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ABSTRACT: The grazing exclusion in degraded grassland has been extensively used to prevent the loss of grassland resources and to improve grassland services. The effects of grazing exclusion on C and N balance, however, have not been well addressed but are essential for assessing grassland C sinks, the sustainable use of grassland resources and the support of grassland services. To understand the response of ecosystem C and N to grazing exclusion in semiarid grassland, we determined the C and N in litter, aboveground biomass, roots and soils from ungrazed grassland fenced at different times in northwest China. Our results showed that the aboveground biomass, root biomass and plant litter were 70-92%, 56-151% and 59-141% higher, respectively, in grazer excluded grassland than in grazed grassland. Grazing exclusion significantly increased C and N stored in plant biomass and litter and increased the concentrations and stocks of C and N in soils. Grazing exclusion thus significantly increased the C and N stored in grassland ecosystems. The increase in C and N stored in soil contributed to more than 95% and 97% of the increases in ecosystem C and N storage. The highest C and N stocks in ecosystems were observed in 17-year grazer excluded grassland. The results from this study indicate that grazing exclusion has the potential to increase C and N storage in degraded semiarid grassland and that the recovery of ecosystem C and N was mainly due to the accumulation of C and N in soils.
PLoS ONE 01/2013; 8(1):e55433. · 4.09 Impact Factor
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ABSTRACT: Black locust (Robinia pseudoacacia) has been widely planted in the Loess Plateau for soil and water conservation. The effects of black locust on soil properties
has significant role in land use and ecosystem management. However, this beneficial effect has been little studied in the
Loess Plateau. The soil properties below black locust and native grass growing in Nanxiaohe and Wangdonggou watersheds, located
in the loessial gully region of the Loess Plateau, were studied for changes in soil properties after establishment of black
locust. The black locust significantly increased soil cation exchange capacity, organic carbon, total nitrogen, nitrate, and
carbon:nitrogen and carbon:phosphorus (P) ratios, as well as some enzymes like alkaline phosphatase and invertase in 0–20cm
or 0–80cm depths of soil compared to the native grassland in Nanxiaohe and Wangdonggou watersheds. However, the effects on
ammonium, total P, and extractable P and potassium were not consistent in both watersheds. There were more obvious differences
in soil properties between black locust land and grassland for Nanxiaohe watershed than for Wangdonggou watershed, suggesting
that the effects of black locust on most soil properties increase with black locust age. The results indicate that black locust
has potential to improve soil properties in the loessial gully region of the Loess Plateau and the improvements were greater
in long-term than middle-term black locust stands.
KeywordsAfforestation-Black locust-Native grass-Soil properties-The Loess Plateau
Plant and Soil 04/2012; 332(1):207-217. · 2.73 Impact Factor
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ABSTRACT: The northern Loess Plateau is an important cropping-pastoral ecotone and wind–water erosion crisscross region in China, but
the distribution of soil organic carbon (C), nitrogen (N) and phosphorus (P) in different land uses across this vulnerable
ecoregion is not well understood. This study was carried out to determine the distribution patterns of soil organic C, N and
P in native grassland and in two woody lands (Chinese Pine land and Korshinsk Peashrub land) that were established on the
native grassland 28years ago. In the north part of the Loess Plateau, the concentrations of soil organic C, N and P were
lower than in the southern Loess Plateau either across or within the land use patterns. The concentrations and stocks of organic
C and total N were significantly decreased in Chinese Pine and Korshinsk Peashrub lands compared with those in native grassland
in the surface 0–40cm soil layer, where more than 70% of the roots were distributed. The decreases in organic C in 0–40cm
soil layers were 2.6 and 3.0Mg C ha−1 (26.3 and 27.7%) by Chinese Pine and Korshrinsk Peashrub, while those of total N were 0.6 and 0.4MgN ha−1 (31.5 and 17.2%), respectively, compared with native grassland. Both concentration and stock of total P varied only slightly
with land use. The findings suggested that the conversion of natural grass into Chinese Pine and Korshinsk Peashrub resulted
in decreased soil organic C and total N in the surface 0 to 40cm soil layer of the northern Loess Plateau. Our results further
indicated that a combination of low temperatures, little precipitation and large soil degradation impede increasing C and
N stocks by afforestation, and the afforestation on grassland should be viewed very critically in such areas.
Biogeochemistry 04/2012; 96(1):149-162. · 3.07 Impact Factor
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ABSTRACT: A vailability and heterogene-ity of resources have a strong influence on com-munity biomass and diversity, which provided a valuable opportunity to evaluate the responses of vegetation on fertilization, to test whether fertili-sation can accelerate vegetation restoration in in-fertile lands. In loess hilly region of China, most newly abandoned infertile lands often undergo heavy soil erosion. It is urgent to promote the restora-tion of these types of lands. As availability and heterogeneity of soil nutrients have a strong influ-ence on plant community, we conducted a fertili-sation experiment with three-factor treatments, to test whether fertilisation can promote the bio-mass and species richness of an Artemisia sco-paria-dominated old field community. The three factors were: spatial patterns (homogeneity and heterogeneity), levels (low, medium and high), and scales (three levels with small, intermediate, and large patches) of fertiliser application. Above-and below-ground biomass and species richness were recorded. The responses of the plant com-munity to the three factors were evaluated and compared with those of the control (no fertilisa-tion). The results show that: (1) The application of fertiliser in either homogeneous or heterogeneous pattern significantly increased the above-ground and below-ground biomass of the plant commu-nity as compared with the control. (2) In hetero-geneous conditions, the above-ground biomass in nutrient-rich patches was significantly greater than the expected value of 50%. Under intermedi-ate and large scales of the low level and all scales of the medium and high levels, the proportion of 0–15 cm below-ground biomass was also signifi-cantly greater than 50%. (3) Both homogeneous and heterogeneous fertilisation greatly increased community richness as compared to the control. Fertilisation, particularly heterogeneous fertilisa-tion, can effectively increase community biomass and diversity. Under patchy habitat, it seems that the responses of vegetation to heterogeneous fer-tilisation are related to the patches scale and the contrast among patches, nutrient usage efficiency, edge effects on plant and soil, and plant compe-tition are responsible for the responses. The re-sults also suggest that heterogeneous fertilisation should be applied widely in infertile old fields to accelerate secondary succession.
Polish Journal of Ecology 01/2012; 60(1):133-144. · 0.51 Impact Factor
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ABSTRACT: The afforestation of abandoned farmland significantly influences soil organic carbon (OC). However, the dynamics between OC inputs after afforestation and the original OC are not well understood. To learn more about soil OC dynamics after afforestation of farmland, we measured the soil OC content in paired forest and farmland plots in Shaanxi Province, China. The forest plots had been established on farmland 18, 24, 48, 100, and 200 yr previously. The natural (13)C abundance of soil organic matter was also analyzed to distinguish between crop- and forest-derived C in the afforested soils. We observed a nonlinear accumulation of total OC in the 0-80 cm depth of the mineral soil across time. Total soil OC accumulated more rapidly under forest stands aged 18 to 48 yr than under forest stands aged 100 or 200 yrs. The rate of OC accumulation was also greater in the 0-10 cm depth than in the 10-80 cm depth. Forest-derived OC in afforested soils also accumulated nonlinearly across time, with the greatest increase in the 0-20 cm depth. Forest-derived OC in afforest soils accounted for 52-86% of the total OC in the 0-10 cm depth, 36-61% of the total OC in the 10-20 cm depth, and 11-50% of the total OC in the 20-80 cm depth. Crop-derived OC concentrations in the 0-20 cm depth decreased slightly after afforestation, but there was no change in crop-derived OC concentrations in the 20-80 cm depth. The results of our study support the claim that afforestation of farmland can sequester atmospheric CO(2) by increasing soil OC stocks. Changes in the OC stocks of mineral soils after afforestation appear to be influenced mainly by the input of forest-derived C rather than by the loss of original OC.
PLoS ONE 01/2012; 7(3):e32054. · 4.09 Impact Factor
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Acta Agriculturae Scandinavica B 03/2010; 60(2):136-143. · 0.70 Impact Factor
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Acta Agriculturae Scandinavica - Section B Soil and Plant Science 01/2010; 60(1):48-56.
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ABSTRACT: As one interaction outcome of soil nitrogen with rainfall and surface runoff, soil nitrogen loss by runoff virtually is the mass transfer among different carriers, runoff, sediment and soil, etc. Rainfall and surface runoff are main impetuses. Soil is the interface on which the interaction takes place, and the "motherland" from which the nitrogen transports. The soil nitrogen involved in loss by runoff only exists in certain soil horizons, the depth of which is named as Effective Depth of Interaction (EDI). Take the soil mineral nitrogen (NH<sub>4</sub> <sup>+</sup> and NO<sub>3</sub> <sup>-</sup> ) for example. According to the results of simulated rainfall experiment, the EDI of soil nitrogen is analyzed, and the methods to confirm EDI of both NH<sub>4</sub>NO<sub>3</sub>-applied experiments and no- NH<sub>4</sub>NO<sub>3</sub>-applied ones are recommended. Meanwhile the two methods' applicability for other chemicals is discussed here. The results are in the following. First, with the same type of fertilization, there are no evident influences of different fertilizer amount on the EDI. Second, the infiltration, transport by runoff and EDI distribution of nitrogen are controlled by the various characters of ions. The EDI of soil NO<sub>3</sub> <sup>-</sup> is deeper than that of soil NH<sub>4</sub> <sup>+</sup>, the balance 3~9 cm. Third, the EDI distribution takes on spatial changes along the slope, deeper in the middle and lower parts, while shallower in the upper part.
Bioinformatics and Biomedical Engineering , 2009. ICBBE 2009. 3rd International Conference on; 07/2009
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ABSTRACT: In a simulated rainfall experiment on Loess slope land, this paper determined the rainfall, surface runoff and the effective depth of interaction (EDI) between rainfall and soil mineral nitrogen, and studied the effects of grass coverage on the EDI and the runoff loss of soil mineral nitrogen. The results showed that with the increase of EDI, soil nitrogen in deeper layers could be released into surface runoff through dissolution and desorption. The higher the grass coverage, the deeper the EDI was. Grass coverage promoted the interaction between surface runoff and surface soil. On the slope land with 60%, 80% and 100% of grass coverage, the mean content of runoff mineral nitrogen increased by 34.52%, 32.67% and 6.00%, while surface runoff decreased by 4.72%, 9.84% and 12.89%, and eroded sediment decreased by 83.55%, 87.11% and 89.01%, respectively, compared with bare slope land. The total runoff loss of soil mineral nitrogen on the lands with 60%, 80%, and 100% of grass coverage was 95.73%, 109.04%, and 84.05% of that on bare land, respectively. Grass cover had dual effects on the surface runoff of soil mineral nitrogen. On one hand, it enhanced the influx of soil mineral nitrogen to surface runoff, and on the other hand, it markedly decreased the runoff, resulting in the decrease of soil mineral nitrogen loss through runoff and sediment. These two distinct factors codetermined the total runoff loss of soil mineral nitrogen.
Ying yong sheng tai xue bao = The journal of applied ecology / Zhongguo sheng tai xue xue hui, Zhongguo ke xue yuan Shenyang ying yong sheng tai yan jiu suo zhu ban 01/2007; 17(12):2297-301.
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ABSTRACT: A field experiment was conducted in the south part of Loess Plateau with 632 mm precipitation each year. Three genotypes winter wheat 9430, Xiaoyan No. 6 and Shang188 were used as test materials to study their grain-filling characters under two nitrogen application levels (0 and 90 kg x hm(-2)). The results showed that genetic difference was the main factor affecting grain-filling characteristics, while nitrogen fertilization had a less effect. There were significant differences among genotypes in the duration of maximum grain filling rate (GFRmaxD), active grain-filling period (D), and the days reaching to the maximum grain-filling rate (GFRmaxGD). For Shang188, Xiaoyan No. 6 and 9430, the GFRmaxD was 17.20, 14.15 and 14.13 d, D was 29.00, 26.40 and 2688 d, and GFRmaxGD was 28.14, 23.90 and 23.89 d, respectively. All the parameters of Shang188 were significantly bigger than those of 9430 and Xiaoyan No. 6, while those of the latter two had no significant difference. There was an interaction between nitrogen fertilization and genotype, but the effect of nitrogen fertilization on the three parameters was relatively small. 1000 kernel weight had a significant positive correlation with GFRmaxD, GFRmaxGD and D, suggesting that the three parameters were the main factors affecting grain weight.
Ying yong sheng tai xue bao = The journal of applied ecology / Zhongguo sheng tai xue xue hui, Zhongguo ke xue yuan Shenyang ying yong sheng tai yan jiu suo zhu ban 02/2006; 17(1):75-9.
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ABSTRACT: In this paper, the transport parameters of chlorine in a slope land soil were determined in situ by fitting breaking-though curve, and the spatial variability of the parameters in a 41 m x 5 m runoff plot was analyzed by using traditional and geo-statistics. The results showed that the average pore-water velocity increased gradually from the top to the bottom of the slope, and the diffusive-dispersive coefficient (D) had no remarkable variation within 20m away from the top but gradually increased with the distance beyond 20m. The dispersivity (alpha) had the same characteristics as D. The pore-water velocity (v) had a floating feature on the slope, while parameters D and alpha showed obvious spatial correlation characteristics, the range of the spatial correlation being 21m and 10m, respectively.
Ying yong sheng tai xue bao = The journal of applied ecology / Zhongguo sheng tai xue xue hui, Zhongguo ke xue yuan Shenyang ying yong sheng tai yan jiu suo zhu ban 08/2005; 16(7):1285-9.
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ABSTRACT: The primary season of nitrate leaching in the Loess Plateau region is the monsoon, which is caused by heavy rainfall during the growth season of corn (Zea mays L.). Nitrate leaching to groundwater is an increasing concern in agriculture, and is one of the major nitrogen losing ways in dryland farming system. Localized compaction and ridge fertilization is a method for nitrogen fertilizer application, by which, less fertilizer leaching would occur. The NO3(-)-N transport in soil profile, corn yields and nitrogen use efficiency under localized compaction and ridge fertilization were investigated through two years field study. The factors that affect NO3(-)-N transport under localized compaction and ridge fertilization were studied, combined with simulated experiment. The results showed that NO3(-)-N was leached to below 90 cm in plat fertilization in the year of about 370 mm rainfall, a mean precipitation during the season, while the NO3(-)-N leakage of the fertilizer zone was reduced by localized compaction and ridge fertilization, as a result that the NO3(-)-N concentration below 60 cm was less than 10 mg.kg-1, and NO3(-)-N accumulated in 20-40 cm with a concentration 80-90 mg.kg-1. There was no significant difference in yield between application methods with 240.0 kg N.hm-2. However, the absorbed amount of nitrogen was improved significantly by localized compaction and ridge fertilization, and the nitrogen use efficiency was increased by 9%. The bulk density of the barriers had an evident effect on NO3(-)-N transport under localized compaction and ridge fertilization, but the effect of ridge slope was insignificant.
Ying yong sheng tai xue bao = The journal of applied ecology / Zhongguo sheng tai xue xue hui, Zhongguo ke xue yuan Shenyang ying yong sheng tai yan jiu suo zhu ban 02/2004; 15(1):68-72.
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ABSTRACT: Studies on the effect of soil water and fertilizer on soybean yield on loess slope farmland showed that soybean yield (Y) increased linearly with the increase of water use efficiency (WUE). Soybean yield and WUE increase with the increase of P fertilizer when P fertilizer was applied alone, but increased firstly and then decreased with the increase of N fertilizer when N fertilizer was applied alone. Therefore, N fertilizer should be applied with P fertilizer. Compared to no fertilizer, fertilizer could significantly increase soybean yield and WUE by 86.76%-470.16% and 69.64%-438.47%, respectively. A combined application of N and P fertilizers could increase more soybean yield and WUE than applied each of them alone, and the rational ratio of N and P (P2O5) was 1.3:1.
Ying yong sheng tai xue bao = The journal of applied ecology / Zhongguo sheng tai xue xue hui, Zhongguo ke xue yuan Shenyang ying yong sheng tai yan jiu suo zhu ban 03/2003; 14(2):211-4.
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ABSTRACT: Using soil as a carbon sink to sequester carbon dioxide has attracted much attention. But there is little research on soil organic carbon (SOC) in the Loess Plateau because of the extremely complex topography. In this study, SOC storage was estimated based on a soil survey of a small catchment in the Loess Plateau, northwest China. The SOC content of 169 profiles and the bulk density of 12 profiles were measured. The study area was classified into six different classes: farmland, grassland, shrub land, woodland, gully, Aeolian sandy soil. Results showed that the soil bulk density and SOC content are affected by land use and soil types, and the relationship between them could be expressed by a power function. Grassland had the highest SOC density, and next came farmland. Gully and Aeolian sandy soil had the lowest SOC density. The SOC content per area in the grassland and farmland was higher than the other classes and the shrub land was similar to the woodland while the Aeolian sandy soil and gully were the lowest. All of the changes in the cumulative SOC storage with the increasing depth follows a logarithmic model. The SOC storage in the catchment of farmland, grassland, shrub land, woodland, gully, and Aeolian sandy soil was estimated as 3.32 × 106 kg, 9.45 × 106 kg, 1.023 × 107 kg, 2.73 × 106 kg, 5.76 × 106 kg, and 2.94 × 106 kg, respectively. The total SOC storage of 100 cm depth in the catchment is 3.443 × 107 kg.
Geoderma 154:261-266. · 2.32 Impact Factor
