• Authors:
    • Li, Y. F.
    • Wang, Y.
    • Zheng, C. Y.
    • Zhang, G.
    • Xin, Y.
  • Source: ACTA AGRICULTURAE SCANDINAVICA SECTION B-SOIL AND PLANT SCIENCE
  • Volume: 65
  • Issue: 4
  • Year: 2015
  • Summary: Soil organic carbon plays an important role in soil fertility and carbon sequestration. In the North China Plain, soil nutrients and organic carbon are still lacking in salt-affected soil after a successfully reclamation in the 1980 s. Our objectives were to investigate the effects of land use types under different soil management practices on soil fertility, organic carbon pools, and the microbial community at this site. Three land use types were investigated: original land without farming, farmland with residue return, and a vegetable greenhouse with farmyard manure amendment. The carbon stocks were calculated according to the equivalent soil mass method, and microbial community structure was determined by phospholipid fatty acid analysis. Over 30 years, the current concentrations of alkali-hydrolysis nitrogen, available potassium (AK), and available phosphorus increased in the three land use types, except for the AK concentration in farmland, which decreased due to the lack of potassium fertilizer input. The nutrients in the greenhouse were significantly higher than those in the original land and farmland. The carbon stocks in the original land, farmland, and greenhouse were increased by 103%, 179%, and 660%, respectively. Both land use types and seasons influenced particulate organic carbon, chemical-labile organic carbon, and microbial biomass carbon. The microbial community structures were distinctly different between the three land use types. Overall, the soil available nutrients and carbon stocks increased compared to their 1980 levels in the three land use types, and labile carbon pools and microbial community structure exhibited different responses in the three land use types. Compared to spontaneous development, mineral fertilization and organic amendment are more effective for recovering soil fertility in reclaimed soils.
  • Authors:
    • Liu, E.
    • Chen, B.
    • He, W.
    • Wang, J.
    • Zhang, Y.
    • Yan, C.
    • Zhang, H.
  • Source: Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
  • Volume: 31
  • Issue: 4
  • Year: 2015
  • Summary: Soil conservation tillage practices such as no-tillage and straw mulching are of great significance for saving energy input in farmland, mitigating greenhouse gas emission to the atmosphere, and increasing carbon sequestration potential in soils. Despite of great interest in the effect of no-tillage (NT) management practice on carbon sequestration and GHG emissions in northern China, long-term effects of different tillage practices in that region on farmland system carbon footprints remain unclear. Based on a 20-year conservation tillage experiment in a winter wheat system at Linfen City in Shanxi province, we evaluated long-term (20-year) effects of NT and conventional tillage (CT) practices on the carbon balance. During the experiment, we measured soil respiration and soil carbon concentration in the field. A random block design with three replications was used to assess both the tillage and its effects on soil carbon sequestration and yield of winter wheat (Triticum aestivum L.). Production, formulation, storage, and distribution of these inputs such as seed, chemical fertilizer and application with tractor equipment cause the combustion of fossil fuel and use of energy from other sources, which also emits CO2 and other GHGs into the atmosphere. Thus, it is essential to understand emissions in kilograms carbon equivalent (kg CE) of various tillage operations, fertilizers, pesticides, harvesting and residue management. The index of carbon emission of different agricultural inputs were taken from literatures. In our study, carbon emission produced by chemical fertilizer with NT and CT practices accounted for 73.3%-77.1% of total carbon emission from agricultural inputs, and has become the main carbon source. Compared with other countries, fertilizer input in China accounts for a greater portion within agricultural production, and fertilizer costs made up about 50% of total costs in china. Reducing fertilizer use is an effective means to decrease indirect carbon emission. Because NT reduced moldboard ploughing, chisel ploughing and stover removal, carbon emission from agricultural inputs under NT was 5.1% less than that under CT. Moreover, T. aestivum L. yield with NT treatment increased by 28.9% over CT treatment. Carbon productivity in the NT system was greater than that in CT. After 20 years, SOC concentration in NT soil was greater than that in the CT soil, but only in the layer between 0 and 10 cm. There was significant SOC accumulation (0-60 cm) in the NT soil (50.86 Mg/hm2) compared with that in the CT soil (46.00 Mg/hm2). The total CO2 flux of soil respiration under NT was greater than that under CT. However, according to a carbon balance analysis, NT acted as a carbon sink compared to CT as a carbon source. This favored carbon sequestration in the farmland system. Therefore, long-term NT practice can increase soil carbon sequestration and reduce GHG emissions. The carbon emission coefficients are from literatures and N2O emission is not considered in the study. These may affect the results, but the trend among the different tillage system remains unchanged. With the improvement of the parameters, the accuracy of the assessment can be further improved. NT can be a significant innovation for carbon-friendly agricultural production technology in Northern China, because of its savings of energy/labor/time, reduction of GHG emissions, and benefits of SOC sequestration.
  • Authors:
    • Lal, R.
    • Pu, C.
    • Wang, M.
    • Xue, J. F.
    • Liu, S. L.
    • Yin, X. G.
    • Zhao, X.
    • Zhang, H. L.
    • Chen, F.
  • Source: CLIMATIC CHANGE
  • Volume: 129
  • Issue: 1-2
  • Year: 2015
  • Summary: Climate change has been a concern of policy makers, scientists, and farmers due to its complex nature and far-reaching impacts. It is the right time to analyze the impacts of climate change and potential adaptations, and identify future strategies for sustainable development. This study assessed changes in climatic factors (e.g., temperature and precipitation) at three typical sites (i.e., Luancheng, Feixiang, and Huanghua) in the North China Plain (NCP), and analyzed adaptations of farming practices. Results indicated that the mean annual temperature followed a significant increasing trend during 1981-2011, with 0.57, 0.47, and 0.44 A degrees C decade(-1) for Luancheng, Huanghua, and Feixiang, respectively. A significant increase of 0.67, 0.53, and 0.38 A degrees C decade(-1) was observed for the winter-wheat (Triticum aestivum L.) season for Luancheng, Huanghua, and Feixiang, respectively (P < 0.05), but no significant change for the summer-corn (Zea mays L.) season for the three sites. The annual accumulated temperature (a parts per thousand yen10 A degrees C) increased significantly during 1981-2011 (P < 0.01), with 17.60, 10.49, and 14.09 A degrees C yr(-1) for Luancheng, Huanghua, and Feixiang, respectively. There was no significant increase of mean annual precipitation, which had large inter-annual fluctuations among the three sites. In addition, significant challenges lie ahead for the NCP due to climate change, e.g., increasing food grain demand, water shortages, high inputs, high carbon (C) emissions, and decreasing profits. Trade-offs between crop production, water resource conservation, and intensive agricultural inputs will inhibit sustainable agricultural development in the NCP. Farming practices have been adapted to the climate change in the NCP, e.g. late seeding for the winter-wheat, tillage conversion, and water saving irrigation. Therefore, innovative technologies, such as climate-smart agriculture, will play important roles in balancing food security and resources use, enhancing water use efficiency, reducing C emissions in the NCP. Coordinated efforts from the government, scientists, and farmers are also necessary, in response to climate change.
  • Authors:
    • Wu, Z.
    • Gong, P.
    • Yang, L.
    • Burger, M.
    • Chen, W.
    • Zhang, L.
  • Source: PLOS ONE
  • Volume: 10
  • Issue: 2
  • Year: 2015
  • Summary: In order to discover the advantages and disadvantages of different fertilization regimes and identify the best management practice of fertilization in greenhouse fields, soil enzyme activities involved in carbon (C) transformations, soil chemical characteristics, and crop yields were monitored after long-term (20-year) fertilization regimes, including no fertilizer (CK), 300 kg N ha-1 and 600 kg N ha-1 as urea (N1 and N2), 75 Mg ha-1 horse manure compost (M), and M with either 300 or 600 kg N ha-1 urea (MN1 and MN2). Compared with CK, fertilization increased crop yields by 31% (N2) to 69% (MN1). However, compared with CK, inorganic fertilization (especially N2) also caused soil acidification and salinization. In the N2 treatment, soil total organic carbon (TOC) decreased from 14.1 +/- 0.27 g kg-1 at the beginning of the long-term experiment in 1988 to 12.6 +/- 0.11 g kg-1 (P<0.05). Compared to CK, N1 and N2 exhibited higher soil alpha-galactosidase and beta-galactosidase activities, but lower soil alpha-glucosidase and beta-glucosidase activities (P<0.05), indicating that inorganic fertilization had different impacts on these C transformation enzymes. Compared with CK, the M, MN1 and MN2 treatments exhibited higher enzyme activities, soil TOC, total nitrogen, dissolved organic C, and microbial biomass C and N. The fertilization regime of the MN1 treatment was identified as optimal because it produced the highest yields and increased soil quality, ensuring sustainability. The results suggest that inorganic fertilizer alone, especially in high amounts, in greenhouse fields is detrimental to soil quality.
  • Authors:
    • Xiong, Z. Q.
    • Zhu, Y. Y.
    • Li, B.
    • Li, Q. L.
    • Fan, C. H.
    • Zhang, M.
  • Source: AGRICULTURE ECOSYSTEMS & ENVIRONMENT
  • Volume: 201
  • Year: 2015
  • Summary: The application of nitrification inhibitors (NIs) is effective in suppressing nitrification and N 2O emissions while promoting crop yields in many agroecosystems. However, the inhibitory effects of different NIs for vegetable production under soil and environmental conditions in China are not fully understood. To evaluate the effects of chemical and biological NIs on N 2O emissions and the nitrogen use efficiency (NUE), a 2-yr field experiment with four treatments (regular urea (Urea), urea+dicyandiamide (DCD), urea+nitrapyrin (CP) and urea+biological nitrification inhibitor (BNI)) performed in triplicate was carried out in an intensive vegetable field using the static chamber and gas chromatography method. The results showed that the CP and BNI treatments shifted the main form of soil inorganic nitrogen (N) from nitrate (NO 3-), which was the case for the Urea and DCD treatments, to ammonium (NH 4+). The variations in soil temperature, moisture and NO 3- content regulated the seasonal fluctuations of N 2O emissions. Moreover, the DCD treatment did not significantly affect N 2O or agronomic NUE relative to the Urea treatment, while CP and BNI significantly decreased annual N 2O emissions by 16.5% and 18.1% and improved NUE by 12.6% and 6.7%, respectively. Thus, a markedly lower global warming potential (GWP) and greenhouse gas intensity (GHGI) was observed in the CP and BNI treatments relative to the Urea and DCD treatments. The results demonstrated that the NIs played important roles in enhancing yields and reducing N 2O emissions from the vegetable ecosystem and that the CP and BNI treatments are suitable for marketing in China.
  • Authors:
    • Mu, J.
    • Xu, Y. H.
    • Guo, J. P.
    • Zhao, J. F.
  • Source: AGRICULTURE ECOSYSTEMS & ENVIRONMENT
  • Volume: 202
  • Year: 2015
  • Summary: To learn the effects of climate change on cultivation patterns of spring maize and its suitability will benefit the strategic decisions for future agricultural adaptation. In this paper, based on the daily data from 68 meteorological stations and 82 agro-meteorological observation stations in Northeast China between 1961 and 2010, the cultivation pattern of spring maize and its climatic suitability in Northeast China were investigated. The agricultural climatic suitability theory was applied. The specific growth phases of spring maize that were most sensitive to environmental limitations were further divided into four stages: from germination to emergence, from emergence to jointing, from jointing to tasseling, and from tasseling to maturity. The average resource suitability index ( Isr) was established to evaluate the effects. Higher values of Isr indicate a higher degree of climatic resource suitability. Over the past five decades, the northern planting boundaries of different maturities (late, medium-late, medium, medium-early and early) of spring maize varieties in Northeast China all markedly extended northward and eastward. Of all the varieties, the medium-late maturity variety had the most expanded planting area. This further illustrated the importance of promoting medium-late range heat-tolerant cultivars of spring maize in reducing the unfavorable effect of climate change in the near future in Northeast China. In addition, the most significant extension was found in the early 21st century. Moreover, the southern planting boundaries of unsuitable planting spring maize areas continually compressed northward from the Tonghe County of Heilongjiang Province (128°49′, 46°21′) to the Huma County of Heilongjiang Province (124°11′, 51°26′). Climate change affected not only the planting patterns of spring maize, but also the climatic suitability of spring maize. Significant temporal and spatial changes of Isr from 1961 to 2010 were found. The Isr showed increasing trends, which increased by 0.19 in Heilongjiang Province, 0.16 in Jilin Province and 0.12 in Liaoning Province. Spatial differences of Isr were obvious, with high values shifting northeastward over the past 50 years, indicating more efficient suitability of agricultural climatic resources in Northeast China.
  • Authors:
    • Zhang, B.
    • Yao, S.
    • Bi, L.
  • Source: Soil and Tillage Research
  • Volume: 152
  • Year: 2015
  • Summary: Soil puddlability measures the susceptibility of a soil to puddling, and can influence transplantation and the growth of rice plants. The effects of chemical fertilizers and organic amendments on soil puddlability of paddy soils are poorly understood. This study used two 26-year field experiments (1) to compare the effects of chemical and organic fertilization on soil puddlability by measuring sinkage resistance and hard clod content after puddling, (2) to characterize physical properties of hard clods and (3) to explain the change in soil puddlability. Each of the two experiments consisted of nine treatments of chemical fertilizers alone or in combination with organic amendments. The sinkage resistance and the content of hard clods were higher in the treatments with chemical fertilization alone than in the treatments with organic amendments. The sinkage resistance was positively correlated with the content of hard clods and negatively correlated to content of soil organic C (SOC) and mean weight diameter (MWD). The bulk density, water sorptivity and apparent porosity were similar among individual hard clods from different treatments, suggesting that the hard clods were formed under the same processes. The formation of hard clods was likely attributed to the breakdown of the compacted topsoil by puddling tillage, which formed due to clogging pores by fine particles produced during previous puddling tillage and due to shrinkage upon drying during rice growth period. Compared with the organic amendment treatments, the chemical fertilization treatments contained more and larger hard clods, indicating that the compacted topsoil was thicker due to higher soil dispersibility due to N fertilization and lower SOC content in the chemical fertilization treatments than in the organic amendment treatments. The study also suggests that continuous input of organic C at an annual rate of >2.5Mgha-1 is needed to maintain SOC content and soil structure under chemical fertilization in the study region. © 2015 Elsevier B.V.
  • Authors:
    • Chen, N.
    • Ti, C.
    • Gao, J.
  • Source: Science Journal
  • Volume: 10
  • Issue: 1
  • Year: 2015
  • Summary: Straw is considered to be a renewable resource for bioenergy and biomaterial. However, about 70% of straw is burned in fields, which causes serious air pollution in China. In this study, a life cycle assessment (LCA) model, together with emergy evaluation, was built to compare four straw applications after harvest vs. direct burning, including bioethanol (BE), combined heat and power plant (CHP), corrugated base paper (CP), and medium-density fiberboard (MDF). The results showed that BE and MDF would avoid greenhouse gas (GHG) emissions by 82% and 36%, respectively, while CHP and CP would emit 57% and 152% more GHG, respectively, compared with direct straw burning. Bioethanol had the highest renewability indicator (RI) of 47.7%, and MDF obtained the greatest profit of 657 Yuan.bale(-1). The applications CHP and CP had low RI (< 10.3%) and profit (< 180 Yuan.bale(-1)). Due to water recycling and electrical power as a coproduct, BE had the lowest value (3 x 10(11) sej.Yuan(-1)) of EmPM (emergy per unit money profit); the EmPM value of CP was 18.6 times higher than that of BE. The four straw applications would also greatly reduce particles emission (57 to 98%) to air. BE was judged to be the most environmentally friendly application among the four straw applications. Imposing a carbon tax would encourage investment in BE, but discourage the applications CHP and CP.
  • Authors:
    • Li, Z.
    • Chen, G.
    • Wang, L.
    • Zhang, L.
    • Yang, Y.
    • Sheng, H.
    • Zhou, C.
    • Han, K.
  • Source: Agronomy Journal
  • Volume: 107
  • Issue: 1
  • Year: 2015
  • Summary: Increasing water and N use efficiency and lowering environmental pollution are primary concerns for both agricultural production and environmental quality in northwestern China. A 2-yr field experiment was conducted to assess and model the effects of irrigation, N, and plant density on maize ( Zea mays L.) when N fertilizer and irrigation were separated in an alternating furrow irrigation system. Regression modeling (a ternary quadratic equation) showed that N fertilization positively affected yield, water use efficiency, N uptake, soil NO 3-N, and NH 3 volatilization. Irrigation improved yield, N uptake, and increased soil NO 3-N in the deeper soil layer (0.6-2.0 m) but reduced water use efficiency, NH 3 volatilization, and soil NO 3-N in the 0- to 0.6-m soil layer. Planting density positively affected yield, water use efficiency, and N uptake but negatively influenced NH 3 volatilization and soil NO 3-N. The combination of 255 kg N ha -1 N fertilizer, 100 mm of irrigation water, and 59,467 plants ha -1 in 2010 and 245 kg N ha -1 N fertilizer, 98 mm of irrigation water, and 58,376 plants ha -1 in 2011 resulted in maximum income for maize yield (7245 kg ha -1 in 2010 and 6972 kg ha -1 in 2011). However, environmental and agronomic objectives did not match. Specifically, the combination of N, irrigation rate, and plant density with maximum yield increased N leaching and NH 3 losses, whereas the combination lowering environmental pollution due to N losses caused a reduction in yield. Therefore, the trade-off in management of N, irrigation, and planting density was emphasized for both environmental and agronomic benefits in our study.
  • Authors:
    • Wang, X.
    • Zhang, T.
    • Liu, J.
    • Ding, C.
    • Li, X.
  • Source: Agronomy Journal
  • Volume: 107
  • Issue: 1
  • Year: 2015
  • Summary: Peanut ( Arachis hypogaea L.) yield and quality are seriously compromised by consecutive monoculturing in southeastern China. This work investigated the population size and community structure of soil nematodes in 3-, 6-, and 20-yr-old peanut monoculturing systems. A grass pasture was used as the control. The results showed that continuous peanut monocropping had detrimental effects on the soil nematode abundance and functional composition compared with the control. The reductions in the abundance of total and microbivorous nematodes with increasing years of monocropping are likely to reduce bioturbation and nutrient mineralization, and an elevated abundance of plant parasitic nematodes may result in serious damage to peanut roots, thus aggravating root rot. Furthermore, the significant variations in soil nematode functional indices across the three monocropped peanut fields may produce negative effects on sustainable agroecosystems. Our study also contributes to the identification of locally applicable indicator species of soil nematodes, i.e., Tylenchus, Doryllium, and Mesorhabditis, which can be applied in the assessment of soil status within monocropped peanut fields. Our results suggest that the soil nematode community exhibits evident responses to peanut monocropping.