• Authors:
    • Zhang, H. L.
    • Lal, R.
    • Chen, Z. D.
    • Dikgwatlhe ,S. B.
    • Chen, F.
  • Source: SOIL & TILLAGE RESEARCH
  • Volume: 144
  • Year: 2014
  • Summary: The importance of soil organic carbon (SOC) and nitrogen (N) sequestration in agricultural soils as climate-change-mitigating strategy has received robust attention worldwide in relation to soil management. This study was conducted to determine the temporal effects of different tillage systems and residue management on distribution, storage and stratification of SOC and N under wheat (Triticum aestivum L.) - maize (Zea mays L.) cropping systems in the North China Plain (NCP). Four tillage systems for winter wheat established in 2001 were: moldboard plow tillage with maize residues removed (PT0), moldboard plow tillage with maize residues incorporated (PT), rotary tillage with maize residues incorporated (RT), and no-till with maize residues retained on the soil surface (NT). Compared with PT0 and PT, significantly higher SOC and N concentrations were observed in the surface layer (0-10cm depth) under NT and RT. In 2004, the SOC stocks were lower (PRT>PT>PT0 in both years. Compared with other treatments, SOC and N stocks were the lowest (P<0.05) under PT0. Therefore, crop residues play an important role in SOC and N management, and improvement of soil quality. The higher SOC stratification was observed under NT and RT than under PT and PT0, whereas the C:N ratio was higher (P<0.05) under PT and PT0 than under NT and RT systems. Therefore, the notion that NT leads to higher SOC stocks than plowed systems requires cautious scrutiny. Nonetheless, some benefits associated with NT present a greater potential for its adoption in view of the long-term environmental sustainability under wheat-maize double-cropping system in the NCP. © 2014 Elsevier B.V.
  • Authors:
    • Zhang, Q.
    • Hu, C.
    • Ren, T.
    • Du, Z.
  • Source: Soil and Tillage Research
  • Year: 2014
  • Summary: Physical protection by soil aggregates is critical for building soil organic carbon (SOC) stock. The objective of this study was to identify SOC sequestrated in the microaggregate holding within macroaggregte (mM) fraction after shifting tillage systems in the North China Plain. Soil samples from 0-5 cm layer of a 6-yr field experiment (MP - R, moldboard plow without residue; MP + R, moldboard plow with residue; RT, rotary tillage with residue; NT, no-till with residue) were collected and separated into different water-stable aggregates. The macroaggregate (250-2000 μm) was further isolated into intra-aggregate particulate organic matter (iPOM) fractions by density flotation, dispersion and sieving. The results showed that the SOC concentration of fine iPOM (250f, 53-250 μm) was increased by 23% in RT and 39% in NT compared with MP + R, whereas the difference in the coarse iPOM (250c, >250 μm) was not observed. The ratio of 250f-250c (i.e., 250f/250c) followed the order of NT (2.12) ≈ RT (1.94) > MP + R (1.50) ≈ MP - R (1.47), indicating the alternative tillage systems decreased the turnover rates of macroaggregates. Adoption of NT and RT improved the mM formation by 36% and 23% and mM associated C concentration by 38% and 31% as relative to MP + R system. Additionally, the soil C concentration and storage of the iPOM and silt plus clay fractions located within the microaggregate were higher under NT and RT than that of MP + R and MP - R systems. Thus applying NT and RT improved mM formation and soil C sequestered inside this fraction. We concluded that adoption of NT and RT enhanced SOC sequestration in the microaggregates of surface soil of the intensive agroecosystem of North China. © 2014 Elsevier B.V. All rights reserved.
  • Authors:
    • Zhang, W.
    • Zhang, Z.
    • Yan, X.
    • Huang, Y.
    • Liu, M.
    • Wang, Y.
    • Gong, J. R.
  • Source: SOIL & TILLAGE RESEARCH
  • Volume: 144
  • Year: 2014
  • Summary: Land use change has greatly affected ecosystem C processes and C exchanges in grassland ecosystems. The aim of this study was to determine the effects of land use (mowing, grazing exclusion, and grazing) on soil respiration (Rs) of a semi-arid temperate grassland during two growing seasons in Inner Mongolia, northern China, and to identify the main factors that affected Rs. During the growing season, Rs for the mowing, grazing exclusion, and grazing land-use types averaged 129, 150, and 194gCm-2yr-1, respectively, in 2011 (a dry year), versus 309, 272, and 262gCm-2yr-1, respectively, in 2012 (a wet year). Root respiration (Rr) accounted for 13-55% of Rs in 2011, versus 10-62% in 2012. Rs was strongly positively correlated with soil moisture for all three land uses, but weakly correlated with soil temperature (R2<0.4 in all cases). Rs was significantly positively correlated with aboveground biomass (R2=0.834), soil organic matter (R2=0.765), root biomass (R2=0.704), lignin mass loss rate (R2=0.422), and the cellulose mass loss rate (R2=0.849) and significantly negatively correlated with the litter C/N (R2=0.609). The temperature sensitivity (Q10) exhibited large monthly changes, and ranged from 0.52 to 2.12. Rainfall plays a dominant role in soil respiration: precipitation increased soil respiration, but the response differed among the land-use types. Thus, soil water availability is a primary constraint on plant growth and ecosystem C processes. Soil temperature plays a secondary role. Litter decomposition rates and litter quality also appear to be important. © 2014 Elsevier B.V.
  • Authors:
    • Li, H.
    • Li, Y.
    • Wilson, G. V.
    • Ouyang, Z.
    • Hou, R.
  • Source: SOIL SCIENCE SOCIETY OF AMERICA JOURNAL
  • Volume: 78
  • Issue: 1
  • Year: 2014
  • Summary: Differences in soil organic carbon (SOC) distribution, water holding capacity, and soil temperature between no-tillage (NT) and conventional tillage (CT) systems can result in different soil CO2 emissions which could affect global warming but few studies have addressed this concern. An open warming experiment was conducted in situ by infrared heating of longterm conservation tillage management plots in North China Plain (NCP) to determine the effects of warming on soil CO2 emissions and the correlation to changes in soil temperature and moisture. This experiment was conducted from February 2010 to June 2012 and included CT and NT plots with and without warming. Warming treatment increased soil temperature by 2.1 and 1.5°C, and decreased volumetric soil-water content by 14 and 10% for CT and NT systems, respectively. Soil CO2 emissions tended to decrease with time in CT while it consistently increased in NT system over the three wheat seasons and two maize seasons under warming. Our results suggest that differences in soil temperature and soil moisture between the two tillage systems could be enlarged with time by warming, and the potential exist for warming to promote more soil CO2 emission under NT relative to CT. There is a need to consider the differences in response to global warming between these two tillage systems to properly assess the benefits of NT to C sequestration.
  • Authors:
    • Guo, Z.
    • Guo, X.
    • Wang, D.
    • Hua, K.
  • Source: PLOS ONE
  • Volume: 9
  • Issue: 9
  • Year: 2014
  • Summary: Soil organic carbon (SOC) sequestration is important for improving soil fertility of cropland and for the mitigation of greenhouse gas emissions to the atmosphere. The efficiency of SOC sequestration depends on the quantity and quality of the organic matter, soil type, and climate. Little is known about the SOC sequestration efficiency of organic amendments in Vertisols. Thus, we conducted the research based on 29 years (1982-2011) of long-term fertilization experiment with a no fertilizer control and five fertilization regimes: CK (control, no fertilizer), NPK (mineral NPK fertilizers alone), NPK+1/2W (mineral NPK fertilizers combined with half the amount of wheat straw), NPK+W (mineral NPK fertilizers combined with full the amount of wheat straw), NPK+PM (mineral NPK fertilizers combined with pig manure) and NPK+CM (mineral NPK fertilizers combined cattle manure). Total mean annual C inputs were 0.45, 1.55, 2.66, 3.71, 4.68 and 6.56 ton/ha/yr for CK, NPK, NPKW1/2, NPKW, NPKPM and NPKCM, respectively. Mean SOC sequestration rate was 0.20 ton/ha/yr in the NPK treatment, and 0.39, 0.50, 0.51 and 0.97 ton/ha/yr in the NPKW1/2, NPKW, NPKPM, and NPKCM treatments, respectively. A linear relationship was observed between annual C input and SOC sequestration rate (SOCsequestration rate = 0.16 Cinput -0.10, R = 0.95, P<0.01), suggesting a C sequestration efficiency of 16%. The Vertisol required an annual C input of 0.63 ton/ha/yr to maintain the initial SOC level. Moreover, the C sequestration efficiencies of wheat straw, pig manure and cattle manure were 17%, 11% and 17%, respectively. The results indicate that the Vertisol has a large potential to sequester SOC with a high efficiency, and applying cattle manure or wheat straw is a recommendable SOC sequestration practice in Vertisols.
  • Authors:
    • Turner, N. C.
    • Fu, T. T
    • Wang, Y. P.
    • Hai, L.
    • Li, X. G.
    • Liu, X. E.
    • Li, F. M.
  • Source: SOIL SCIENCE SOCIETY OF AMERICA JOURNAL
  • Volume: 78
  • Issue: 4
  • Year: 2014
  • Summary: Alleviating the hydrothermal limitations to growth, clear film fully mulched ridge-furrow (FMRF) cropping significantly improves maize (Zea mays L.) grain yield on the Loess Plateau of China. Major concerns for FMRF cropping are the stability of maize productivity and whether the system is detrimental to the soil organic C (SOC) balance under changed hydrothermal conditions. We investigated the effects of maize production with FMRF and its effect on SOC concentration for five consecutive years from 2008 to 2012. Three treatments were imposed: no mulch (narrow ridges with the crop sown beside the ridges), half mulch (the same as no mulch, except the narrow ridges were mulched), and full mulch (i.e., FMRF; alternate narrow and wide ridges, all mulched, with maize in furrows). The 5-yr average of the grain yield was 3.8 Mg ha -1 under no mulch. Half and full mulch increased the grain yield by 68 and 102%, respectively, relative to no mulch. Root biomass was 69 and 104% greater under half and full mulch, respectively, than no mulch. The maize yield and biomass differed among years depending on the growingseason precipitation and its distribution, but the increased yield and biomass from mulching was consistent in all years. The mulch stimulated SOC mineralization and enzymatic activity but had no effect on light (density <1.8 gcm-3) and total SOC concentrations compared with no mulch. We conclude that increased SOC mineralization under FMRF was offset by increased SOC addition; FMRF cropping increased maize productivity without detriment to the SOC balance. © Soil Science Society of America, 5585 Guilford Rd., Madison WI 53711 USA All rights reserved.
  • Authors:
    • Shangguan, Z.
    • Yang, Q.
    • Deng, L.
    • Shao, R.
  • Source: SOIL & TILLAGE RESEARCH
  • Volume: 143
  • Year: 2014
  • Summary: As the largest reservoir of terrestrial carbon (C), soil is a source or sink for atmospheric carbon dioxide (CO2). Understanding the processes whereby soil CO2 is released into the atmosphere as a result of using inorganic nitrogen (N) fertilizers may provide us with knowledge of processes to offset the increasing concentration of CO2. The main objective of this study was to investigate the effects of different N levels on soil CO2 efflux with one controlled experiment. A field experiment was carried out in a non-irrigated winter wheat (Triticum aestivum L.) - cropland in Northwest China to investigate the effects of N fertilization on soil CO2 efflux in two consecutive growing seasons (2007-2009). The soil CO2 efflux to which N was applied at four different levels (0, 90, 180, and 360kg Nha-1) was measured during the growing seasons in 2007-2009. At most growth stages during the growing season, the soil CO2 efflux increased significantly with increased N application. The effect of N fertilization on the cumulative soil CO2 efflux was obvious. In the 10-20cm soil layer, the seasonal variations in soil CO2 effluxes were influenced by soil temperature (ST) rather than by soil water content (SWC). When ST >20°C, however, the low soil CO2 efflux was mainly due to low SWC, which was close to the permanent wilting point (8.5g H2O 100g dry soil-1). In addition, soil CO2 effluxes after anthesis were higher than those at seedling stage and were highest nearby anthesis stage. The results indicated that N fertilization probably had a positive effect on both the seasonal and cumulative soil CO2 effluxes during the growing season.
  • Authors:
    • Qiao, X.
    • Liang, Z.
    • Rasaily, R. G.
    • Sarker, K. K.
    • He, J.
    • Li, H.
    • Lu, C.
    • Wang, Q.
    • Li, H.
    • Mchugh, A. D. J.
  • Source: SOIL & TILLAGE RESEARCH
  • Volume: 137
  • Year: 2014
  • Summary: Soil sodicity and salinization are two major issues concerning agricultural production in Northern China and the affected areas are expanding at a rate of 1-1.5. Mha/year. The effects of two treatments, i.e. no-tillage with subsoiling and straw cover (NTSC) and conventional tillage with ploughing and straw removal (CTSR), on soil physical and chemical properties and yields were compared from 1999 to 2011. The results showed that NTSC reduced soil bulk density in the 0-30. cm soil layer, but more importantly the treatment increased total porosity by 20.9%, water stable aggregates and pore size class distribution. The enhance soil structure and improved infiltration in NTSC treatments contributed to reducing soil salinity by 20.3%-73.4% when compared with CTSR. Soil organic matter was significantly greater to 30. cm in NTSC, while total soil nitrogen was lower than CTSR treatments; however, available P was significantly higher in the 0-5. cm soil surface. During the first 3 years, there was no difference in spring maize yield between NTSC and CTSR, but yield significantly increased in NTSC compared with CTSR during the remaining years due to reduced salinity stress and increased soil health. In conclusion, NTSC soil management practices appear to be a more sustainable approach to farming than conventional methods that utilize intensive tillage and crop residue removal.
  • Authors:
    • Liang, L.
    • Jia, Z.
    • Wang, X.
  • Source: JOURNAL OF SOIL AND WATER CONSERVATION
  • Volume: 69
  • Issue: 5
  • Year: 2014
  • Summary: Field experiments were conducted from 2008 to 2010 in the Weibei Highlands of China to study the effects of straw incorporation on soil moisture, evapotranspiration (ET), and rainfall-use efficiency (RUE) of maize (Zea mays L.) under semiarid conditions in dark loessial soil. The straw application rates were at low straw ([LS] 4.5 t ha(-1)), medium straw ([MS] 9 t ha(-1)), and high straw ([HS] 13.5 t ha(-1)) rates combined with fixed levels of chemical fertilizers compared with only chemical fertilizers. Straw incorporation significantly increased surface soil moisture at the grain filling stage of maize and significantly improved RUE in the whole growth period of maize. Evapotransipiration at the ten leaf collar to tasseling and the grain filling to maturity stages of maize were significantly increased by straw incorporation. However, ET at the tasseling to grain filling stage of maize was significantly reduced by straw incorporation. Medium straw and HS treatments significantly improved surface soil moisture at the tasseling stage of maize and RUE at the five leaf collar to maturity stage of maize. Increasing straw application rates significantly reduced ET at the grain filling to maturity stage of maize. With increasing experimental years, LS treatment significantly improved surface soil moisture at the five leaf collar to tasseling stage of maize and RUE at the five and ten leaf collar stage of maize, MS treatment significantly increased surface soil moisture at the five and ten leaf collar stages of maize, and HS treatment significantly reduced ET at the sowing to five leaf collar stage of maize. We conclude that a reasonable combination application of straw and chemical fertilizers could make full use of surface soil moisture, inhibit soil evaporation, reduce the ineffective evaporation of crop, and increase RUE at a different growth period of maize and grain yield. In this experiment, the optimum straw application rate for improving RUE and grain yield was MS treatment.
  • Authors:
    • Zhang, J. H.
    • Wang, Y.
    • Li, F. C.
  • Source: JOURNAL OF SOIL AND WATER CONSERVATION
  • Volume: 69
  • Issue: 5
  • Year: 2014
  • Summary: Few studies have demonstrated the long-term effects of different tillage practices on changes of soil quality; however, understanding such effects is vital for the selection and establishment of appropriate soil conservation measures on steep hillslopes. This study was conducted at two adjacent sites in the Sichuan Basin, China, with one cultivated by traditional tillage (TT; i.e., hoeing starts at the bottom position and soil is moved downslope because of gravity and drag) and the other cultivated by conservation tillage (CT; i.e., hoeing is performed from hilltop to bottom, but soil is moved uphill because of drag). We used the Cesium-137 (Cs-137) tracer technique to identify the pattern of soil constituent distribution and soil quality differences between the two tillage practices. The Cs-137 residual rate for the CT practice ranged from -29.44% to 34.16% with an average of -8.56%, and the TT practice ranged from -57.12% to 4.63% with an average of -29.49%. A greater increase (ranging from 18.43% to 50.69%) in soil constituents (i.e., soil organic matter, total nitrogen [N], phosphorus [P], and potassium [K], available N, and extractable P and K) was found in the CT soils than in the TT soils. The CT treatment site exhibited markedly higher concentrations of soil constituents in each soil depth profile (0 to 40 cm [0 to 15.7 in] and each 5 cm [2 in] in length increment). The soil degradation index (SDI) for the CT practice significantly increased compared to the TT practice in the 0 to 15 cm (0 to 5.9 in) and 15 to 40 cm (5.9 to 15.7 in) depth of the profiles (p < 0.05). The greatest difference in SDI induced by these two tillage practices occurred at the summit and toeslope positions, with an increase in SDI of 28.07% and 15.76% in the 0 to 15 cm (0 to 5.9 in) depth and of 49.16% and 31% in the 15 to 40 cm (5.9 to 15.7 in) depth, respectively. The Cs-137 residual rate showed a corresponding relationship with the SDI changing trend, which implied that the Cs-137 residual rate may be considered an indicator for appraising soil quality for eroding hillslopes. It is suggested that the long-term practice of CT largely diminishes soil degradation because of upslope soil translocation; therefore, would also significantly improve soil quality in steeply sloping fields.