• Authors:
    • [Anonymous]
  • Source: Soils Newsletter
  • Volume: 34
  • Issue: 1
  • Year: 2011
  • Summary: Through an IAEA technical cooperation project, the Turkish Atomic Energy Agency, in cooperation with the Nigde Potato Research Institute and the Soil and Fertilizer Research Institute, an innovative drip fertigation technology was implemented to improve water and nitrogen fertilizer use efficiency in potato production in the Nigde-Nevsehir Region. This technology reduced the amount of irrigation water needed by 50% and nitrogen fertilizer use by 40%, from 1000 to 600 kg N/ha. Drip fertigation technology increased water and nitrogen use efficiency by applying water and nitrogen directly to the immediate vicinity of the plant roots through a network of pipes and water emitters. Considering the magnitude and importance of potato production in the arid and semiarid areas of Turkey, the 50% reduction in crop water requirements through drip fertigation has a major impact on agricultural production and water management strategies in these areas. It was calculated that a transition from sprinkler irrigation to drip fertigation requires an initial investment cost of up to US $200/ha, depending on the sophistication of the drip fertigation system. This investment can be balanced against projected savings in time, energy, fertilizer and labour costs amounting to an estimated US $2000/ha/year. As a consequence, interest in drip fertigation has been remarkable among potato farmers in the region, so that in only three years the area under drip fertigation has increased from humble beginnings of 500 ha in 2005 to 4000 ha in 2007 and to nearly 7000 ha in 2010.
  • Authors:
    • Benismailc, M.
    • El-Otmanic, M.
    • Fadlc, A.
    • Hammoutib, B.
    • Salghia, R.
    • Abouatallaha, A.
    • Eljaouharic, N.
    • Kabousc, E.
    • Zianic, A.
  • Source: Der Pharma Chemica
  • Volume: 3
  • Issue: 6
  • Year: 2011
  • Summary: Capacitance probes were tested in a young citrus orchard for irrigation water saving; Cumulative water received by the plot reached 334 mm and 398 mm for the first and second year period respectively (irrigation+useful rain). Irrigations were made in 521 interventions when the lowest dose of 1.05 mm was used and in 210 interventions when the highest dose of 2.6 mm was applied. Capacitance probes were giving values statistically different compared to the gravimetric method, but with, however, a meaningful interrelationship; A good correlation was then obtained between real values and reading from capacitance probes, a value of 16% showed by the C-probe is equivalent to 22%. The parameters of growth, trunk diameter microvariations probes (LVDT) and components of yield are well correlated with Soil moisture and Vapor Pressure Deficit (VPD). Treatment 1 (T1) was better in cold period (December, January and February), while Treatment 4 (T4) was more efficient from flowering (March) and developed deep roots (more than 50 cm). Leaf water potential and LVDT showed the sensitivity of T1 towards climate changes during high evaporative demand days. Analysis of soil moisture data showed that the field capacity was maintained at not more than 30 cm soil depth for T1, which developed very superficial roots (45% at only 10 cm). The number of roots was significantly different between treatments, T4 was distinguished by a greater concentration of roots (8843), compared to T1 (4104). After 27 months from plantation, the Yield showed a performance of 46 T/ha recorded for the dose of 2.1 mm, when the fruit size was 70% of Size 1-3; water saving was about 50% and valuated at 105 l/kg produced.
  • Authors:
    • Alvaro-Fuentes, J.
    • Paustian, K.
  • Source: Plant and Soil
  • Volume: 338
  • Issue: 1/2
  • Year: 2011
  • Summary: Climate change is projected to significantly impact vegetation and soils of managed ecosystems. In this study we used the ecosystem Century model together with climatic outputs from different atmosphere-ocean general circulation models (AOGCM) to study the effects of climate change and management on soil organic carbon (SOC) dynamics in semiarid Mediterranean conditions and to identify which management practices have the greatest potential to increase SOC in these areas. Five climate scenarios and seven management scenarios were modeled from 2010 to 2100. Differences in SOC sequestration were greater among management systems than among climate change scenarios. Management scenarios under continuous cropping yielded greater C inputs and SOC gain than scenarios under cereal-fallow rotation. The shift from rainfed conditions to irrigation also resulted in an increase of C inputs but a decrease in the SOC sequestered during the 2010-2100 period. The effects of precipitation and temperature change on SOC dynamics were different depending on the management system applied. Consequently, the relative response to climate and management depended on the net result of the influences on C inputs and decomposition. Under climate change, the adoption of certain management practices in semiarid Mediterranean agroecosystems could be critical in maximizing SOC sequestration and thus reducing CO 2 concentration in the atmosphere.
  • Authors:
    • Sanjani, S.
    • Bannayan, M.
  • Source: Agricultural and Forest Meteorology
  • Volume: 151
  • Issue: 12
  • Year: 2011
  • Summary: Climate variability and weather extremes are principal sources of fluctuations of annual productivity of many crops in arid and semi-arid environments. Temperature and precipitation are the major weather variables that determine the variability of crop yields. In this study, the relationship between weather descriptors and major irrigated crops yield were assessed for Khorasan province in northeast of Iran. Long term daily weather (1984-2007) and crop yield (wheat, barley, sugarbeet, cotton, potato, chickpea, alfalfa) data were analyzed with simple correlation analysis and also the iterative chi-square analysis identified relationships of low and high wheat yield years to maximum and minimum air temperatures within each region. Our results indicated that association between various crop yield and descriptors varied in different study location. As in Bojnourd located in the north of Khorasan yields of the crops studied did not correlate with temperature indicators, whereas in Birjand the relationship between temperature descriptors and crop yields were strong. Correlation between growing season precipitation and wheat, barley, chickpea and sugarbeet yields was positive while cotton yield decreased with increasing precipitation during the growing season. The results of chi-square analysis for wheat yield demonstrated that the critical time in which extreme temperature led to yield loss differed among regions. In Bojnourd, in late April to early May, and excess days (high or low yield years have more days meeting a cardinal value than normal years) with maximum temperature higher than 30 degrees C, wheat yield decreased while in Birjand, cooler maximum temperature (
  • Authors:
    • Scicolone, B.
    • Consoli, S.
    • Capra, A.
  • Source: Acta Horticulturae
  • Issue: 922
  • Year: 2011
  • Summary: Citrus orchards are economically one of the most important crops in South Italy, where climate is semi-arid with scarce rain and high evaporative demand. One way to optimize water resources in this region is to adopt deficit irrigation (DI) strategies, such as regulated deficit irrigation (RDI). In Mediterranean regions, DI criteria have been widely applied and crop physiological responses to water deficit application have been studied in depth, but the profitability of these strategies in commercial orchards is still largely unknown. The objective of this study was to determine the economic feasibility of DI treatment on orange orchards in Sicily (South Italy), by estimating optimum levels of applied water which provide maximum profit under limited resource availability (e.g. land or water). The applied methodology follows the economic analysis on DI suggested by English in 1990. The analysis of the profit/total costs ratio showed that Deficit Irrigation strategies would increase the generated income, thus being more profitable (up to a maximum of 100%) than the current irrigation water supply management in the area.
  • Authors:
    • Thakur, A.
    • Dalal, R.
  • Source: Advances in Horticultural Science
  • Volume: 25
  • Issue: 1
  • Year: 2011
  • Summary: The root distribution pattern of 17-year-old pineapple orange trees budded on Rough lemon, Cleopatra and Troyer citrange rootstocks were studied by root excavation method at four radial distances, 0-75, 75-150, 150-225 and 225-300 cm from tree trunk, and at three depths, 0-15, 15-30 and 30-60 cm. Fibrous root length density (FRLD) and fibrous root length percentage differed significantly at various depths and radial distances among rootstocks. FRLD was closer to tree trunk on both horizontal and vertical planes. Root density decreased from 0.183 to 0.084, 1.051 to 0.238 and 0.238 to 0.095 cm.cm -3 from 0-15 cm to 30-60 cm depth within 0-75 cm radial distances from tree trunk in trees on Rough lemon, Cleopatra and Troyer citrange, respectively. Cleopatra contains the highest 0.231 cm.cm -3 FRLD as compared to 0.051 cm.cm -3 in Rough lemon and Troyer citrange. Troyer citrange has intensive lateral root development with 84% fibrous roots (FR) within 75 cm radial distance, whereas Rough lemon and Troyer has an appreciable amount up to 225 cm distance (extensive lateral). Cleopatra contained 57% FR in upper soil layer (0-15 cm) (intensive vertical). In Rough lemon and Troyer 54% FR are confined to lower depth 15-60 cm (extensive vertical root development). Troyer and Rough lemon had the same vertical, whereas Rough lemon and Cleopatra showed the same horizontal rooting pattern under arid irrigated ecosystem. Thus, irrigation depth and fertilizer placement should be critically rootstock specific.
  • Authors:
    • Muriel-Fernández, J. L.
    • Durán-Zuazo, V. H.
    • García-Tejero, I.
    • Martínez-García, G.
    • Jiménez-Bocanegra, J. A.
  • Source: Agronomy for Sustainable Development
  • Volume: 31
  • Issue: 4
  • Year: 2011
  • Summary: Citrus is a crop of major economic importance in Spain, cultivated during the dry season when irrigation is essential to guarantee yields of high quality. As water resources are progressively more insufficient, more effective water management in agriculture is crucial. Deficit irrigation in many agricultural crops has frequently proved to be an efficient tool for improving water-use efficiency. We hypothesise that, despite the effectiveness of deficit irrigation, the most suitable strategy in citrus orchards remains to be defined for Mediterranean environment. In this study, for the period from 2006 to 2008, a 12-year-old orange orchard, Citrus sinensis L. Osb. cv. Navelina, grafted onto Carrizo citrange, C. sinensis L. Osb. * Poncirus trifoliata L. Osb., were subjected under two deficit-irrigation strategies defined as follows: (1) low-frequency deficit irrigation applied according to the plant-water status, and (2) sustained-deficit irrigation with a water-stress ratio of 0.6, defined as the ratio of actual water-limited supply in this treatment related to the water supply of the control treatment. The control treatment was irrigated at 100% of ET C for the entire irrigation season (ET C: crop evapotranspiration). Midday stem-water potential (Psi stem) and stomatal conductance ( gS) were used to estimate the water status of the trees. The lowest Psi stem and g S values were registered in the deficit-irrigation treatments with a seasonal pattern consistent with the irrigation dynamics applied in each case. Psi stem and gS values significantly differed from those of the control trees. Although the integrated stress levels were similar in deficit-irrigation treatments, differences in yield and fruit quality were found, having a more positive response to low-frequency deficit irrigation with an increase of 25% in yield in comparison to the sustained-deficit irrigation treatment. Here, we thus demonstrate the significant differences in water productivity. Indeed, water productivity parameter not only depends on the amount of water, but also on the irrigation strategy applied, which promoted substantial water savings without significant impact on yield. The present study highlights that low-frequency deficit irrigation should be adopted as a most appropriate strategy for achieving sustainable water management and attains reasonable yields and improves quality in citrus orchards under Mediterranean semiarid climate.
  • Authors:
    • Muriel-Fernández, J. L.
    • Durán-Zuazo, V. H.
    • García-Tejero, I. F.
    • Jiménez-Bocanegra, J. A.
  • Source: Functional Plant Biology
  • Volume: 38
  • Issue: 2
  • Year: 2011
  • Summary: The continuous monitoring of crop water status is key to the sustainable management of water stress situations. Two deficit irrigation (DI) treatments were studied during the maximum evapotranspirative demand period in an orange orchard ( Citrus sinensis (L.) Osb. cv. Navelina): sustained deficit irrigation irrigated at 55% crop evapotranspiration (ET C), and low-frequency deficit irrigation treatment, in which the plants were irrigated according to stem water potential at midday (Psi stem). Additionally, a control treatment irrigated at 100% of ET C was established. The daily canopy temperature ( TC) was measured with an infrared thermometer camera together with measurements of trunk diameter fluctuations (TDF), Psi stem and stomatal conductance ( gS). The time course of all physiological parameters and their relationships were analysed, confirming that canopy air temperature differential ( TC- Ta) variations and TDF are suitable approaches for determining the water stress. In addition, the maximum daily shrinkage (MDS) and TC- Ta showed high sensitivity to water stress in comparison to Psi stem and gS. Significant relationships were found among MDS and TC- Ta with Psi stem and gS, for monitoring the crop water status by means of MDS vs Psi stem and TC- Ta vs Psi stem. Thus, the combination of these techniques would be useful for making scheduling decisions on irrigation in orchards with high variability in plant water stress.
  • Authors:
    • Zhang, F. C.
    • Li, P. L.
  • Source: Transactions of the Chinese Society of Agricultural Engineering
  • Volume: 27
  • Issue: 2
  • Year: 2011
  • Summary: To explore the regulation effects of water and nitrogen on cotton population growth and development under the furrow irrigation, a cotton field furrow irrigation experiment was conducted. In the experiments, three kinds of furrow irrigation patterns and three irrigation and nitrogen fertilization levels were designed. The change trends of the cotton population physiological indices were simulated using single peak Gaussian distribution model. The results showed that the model simulation accuracy was relatively high. Compared with the peak values of leaf area duration (LAD) under conventional furrow irrigations (CFI), it decreased by 39.3% under alternative furrow irrigations (AFI) and low nitrogen treatments. Under medium nitrogen treatments, there was no significant difference in all indices. Under high nitrogen treatments, the LAD peak value increased by 17.26%, while the net assimilation rate (NAR) decreased by 21.69%. Meanwhile, under fixed furrow irrigations (FFI) and different nitrogen treatments, the peak value of each indices decreased by 35.1%-44.0%. Compared with the CFI, the LAD peak value decreased by 23.94% under AFI low water treatments. LAD peak value increased by 13.63% and leaf area index (LAI) decreased by 14.2% under AFI medium water treatments. Under AFI high water treatments, there was no significant difference in all indices. Under the FFI and different irrigation treatments, each index decreased by 20.7%-47.22%. Compared with the changes of cotton biomass and yield, the changes of ground dry weight and yield were insignificant under AFI and all water and nitrogen treatments. The FFI ground dry weight decreased by 9.8%-19.3% and the cotton yield decreased by 7.6%-8.9%. The experimental results show that AFI has obvious advantage of regulation effects of water and nitrogen on the performance of cotton population and it can be used to control the population growth and development of cotton effectively. Thus, AFI is recommended in practical applications of cotton water and fertilizer managements.
  • Authors:
    • Martin-Gorriz, B.
    • Ruiz-Salleres, I.
    • Gonzalez-Real, M. M.
    • Baille, A.
    • Nortes, P. A.
    • Egea, G.
    • Verhoef, A.
  • Source: Acta Horticulturae
  • Issue: 922
  • Year: 2011
  • Summary: The focus of the work reported here is the impact of severe heat stress conditions on orchards' carbon dioxide exchange rate (NEE, Net Ecosystem Exchange). NEE was monitored by means of the eddy-covariance technique over an irrigated orange-tree orchard during summer 2009 in Southern Spain. In that period, severe heat spells occurred (maximum air temperature and vapour pressure deficit up to 38degreesC and 5 kPa, respectively). Under these conditions, orange trees maintained their transpiration rates at levels similar to those observed for normal sunny days, while canopy stomatal conductance and NEE were strongly reduced, thereby leading to a marked decrease in water use efficiency. The experimental results are discussed in the context of (i) stomatal and non-stomatal limitations to CO 2 exchange and (ii) orchard respiration loss. As the frequency of extreme events is expected to increase in the Mediterranean Basin, our results suggest that water productivity of irrigated orchards may be significantly affected by climate change.