• Authors:
    • Xu,X.
  • Source: Acta Scientiae Circumstantiae
  • Volume: 35
  • Issue: 8
  • Year: 2015
  • Summary: Farmland releases greenhouse gases, therefore is of great importance to climate change. Carbon footprint is an ideal method to evaluate comprehensive greenhouse gas emissions of crops through the entire life cycle. This study took Jinzhong City, Shanxi Province, a typical winter wheat planting area as an example. Carbon footprint of wheat production was calculated using life cycle assessment. Furthermore, carbon footprint was optimized based on nonlinear programming aiming at reducing carbon emission as well as increasing crop unit yield. Results showed that, after energy-based allocating, carbon footprint for 1000 kg wheat production was 1357.28 kg CO2 equivalent under traditional farm management. Two major phrases of carbon footprint generation were N2O emission from farmland and urea manufacture. Through altering the fertilizer amount and adjusting the ratio of urea and mature, carbon footprint of 1000 kg wheat production could be reduced to 469.99 kg CO2 equivalent, with 9.13% increase in unit yield. Carbon footprint of wheat production in Jinzhong City showed great difference with results from previous studies in China, which was most likely due to various fertilizer amounts and N2O emission coefficients in different studies. This study provides important information in integrated greenhouse gas emissions of wheat production and quantitative methods to decrease carbon emission and increase crop yield. ©, 2015, Science Press. All right reserved.
  • Authors:
    • Mu, J.
    • Guo, J.
    • Zhao, J.
  • Source: Science Article
  • Volume: 207
  • Year: 2015
  • Summary: Understanding regional relationships between climate change and crop yield will help with making the strategic decisions for food security in China under climate change. In this study, the contributions of climate change to spring maize yield over the past three decades in Northeast China were decoupled based on the daily climate variables gathered from 68 meteorological stations and detailed observed data of spring maize from 55 agricultural meteorological experimental stations for the period 1978-2010 in Northeast China, analyzed with a linear statistical model. Then, the key climatic factors limiting the climate-induced yield of spring maize were identified. The agro-climatic similarity theory was applied. Finally, the relationships between the climatic variables and the climate-induced yield of spring maize were further explored by provinces. The results show that: from 1978 to 2010, the observed yields of spring maize in Northeast China increased markedly, with inter-annual fluctuations. Compared with the methods of moving average and harmonic average, Logistic regression optimally decoupled the climate-induced yield of spring maize. The key meteorological factors limiting the climate-induced yield were temperature, precipitation and sunshine, varying in the different regions. In Heilongjiang Province, the climate-induced yields of spring maize were mainly affected by maximum temperatures in August and precipitation in June. In Jilin Province, climate-induced yield was closely related to precipitation during daily the average temperature stably passing 10°C (≥10°C). In Liaoning Province, when the maximum temperature was high and the sunshine was abundant in June, the climate-induced yield of spring maize significantly increased. Finally, the regression models between climatic variables and climate-induced yield of spring maize in 11 representative zones in Northeast China also established geographical differences.
  • Authors:
    • Gao,Wei
    • Yang,Jun
    • Ren,Shun-rong
    • Liu Hailong
  • Source: Nutrient Cycling in Agroecosystems
  • Volume: 103
  • Issue: 1
  • Year: 2015
  • Summary: Evaluating the effects of management practices on the soil organic carbon (SOC), total nitrogen (TN) and grain yields would be valuable to explain field-level variability in crop production. A 33-year field experiment on the fluvo-aquic soil of North China with six treatments in a wheat (Triticum aestivium L.)-maize (Zea mays L.) rotation was evaluated. The six treatments were: non-fertilization (CK), nitrogen (N), nitrogen-phosphorus fertilization (NP), nitrogen-phosphorus-potassium fertilization (NPK), manure and nitrogen fertilization (NM), and straw returned with nitrogen fertilizers (NS). The results showed that the content of SOC and TN significantly increased in NM treatment. Application of inorganic fertilizers had small influence on SOC, but SOC and TN increased significantly in NM treatment over the long-term experiment. Compared to control, grain yield of wheat and maize increased two times under all treatments. The highest grain yield was detected in NM and NPK treatments. However, wheat yield was not significantly different (P > 0.05) between control and N treatment. Grain yields were more than doubled under fertilization for both wheat and maize, with the highest yield under the NM and NPK treatments and the lowest under CK treatment for maize and N treatment for wheat. The NP fertilization had little effect on maize yield in long-term, suggesting that potassium was not the primary limiting nutrients in the study site. Statistical analysis indicated that maize yield was significantly correlated with SOC and TN, and wheat yield was significantly correlated with SOC only. However, the relationships were stronger with TN (r = 0.26-0.42) than SOC (r = 0.12-0.37), indicating the importance of maintaining TN in agricultural soils. There was a strong positive linear correlation between carbon sequestered and carbon input (r = 0.828, P < 0.01) in the study site, indicating that the conversion rate of carbon input to SOC was 8.5 %. SOC did not reach the saturation in fluvo-aquic soil and have the potential to sequester more carbon.
  • Authors:
    • Hua,Keke
    • Zhu,Bo
    • Wang,Xiaoguo
  • Source: Nutrient Cycling in Agroecosystems
  • Volume: 103
  • Issue: 1
  • Year: 2015
  • Summary: Soil carbon dioxide (CO2) and methane (CH4) emissions, as well as runoff and leaching are major pathways of soil organic carbon (SOC) loss, which affect SOC sequestration in croplands. However, fluxes and relationships of the four pathways are still poorly understood. Static chamber-GC techniques were used to measure soil heterotrophic respiration rate and CH4 emission flux on hillslope upland of Regosol soil in Southwest China under traditional mineral fertilizer treatment from 2010 to 2012. Synchronously, SOC loss flux via overland flow, leaching and sediment was measured using free-drained lysimeters (8 m x 4 m). Average annual cumulative soil CO2 emission and CH4 uptake fluxes were 462.8 +/- A 52.2 and -1.1 +/- A 0.16 g cm(-2). Average annual cumulative dissolved organic carbon (DOC) loss fluxes via overland flow and leaching were 0.16 +/- A 0.03 and 0.92 +/- A 0.08 g cm(-2), respectively and organic C loss via sediment was 2.2 +/- A 0.3 g cm(-2). Relationship between DOC loss fluxes and soil heterotrophic respiration rates under natural rainfall events could be described by a significant exponential decay function (R = -0.63, P < 0.01). Moreover, a significantly negative correlation was also found between DOC loss flux and soil DOC content in topsoil at 15 cm depth (R = -0.75, P < 0.05). In conclusion, DOC loss decreases soil DOC content and is an underrated negative regulating factor of soil CO2 emission, especially in the regions where high DOC losses occur.
  • Authors:
    • Mu WeiSong
    • Yan ZhiYong
    • Gavrila,S. P.
    • Moga,L. M.
    • Feng JianYing
    • Jianu,I.
  • Source: Journal of Environmental Protection and Ecology
  • Volume: 16
  • Issue: 2
  • Year: 2015
  • Summary: (Will open in Google Docs) Greenhouse grape cultivation (GGC) has been an important part in grape production in China, and the ecological impact of the production system is vital for its sustainable development. This paper aims to evaluate the net carbon emissions and the overall impact on atmosphere of GGC and open-field grape cultivation (OGC) systems. A methodology of full carbon cycle analysis was adopted, and the net primary production, net ecosystem productivity and net carbon flux were chosen as the main indexes. The data were acquired through field investigations and chemical experiments. The results showed that both systems were the carbon source. The net carbon flux were 9.77 mg ha -1 year -1 and 1.17 mg ha -1 year -1. Compared to the OGC system, the GGC system is a bigger carbon source, however the carbon sink ability was improved and the NEP was increased by 2.18 mg ha -1 year -1. Minimisation the use of high carbon material in greenhouse building is a practical solution to reduction of carbon emission.
  • Authors:
    • Yao ChunXue
    • Joseph,S.
    • Li LianQing
    • Pan GenXing
    • Lin Yun
    • Munroe,P.
    • Pace,B.
    • Taherymoosavi,S.
    • Zwieten,L. van
    • Thomas,T.
    • Nielsen,S.
    • Ye Jun
    • Donne,S.
  • Source: Pedosphere
  • Volume: 25
  • Issue: 5
  • Year: 2015
  • Summary: Utilization of biochar at high application rates can increase soil C and crop yields, decrease greenhouse gas emissions and reduce nutrient run-off from soils. However, the high application rate of 10 t ha -1 may not return a profit to the farmer due to the high cost of biochar. In this study biochar was modified through pre-treating the biomass and post-treating with phosphoric acid, minerals and different chemical fertilisers to study the effects of two new enhanced biochar fertilisers on the yield and quality of green pepper in a field experiment with 5 fertilisation treatments and 3 replications. The two new biochar fertilisers significantly ( P<<0.05) increased the yield of green pepper (11.33-11.47 t ha -1), compared with the conventional chemical fertiliser (9.72 t ha -1). The biochar fertiliser treatments improved the vitamin C content of green pepper from 236.99 to 278.28 mg kg -1, and also significantly ( P<0.05) reduced the nitrate content from 132.32 to 101.92 mg kg -1, compared with chemical fertiliser. This study indicated that, compared to the use of conventional chemical fertiliser, all of the biochar fertiliser treatments could significantly improve the yield and quality of green pepper.
  • Authors:
    • Wang, Z.
    • Wang, S.
    • Li, M.
    • Chen, H.
    • Wang, X.
    • Tian, X.
    • Liu, T.
    • Chen, Y.
  • Source: Agronomy Journal
  • Volume: 107
  • Issue: 6
  • Year: 2015
  • Summary: Revealing the response of cereal yield and water use efficiency (WUE) to water management practices is crucial for achieving high and stable grain yields in drylands. A 3-yr field study was conducted to develop a high-yield, water-saving cultivation strategy for winter wheat in the Loess Plateau of China. The study's treatments included (i) a control (CK), that is, no mulch or fertilizer, (ii) nitrogen and phosphorus fertilizers (NP), (iii) plastic film mulch plus fertilizers (NP+PF), (iv) straw mulch plus fertilizers (NP+S), and (v) plastic film combined with straw mulch plus fertilizers (NP+PF+S). The results indicated that, compared with CK, the NP treatment improved the grain yield (112%) and WUE (96%) of winter wheat but resulted in a 12% reduction in soil water storage after the jointing stage. With the NP+S treatment, there was no difference recorded in grain yield, yield components, or WUE of winter wheat (relative to the NP treatment). With the NP+PF treatment, there was a 53% increase in grain yield, a 46% increase in WUE, and a 21% increase in soil water storage after jointing compared to the NP treatment. The plastic film could also modify soil temperature, resulting in maximized soil water retention. Additionally, the NP+PF and NP+PF+S treatments resulted in similar results. Taking into account agricultural, environmental, and economic factors, in addition to optimal fertilization (NP), plastic film mulch is the recommended practice for maximum yield and water retention in tablelands, whereas plastic film combined with straw mulch is recommended in terraces.
  • Authors:
    • Lin, E.
    • Ju. H.
    • Wheeler, T.
    • Li, Y.
    • Wang, H.
    • Lam, S.
    • Hao, X.
    • Han, X.
  • Source: Article
  • Volume: 209
  • Year: 2015
  • Summary: Fossil fuel combustion and deforestation have resulted in a rapid increase in atmospheric [CO 2] since the 1950's, and it will reach about 550 mol mol -1 in 2050. Field experiments were conducted at the Free-air CO 2 Enrichment facility in Beijing, China. Winter wheat was grown to maturity under elevated [CO 2] (55017 mol mol -1) and ambient [CO 2] (41516 mol mol -1), with high nitrogen (N) supply (HN, 170 kg N ha -1) and low nitrogen supply (LN, 100 kg N ha -1) for three growing seasons from 2007 to 2010. Elevated [CO 2] increased wheat grain yield by 11.4% across the three years. [CO 2]-induced yield enhancements were 10.8% and 11.9% under low N and high N supply, respectively. Nitrogen accumulation under elevated [CO 2] was increased by 12.9% and 9.2% at the half-way anthesis and ripening stage across three years, respectively. Winter wheat had higher nitrogen demand under elevated [CO 2] than ambient [CO 2], and grain yield had a stronger correlation with plant N uptake after anthesis than before anthesis at high [CO 2]. Our results suggest that regulating on the N application rate and time, is likely important for sustainable grain production under future CO 2 climate.
  • Authors:
    • Maxted, N.
    • Kang, D.
    • Wei, W.
    • Ford-Lloyd,B.
    • Chen, B.
    • Qin, H.
    • Kell, S.
  • Source: Science Article
  • Volume: 209
  • Year: 2015
  • Summary: The potentially devastating impacts of climate change on crop production and food security are now widely acknowledged. An important component of efforts to mitigate these impacts is the production of new varieties of crops which will be able to thrive in more extreme and changeable environmental conditions. There is therefore an urgent need to find new sources of genetic diversity for crop improvement. Wild plant species closely related to crops (crop wild relatives) contain vital sources of such genes, yet these resources themselves are threatened by the effects of climate change, as well as by a range of other human-induced pressures and socio-economic changes. The flora of China comprises more than 20,000 native higher plant species, a proportion of which have known or potential value as gene donors for crop improvement. However, until now, the full range of these valuable crop wild relative species had not been identified. In this paper we present a methodology for creating a checklist of, and prioritizing China's crop wild relatives, and reveal that 871 native species are related to crops that are of particularly high socio-economic importance in China-including rice, wheat, soybean, potato, sweet potato, millet and yam-crops which are also of notably high value for food and economic security in other parts of the world. Within this list we have identified species that are in particular need of conservation assessment based on their relative Red List status and potential for use in crop improvement programs. Endemic species that have particularly high economic value potential in China and that are under severe threat of genetic erosion and thus in need of urgent conservation action include wild relatives of tea ( Camellia fangchengensis S. Yun Liang et Y.C. Zhong and C. grandibracteata H.T. Chang et F.L. Yu), apple ( e.g., Malus honanensis Rehder, M. ombrophila Hand.-Mazz. and M. toringoides (Rehder) Hughes), and pear ( Pyrus pseudopashia T.T. Yu). We provide recommendations for developing a systematic and comprehensive national CWR conservation strategy for China, highlighting the challenges and requirements of taking the strategy forward to the implementation phase.
  • Authors:
    • Hu, W.
    • Cao, Y.
    • Xu, J.
    • Wang, Y.
    • Peng, Z.
    • Wang, H.
    • Han, X.
    • Xiong, W.
    • Lin, E.
    • Ju, H.
    • Huang, H.
    • Li, Y.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 209
  • Year: 2015
  • Summary: Drought is one of the major climatic disasters intimidating winter wheat production in the Huang-Huai-Hai (3H) Plain of China. The yield damage caused by drought tends to increase in the future, indicated by a pronounced uprising of drought events under RCP 8.5 scenario in terms of its affecting magnitude and area. This paper presents a modeling approach by using crop model DSSAT and hydrological indices to assess the vulnerability of winter wheat to future potential drought, based on an integrated assessment of exposure, sensitivity and adaptive capacity. Our results demonstrate that Beijing, Tianjin, Hebei and Shandong are more exposed and sensitive to potential drought than other regions in 3H. Traditional irrigation has the greater benefits in northern 3H Plain than southern regions, but is still insufficient to impede the yield loss due to potential drought. Under RCP 8.5 emission scenario and the period of 2010-2050, the worst drought effect is projected to occur around 2030. More than half of 3H plain are subject to high drought vulnerability. With increasing drought risks, we suggest immediate and appropriate adaptation actions to be taken before 2030s, especially in Shandong and Hebei, the most vulnerable provinces of 3H plain.