• 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:
    • Northupl,B. K.
    • Rao,S. C.
  • Source: Crop Economics, Production & Management
  • Volume: 107
  • Issue: 5
  • Year: 2015
  • Summary: Continuous winter wheat ( Triticum aestivum L. em Thell.) is the foundation for most US Southern Great Plains (SGP) agriculture. Inorganic N fertilizers are important to wheat production, but increasing N prices have caused producers to reconsider growing legumes during summer fallow for green N. This study was conducted during 2008 to 2012 to determine the potential for using lablab [ Lablab purpureus (L.) Sweet cv. Rio Verde] to support wheat under conventional and no-till management compared with soybean [ Glycine max (L.) Merr. cv. Laredo] and three inorganic fertilizer treatments (none, 40, and 80 kg N ha -1). Legume seeds were inoculated and sown after wheat harvest each year, grown from June to August, and terminated in early September. Wheat was then sown with or without preplant tillage and grown to maturity. Grain yield, N concentration, and N accumulated in grain were analyzed to define N treatment, tillage system, and year effects. The amount and distribution of precipitation during 2008 to 2012 varied from 53 to 92% and 63 to 160% of the long-term averages for wheat (688 mm) and legume (162 mm) phases. Tillage effects were nonsignificant ( P<0.76), but N treatment * year interactions were significant for grain yield, N concentration, and N accumulated in grain ( P<0.01). The legumes resulted in some single-year increases in grain yield, but the overall yield response was inconsistent. The legume treatments reduced N concentration in wheat grain compared with the unfertilized control. These results show that neither legume was an effective short-term (≤4-yr) N source for systems of continuous wheat production in the SGP.
  • Authors:
    • Banger,Kamaljit
    • Tian,Hanqin
    • Tao,Bo
    • Ren,Wei
    • Pan,Shufen
    • Dangal,Shree
    • Yang,Jia
  • Source: Climatic Change
  • Volume: 132
  • Issue: 4
  • Year: 2015
  • Summary: India is very important but relatively unexplored region in terms of carbon studies, where significant environmental changes have occurred in the 20th century that can alter terrestrial net primary productivity (NPP). Here, we used a process-based, Dynamic Land Ecosystem Model (DLEM), driven by land cover and land use change (LCLUC), climate change, elevated atmospheric CO2 concentration, atmospheric nitrogen deposition (NDEP), and tropospheric ozone (O-3) pollution to estimate terrestrial NPP in India during 1901-2010. Over the country, terrestrial NPP showed significant inter-annual variations ranging 1.2 Pg C year(-1) to 1.7 Pg C year(-1) during the 1901-2010. Overall, multiple environmental changes have increased terrestrial NPP by 0.23 Pg C year(-1). Elevated atmospheric CO2 concentration has increased NPP by 0.29 Pg C; however climate change has offset a portion of terrestrial NPP (0.11 Pg C) during this study period. On an average, terrestrial NPP reduced by 0.12 Pg C year(-1) in drought years; when precipitation was 100 mm year(-1) lower than long term average, suggesting that terrestrial carbon cycle in India is strongly linked to climate change. LCLUC, including land conversions and cropland management practices, increased terrestrial NPP by 0.043 Pg C year(-1) over the country. Tropospheric O-3 pollution reduced terrestrial NPP by 0.06 Pg C year(-1) and the decrease was comparatively higher in croplands than other biomes after the 1980s. Our results have shown that climate change and tropospheric O-3 pollution may partially offset terrestrial NPP increase caused by elevated CO2 concentration, LCLUC, and NDEP over India.
  • 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.
  • Authors:
    • Korth, K.
    • Chen, P.
    • Gbur, E. E.
    • Brye, K. R.
    • Smith, F.
  • Source: Soil Science
  • Volume: 179
  • Issue: 3
  • Year: 2014
  • Summary: One of the most significant contributors to the greenhouse effect is carbon dioxide (CO2) gas in the atmosphere. Soil respiration, the combined production of CO2 from soil, as a result of root and microorganism respiration, is the largest flux of CO2 from the terrestrial ecosystem to the atmosphere. Considering land use can greatly impact soil C storage and cycling, agricultural management practices can also greatly affect soil respiration and CO2 emissions. Therefore, the effects of long-term residue management (i.e., residue burning and nonburning, and conventional [CT] and no-tillage [NT]) and residue level (i.e., high and low) on soil respiration during the soybean [Glycine max (L.) Merr.] growing season were examined over 2 consecutive years (i.e., 2011 and 2012) in a wheat (Triticum aestivum L.)-soybean, double-crop system in a silt-loam soil (Aquic Fraglossudalf) in the Mississippi River Delta region of eastern Arkansas after more than 9 years of consistent management. Soil respiration rates from individual plots ranged from 0.53 to 40.7 and from 0.17 to 13.1 mol CO2.m(-2).s(-1) throughout the 2011 and 2012 soybean growing seasons, respectively, and differed (P < 0.05) among treatment combinations on two and five of nine and 11 measurement dates in 2011 and 2012, respectively. Regardless of residue level, soil respiration was generally greater (P < 0.05) from CT than NT. Estimated season-long CO2 emissions were 10.2% less (18.5 Mg CO2 ha(-1)) from residue burning than from non-burning (20.6 Mg CO2.ha(-1); P = 0.032). Averaged over years and all other field treatments, estimated season-long CO2 emissions were 15.5% greater from CT (21.0 Mg CO2 ha(-1)) than from NT (18.1Mg CO2 ha(-1); P = 0.020). Understanding long-term management effects on soil C losses, such as soil respiration, from common and widespread agricultural systems, such as the wheat-soybean, double-crop system, in eastern Arkansas can help improve policies for soil and environmental sustainability throughout the lower Mississippi River Delta region.
  • Authors:
    • Christie, P.
    • Gao, B.
    • Huang, T.
    • Ju, X.
  • Source: Biogeosciences
  • Volume: 10
  • Issue: 12
  • Year: 2013
  • Summary: The effects of nitrogen and straw management on global warming potential (GWP) and greenhouse gas intensity (GHGI) in a winter wheat-summer maize double-cropping system on the North China Plain were investigated. We measured nitrous oxide (N2O) emissions and studied net GWP (NGWP) and GHGI by calculating the net exchange of CO2 equivalent (CO2-eq) from greenhouse gas emissions, agricultural inputs and management practices, as well as changes in soil organic carbon (SOC), based on a long-term field experiment established in 2006. The field experiment includes six treatments with three fertilizer N levels (zero N (control), optimum and conventional N) and straw removal (i.e. N-0 N-opt and N-con) or return (i.e. SN0, SNopt and SNcon). Optimum N management (N-opt, SNopt) saved roughly half of the fertilizer N compared to conventional agricultural practice (N-con, SNcon), with no significant effect on grain yields. Annual mean N2O emissions reached 3.90 kg N2O-N ha(-1) in N-con and SNcon, and N2O emissions were reduced by 46.9% by optimizing N management of N-opt and SNopt. Straw return increased annual mean N2O emissions by 27.9 %. Annual SOC sequestration was 0.40-1.44Mg C ha(-1) yr(-1) in plots with N application and/or straw return. Compared to the conventional N treatments the optimum N treatments reduced NGWP by 51 %, comprising 25% from decreasing N2O emissions and 75% from reducing N fertilizer application rates. Straw return treatments reduced NGWP by 30% compared to no straw return because the GWP from increments of SOC offset the GWP from higher emissions of N2O, N fertilizer and fuel after straw return. The GHGI trends from the different nitrogen and straw management practices were similar to the NGWP. In conclusion, optimum N and straw return significantly reduced NGWP and GHGI and concomitantly achieved relatively high grain yields in this important winter wheat-summer maize double-cropping system.
  • Authors:
    • Zhang, X-C.
    • Zheng, Z-Q.
    • Lu, Z.-Y.
    • Lu, C.-Y.
    • Sivelli,A.
    • Li, H.-W.
    • Wang, Q-J.
    • He, J
    • Li, H.
  • Source: Soil Science
  • Volume: 178
  • Issue: 1
  • Year: 2013
  • Summary: Traditional tillage (TT) in the North China Plain has maintained grain productivity in the past 50 years. Nonetheless, it has also been a major contributor to global greenhouse gas emissions, biodiversity and soil fertility loss, soil degradation, and even desertification. Permanent raised beds (PRB) have been proposed as a viable solution to achieve sustainable farming in this plain. The effects on soil chemical properties of the PRB treatment and two other treatments, namely, no-tillage and TT treatments, were measured between 2005 and 2011 in the annual double cropping regions of the North China Plain. The soil properties significantly ( P1.35) were significantly ( P<0.05) higher than those under no-tillage and TT. In the cropping zone of PRB, the bulk density was significantly reduced by 14.4%, whereas soil organic carbon, total nitrogen, phosphorus, and potassium and available nitrogen, phosphorus, and potassium in the 0- to 10-cm soil layer were significantly increased by 24.8%, 78.8%, 121.9%, 81.8%, 46.2%, 7.0%, 2.9%, respectively, in comparison with those of TT treatments. Winter wheat and summer maize yields in PRB also underwent a slight increase. Permanent raised beds seem to be an improvement on current farming systems in the North China Plain and valuable for the sustainability of farming in this region.
  • Authors:
    • Zhang, X.
    • Zheng, Z.
    • Lu, Z.
    • Lu, C.
    • Sivelli, A.
    • Li, H.
    • Wang, Q.
    • He, J.
    • Li, H.
  • Source: Soil Science
  • Volume: 178
  • Issue: 1
  • Year: 2013
  • Summary: Traditional tillage (TT) in the North China Plain has maintained grain productivity in the past 50 years. Nonetheless, it has also been a major contributor to global greenhouse gas emissions, biodiversity and soil fertility loss, soil degradation, and even desertification. Permanent raised beds (PRB) have been proposed as a viable solution to achieve sustainable farming in this plain. The effects on soil chemical properties of the PRB treatment and two other treatments, namely, no-tillage and TT treatments, were measured between 2005 and 2011 in the annual double cropping regions of the North China Plain. The soil properties significantly (P 1.35) were significantly (P < 0.05) higher than those under no-tillage and TT. In the cropping zone of PRB, the bulk density was significantly reduced by 14.4%, whereas soil organic carbon, total nitrogen, phosphorus, and potassium and available nitrogen, phosphorus, and potassium in the 0- to 10-cm soil layer were significantly increased by 24.8%, 78.8%, 121.9%, 81.8%, 46.2%, 7.0%, 2.9%, respectively, in comparison with those of TT treatments. Winter wheat and summer maize yields in PRB also underwent a slight increase. Permanent raised beds seem to be an improvement on current farming systems in the North China Plain and valuable for the sustainability of farming in this region.
  • Authors:
    • Feizian, M.
    • Khalili, A.
    • Heidari, S.
    • Moradii, J.
    • Azizi, K.
  • Source: International Journal of AgriScience
  • Volume: 2
  • Issue: 4
  • Year: 2012
  • Summary: This experiment was undertaken to study the effect of different levels of gibberellic acid (GA 3) as a hormone on the yield components of soybean genotypes in summer double cropping as the second crop following a wheat harvest. The experiment was carried out in 4*2 factorial arrangement of a randomized complete block design (RCBD) with four replicates at the experimental farm of Lorestan Meteorological Office located in Khorramabad. 4 levels of GA 3 concentration (0.0 (as control), 125, 250, and 375 ppm) were sprayed over the plants and 2 levels of soybean genotypes (M 11 and L 17) were used for the experiment. The results showed that interactions between different levels of GA 3 and the soybean genotypes had significant effect on pod number per plant, seed number per pod, 1000-seed weight, and economic and biological yield ( p
  • Authors:
    • Fan, M. S.
    • Hao, Y. F.
    • Hu, B.
  • Source: China Vegetables
  • Issue: 10
  • Year: 2012
  • Summary: The effects of Chinese cabbage N application rate on Chinese cabbage yields, nitrogen utilization, nitrate contents, and nitrate nitrogen accumulation in soil were studied under potato-Chinese cabbage double cropping system in Hetao irrigated area of Inner Mongolia with 5 N application rates at Chinese cabbage planting season. The results showed that the yields and the double cropping net economic returns were the highest with the Chinese cabbage N application rate of 120 kg.hm -2; the double cropping system N accumulation and N recovery ratio were enhanced at the total N application rate from 225 kg.hm -2 to 405 kg.hm -2, compared with that of the conventional mono potato production in the open field at the N application rate of 225 kg.hm -2; the nitrate contents in Chinese cabbage and the nitrate accumulations within 0-160 cm soil profiles were increased with the increscent N applied rates. At the Chinese cabbage N application rate was ≥120 kg.hm -2, the nitrate contents in Chinese cabbage reached a high level, and the nitrate accumulations within 0-160 cm soil profiles were ≥162 kg.hm -2, hence the risk of nitrate contamination in underground water was increased for autumn irrigation. Reasonable N application rate had an effective effects on reducing nitrate contamination in groundwater, reducing nitrate content in Chinese cabbage, and increasing net economic return.