Towards sustainable intensification of apple production in China—— Yield gaps and nutrient use efficiency in apple farming systems WANG Na, Joost Wolf, ZHANG Fu-suo (1 Fujian Key Lab of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou 350002, P.R.China 2 Key Lab for Biopesticide and Chemical Biology, Ministry of Education/Fujian Agriculture and Forestry University, Fuzhou 350002, P.R.China)
Journal of Integrative Agriculture,
04/2016, Volume:
15, Issue:
4
Journal Article
Peer reviewed
Open access
China is in a dominant position in apple production globally with both the largest apple growing area and the largest export of fresh apple fruits. However, the annual productivity of China＇s apple ...is significantly lower than that of other dominant apple producing countries. In addition, apple production is based on excessive application of chemical fertilizers and the nutrient use efficiency （especially nitrogen） is therefore low and the nutrient emissions to the environment are high. Apple production in China is considerably contributes to farmers＇ incomes and is important as export product. There is an urgent need to enhance apple productivity and improve nutrient use efficiencies in intensive apple production systems in the country. These can be attained by improved understanding of production potential, yield gaps, nutrient use and best management in apple orchards. To the end, priorities in research on apple production systems and required political support are described which may lead to more sustainable and environmental-friendly intensification of apple production in China.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•A protocol for selecting data sources for crop modeling was developed.•The methodology can be applied across widely different levels of data availability and quality.•The protocol can help identify ...the most critical “data gaps” and focus efforts to fill them.•This paper sets quality standards for future studies on yield gaps and other studies that rely on crop yield simulations.
Numerous studies have been published during the past two decades that use simulation models to assess crop yield gaps (quantified as the difference between potential and actual farm yields), impact of climate change on future crop yields, and land-use change. However, there is a wide range in quality and spatial and temporal scale and resolution of climate and soil data underpinning these studies, as well as widely differing assumptions about cropping-system context and crop model calibration. Here we present an explicit rationale and methodology for selecting data sources for simulating crop yields and estimating yield gaps at specific locations that can be applied across widely different levels of data availability and quality. The method consists of a tiered approach that identifies the most scientifically robust requirements for data availability and quality, as well as other, less rigorous options when data are not available or are of poor quality. Examples are given using this approach to estimate maize yield gaps in the state of Nebraska (USA), and at a national scale for Argentina and Kenya. These examples were selected to represent contrasting scenarios of data availability and quality for the variables used to estimate yield gaps. The goal of the proposed methods is to provide transparent, reproducible, and scientifically robust guidelines for estimating yield gaps; guidelines which are also relevant for simulating the impact of climate change and land-use change at local to global spatial scales. Likewise, the improved understanding of data requirements and alternatives for simulating crop yields and estimating yield gaps as described here can help identify the most critical “data gaps” and focus global efforts to fill them. A related paper (Van Bussel et al., 2015) examines issues of site selection to minimize data requirements and up-scaling from location-specific estimates to regional and national spatial scales.
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To investigate whether altered megakaryocyte morphology contributes to reduced platelet production in idiopathic thrombocytopenic purpura (ITP), ultrastructural analysis of megakaryocytes was ...performed in 11 ITP patients. Ultrastructural abnormalities compatible with (para-)apoptosis were present in 78% ± 14% of ITP megakaryocytes, which could be reversed by in vivo treatment with prednisone and intravenous immunoglobulin. Immunohistochemistry of bone marrow biopsies of ITP patients with extensive apoptosis showed an increased number of megakaryocytes with activated caspase-3 compared with normal (28% ± 4% versus 0%). No difference, however, was observed in the number of bone marrow megakaryocyte colony-forming units (ITP, 118 ± 93/105 bone marrow cells; versus controls, 128 ± 101/105 bone marrow cells; P = .7). To demonstrate that circulating antibodies might affect megakaryocytes, suspension cultures of CD34+ cells were performed with ITP or normal plasma. Morphology compatible with (para-)apoptosis could be induced in cultured megakaryocytes with ITP plasma (2 of 10 samples positive for antiplatelet autoantibodies). Finally, the plasma glycocalicin index, a parameter of platelet and megakaryocyte destruction, was increased in ITP (57 ± 70 versus 0.7 ± 0.2; P = .009) and correlated with the proportion of megakaryocytes showing (para-) apoptotic ultrastructure (P = .02; r = 0.7). In conclusion, most ITP megakaryocytes show ultrastructural features of (para-) apoptosis, probably due to action of factors present in ITP plasma.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Our objective was to analyze the effects of age, gender, and the use of oral contraceptives (OCs) on coagulation using thrombelastography (TEG), a single test to analyze both plasma coagulation ...factors and cellular elements in whole blood.
TEG variables were measured in native whole blood and in recalcified citrated blood from 120 healthy adults (60 men and 60 women) with various ages and in an additional 29 healthy women using OCs.
We observed hypercoagulability in women compared with men and in women using OCs compared with age-matched nonusers. Moreover, we found hypercoagulability with aging. Using the method of Bland and Altman (Lancet 1986;1:307-10), we demonstrated no correlation between TEG measurements in native and recalcified citrated blood.
Aging, female gender, use of OCs, and low-normal hematocrit levels have significant procoagulant effects. TEG measurements in native and recalcified citrated blood are not interchangeable, as indicated by differences between the 2 measurements ranging from 20% in maximal amplitude to 246% in clotting time. Furthermore, the limits of agreement strongly exceeded clinical acceptability to conclude interchangeability.
Bedside thromboelastography is increasingly used, but an assessment of the clinical interchangeability of the 2 major systems, TEG (Hemoscope) and RoTEM (Pentapharm), has not been performed.
We ...measured blood samples from 46 cardiac surgical patients after induction of anesthesia with kaolin TEG(R) (kaoTEG), native TEG(R) (natTEG), intrinsic RoTEM (inTEM), and extrinsic RoTEM (exTEM). Each measurement consisted of reaction time (R), coagulation time (K), maximum amplitude (MA), and angle (alpha). Bland-Altman plots and mixed-model analysis were used. To assess repeatability, we made 7 replicated measurements in rapid succession in 2 volunteers.
One hundred sixty-six measurements were available for analysis. The R time of the kaoTEG (345 + or - 102 seconds, mean + or - sd) was longer than that of the inTEM (179 + or - 74 seconds, P < 0.001) and the exTEM (55 + or - 28 seconds, P < 0.001). The K time of the kaoTEG (78 + or - 18s) was not different from that of the inTEM (75 + or - 52 seconds, P = 0.60) but was longer than the K time of the exTEM (61 + or - 24 seconds, P < 0.003). The MA of the kaoTEG (71 + or - 6.5 mm) was larger than the MA of the inTEM (67 + or - 5.2 mm, P < 0.02) and almost similar to that of the exTEM (69 + or - 6.3 mm). The alpha of the kaoTEG (72 degrees + or - 4.1 degrees ) was not significantly different from that of both the inTEM (76 degrees + or - 7 degrees ) and the exTEM (79 degrees + or - 4.5 degrees ). The variability for MA and alpha was <10%. The repeatability of the R and K times was poor in both devices, whereas the repeatability of the MA and alpha was sufficient for clinical purposes.
The TEG and RoTEM measurements demonstrated a close correlation for the MA, but the alpha did not for the R and K variables. The kaoTEG had the best agreement with the exTEM measurement. Therefore TEG and RoTEM measurements are not completely interchangeable, and the clinical interpretation of thromboelastograhic data should be used with caution.
► Autumn-sown wheat yield gaps for the EU25 were calculated with CGMS (regional WOFOST). ► In parts of southern Europe simulated yields and crop characteristics were unrealistic. ► Unrealistic crop ...characteristics are mainly caused by wrong values of crop parameters. ► Yield gap is between 2 and 4tha−1 in the main parts of the EU25. ► With small changes CGMS is suitable to calculate yield gaps over Europe.
Wheat is Europe's dominant crop in terms of land use in the European Union (EU25). Most of this wheat area is sown in autumn, i.e., winter wheat in all EU25 countries, apart from southern Italy, southern Spain and most of Portugal, where spring wheat varieties are sown in late autumn. We evaluated the strengths and limitations of a regional implementation of the crop growth model WOFOST implemented in the Crop Growth Monitoring System (CGMS) for calculating yield gaps of autumn-sown wheat across the EU25. Normally, CGMS is used to assess growing conditions and to calculate timely and quantitative yield forecasts for the main crops in Europe. Plausibility of growth simulations by CGMS in terms of leaf area, total biomass and harvest index were evaluated and simulated yields were compared with those from other global studies. This study shows that water-limited autumn-sown wheat yields, being the most relevant benchmark for the largely rain fed wheat cultivation in Europe, are plausible for most parts of the EU25 and can be used to calculate yield gaps with some precision. In parts of southern Europe unrealistic simulated harvest index, maximum leaf area index and biomass values were found which are mainly caused by wrong values of phenology related crop parameters. Furthermore CGMS slightly underestimates potential and water-limited yields, which calls for a calibration using new field experiments with recent cultivars. Estimated yield gap is between 2 and 4tha−1 in main parts of the EU25, is smaller north-western Europe and highest in Portugal.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Effects of red blood cells on hemostasis Roeloffzen, Wilfried W.H.; Kluin-Nelemans, Hanneke C.; Bosman, Lotte ...
Transfusion,
July 2010, Volume:
50, Issue:
7
Journal Article
Peer reviewed
Open access
BACKGROUND: Currently there is no sensitive laboratory test to establish the influence of red blood cells (RBCs) on hemostasis. As thromboelastography (TEG) measures hemostasis in whole blood, taking ...into account the interactions of all cellular elements, we used this instrument to investigate the role that RBCs play in hemostasis.
STUDY DESIGN AND METHODS: In 29 patients with chemotherapy‐induced anemia we studied the effect of progressive anemia on the coagulation profile. In 24 patients with chronic anemia we studied the effect of transfusion of RBCs on coagulation. Finally, in 18 patients we evaluated whether storage time of RBCs has additional effects on hemostasis.
RESULTS: We observed a significant negative correlation between hemoglobin and TEG variables related to both clot strength and elasticity (p < 0.05). Moreover, anemia was associated with a delay in the initiation of the coagulation cascade. Correction of anemia by RBC transfusion resulted in significant shortening of this initiation phase with now the opposite effect on clot strength and elasticity. The negative effects on clot quality were significantly worse when fresh RBCs were transfused compared to longer‐stored RBCs. Furthermore, in contrast to the longer‐stored RBCs, fresh RBCs did not enhance initial fibrin formation.
CONCLUSIONS: In this study we found that anemia was associated with a delay in the initiation of the coagulation cascade with a finally formed clot with superior strength and viscoelastic properties. Transfusion of RBCs was associated with impaired clot quality, with even worse effects on the initial fibrin build‐up and clot quality by fresh RBCs.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
•A protocol for scaling up field yield gaps to larger spatial areas was developed.•We found the proposed protocol to be reasonably robust.•Areas with large variability in rainfall are an ...exception.•Poor data availability and heterogeneous topography limited protocol application.
Accurate estimation of yield gaps is only possible for locations where high quality local data are available, which are, however, lacking in many regions of the world. The challenge is how yield gap estimates based on location-specific input data can be used to obtain yield gap estimates for larger spatial areas. Hence, insight about the minimum number of locations required to achieve robust estimates of yield gaps at larger spatial scales is essential because data collection at a large number of locations is expensive and time consuming. In this paper we describe an approach that consists of a climate zonation scheme supplemented by agronomical and locally relevant weather, soil and cropping system data. Two elements of this methodology are evaluated here: the effects on simulated national crop yield potentials attributable to missing and/or poor quality data and the error that might be introduced in scaled up yield gap estimates due to the selected climate zonation scheme. Variation in simulated yield potentials among weather stations located within the same climate zone, represented by the coefficient of variation, served as a measure of the performance of the climate zonation scheme for upscaling of yield potentials.
We found that our approach was most appropriate for countries with homogeneous topography and large climate zones, and that local up-to-date knowledge of crop area distribution is required for selecting relevant locations for data collection. Estimated national water-limited yield potentials were found to be robust if data could be collected that are representative for approximately 50% of the national harvested area of a crop. In a sensitivity analysis for rainfed maize in four countries, assuming only 25% coverage of the national harvested crop area (to represent countries with poor data availability), national water-limited yield potentials were found to be over- or underestimated by 3 to 27% compared to estimates with the recommended crop area coverage of ≥50%. It was shown that the variation of simulated yield potentials within the same climate zone is small. Water-limited potentials in semi-arid areas are an exception, because the climate zones in these semi-arid areas represent aridity limits of crop production for the studied crops. We conclude that the developed approach is robust for scaling up yield gap estimates from field, i.e. weather station data supplemented by local soil and cropping system data, to regional and national levels. Possible errors occur in semi-arid areas with large variability in rainfall and in countries with more heterogeneous topography and climatic conditions in which data availability hindered full application of the approach.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
► Six agro-climate zone schemes used in yield gap and crop production analyses were reviewed and compared. ► Within-zone climate heterogeneity was analyzed for each scheme. ► Number of zones required ...to adequately cover the harvested area of a target crop was calculated for each scheme. ► The Global Yield Gap Atlas Extrapolation Domain seems to be the best currently available scheme for interpolation of point-based simulated yield potential.
Yield gap analysis, which evaluates magnitude and variability of difference between crop yield potential (Yp) or water limited yield potential (Yw) and actual farm yields, provides a measure of untapped food production capacity. Reliable location-specific estimates of yield gaps, either derived from research plots or simulation models, are available only for a limited number of locations and crops due to cost and time required for field studies or for obtaining data on long-term weather, crop rotations and management practices, and soil properties. Given these constraints, we compare global agro-climatic zonation schemes for suitability to up-scale location-specific estimates of Yp and Yw, which are the basis for estimating yield gaps at regional, national, and global scales. Six global climate zonation schemes were evaluated for climatic homogeneity within delineated climate zones (CZs) and coverage of crop area. An efficient CZ scheme should strike an effective balance between zone size and number of zones required to cover a large portion of harvested area of major food crops. Climate heterogeneity was very large in CZ schemes with less than 100 zones. Of the other four schemes, the Global Yield Gap Atlas Extrapolation Domain (GYGA-ED) approach, based on a matrix of three categorical variables (growing degree days, aridity index, temperature seasonality) to delineate CZs for harvested area of all major food crops, achieved reasonable balance between number of CZs to cover 80% of global crop area and climate homogeneity within zones. While CZ schemes derived from two climate-related categorical variables require a similar number of zones to cover 80% of crop area, within-zone heterogeneity is substantially greater than for the GYGA-ED for most weather variables that are sensitive drivers of crop production. Some CZ schemes are crop-specific, which limits utility for up-scaling location-specific evaluation of yield gaps in regions with crop rotations rather than single crop species.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Impacts of climate change on European agricultural production, land use and the environment depend on its impact on crop yields. However, many impact studies assume that crop management remains ...unchanged in future scenarios, while farmers may adapt their sowing dates and cultivar thermal time requirements to minimize yield losses or realize yield gains. The main objective of this study was to investigate the sensitivity of climate change impacts on European crop yields, land use, production and environmental variables to adaptations in crops sowing dates and varieties' thermal time requirements. A crop, economic and environmental model were coupled in an integrated assessment modelling approach for six important crops, for 27 countries of the European Union (EU27) to assess results of three SRES climate change scenarios to 2050. Crop yields under climate change were simulated considering three different management cases; (i) no change in crop management from baseline conditions (NoAd), (ii) adaptation of sowing date and thermal time requirements to give highest yields to 2050 (Opt) and (iii) a more conservative adaptation of sowing date and thermal time requirements (Act). Averaged across EU27, relative changes in water-limited crop yields due to climate change and increased CO2 varied between −6 and +21% considering NoAd management, whereas impacts with Opt management varied between +12 and +53%, and those under Act management between −2 and +27%. However, relative yield increases under climate change increased to +17 and +51% when technology progress was also considered. Importantly, the sensitivity to crop management assumptions of land use, production and environmental impacts were less pronounced than for crop yields due to the influence of corresponding market, farm resource and land allocation adjustments along the model chain acting via economic optimization of yields. We conclude that assumptions about crop sowing dates and thermal time requirements affect impact variables but to a different extent and generally decreasing for variables affected by economic drivers.
•Climate change most likely causes an overall increase in crop yields at EU27 level.•Adjusting crop sowing dates and varieties leads to yield improvements.•Sowing dates and varieties have less impact on economic and environmental outcomes.•Technical progress has a higher impact on crop yields than climate change.•Environmental impacts are mainly driven by changes in land use.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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