Northeast Institute of Geography and Agroecology, Chinese Academy Of Sciences
Not a member yet
4476 research outputs found
Sort by
黑土颗粒有机碳和氮含量对有机肥剂量响应的定量关系
No full text黑土是一种非常重要的耕种土壤,但是由于过度地开发利用和水土流失导致土壤有机质含量迅速下降,严重影响了耕地生产力和作物产量。为了能够快速恢复黑土肥力,利用海伦国家野外科学观测研究站内的长期定位试验,定量分析了黑土颗粒有机碳和氮含量对有机肥剂量的响应。田间试验开始于2001年,设置了4个施肥处理,分别为:①单施化肥(OMO);②低剂量有机肥与化肥配施(OM1);③中剂量有机肥与化肥配施(OM2);④高剂量有机肥与化肥配施(OM3)。在2011年播种前,采集各处理0 ~ 20 cm耕层土壤样品。应用有机碳物理分组方法,测定分析了土壤有机碳、氮及各组分的含量。研究结果表明长期不同剂量有机肥输入能够显著增加黑土总有机碳和全氮含量(POM2>OM1>OM0,而减小了土壤中矿质结合态组分的含量;随着有机肥施入量的增加,粗颗粒和细颗粒土壤有机碳和氮的含量呈增加的趋势,而矿质结合态中的有机碳含量则略有下降,表明粗颗粒和细颗粒有机碳和氮是黑土有机碳和氮的主要储存库,有机无机配施对土壤有机碳、氮的提升作用主要集中于对活性组分颗粒有机质的形成和积累。与OM0处理相比,有机肥的施入显著降低了颗粒有机质和矿质结合态有机质的C/N,并且随着有机肥施入量的增加而逐渐降低。与单施化肥相比,化肥有机肥配施能够显著增加土壤的总有机碳,全氮,颗粒有机碳、氮含量,其中以化肥配施高剂量有机肥效果最佳,有利于黑土土壤肥力的快速提升,改善黑土的土壤质量
Assessment of Micro-Basin Tillage as a Soil and Water Conservation Practice in the Black Soil Region of Northeast China
No full textMicro-basin tillage is a soil and water conservation practice that requires building individual earth blocks along furrows. In this study, plot experiments were conducted to assess the efficiency of micro-basin tillage on sloping croplands between 2012 and 2013 (5 degrees and 7 degrees). The conceptual, optimal, block interval model was used to design micro-basins which are meant to capture the maximum amount of water per unit area. Results indicated that when compared to the up-down slope tillage, micro-basin tillage could increase soil water content and maize yield by about 45% and 17%, and reduce runoff, sediment and nutrients loads by about 63%, 96% and 86%, respectively. Meanwhile, micro-basin tillage could reduce the peak runoff rates and delay the initial runoff-yielding time. In addition, micro-basin tillage with the optimal block interval proved to be the best one among all treatments with different intervals. Compared with treatments of other block intervals, the optimal block interval treatments increased soil moisture by around 10% and reduced runoff rate by around 15%. In general, micro-basin tillage with optimal block interval represents an effective soil and water conservation practice for sloping farmland of the black soil region
Assessment of the effects of shelterbelts on crop yields at the regional scale in Northeast China
No full textThe Three-North Shelter Forest Program (TNSFP), which is the largest ecological afforestation program worldwide, was launched in 1978 and will last until 2050 in the Three-North regions (accounting for 42.4% of China's territory). As a dominant component in the TNSFP, shelterbelts or windbreaks play an important role in preventing from wind damage and erosion and providing appropriate microclimate conditions for crop growth, thus improving crop yields. However, how shelterbelts influence crop yields at the regional scale has not yet been determined because there are certain difficulties in identifying the effects of shelterbelts on crop yields due to other factors such as climatic factors, crop seeds, fertilizer and management measures. In this study, a new approach is used to estimate the effects of shelterbelts on crop yields while overcoming these difficulties. The specific processes used in this study are detailed as follows. First, the climatic potential productivity, which is a combination of solar radiation, temperature and precipitation, was estimated using the multi-sensor remote data. All farmland in the region was divided into high, middle and low climatic potential productivity zones. Second, the crop (i.e., maize) yield across the Northeast China was estimated using the harvest index method and MODIS data. Third, according to the effectively protected distance, the levels of protection provided by the shelterbelts to the farmland at the regional scale were calculated by combining the stand age and the growth status of the shelterbelts using a time series of Landsat images. Finally, the levels of protection and the corresponding maize yields in pixels were extracted and averaged to identify the effects of shelterbelts on crop yields. The results of this study indicated that shelterbelts could enhance crop yields at the regional scale. The contribution rates of shelterbelts to increasing maize yields were found to be 4.68%, 4.28% and 9.45% in the high, middle and low climatic potential productivity zones, respectively. In Northeast China, the average level of protection of farmland was 18.28%, which was obviously lower than the optimal level of protection (i.e., approximately 80%); thus, many shelterbelts must be planted in the future. The findings of this study provide a sound theoretical foundation for increasing crop yields by planning shelterbelts in farmland regions similar to those in Northeast China. (C) 2015 Elsevier Ltd. All rights reserved
Change in soil organic carbon between 1981 and 2011 in croplands of Heilongjiang Province, northeast China
No full textBACKGROUNDSoil organic carbon (SOC) is fundamental for mitigating climate change as well as improving soil fertility. Databases of SOC obtained from soil surveys in 1981 and 2011 were used to assess SOC change (0-20cm) in croplands of Heilongjiang Province in northeast China. Three counties (Lindian, Hailun and Baoqing) were selected as typical croplands representing major soil types and land use types in the region. RESULTSThe changes in SOC density (SOCD) between 1981 and 2001 were -6.6, -14.7 and 5.7Mg C ha(-1) in Lindian, Hailun and Baoqing Counties respectively. The total SOC storage (SOCS) changes were estimated to be -11.3, -19.1 and 16.5% of those in 1981 in the respective counties. The results showed 22-550% increases in SOCS in rice (Oryza sativa L.) paddies in the three counties, but 28-33% decreases in dry cropland in Lindian and Hailun Counties. In addition, an increase of 11.4Mg C ha(-1) in SOCD was observed in state-owned farms (P < 0.05), whereas no significant change was observed in family-owned farms. CONCLUSIONSoil C:N ratio and initial SOCD related to soil groups were important determinants of SOCD changes. Land use and residue returning greatly affected SOC changes in the study region. To increase the topsoil SOCD, the results suggest the conversion of dry croplands to rice paddies and returning of crop residue to soils. (c) 2015 Society of Chemical Industr
Dating the period when intensive anthropogenic activity began to influence the Sanjiang Plain, Northeast China
No full textDating the start of intensive anthropogenic influence on ecosystems is important for identifying the conditions necessary for ecosystem recovery. However, few studies have focused on determining when anthropogenic influences on wetland began through sedimentary archives. To fill this critical gap in our knowledge, combustion sources and emission intensities, reconstructed via black carbon (BC) and polycyclic aromatic hydrocarbons (PAHs) were analyzed in two wetlands in the Sanjiang Plain in Northeast China. C-14 provided age control for the sedimentary records. By combining previous sedimentary and archaeological studies, we attempt to date the beginning of intensive anthropogenic influences on the Sanjiang Plain. Our results showed that BC deposition fluxes increased from 0.02 to 0.7 g C/m(2).yr during the last 10,000 years. An upward trend was apparent during the last 500 years. Before 1200 cal yr BP, human activities were minor, such that the wetland ecosystem in the Sanjiang Plain before this period may represent the reference conditions that for the recovery of these wetlands. As the human population increased after 1200 cal yr BP, combustion sources changed and residential areas became a major source of BC and PAHs. In this way, the wetland ecosystem gradually became more heavily influenced by human activities
Diversity and distribution patterns of acidobacterial communities in the black soil zone of northeast China
No full textAlthough Acidobacteria are ubiquitous and are commonly one of the most abundant bacterial phyla in soils, knowledge regarding their diversity and distribution is still limited. Our previous studies discovered the biogeographical distribution patterns of bacterial and fungal communities in the black soil zone of northeast China. In this study, we further investigated the diversity and composition of acidobacterial communities generated with the Acidobacteria-specific primers ACIDO/342r in the same soil samples using quantitative PCR and Illumina MiSeq sequencing methods. A total of 412,203 acidobacterial 16S rRNA gene sequences were obtained from 26 soil samples that were collected from arable lands across the black soil zone. These sequences belonged to 21 subgroups, and GP1, GP3, GP4 and GP6 were the most abundant subgroups, accounting for 22.63%, 17.17%, 23.82% and 27.47% of acidobacterial sequences across all soils, respectively. The abundance of Acidobacteria displayed a more significant positive correlation with soil carbon content than with soil pH, and the relative abundance of certain subgroups was significantly positive or negative related with soil pH. The OTU richness, phylogenetic diversity and community composition of Acidobacteria were significantly correlated with soil pH. A variance partitioning analysis showed that the soil pH contributed 25% of the community variation, while the geographic distance explained only approximately 5% of the variation. These results indicated that soil pH was a main factor structuring acidobacterial communities in the black soil zone of northeast China. Our results also suggested that the Acidobacteria-specific primers could be better used for studying the distribution of acidobacterial communities in soils. (C) 2016 Elsevier Ltd. All rights reserved
The effects of population density changes on ecosystem services value: A case study in Western Jilin, China
No full textIn recent decades, the semi-arid ecosystem of China's Western Jilin province has changed dramatically due to intensive human activities. This article simulated the population density in Western Jilin using a Kernel Density Estimation method and explored the influence of population density on both the value and structure of ecosystem services in various regions. The results showed that lower population density correlated with higher values of ecosystem services per unit area. Apart from food production value, the value of each type of ecosystem service per unit area decreased as population density increased, with the greatest change observed in the value of waste disposal and the lowest in the value of raw materials. Analysis of demographic change on the structure of ecosystem services value produced a Gourd Phenomenon. Sensitivity analysis showed that the sensitivity coefficient of farmland ecosystems was highest, followed by wetland ecosystems and water ecosystems. Therefore, we should restore farmland to grassland and wetland (with its associated rivers and lakes) when reconstructing the eco-environment in Western Jilin. (C) 2015 Elsevier Ltd. All rights reserved
Effects of substituting finely ground sorghum for finely ground corn on feed digestion and meat quality in lambs infected with Haemonchus contortus
No full textThe objective of this study was to determine the effects of substituting different levels of finely ground sorghum (FGS) for finely ground corn (FGC) on feed digestion and meat quality in lambs infected with Haemonchus contortus. Twenty-four male Ujumqin lambs at 90 +/- 6.3 days of age were randomly assigned to receive one of four dietary treatments for 8 weeks prior to slaughter, The four diets contained 0 g/kg FGS and 400 g/kg FGC (CON), 100 g/kg FGS and 300 g/kg FGC (LFGS), 200 g/kg FGS and 200 g/kg FGC (MFGS), and 400 g/kg FGS and 0 g/kg FGC (HFGS). Before feeding, all lambs were dewormed and experimentally infected with 10,000 H. contortus third stage larvae. After a 28-day adaption to larvae infection, the feeding period was started. Fecal and blood samples were collected and lambs were weighed every 2 weeks. At the end of the feeding period, lambs were slaughtered, meat samples were collected, and the H. contortus burden in the abomasum was determined. The results demonstrated interaction effects between treatment and sampling time on fecal egg count (FEC; P<0.001) and packed cell volume (PCV; P<0.001) in lambs. The FEC decreased and the PCV increased significantly over the feeding period. As the dietary FGS content increased, the H. contortus burden in the abomasum, the abomasal mucosal surface (HBAM), and the abomasal contents (HBAC) decreased linearly (P<0.001). In addition, the ratio of HBAM to HBAC decreased numerically but not linearly (P=0.196) and the ratio of male to female H. contortus increased linearly (P=0.016). Although dry matter intake decreased linearly (P=0.001) as the dietary FGS content increased, no differences in the average daily weight gain and feed conversion ratio were observed between lambs in the FGS substitution groups and CON group. The apparent digestibility of all feed nutrients in the MFGS diet was numerically higher than those in other diets. As the dietary FGS content increased, the dressing percentage of lambs (P<0.001), total heme pigment content (P<0.001), and amount of tannins in meat increased linearly (P<0.001). Diets containing 100-400 g/kg FGS did not affect total amino acids levels in meat, although levels of some individual essential amino acids increased as the FGS in diets increased. In conclusion, substitution of 100-400 g/kg FGS inclusion for equal amounts of FGC in diets is not only beneficial for protection of lambs against H. contortus infection but also for improving the meat color in lambs by increasing the deposition of antioxidant tannins in the meat. (C) 2015 Published by Elsevier B.V
Estimation of snow depth from passive microwave brightness temperature data in forest regions of northeast China
No full textSnow depth is an important factor in water resources management in Northeast China. Forest covers 40% of Northeast China, and the presence of forests influences the accuracy of snow depth retrievals from passive microwave remote sensing data. An optimal iteration method was used to retrieve the forest transmissivities at 18 and 36 GHz based on the snow and forest microwave radiative transfer models and the snow properties measured in field experiments. The transmissivities at 18 and 36 GHz are 0.895 and 0.656 in the horizontal polarization, and 0.821 and 0.615 in the vertical polarization, respectively. Furthermore, the forest transmissivity and snow properties were input into the Microwave Emission Model of Layered Snowpacks (MEMLS) to establish a dynamic look-up table (LUT). Snow depths were retrieved from satellite passive microwave remote sensing data based on the LUT method, and these retrievals were verified by snow depth observations at 103 meteorological stations. The results showed that the bias between the retrieved and measured snow depths is very small, with root mean square errors (RMSEs) of approximately 6 cm in forest regions and 4 cm in non-forest regions. When compared with the existing snow products, the snow depth retrieved in this work presented the highest level of accuracy. The regional snow depth product in China is superior to the GlobSnow and NASA AMSR-E standard SWE products in non-forest regions, whereas the GlobSnow estimate is superior to the regional snow depth product in China and NASA AMSR-E standard SWE product estimates in forest regions. Therefore, we conclude that 1) the influence of forest on snow depth retrieval is important, and the appropriate forest parameters should be considered in the estimation of snow depth from passive microwave brightness temperature data; and 2) the snow depth retrieval algorithm based on the dynamic LUT method proved to be efficient in Northeast China. (C) 2016 Elsevier Inc. All rights reserved
Euedaphic and hemiedaphic Collembola suffer larger damages than epedaphic species to nitrogen input
No full textWetlands are commonly limited in available nitrogen. But marshes in the Sanjiang Plain, Northeastern China suffer large amounts of exogenous nitrogen from agriculture fertilization after wetland reclamation. This paper focuses on the ecological effects of a short-term increase of nitrogen input on collembolan communities. Our results show a significant decrease in collembolan abundance and Shannon diversity index, and the abundance of euedaphic and hemiedaphic collembolans decreased faster than epedaphic collembolans. These results indicate that euedaphic or hemiedaphic fauna suffer more biodiversity loss caused by nitrogen deposition than epedaphic fauna and call for more researches on trait-based approaches under environmental stress in the future. (C) 2015 Elsevier Ltd. All rights reserved