• Authors:
    • Wang, Z.
    • He, M.
    • Chen, X,
    • Zou, C.
    • Cui, Z.
    • Pan, J.
    • Lu, F.
    • Lu, D.
  • Source: Web Of Knowledge
  • Volume: 107
  • Issue: 6
  • Year: 2015
  • Summary: Grain yields can be limited from delayed seeding worldwide. Perhaps yield suppressions can be overcome by applying farm manure. The objective of this study was to determine the influence of manure application and sowing date on wheat ( Triticum aestivum L.) yield and population development. A field experiment was conducted over two seasons, with three sowing dates (early [ES] - 5 October; mid [M] - 10 October; late [LS] - 15 October) with or without manure application (each plot receiving same chemical N, P, and K fertilizer) in the North China Plain (NCP). Comparing early to LS, delayed sowing reduced wheat yield from 9.5 to 7.8 t ha -1. Furthermore, manure application provided a 16 and 11% yield compensation for the M and LS date treatments, respectively, but did not significantly increase yield for ES. These results were attributed to manure increasing the wheat pre-winter tiller numbers for the mid-seeding date and manure increasing the spring tiller numbers for the LS date. High tiller mortality rate of ES treatment with manure application resulted in similar spike number and wheat yield as no manure treatment. Manure application improved plant N, P, and K concentration and soil temperature at a depth of 5 cm (0.4°C for pre-winter and 0.5-0.8°C for post-stem elongation), actions that may be important for improving population development.
  • Authors:
    • Nayak, D.
    • Lu, Y.
    • Pan, G.
    • Newbold, J.
    • Cardenas, L.
    • Yan, X.
    • Moran, D.
    • Liu, J.
    • Wang, J.
    • Zhu, W.
    • Cheng, Y.
    • Koslowski, F.
    • Wang, W.
    • Cheng, K.
    • Saetnan, E.
    • Smith, P.
  • Source: Article
  • Volume: 209
  • Year: 2015
  • Summary: Agriculture accounts for approximately 11% of China's national greenhouse gas (GHG) emissions. Through adoption of region-specific best management practices, Chinese farmers can contribute to emission reduction while maintaining food security for its large population (>1300 Million). This paper presents the outcome of a bottom-up assessment to quantify technical potential of mitigation measures for Chinese agriculture using meta-analysis of data from 240 publications for cropland, 67 publications for grassland and 139 publications for livestock, and provides the reference scenario for the cost analysis of identified mitigation measures. Management options with greatest mitigation potential for rice, or rice-based cropping systems are conservation tillage, controlled irrigation; replacement of urea with ammonium sulphate, nitrogen (N) inhibitor application, reduced N fertilizer application, integrated rice-fish-duck farming and biochar application. A 15% reduction in current average synthetic N fertilizer application for rice in China i.e., 231 kg N ha -1, would result in 12% decrease in direct soil nitrous oxide (N 2O) emissions. Combined application of chemical and organic fertilizer, conservation tillage, biochar application and reduced N application are possible measures that can reduce overall GHG emissions from upland cropping systems. Conventional fertilizer inputs for greenhouse vegetables are more than 2-8 times the optimal crop nutrient demand. A 20-40% reduction in N fertilizer application to vegetable crops can reduce N 2O emissions by 32-121%, while not negatively impacting the yield. One of the most important mitigation measures for agricultural grasslands could be conversion of low yielding cropland, particularly on slopes, to shrub land or grassland, which is also a promising option to decrease soil erosion. In addition, grazing exclusion and reduced grazing intensity can increase SOC sequestration and decrease overall emissions while improving the largely degraded grasslands. For livestock production, where poor quality forage is commonly fed, improving grazing management and diet quality can reduce methane (CH 4) emissions by 11% and 5%, on average. Dietary supplements can reduce CH 4 emissions further, with lipids (15% reduction) and tannins or saponins (11% reduction) showing the greatest potential. We also suggest the most economically cost-effective mitigation measures, drawing on related work on the construction of marginal abatement cost curves for the sector.
  • Authors:
    • Ju, X.
    • Norse, D.
  • Source: Article
  • Volume: 209
  • Year: 2015
  • Summary: China's successful achievement of food security in recent decades has resulted in serious damage to the environment upstream of the agricultural sector, on farm and downstream. The environmental costs of this damage are not only agro-ecosystem function and the long-term sustainability of food production, but also bio-physical including human health with impacts at all levels from the local to the global, and with economic loss estimates ranging from 7 to 10% of China's agricultural gross domestic product (GDP). This paper presents a systematic analysis of the causes and impacts of these environmental costs for China's cropping systems and crop-based livestock systems, and focuses on the nitrogen management. Since the 1980s most of the environmental costs have been related to the intensification of first grain production stimulated by high nitrogen fertilizer and irrigation subsidies, and then vegetable production and fruit trees, with the overuse and misuse of synthetic nitrogen fertilizer and manure being the dominant cause of eutrophication, soil acidification and high greenhouse gas emissions. However, during the last 10 years or so the expansion of intensive livestock production has become a serious cause of direct and indirect air and water pollution and is destined to be the main agricultural threat to China's environment in the long-term unless a holistic strategy for sustainable intensification is adopted for the next and future 5 Year Plans. This strategy should focus on improving nutrient management to limit nitrogen overuse, which is now the main cause of the economic losses from agriculture's damage to the environment.
  • Authors:
    • Gregorich, E. G.
    • Wu, S.
    • Xu, Y.
    • Li, B.
    • Ouyang, Z.
    • Wu, L.
    • Qiu, Q.
  • Source: Article
  • Volume: 96
  • Year: 2015
  • Summary: Dissolved organic matter (DOM) in soils play an essential role in soil physical, chemical and biological processes, but little information is available on the biodegradability of plant-derived DOM and its effect on soil carbon and nitrogen sequestration in field soils. The objectives of this study were to investigate the impacts of crop residue-derived DOM on soil CO 2 and N 2O emissions, as well as soil carbon and nitrogen sequestration by adding water extracts of maize stalk (i.e., plant-derived DOM) to soils. In this study, wheat was grown in pots under field conditions with treated soils, the soils treatments were: plant-derived DOM (PDOM), urea nitrogen (N), PDOM + urea nitrogen (PDOM + N), as well as a control with no additions to soil (CK). Adding plant-derived DOM to soil increased soil CO 2 and N 2O emissions ( P<0.05). During the wheat growing season, the cumulative CO 2-C emission from CK, PDOM, N and PDOM + N was 1071, 1577, 1362 and 1496 g C m -2, respectively. Meanwhile, the cumulative N 2O-N emission from CK, PDOM, N and PDOM + N was 1888, 2565, 23910 and 2587 mg N m -2, respectively. Compared with N treatment, DOM addition had little effect on soil N sequestration, but it accelerated the decomposition of native soil organic carbon (SOC) and caused a net loss of SOC. The soil C sequestration decreased about 15167 and 5145 g C m -2 in PDOM and PDOM + N treatments, respectively. The increased microbial biomass and root biomass were responsible for the greater CO 2 emission in DOM-amended soils. Negative correlation between dissolved organic carbon (DOC) content and N 2O flux suggested that the release of N 2O was dependent on the supply of DOC. These results indicated that the supply of plant-derived DOM exacerbated soil CO 2 and N 2O emissions and reduced soil C sequestration. Therefore, agricultural management practices that increase the stability of highly soluble C inputs and/or retard the decomposition of crop residues should be adopted to decrease soil greenhouse gas emission and increase soil C sequestration.
  • Authors:
    • Vogel, A.
    • Strecker, T.
    • Steinauer, K.
    • Richter, A.
    • Ramirez, N.
    • Pierce, S.
    • Rong, J.
    • HongYan, G.
    • FuXun, A.
    • Tilman, D.
    • Scheu, S.
    • Reich, P.
    • Power, S.
    • Roscher, C.
    • Niklaus, P.
    • Manning, P.
    • Milcu, A.
    • Thakur, M.
    • Eisenhauer, N.
  • Source: Global Change Biology
  • Volume: 21
  • Issue: 11
  • Year: 2015
  • Summary: Soil microbial biomass is a key determinant of carbon dynamics in the soil. Several studies have shown that soil microbial biomass significantly increases with plant species diversity, but it remains unclear whether plant species diversity can also stabilize soil microbial biomass in a changing environment. This question is particularly relevant as many global environmental change (GEC) factors, such as drought and nutrient enrichment, have been shown to reduce soil microbial biomass. Experiments with orthogonal manipulations of plant diversity and GEC factors can provide insights whether plant diversity can attenuate such detrimental effects on soil microbial biomass. Here, we present the analysis of 12 different studies with 14 unique orthogonal plant diversity * GEC manipulations in grasslands, where plant diversity and at least one GEC factor (elevated CO 2, nutrient enrichment, drought, earthworm presence, or warming) were manipulated. Our results show that higher plant diversity significantly enhances soil microbial biomass with the strongest effects in long-term field experiments. In contrast, GEC factors had inconsistent effects with only drought having a significant negative effect. Importantly, we report consistent non-significant effects for all 14 interactions between plant diversity and GEC factors, which indicates a limited potential of plant diversity to attenuate the effects of GEC factors on soil microbial biomass. We highlight that plant diversity is a major determinant of soil microbial biomass in experimental grasslands that can influence soil carbon dynamics irrespective of GEC.
  • Authors:
    • Liang, L.
    • Jia, Z.
    • Wang, X.
  • Source: Soil and Tillage Research
  • Volume: 153
  • Year: 2015
  • Summary: Field experiments were conducted in 2008-2010 in the Loess Plateau of China to study the effects of straw incorporation on maize growth and biomass water use efficiency (WUE) under semi-arid condition in dark loessial soil. Low (LS 4.5tha-1), medium (MS 9.0tha-1), and high (HS 13.5 tha-1) levels of straw were incorporated into the surface soil combined with fixed levels of inorganic fertilizers (CK) as control. Straw incorporation compared with CK significantly improved biomass yield at the tasseling-maturity stage of maize and WUE at the jointing-ten leaf collar and the tasseling-grain filling stages. WUEs with LS and MS treatments were significantly lower than that with CK at the ten leaf collar-tasseling stage, although the WUEs with MS and HS treatments were significantly higher in the whole growth period. HS treatment compared with LS treatment significantly increased biomass yield at the ten leaf collar-maturity stage and WUE at the jointing-tasseling stage. Meanwhile, MS and HS treatments compared with LS treatment significantly increased the biomass yield at the late grow period. Straw incorporation significantly improved WUE at the sowing-jointing stage and soil organic carbon relative to CK. Biomass yield at the ten leaf collar stage and WUE in whole growth period with LS treatment were significantly higher compared with CK. WUE at the ten leaf collar-tasseling and the grain filling-maturity stages were significantly higher with HS treatment compared with CK. In the long term, the rational straw incorporation level in improving maize biomass yield and WUE was 9.0tha-1. © 2015 Elsevier B.V..
  • Authors:
    • Chen, D.
    • Weng, B.
    • Zhang, J.
    • Zheng, X.
    • Hu, X.
    • Zhang, Y.
    • Li, S.
    • Ding, H.
  • Source: Nutrient Cycling in Agroecosystems
  • Volume: 103
  • Issue: 3
  • Year: 2015
  • Summary: To investigate the fate of urea nitrogen (N) applied to vegetable fields, three N rates, N0 (0 kg N/ha), N1(225 or 240 kg N/ha) and N2 (450 or 480 kg N/ha) were applied to a rotation system. Nitrogen fertilizer recovery (NFR), N residue in soil, and N losses were measured in situ. Higher N application rates resulted in lower NFR, and increased N residues in soil and losses. The NFR, Chinese cabbage, and eggplant were different in the N1 and N2 groups (P < 0.01). The ratios of N fertilizer residue at 0-60 cm deep ranged from 30.2 to 41.1 % (N1), and 33.1 to 57.7 % (N2). The N loss ratios were only 6.6 % (N1) and 11.9 % (N2), because of the lower precipitation rates and temperatures characteristic of its growing season; meanwhile, N losses were 31.1 and 37.4 % in cayenne pepper, and 24.1 and 29.2 % in eggplants in the N1 and N2 treatments, respectively. The main pathways of N loss were leaching, followed by gaseous losses; these were major pathways of N loss in seasons with lower precipitation rates. NH3 volatilization was correlated with soil temperature (P < 0.01), and N2O emissions were correlated with soil moisture in the N1 treatment and with soil NH4 (+)-N concentration in the N2 treatment (P < 0.01). Denitrification rates were correlated with soil moisture in the N0 and N1 treatments, and with NO3 (-)-N content in the N2 treatment (P < 0.01). Finally, loss due to runoff was correlated with precipitation (P < 0.01).
  • Authors:
    • Shu, X.
    • Xu, X. H.
    • Zhang, J. B.
    • Chen, X. M.
    • Zhu, A. N.
    • Yang, W. L.
  • Source: NUTRIENT CYCLING IN AGROECOSYSTEMS
  • Volume: 99
  • Issue: 1-3
  • Year: 2014
  • Summary: The backward Lagrangian stochastic (BLS) model and open-path tunable diode laser (OPTDL) analyzer were used to monitor ammonia (NH3) emissions from urea applied to winter wheat in the North China Plain. The high-temporal resolution measurements of ammonia concentrations provided an opportunity for estimating the diel patterns of ammonia emissions, as well as valuable information about the factors that influence NH3 emissions. The results showed both large diel variability and daily variability in NH3 volatilization, with NH3 emissions highest during the daytime. The diel pattern of ammonia volatilization depended mainly on the diel variation of wind speed and soil temperature, while the overall pattern of NH3 loss was strongly affected by soil moisture content, soil NH4 (+)-N concentration, wind speed and soil temperature. At the end of the measurement period, the cumulative NH3 loss was 12.21-16.43 kg N ha(-1), calculated based on different time scale average Q (BLS). Due to sensitivity of the OPTDL analyzer, the estimated total ammonia loss was still doubtful in this study.
  • Authors:
    • Wang, J.
    • Luo, H. H.
    • Zhang, Y. L.
    • Xu, Z. Z.
    • Yang, L.
    • Zhang, Q. B.
    • Zhang, W. F.
  • Source: JOURNAL OF ARID LAND
  • Volume: 6
  • Issue: 4
  • Year: 2014
  • Summary: Changes in both soil organic C storage and soil respiration in farmland ecosystems may affect atmospheric CO 2 concentration and global C cycle. The objective of this field experiment was to study the effects of three crop field management practices on soil CO 2 emission and C balance in a cotton field in an arid region of Northwest China. The three management practices were irrigation methods (drip and flood), stubble managements (stubble- incorporated and stubble-removed) and fertilizer amendments (no fertilizer (CK), chicken manure (OM), inorganic N, P and K fertilizer (NPK), and inorganic fertilizer plus chicken manure (NPK+OM)). The results showed that within the C pool range, soil CO 2 emission during the whole growing season was higher in the drip irrigation treatment than in the corresponding flood irrigation treatment, while soil organic C concentration was larger in the flood irrigation treatment than in the corresponding drip irrigation treatment. Furthermore, soil CO 2 emission and organic C concentration were all higher in the stubble-incorporated treatment than in the corresponding stubble-removed treatment, and larger in the NPK+OM treatment than in the other three fertilizer amendments within the C pool range. The combination of flood irrigation, stubble incorporation and application of either NPK+OM or OM increased soil organic C concentration in the 0-60 cm soil depth. Calculation of net ecosystem productivity (NEP) under different management practices indicated that the combination of drip irrigation, stubble incorporation and NPK+OM increased the size of the C pool most, followed by the combination of drip irrigation, stubble incorporation and NPK. In conclusion, management practices have significant impacts on soil CO 2 emission, organic C concentration and C balance in cotton fields. Consequently, appropriate management practices, such as the combination of drip irrigation, stubble incorporation, and either NPK+OM or NPK could increase soil C storage in cotton fields of Northwest China.
  • Authors:
    • Kucukalbay, M.
    • Akbolat, D.
  • Source: POLISH JOURNAL OF ENVIRONMENTAL STUDIES
  • Volume: 23
  • Issue: 4
  • Year: 2014
  • Summary: This study determined carbon dioxide (CO2) emissions from the cultivation of chickpeas cultivated in Usak using conventional wheat-chickpea crop rotation methods as a function of conventional tillage (CT), reduced tillage (RT), and direct seeding (DS). Measurements of carbon dioxide (CO2) emissions from the soil were started after planting using a portable CO2 measurement system (PP System) for a period of 55 days. Our results indicated CO2 emissions at rates of 4.1, 4.5, and 5.3 g.m(-2).h(-1) in response to the CT, RT, and DS treatments, respectively. A significant difference was found between CT and RT, and CO2 emissions under the DS treatment were higher than those of the other two treatments (p<0.05). Soil evaporation rates were estimated at 11.6, 10.9, and 13.1 g.m(-2).h(-1) under the CT, RT, and DS treatments, respectively. Mean soil temperafure was 17.5, 18.1, and 18.3 degrees C for the CT, RT, and DS treatments, respectively (p<0.05). Mean values of soil moisture content (wet base) after tillage were 19.7%, 19.1%, and 18.8% for CT, RT, and DS, respectively. Soil temperature and seedbed preparation methods appeared to influence soil CO2 emissions.