Northeast Institute of Geography and Agroecology, Chinese Academy Of Sciences
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延长光周期对罗汉松和鸡爪槭苗期生长及养分吸收利用的影响
No full text采用盆栽试验,通过每天将光周期延长至约18 h的处理对罗汉松和鸡爪槭容器苗木进行培育,以自然光周期为对照,研究2种苗木在养分吸收和利用方面的响应。结果表明:和自然光周期处理相比,在延长光周期培育下罗汉松和鸡爪槭的苗高增幅分别达到17%(P=0.004 8)和20%(P=0.023 0),但新根数分别下降了31%(P=0.044 2)和21%(P=0.026 5),地径和根长均未出现显著响应;光周期延长也使鸡爪槭苗木的生物量(P=0.005 5)和氮(N)(P=0.018 3)、磷(P)(P=0.012 5)、钾(K)(P=0.001 4)含量均显著增加,却并未引起罗汉松体内P和K含量发生变化;试验结束时,罗汉松体内N、P、K质量分数分别为(1.57±0.14)%、(0.93±0.25)%和(1.21±0.15)%,分别比鸡爪槭高8%(P=0.045 8)、87%(P<0.000 1)和110%(P<0.000 1);延长光周期会同时提高苗木对N的吸收和利用效率,但是不会影响养分淋溶。总体上,虽然延长光周期处理对2种苗木的生长和养分吸收产生了一定的促进作用,但也容易导致苗木出现"头重脚轻"的形态,并且在苗体养分浓度稀释方面存在极大的隐患
Analysis of root-knot nematode and fusarium wilt disease resistance in cotton (Gossypium spp.) using chromosome substitution lines from two alien species
No full textChromosome substitution (CS) lines in plants are a powerful genetic resource for analyzing the contribution of chromosome segments to phenotypic variance. In this study, a series of interspecific cotton (Gossypium spp.) CS lines were used to identify a new germplasm resource, and to validate chromosomal regions and favorable alleles associated with nematode or fungal disease resistance traits. The CS lines were developed in the G. hirsutum L. TM-1 background with chromosome or chromosome segment substitutions from G. barbadense L. Pima 3-79 or G. tomentosum. Root-knot nematode (Meloidogyne incognita) and fusarium wilt (Fusarium oxysporum f. sp. vasinfectum) (races 1 and 4) resistance alleles and quantitative trait loci (QTL) previously placed on cotton chromosomes using SSR markers in two interspecific recombinant inbred line populations were chosen for testing. Phenotypic responses of increased resistance or susceptibility in controlled inoculation and infested field assays confirmed the resistance QTLs, based on substitution with the positive or negative allele for resistance. Lines CS-B22Lo, CS-B04, and CS-B18 showed high resistance to nematode root-galling, confirming QTLs on chromosomes 4 and 22 (long arm) with resistance alleles from Pima 3-79. Line CS-B16 had less fusarium race 1-induced vascular root staining and higher percent survival than the TM-1 parent, confirming a major resistance QTL on chromosome 16. Lines CS-B(17-11) and CS-B17 had high fusarium race 4 vascular symptoms and low survival due to susceptible alleles introgressed from Pima 3-79, confirming the localization on chromosome 17 of an identified QTL with resistance alleles from TM1 and other resistant lines. Analyses validated regions on chromosomes 11, 16, and 17 harboring nematode and fusarium wilt resistance genes and demonstrated the value of CS lines as both a germplasm resource for breeding programs and as a powerful genetic analysis tool for determining QTL effects for disease resistance. CS lines carrying small alien chromosome segments with favorable QTL alleles could be used for effective introgression of biotic stress resistance or many other desirable traits by targeting gene interactions and reducing linkage drag effects
Analysis of the soil water balance for large-scale reforestation with Eucommia ulmoides in the hilly red soil region of southern China
No full textReturning farmland to forests is important for the protection of ecological values. Eucommia ulmoides is considered to be a suitable species for reforestation in the hilly red soil region of southern China. The objective of this study was to investigate the relationship between the water supply and demand of an E. ulmoides plantation to provide insights into the feasibility of large-scale planting for ecological restoration and forest management activities in the hilly red soil region of southern China. With the measured precipitation, surface runoff and interflow and actual evapotranspiration (ETc) estimated by the modified P-M model, soil water storage (SWS) was estimated based on the water balance equation. Monthly variations of SWS were then compared with in situ measured SWS. The results showed that the estimated mean monthly water losses (the sum of the surface runoff, interflow and ETc) were 139.8 mm in a wet year and 120.0 mm in a dry year, while the measured mean monthly water input values (net precipitation) were 131.2 mm in a wet year and 70.8 mm in a dry year. Net soil water storage (Delta SWS) was negative in each month of the growing season in a dry year, but the soil water deficit was replenished during the following season. The model performance showed that the modified P-M model can be adapted to estimate the soil water storage in other forest catchments where no adequate in situ data are available. As a result of estimating the water balance and observing soil water storage in two different hydrological years, E. ulmoides is recommended as a suitable forest rehabilitation species in the study area, and a suitable plant region has been defined by the GIS technique based on the water balance model
Assimilation and Translocation of Dry Matter and Phosphorus in Rice Genotypes Affected by Salt-Alkaline Stress
No full textSalt-alkaline stress generally leads to soil compaction and fertility decline. It also restricts rice growth and phosphorus acquisition. In this pot experiment, two relatively salt-alkaline tolerant (Dongdao-4 and Changbai-9) and sensitive (Changbai-25 and Tongyu-315) rice genotypes were planted in sandy (control) and salt-alkaline soil to evaluate the characteristics of dry matter and phosphorus assimilation and translocation in rice. The results showed that dry matter and phosphorus assimilation in rice greatly decreased under salt-alkaline stress as the plants grew. The translocation and contribution of dry matter and phosphorus to the grains also increased markedly; different performances were observed between genotypes under salt-alkaline stress. D4 and C9 showed higher dry matter translocation, translocation efficiency and contribution of dry matter assimilation to panicles than those of C25 and T315. These changes in D4 and C9 indexes occurred at low levels of salt-alkaline treatment. Higher phosphorus acquisition efficiency of D4 and C9 were also found under salt-alkaline conditions. Additionally, the phosphorus translocation significantly decreased in C25 and T315 in the stress treatment. In conclusion, the results indicated that salt-alkaline-tolerant rice genotypes may have stronger abilities to assimilate and transfer biomass and phosphorus than sensitive genotypes, especially in salt-alkaline conditions
Attribute Analysis of Aridity Variability in North Xinjiang, China
No full textIdentifying the dominant meteorological factors affecting aridity variability can improve our understanding of climate change and its future trend in arid and semiarid regions. This study investigated the spatiotemporal aridity variability in North Xinjiang, China, from 1961 to 2013, based on the UNESCO aridity index (precipitation/potential evapotranspiration), and analyzed its association with meteorological factors. The results suggest that North Xinjiang is becoming more humid with an increasing trend in aridity index. Precipitation, temperature, and relative humidity have positive correlation with aridity, and evapotranspiration, sunshine hours, and wind speed have negative correlation with aridity. Wind speed and sunshine hours have a higher sensitivity and more contribution to aridity. This study provides an understanding of the effect of recent climate change on drought in northwest China
Black carbon deposition and storage in peat soils of the Changbai Mountain, China
No full textBlack carbon (BC) is produced by incomplete combustion of fossil fuels and biomass and emissions are influenced by human activities. Due to its refractory nature and long half-life times, BC contributes to carbon sequestration in soils. Here, we investigated BC concentrations and storage in peatlands of the Changbai Mountains (Northeast China) and reconstructed historical trends of deposition fluxes from four peat cores. Results showed that there were no significant differences of BC deposition fluxes in different cores sampled at similar altitudes, but BC deposition fluxes at low altitudes were stronger influenced by human activities than those at high altitudes. During the last 150 years, more BC was emitted by increasing anthropogenic sources, and therefore the BC deposition fluxes accordingly increased. Total BC storage in peat soils of the Changbai Mountains was estimated to 1.61 Tg (5.13 Gg C km(-2)) and a deposition flux of 3.30 Gg yr(-1) of BC was calculated. The high BC deposition fluxes the fact that about 5% of carbon storage in peatland could be regarded as BC support that BC represents an important fraction of carbon storage in peatland ecosystems. (C) 2016 Elsevier B.V. All rights reserved
A brief discussion on energy use and greenhouse gas emmision in organic farming
No full textOrganic farming has become increasingly popular in the world. This is mostly attributed to escalating consumer concerns over the impacts of pesticides and chemical fertilizers on human health as well as growing concerns over environmental pollution derived from modern agricultural practices, such as rising greenhouse gas emissions and water contaminations. But does organic farming actually displace the environmental impacts commonly associated with conventional agriculture? In this article, we analysed the recent results of environmental impacts from organic farming. The aim was to fill the gap in assessing organic farming's relationship to climate change and evaluating sustainability of this system with a minimal energy and environmental damage over time. Despite the efforts of recent years, there is still considerable room for the environmental optimisation of organic farming systems. The lower, similar or higher impacts of organic farming, depended on crop types, site effects and differences in management intensity. The conclusions here are exploratory and act as a call to action to natural scientists to further explore how organic farming functions. Feeding the growing world population under conditions of restricted land for agricultural cultivation, restricted natural resources and changing climate demands new and innovative solutions. These solutions require the agricultural community, to address agricultural systems from a perspective of increasing the productivity per area with lower external inputs and enhancing resource use efficiency without negative effects on crop yield and system sustainability
Changes of soil properties and carbon fractions after long-term application of organic amendments in Mollisols
No full textLand degradation threatens soil fertility as well as environmental security. To assess the extent of degradation of black Mollisols in northeast China, chemical and microbial indicators of soil quality were determined after long-term application of organic amendments combined with chemical fertilizers. The application of high amounts of organic manure plus chemical fertilizer (NPK) significantly increased soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), and mineral nitrogen (N-min), as well as microbial biomass carbon (MBC), extractable dissolved organic carbon (DOC), microbial quotient (qMIC), carbon (C) in free light fraction (fLF) and its percentage of total soil C. Soil C/N ratio and C portion in heavy fraction (HF) both decreased significantly, which might have resulted from accelerated mineralization of stable C. Application of straw at a low rate plus NPK significantly increased N-min and MBC concentrations and qMIC Compared with the unamended control, no negligible differences were found for most of the selected parameters under the treatments NPK alone, high-rate straw plus NPK, and low-rate manure plus NPK. These results indicated that NPK along with either a high rate of manure or a low rate of straw profoundly changed certain key soil chemical and microbial properties. Despite these apparent benefits in soil properties, however, high rates of manure application is likely contributing little to soil C stabilization. Low rates of organic amendments, especially crop straw, are therefore recommended, as this practice can improve or at least maintain soil properties in degraded Mollisols, while minimizing the adverse impacts of more intense applications. (C) 2016 Elsevier B.V. All rights reserved
Effects of burial depth and water depth on seedling emergence and early growth of Scirpus planiculmis Fr. Schmidt
No full textSeed burial and water regime are both crucial factors influencing seedling emergence and plant growth in wetlands and thus exert important effects on revegetation in degraded wetlands. We conducted a pot experiment to determine the effects of burial depth and water depth on the seedling emergence and growth of Scirpus planiculmis Fr. Schmidt. Seeds of S. planiculmis were buried at 0, 0.5, 1 and 2 cm depths in plastic pots with non-sterilized sediment under exposed ( 5 cm), waterlogged (0 cm) and submerged (5 and 10 cm water depths relative to sediment surface) water regimes. The results showed that the percentage of seedling emergence at a burial depth of 0 cm was enhanced under 10 cm and 5 cm water depths (78.89% and 81.37%, respectively) in comparison to the results under 5 cm and 0 cm water depths (0 and 2.22%, respectively). Seedlings did not grow through the water to the surface and no tuber formed when covered by 10 cm of water. The total biomass per seedling was generally higher at 0.5 cm or 1 cm burial depths than that at other burial depths. The tuber number per seedling was highest at a 0.5 cm burial depth, while the value was lowest at a 0 cm burial depth. Our results provide valuable guidance for the establishment of S. planiculmis from seeds in wetland revegetation programs. (C) 2015 Elsevier B.V. All rights reserved
Effects of structural and depositional crusts on soil erosion on the Loess Plateau of China
No full textConventional tillage practices used on the Loess Plateau lead to different soil surface micro-topography which results in forming two types of soil crusts. The objective of this study was to explore the formation position, properties and erosion characteristics of structural crusts and depositional crusts under the influences of the microtopography in the rainfall experiments. Two simulated rainstorms were applied in the experiments. The first rainfall event was used for soil crust formation, then the following simulated rainfall storms at 40 mm h 1, 60 mm h 1, and 80 mm h 1 rates were applied to the soil boxes set to a 17.6% (10 degrees) slope under three tillage types (contour tillage, artificial digging, and straight slope conditions) to investigate the resulting runoff discharge rate and sediment yield on crusted soil surface. Results show that: (1) structural crusts formed on the mounds, and depositional crusts formed in the depressions after the first rainfall events; structural crusts exhibit a lower thickness, bulk density, higher porosity and shear strength than depositional crusts; (2) structural crusts increased the runoff yield less and decreased the sediment yield more than depositional crusts; and (3) the runoff yield was significantly greater, and the sediment yield was lower on the crusted soil surface than that on the uncrusted soil surface, regardless of the effect of the tillage treatments