diagnosis of laboratory confirmed their absence. The isolations achieved from the roots and soil put often in evidence the presence of Fusarium flora dominated by Fusarium solani and Fusarium oxysporum species. The implication of these species is joined to the pedological features and to the technical practices, notably the irrigation.
  • Authors:
    • Singh, J.
    • Bhatnagar, P.
    • Kaul, M.
  • Source: Acta Horticulturae
  • Issue: 922
  • Year: 2011
  • Summary: Studies of variation in plant environmental factors of Kinnow mandarin for at Agriculture Research Station, SriGanganagar district of Rajasthan state in India during 2002-04 with respect to three differential irrigation treatments revealed that overall maximum carboxylation efficiency (A) was estimated at 70% Etc treatment from April to June with a linear trend. It showed depression in September and October followed by a steady rise in November and December months. Stomatal conductance revealed oscillating trend with maximum in 70% Etc treatment for April and May months followed by steep rise in 40% Etc treatment for June-July. It remained static in August and September, but a trend reversal occurred in October-November with maximum stomatal conductance in 100% Etc treatment. The cumulative overall high stomatal resistance in 40% treatment might have attributed to low photosynthetic rates followed by 100% treatment and the better assimilation rates were observed under 70% treatment and were correlated with low rates of stomatal resistance. The daily course of transpiration in all the three irrigation treatments was not closely linked to solar irradiation but rather to leaf temperature. Temperatures of 25-30degreesC are optimal for photosynthesis but temperatures above 30degreesC definitely reduce photosynthetic activity. The annual trend for three consecutive years' data revealed occurrence of cyclic oscillations in photosynthesis, stomatal conductance, stomatal resistance, transpiration rate and photosynthetic active radiation under field conditions. Citrus belong to C3 plants, with photosynthetic rates lower than C4 plants. Assimilation rates ranging from 1.28 to 7.93 mmol m -2 s -1 observed under differential irrigation treatments seem realistic under optimal irrigated conditions of Western Rajasthan.
  • Authors:
    • Mhamdi, M.
    • Boughalleb, F.
    • Hajlaoui, H.
  • Source: Agricultural Journal
  • Volume: 6
  • Issue: 3
  • Year: 2011
  • Summary: Experiments were conducted with lemon ( Citrus limon v. Eureka) and orange trees ( Citrus sinensis cv. Maltese) to determine the optimum NPK fertilizer rates for young citrus trees in greenhouse and field conditions. Greenhouse nursery trees received 0-0-0, 0-25-50, 25-25-50, 50-25-50 or 100-25-50 mg L -1 of N-P 2O 5-K 2O via drip irrigation. The results showed that increased N rates improved leaf number, shoot length, total leaf area and stem diameter. The optimum tree growth was occurred with 50 and 100 mg N L -1. Results also showed that the percentages of N in the leaves were increased in proportion to the amount of N added while the percentage of P and K were decreased. However, the concentrations of Ca, Mg, Fe, Mn and Zn were unaffected by N rates but the leaf Cu concentration increased significantly. Leaf Mg concentration was increased by the presence of K in the nutrition solution. Form this study, we recommended the use of 100 N-25 P 2O 5-50 K 2O mg L -1 for the good growth of nursery citrus plants in the absence of any possibility of deficiency or excessive accumulation of mineral elements. In the second experiment, two fertilizers mix 180-90-180 and 360-90-180 of N-P 2O 5-K 2O kg ha -1 were applied to young citrus tree in field condition. Increased the level of N had no effect on leaf number and stem diameter in Eureka lemon however shoot length and total leaf area were slightly increased and these increment in growth was higher in Maltese orange.
  • Authors:
    • Pendergast, L.
    • Torabi, M.
    • Bhattarai, S.
    • Dhungel, J.
    • Chen, X.
    • Midmore, D.
  • Source: Journal of Plant Ecology
  • Volume: 4
  • Issue: 4
  • Year: 2011
  • Summary: Aims Oxygation refers to irrigation of crops with aerated water, through air injection using the venturi principle or the supply of hydrogen peroxide in the root zone, both using subsurface drip irrigation (SDI) system. Oxygation improves water use efficiency (WUE), producing more yield and, and therefore, optimizes the use of drip and SDI. But the efficiency of oxygation is quite possibly dependent on a number of factors. The primary objective of this study was, therefore, to quantify the effects of oxygation, emitter depths and soil type on crop root zone oxygen content, soil respiration, plant physiological response, biomass yield, quality and WUE of three crop species. Methods This study investigated the potential of oxygation to enhance soil respiration, plant growth, yield and water use efficiencies (WUE) of cotton and wheat in experiments in enclosed heavy-duty concrete troughs (tubs) and pineapple and cotton in field experiments. Experimental treatments in tubs for wheat included comparisons between two soil types (vertisol and ferrosol) and superimposed were two oxygation methods (Mazzei air injector and Seair Diffusion System) compared to a control, and for cotton, emitters at two depths using Mazzei air injectors were compared to a control. The field experiments compared Mazzei air injectors and a control for cotton in Emerald and pineapple in Yeppoon, both in central Queensland, Australia. Important findings In all experiments, soil oxygen content and soil respiration markedly increased in response to the oxygation treatments. The O-2 concentration in the crop root zone increased by 2.4-32.6%, for oxygation compared to control at the same depth. The soil respiration increased by 42-100%. The number of wheat ears, leaf dry weight and total dry matter were significantly greater in Mazzei and Seair oxygation compared to the control. Fresh biomass of wheat increased by 11 and 8%, and dry weight of wheat increased by 8 and 3% in Mazzei and Seair oxygation treatments compared to the control, respectively. Likewise, the irrigation water use efficiency increased with oxygation compared to the control in wheat. The yield, WUE and number of other physiological parameters in wheat were enhanced in vertisol compared to ferrosol. The seed cotton yield in the tub experiment increased with oxygation by 14%, and significant differences for fresh biomass, dry matter and yield were also noted between oxygation and the control in the field. Lint yield and WUE both increased by 7% using Mazzei in the cotton field trial during 2008-09. There were significant effects of oxygation on pineapple fresh biomass, and dry matter weight, industry yield and a number of quality parameters were significantly improved. The total fruit yield and marketable increased by 17 and 4% and marketable WUE increased by 3% using Mazzei. Our data suggest that the benefits of oxygation are notable not only for dicotyledonous cotton but also for monocotyledonous wheat and pineapple representing different rooting morphologies and CO2 fixation pathways.
  • Authors:
    • Verstraeten, W. W.
    • Strever, A.
    • Stuckens, J.
    • Verreynne, S. J.
    • Dzikiti, S.
    • Swennen, R.
    • Theron, K.
    • Coppin, P.
  • Source: Agricultural and Forest Meteorology
  • Volume: 151
  • Issue: 8
  • Year: 2011
  • Summary: This study describes the diurnal and seasonal dynamics of the canopy reflectance, water use and water status of Midknight Valencia citrus trees under semi-arid conditions. Hyperspectral canopy reflectance data was collected on 30 trees at monthly intervals over a period of 16 months in a commercial orchard in South Africa. The mean canopy reflectance in the wavelength range 350-2500 nm followed a clear seasonal trend influenced by environmental conditions and tree phenology. Mean monthly reflectance peaked in summer (~22%) while the lowest value (~15%) was reached in winter with the seasonal changes in the sun's position accounting for a significant proportion of the variations. A sensitivity analysis of a Penman-Monteith transpiration model showed that water use by individual trees changed by up to 13% when the canopy reflectance was varied over the seasonal range of measured values. This suggested that the seasonal changes in tree water use influenced the seasonal trend of the canopy reflectance. Thus monitoring the canopy reflectance of citrus trees could offer information on the tree water status. To test this, sap flow data of water uptake and loss by the trees were compared with the canopy spectra. Sap flow data showed a heavy reliance by the citrus trees on the internally stored water with up to 25% of the daily total transpiration withdrawn from the trees' internal water storage pools when soil water was limited. This depletion of internally stored water, and hence the change in tree water status, was detected using spectral indices based on the first order derivatives of the canopy reflectance centered at two and, at most, four spectral bands. We conclude that even if citrus trees are evergreen, their canopy reflectance changes significantly throughout the year with a considerable impact on tree energy balance and water use. In addition, the contribution of the internally stored water to daily transpiration is a possible indicator of drought stress for citrus trees detectable from changes in canopy reflectance and it has potential applications in irrigation scheduling using canopy level spectral information.