• Authors:
    • Rimmington, G. M.
    • Chen, X.
    • Zheng, Y.
    • Luo, L.
    • Wang, Y.
    • Jiang, L.
    • Zhao, X.
    • Lai, L.
  • Source: PLOS ONE
  • Volume: 7
  • Issue: 10
  • Year: 2012
  • Summary: The variation of different ecosystems on the terrestrial carbon balance is predicted to be large. We investigated a typical arid region with widespread saline/alkaline soils, and evaluated soil respiration of different agricultural and natural ecosystems. Soil respiration for five ecosystems together with soil temperature, soil moisture, soil pH, soil electric conductivity and soil organic carbon content were investigated in the field. Comparing with the natural ecosystems, the mean seasonal soil respiration rates of the agricultural ecosystems were 96%-386% higher and agricultural ecosystems exhibited lower CO2 absorption by the saline/alkaline soil. Soil temperature and moisture together explained 48%, 86%, 84%, 54% and 54% of the seasonal variations of soil respiration in the five ecosystems, respectively. There was a significant negative relationship between soil respiration and soil electrical conductivity, but a weak correlation between soil respiration and soil pH or soil organic carbon content. Our results showed that soil CO2 emissions were significantly different among different agricultural and natural ecosystems, although we caution that this was an observational, not manipulative, study. Temperature at the soil surface and electric conductivity were the main driving factors of soil respiration across the five ecosystems. Care should be taken when converting native vegetation into cropland from the point of view of greenhouse gas emissions.
  • Authors:
    • Tian, C.
    • Chen, F.
    • Wang, X.
    • Zhang, R.
    • Li, Z.
  • Source: PLOS ONE
  • Volume: 7
  • Issue: 11
  • Year: 2012
  • Summary: There is much interest in the role that agricultural practices might play in sequestering carbon to help offset rising atmospheric CO2 concentrations. However, limited information exists regarding the potential for increased carbon sequestration of different management strategies. The objective of this study was to quantify and contrast carbon dioxide exchange in traditional non-mulching with flooding irrigation (TF) and plastic film mulching with drip irrigation (PM) cotton (Gossypium hirsutum L.) fields in northwest China. Net primary productivity (NPP), soil heterotrophic respiration (R-h) and net ecosystem productivity (NEP) were measured during the growing seasons in 2009 and 2010. As compared with TF, PM significantly increased the aboveground and belowground biomass and the NPP (340 g C m(-2) season(-1)) of cotton, and decreased the R-h (89 g C m(-2) season(-1)) (p < 0.05). In a growing season, PM had a higher carbon sequestration in terms of NEP of similar to 429 g C m(-2) season(-1) than the TF. These results demonstrate that conversion of this type of land use to mulching practices is an effective way to increase carbon sequestration in the short term in cotton systems of arid areas.
  • Authors:
    • Guo-Feng, L.
    • Si-Bo, R. U.
    • Jun, Y. E.
    • Ning, L. V.
    • Li, M.
    • Zhen-An, H. O. U.
  • Source: Chinese Journal of Eco-Agriculture
  • Volume: 20
  • Issue: 8
  • Year: 2012
  • Summary: Soil organic carbon is critical for soil fertility and crop yield. Biochar (BC) is a carbon-rich organic material derived from incomplete pyrolysis of biomass and can constitute a significant fraction of soil carbon due to its prolonged lifespan in soils. The study investigated the influence of biochar on wheat growth and soil organic carbon in grey desert soils under greenhouse experiment. The objective was to learn how this soil amendment improved crop growth and increased soil carbon storage. Biochar was produced from dried cotton stalks via pyrolysis in oxygen-limited conditions. Three qualities of biochar produced at 450°C, 600°C and 750°C (referred as BC450, BC600 and BC750) were used as the soil organic amendment in the study. The experiment was that of 3*3 factorial design with three qualities of biochar (BC450, BC600 and BC750) and three application rates (5 g.kg -1, 10 g.kg -1 and 20 g.kg -1 of soil weight) plus an un-amended soil set as the control (CK). Wheat was planted for two consecutive growth seasons in 2009. The first-season of wheat was May 8 to July 15 and the second was August 8 to October 15. The results showed that dry matter weight of wheat under added BC treatments were significantly higher than that under CK. There were no significant differences among the three types and three application rates of biochar in terms of the first-season wheat dry matter weight. However, the second-season wheat dry matter weight was significantly affected by biochar qualities, application rates and the interaction of them. The highest wheat dry matter weight was under BC750 with an application rate of 20 g.kg -1. Soil total organic carbon increased with increasing biochar pyrolysis temperature and application rate. Soil total organic carbon under BC450, BC600 and BC750 was 2.11, 3.32 and 4.19 times of CK, respectively. Soil readily oxidizable carbon content was significantly higher under biochar treatments than the control. Water-soluble organic carbon was significantly higher under biochar treatments at 5 g.kg -1 and 10 g.kg -1 application rates than the control. However, there was no significant difference between 20 g.kg -1 biochar treatment and the control. Microbial biomass carbon increased significantly under biochar treatment, except for BC750 biochar at 5 g.kg -1 application rate. Readily oxidizable carbon and microbial biomass carbon contents of soil changed in the following order of BC450 > BC600 > BC750. However, soil water-soluble organic carbon content was not affected by biochar pyrolysis temperature. The order of influence of different biochar application rates on readily oxidizable soil carbon was 10 g.kg -1=20 g.kg -1> 5 g.kg -1, and that of water-soluble organic carbon was 5 g.kg -1=10 g.kg -1 > 20 g.kg -1. For soil microbial quotient, BC450 and BC600 at 5 g.kg -1 application rate were higher than CK. Also BC450 at 10 g.kg -1 and 20 g.kg -1 application rates were not significantly different from CK. Other biochar treatments were as well lower than CK. These results suggested that application of biochar as soil organic amendment was an efficient way of increasing soil carbon reserve, changing soil organic carbon fraction and promoting soil productivity.
  • Authors:
    • Gu, X. X.
    • Wang, F. X.
    • Tao, L. J.
  • Source: Chinese Journal of Eco-Agriculture
  • Volume: 20
  • Issue: 3
  • Year: 2012
  • Summary: A pot experiment was conducted in a greenhouse to compare the influences of flood (F) and drip (D) irrigations on soil concentrations of CO 2 and CH 4 during potato cropping season using the static opaque chamber and gas chromatography technique. Two agronomic measures were evaluated for each irrigation regime under mulched (M) and non-mulched conditions. Three more treatments were set under mulched drip irrigation (MD) based on different wet ratio ( P) - P1 ( P=25%), P2 ( P=33%) and P3 ( P=50%). There were six treatments altogether, denoted as DP1, MDP1, MDP2, MDP3, FC and MF. Bare soils with (MBS) and without (BS) plastic film mulching were set as control treatments. Results suggested that mulching treatments increased soil CO 2 concentration by 10.4%-94.5% due to plastic film mulching increasing effect on temperature and moisture, and barrier effects on natural air transmission of the soil-atmosphere system. Mulching treatments decreased soil CH4 concentration by 5.1%-47.4%. Because of dry-wet alternation under drip-irrigation and decreased soil aeration under flood irrigation, CO 2 concentration was 7.4%-49.7% higher under flood irrigation and CH 4 concentration 6.6%-68.2% lower under drip irrigation. Soil moisture influenced greenhouse gas emission by altering soil aeration and soil dissolved organic matter. The higher the wet ratio under MD, the lower was CO 2 concentration. However, the effect of wet ratio on CH 4 concentration was not clear. Soil temperature was the main driving factor of soil respiration, which also regulated CH 4 oxidation processes. The greenhouse gas concentration in soils after DP1 irrigation showed a significant positive correlation between soil temperature and soil CO 2 concentration. Also after DP1 irrigation, a significant negative correlation existed between soil temperature and soil CH 4 concentration while a significant negative correlation was noted between soil CO 2 and CH 4 concentrations.
  • Authors:
    • Shu, B.
    • Zhang, J. J.
    • Wang, P.
    • Xia, R. X.
  • Source: Plant, Soil and Environment
  • Volume: 58
  • Issue: 7
  • Year: 2012
  • Summary: Communities of arbuscular mycorrhizal fungi (AMF) were studied in sod culture (SC), straw mulching (NM), and herbicide treated and no-tillage (NH) citrus orchards, respectively. The highest total colonization rate (39.47%) and hyphal length density (1.15 m/g soil) were found in SC, the highest spore numbers (1024 spores/100 g soil) in NM, while the lowest ones (31.50%, 0.94 m/g soil and 719 spores/100 g soil) in NH and they varied significantly among three different types of orchards. Total 18 AMF species belonging to five families, Acaulosporaceae (four species), Claroideoglomeraceae (two species), Gigasporaceae (one species), Glomeraceae (nine species) and Pacisporaceae (two species) were identified, and Glomus aggregatum and Claroideoglomus etunicatum were the dominant species in all surveyed plots. The redundancy analysis showed that AMF community structure was influenced greatly by pH, soil management, soil organic matter (C ox) and available phosphorus (P Olsen). In SC orchards, species richness and Shannon-Wiener index of AMF were notably higher than in other treated orchards. So, it is reasonable to select SC as the best practice in citrus orchard in order to enhance AMF benefits.
  • Authors:
    • Liu, S.
    • Jiang, S.
    • Liu, S.
    • Hu, W.
    • Wan, S.
    • Kang, Y.
    • Wang, R.
  • Source: Agricultural Water Management
  • Volume: 110
  • Year: 2012
  • Summary: In order to evaluate the effects of different amounts of water, applied by drip irrigation, to a saline-sodic soil (surface ECe > 40 dS/m; SAR > 40), on cotton growth and soil salinity, a three-year experiment was conducted on a saline wasteland in Xinjiang Northwest China during 2008-2010. Five water treatments were used for this experiment based on the soil-water matric potential (SMP) measured 20 cm beneath a drip emitter located close to the plant: the SMP levels used to determine when to irrigate were -5 kPa (S1), -10 kPa (S2). -15 kPa (S3), -20 kPa (S4), and -25 kPa (S5). After three years, both the soil salinity (ECe) and sodicity (SAR) declined significantly in 0-120 cm depth and more reduction were achieved in 0-40 cm soil depth than in 40-80 and 80-120 cm depths. Moreover, the reductions of SAR were smaller than those of ECe. Additionally, the amount of salt removed from the 0 to 80 cm depth decreased with decreasing SMP threshold. The S1 treatment resulted in the highest lint yields in 2009 and 2010. Considering the effects of leached salts on the environment of deep soil layer and the yield of cotton, an SMP of -10 kPa can be used to trigger irrigation for cotton in the first three years for saline wasteland reclamation in Xinjiang Northwest China. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved.
  • Authors:
    • Manzur, C. L.
    • Cai, D.
    • Zhang, G.
    • Wu, H.
    • Wu, X.
    • Zheng, Y.
    • Hu, Y.
    • Zhao, Q.
    • Wang, X.
  • Source: Irrigation Science
  • Volume: 30
  • Issue: 3
  • Year: 2012
  • Summary: The field experiment for cotton crop (Gossypium hirsutum L.) was conducted at the Zhongjie Farm, Huanghua city of Hebei province in the coastal salinity-affected areas in North China Plain, to determine the effects of an alternative of irrigation water sources/methods and agronomic practices on seedling emergence and yields of cotton, soil water-salt distributions, and soil pH changes during cotton growth stages. The experiment was setup using split-plot design with two water sources as main treatments (well water/desalinized sea-ice water); two irrigation methods (+PAM (Polyacrylamide)/-PAM); and four fertilization modes: check (CK), mineral fertilizer (F), mineral + organic fertilizer (FM), and mineral fertilizer + gypsum (FG). Using desalinized sea-ice water irrigation showed the same effects on top-soil salt leaching and desalinization as using well water did. There was no significant difference in seedling emergence and cotton yields between two irrigation water sources for cotton irrigation. Using PAM-treated irrigation, the 10-cm top-soil salinity significantly decreased to about 2.3-3.9 g kg(-1) from 4.6 to 8.6 g kg(-1) (PAM untreated). The PAM-treated irrigation increased seedling emergence by about 13, 29 and 36% and yields by about 50, 49, and 70%, with F, FM, and FG, respectively, as compared with CK. PAM-treated irrigation, either using well water or desalinized sea ice, especially in combination with gypsum-fertilization, shows the best practice for both seedling emergence and cotton yields. In conclusion, the desalinized sea-ice water used as an alternative water source, integrated with better agronomic practices of soil water-salt management could be acceptable for cotton irrigation in the coastal saline areas.
  • Authors:
    • Liu, H. Y.
    • Wu, X. K.
    • Wei, J. F.
    • Wei, D. P.
  • Source: Guizhou Agricultural Sciences
  • Issue: 4
  • Year: 2012
  • Summary: Water plays an important role in growth and development, yield and quality of potato. Water is required in large quantity for potato growth and development, but generally lack in the soil, and has to be appropriately supplied to meet the needs for its normal growth. Study the water requirements characteristics is the prerequisite and basis for rational irrigation of potato production. The water requirements characteristic of potato was summarized according to some relevant literature in this article, which included the water requirements and suitable soil moisture index for potato in growth period. Moreover, the effects of drought strees and supplementary water on physiological and biochemical reaction, growth and development, yield and quality of potato were introduced. Finally, the further research topics of water requirements in potato were also proposed.
  • Authors:
    • Wang, J.
    • Wang, X. J.
    • Ma, T. F.
    • Wei, C. .Z.
  • Source: Journal of Arid Land
  • Volume: 4
  • Issue: 3
  • Year: 2012
  • Summary: Quantitative information on the fate and efficiency of nitrogen (N) fertilizer applied to coarse textured calcareous soils in arid farming systems is scarce but, as systems intensify, is essential to support sustainable agronomic management decisions. A mesh house study was undertaken to trace the fate of N fertilizer applied to cotton (Gossypium hirsutum L. cv., Huiyuan701) growing on a reconstructed profile (0-100 cm) of a calcareous (>15% CaCO3) sandy loam soil. Two irrigation methods (drip irrigation, DI; and furrow irrigation, Fl) and four N application rates (0, 240, 360 and 480 kg/hm(2), abbreviated as N-0, N-240, N-360, and N-480, respectively) were applied. N-15-labelled urea fertilizer was applied in a split application. DI enhanced the biomass of whole plant and all parts of the plant, except for root; more fertilizer N was taken up and mostly stored in vegetative parts; N utilization efficiency (NUE) was significantly greater than in Fl. N utilization efficiency (NUE) decreased from 52.59% in N-240 to 36.44% in N-480. N residue in soil and plant N uptake increased with increased N dosage, but recovery rate decreased consistently both in DI and Fl. Plant N uptake and soil N residue were greater in DI than in FI. N residue mainly stayed within 0-40 cm depth in DI but within 40-80 cm depth in Fl. Fl showed 17.89% of N leached out, but no N leaching occurred in DI. N recovery rate in the soil-plant system was 75.82% in DI, which was markedly greater than the 55.97% in Fl. DI exhibited greater NUE, greater residual N in the soil profile and therefore greater N recovery rate than in Fl; also, N distribution in soil profile shallowed in DI, resulting in a reduced risk of N leaching compared to Fl; and enhanced shoot growth and reduced root growth in DI is beneficial for more economic yield formation. Compared to furrow irrigation, drip irrigation is an irrigation method where N movement favors the prevention of N from being lost in the plant-soil system and benefits a more efficient use of N.
  • Authors:
    • Zhang, S. B.
    • Gong, X. F.
    • Zhang, R. F.
    • Wang, X. X.
    • Xie, K. Y.
    • Mares,V.
    • Gavilan,C.
    • Posadas,A.
    • Quiroz,R.
  • Source: Scientia Horticulturae
  • Volume: 134
  • Year: 2012
  • Summary: Two field experiments were conducted in two semi-arid areas in northern China to test the response of three potato varieties to supplemental irrigation. Conventional furrow irrigation was compared to the partial root-zone drying (PRD) irrigation system at different watering levels, with and without plastic mulching. Reducing the supplementary water to one half, under both soil-climate conditions tested, did not affect fresh tuber yield; whereas water use efficiency (WUE) was equally incremented by all the reduced water treatments. When this reduction in the amount of supplementary water was managed through the PRD system, the distribution of moisture in the soil seemed to be improved and the potential evaporation was decreased due to the reduced evaporative surface exposed by PRD. The results showed that application of irrigation water per unit area can be reduced relative to common practice in Inner Mongolia and Gansu, maintaining the tuber yields currently obtained by local farmers. A further reduction in the amount of supplemental water, without a substantial decrease in yield, might be feasible with the PRD technique but this may require a more sophisticated irrigation management; and further research to estimate the cost-benefit ratio of such sophistication is needed. Results also showed that under low precipitation and low water retention capacity, the use of plastic mulching and a potato variety selected for drought-prone environments can make the difference for maintaining a high yield while reducing the wasteful use of the water resources.