旱作区甘薯田保水剂的施用技术及增产效果     

王泽义  雷震宇  李连科  王承荣  韩保泉  任春平 《中国农学通报》2004,20(5):162-163

在壤质褐土,有效应用保水剂可使甘薯苗抗旱力增强,整株鲜重、干重明显增加;单株茎数、平均薯块重均有增加,田间生产增产4.6%~31%。在本试验条件下,保水剂使用量为45kg/hm2时,增产效果最好;采取穴施的方法与用保水剂液蘸根增产效果差异不明显。但蘸根法方便易行,较为可取。  相似文献   

Gross nitrogen transformations in adjacent native and plantation forests of subtropical Australia     

Joanne Burton  Chengrong Chen  Hossein Ghadiri 《Soil biology & biochemistry》2007,39(2):426-433

The impact of land-use change on soil nitrogen (N) transformations was investigated in adjacent native forest (NF), 53 y-old first rotation (1R) and 5 y-old second rotation (2R) hoop pine (Araucaia cunninghamii) plantations. The ¹⁵N isotope dilution method was used to quantify gross rates of N transformations in aerobic and anaerobic laboratory incubations. Results showed that the land-use change had a significant impact on the soil N transformations. Gross ammonification rates in the aerobic incubation ranged between 0.62 and 1.78 mg N kg⁻¹ d⁻¹, while gross nitrification rates ranged between 2.1 and 6.6 mg N kg⁻¹ d⁻¹. Gross ammonification rates were significantly lower in the NF and the 1R soils than in the 2R soils, however gross nitrification rates were significantly higher in the NF soils than in the plantation soils. The greater rates of gross nitrification found in the NF soil compared to the plantation soils, were related to lower soil C:N ratios (i.e. more labile soil N under NF). Nitrification was found to be the dominant soil N transformation process in the contrasting forest ecosystems. This might be attributed to certain site conditions which may favour the nitrifying community, such as the dry climate and tree species. There was some evidence to suggest that heterotrophic nitrifiers may undertake a significant portion of nitrification.  相似文献   

齐齐哈尔市县级图书馆建设现状分析     

张成荣 《农业图书情报学刊》2012,24(5):29-33

通过对齐齐哈尔市县级图书馆办馆条件、基础业务建设、读者服务工作、业务辅导工作等方面的调查分析,发现存在的问题并提出解决对策。  相似文献   

Effects of warming and increased precipitation on soil carbon mineralization in an Inner Mongolian grassland after 6?years of treatments   总被引：1，自引：0，他引：1  

Xiaoqi Zhou  Chengrong Chen  Yanfen Wang  Zhihong Xu  Zhengyi Hu  Xiaoyong Cui  Yanbin Hao 《Biology and Fertility of Soils》2012,48(7):859-866

Understanding the responses of soil C mineralization to climate change is critical for evaluating soil C cycling in future climatic scenarios. Here, we took advantage of a multifactor experiment to investigate the individual and combined effects of experimental warming and increased precipitation on soil C mineralization and ¹³C and ¹⁵N natural abundances at two soil depths (0–10 and 10–20?cm) in a semiarid Inner Mongolian grassland since April 2005. For each soil sample, we calculated potentially mineralizable organic C (C ₀) from cumulative CO₂-C evolved as indicators for labile organic C. The experimental warming significantly decreased soil C mineralization and C ₀ at the 10–20-cm depth (P?<?0.05). Increased precipitation, however, significantly increased soil pH, NO ₃ ^? -N content, soil C mineralization, and C ₀ at the 0–10-cm depth and moisture and NO ₃ ^? -N content at the 10–20-cm depth (all P?<?0.05), while significantly decreased exchangeable NH ₄ ⁺ -N content and ¹³C natural abundances at the two depths (both P?<?0.05). There were significant warming and increased precipitation interactions on soil C mineralization and C ₀, indicating that multifactor interactions should be taken into account in future climatic scenarios. Significantly negative correlations were found between soil C mineralization, C ₀, and ¹³C natural abundances across the treatments (both P?<?0.05), implying more plant-derived C input into the soils under increased precipitation. Overall, our results showed that experimental warming and increased precipitation exerted different influences on soil C mineralization, which may have significant implications for C cycling in response to climate change in semiarid and arid regions.  相似文献   

Soil carbon and nutrient pools, microbial properties and gross nitrogen transformations in adjacent natural forest and hoop pine plantations of subtropical Australia   总被引：9，自引：8，他引：1  

Zhihong Xu  Sally Ward  Chengrong Chen  Tim Blumfield  Nina Prasolova  Juxiu Liu 《Journal of Soils and Sediments》2008,8(2):99-105

Background, Aims, and Scope  An improved understanding of important soil carbon (C) and nutrient pools as well as microbial activities in forest ecosystems is required for developing effective forest management regimes underpinning forest productivity and sustainability. Forest types and management practices can have significant impacts on soil C and nutrient pools as well as biological properties in forest ecosystems. Soil C and nutrient pools were assessed for adjacent natural forest (NF), first rotation (1R) (50-year-old), and second rotation (2R) (1-year-old) hoop pine (Araucaria cunninghamii Ait. ex D. Don) plantations in southeast Queensland of subtropical Australia. Materials and Methods  Five transects spaced 3 m apart with 9 sampling points along each transect were selected (9.6 m × 12.0 m each site), with 45 soil cores (7.5 cm in diameter) collected and separated into 0–10 and 10–20 cm depths. These soils were analysed for total C, total nitrogen (N), C (δ¹³C) and N (δ¹⁵N) isotope composition. The 0–10 cm soils were analysed for pH, CEC, exchangeable cations, total P and total K, and assayed for microbial biomass C and N, respiration, metabolic quotient, potential mineralizable N (PMN), gross N mineralization (M) and immobilization (I). Results  Total C and N in 0–10 cm soils were higher under NF and 1R plantation than under 2R plantation, while they were highest in 10–20 cm soils under NF, followed by the 1R and then 2R plantation. δ¹³C was lower under NF than under the plantations, while δ¹⁵N was higher under NF than under the plantations. Total P was the highest under NF, followed by the 1R and then 2R plantation, while total K was higher under the 2R plantation. No significant differences were detected for pH, CEC, exchangeable cations, microbial C and N, respiration and metabolic quotient among the 3 sites. PMN and M were higher under NF, while I was the highest under the 2R plantation, followed by the NF and then 1R plantation. Discussion  Soil total C and N in 0–10 cm depth were significantly lower under 2R hoop pine plantation than those under NF and 1R hoop pine plantation. There were significant reductions in soil total C and N from NF to 1R and from 1R to 2R hoop pine plantations in 10–20 cm depth. This highlights potential N deficiency in the 2R hoop pine plantations, and application of N fertilizers may be required to improve the productivity of 2R hoop pine plantations. There were no significant differences in other soil chemical and physical properties in 0–10 cm depth among the 3 sites under NF, 1R and 2R hoop pine plantations, except for soil total P and K. Soil microbial biomass C, CO₂ respiration and metabolic quotient did not differ among the 3 sites assessed, perhaps mainly due to these biological variables being too sensitive to variations in soil chemical and physical properties and thereby being associated with a larger variability in the soil biological properties. However, soil potential mineralizable N, gross N mineralization and immobilization were rather sensitive to the conversion of NF to hoop pine plantation and forest management practices. Conclusions  Total C and N in the top 20 cm soil were highest under NF, followed by 1R and then 2R hoop pine plantations, indicating that N deficiency may become a growth-limiting factor in the 2R hoop pine plantations and subsequent rotations of hoop pine plantation. The sample size for soil δ¹³C seems to be much smaller than those for soil total C and N as well as δ¹⁵N. The significant reductions in soil total P from NF to 1R and then from 1R to 2R hoop pine plantations highlight that P deficiency might become another growth-limiting factor in the second and subsequent rotations of hoop pine plantations. Soil microbial properties may be associated with large spatial variations due to these biological properties being too sensitive to the variations in soil chemical and physical properties in these forest ecosystems. Recommendations and Perspectives  Soil potential mineralizable N, gross N mineralization and immobilization were useful indices of soil N availability in response to forest types and management practices. The sampling size for soil δ¹³C was much smaller than the other soil chemical and biological properties due to the different patterns of spatial variation in these soil properties.  相似文献   

Trends and challenges in soil research 2009: linking global climate change to local long-term forest productivity   总被引：1，自引：1，他引：0  

Zhihong Xu  Chengrong Chen  Jizheng He  Juxiu Liu 《Journal of Soils and Sediments》2009,9(2):83-88

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Assessing management impacts on soil organic matter quality in subtropical Australian forests using physical and chemical fractionation as well as C NMR spectroscopy     

Yan He  Chengrong Chen  David Williams 《Soil biology & biochemistry》2009,41(3):640-236

Successful soil organic matter (SOM) quality assessment is needed to improve our ability to manage forest soils sustainably. Our objective was to use a multivariate data set to determine whether the land use conversion from native forest (NF) to hoop pine plantation and the following rotation and site preparation practices had altered SOM quality at three adjacent sites of NF, first (1R) and second rotation (2R, including tree planting row (2R-T) and windrow of harvest residues (2R-W)) of hoop pine plantations in southeast Queensland, Australia. Cross-polarization magic angle spinning ¹³C nuclear magnetic resonance (CPMAS ¹³C NMR) spectroscopy and sequential hot water and acid hydrolysis were conducted on SOM fractions separated by wet-sieving and density fractionation procedures to characterize SOM quantitative and qualitative relevant parameters, including carbon (C) functional groups, C and nitrogen (N) contents, C/N ratios, and C and N recalcitrant indices. Analysis of variance (ANOVA) and principal component analysis (PCA) of these multivariate parameters together indicated a complicated interaction between physical protection and biochemical recalcitrance, making the land use and management induced changes of SOM quality more complex. Knowledge of PCA based on the refined set of 41 SOM quantitative and qualitative parameters identified that principal component 1 (PC1), which explained 55.7% of the total variance, was most responsible for the management induced changes in soil processes. This was reflected by the dynamics of SOM regarding the aspects of total stock, soil basal and substrate induced respirations, gross and net N mineralization and nitrification, and microbial biomass, microbial diversity of C utilization patterns. Further, the macroaggregates (F_{250-2000 μm}) and the C/N ratio of acid extracts of SOM physical fractions, which represented the most informative and unique variables loading on PC1, might be the most promising physical and chemical measures for SOM quality assessment of land use and management impacts in subtropical Australian forests.  相似文献   

Effects of the Removal of Soil Extractable Oxytetracycline Fractions on Its Bioaccumulation in Earthworm and Horsebean     

Bao  Yanyu  Li  Yunxia  Pan  Chengrong 《Water, air, and soil pollution》2018,229(3):1-16

Water, Air, & Soil Pollution - The layered double hydroxides (LDHs) with a hydrotalcite-like structure are believed to possess great potentials as environmental remediation materials including...  相似文献   

橙酮类似物的合成及抑菌活性     

席拓  宋成荣  张毅文  胡雷  周文明 《农药学学报》2012,14(5):579-582

以芝麻酚和芳香醛为主要原料,经傅-克酰基化、关环和羟醛缩合反应,设计合成了14个未见文献报道的橙酮类似物,其结构均经1H NMR、MS和IR确证。初步抑菌活性测定结果表明:在100 mg/L下,所有目标化合物对7种供试病原菌均有不同程度的抑制作用,其中化合物 3a、3b、3c和3d 对番茄灰霉病菌Botrytis cirerea的抑制率达到100%, 3g 对小麦赤霉病菌Fusarium graminearum、玉米弯孢叶斑病菌Curvulavia lunata、棉花枯萎病菌Fusarium oxysporum vasinfectum、水稻稻瘟病菌Magnaporthe grisea的抑制率均大于80%, 3m 对马铃薯干腐病菌Fusarium solani和玉米弯孢叶斑病菌的抑制率分别为100%和83.8%。  相似文献   

上海浦东地区犬戊型肝炎病毒流行情况调查     

瞿浩生  施建标  倪惠军  俞向前  叶承荣 《中国动物检疫》2007,24(6):30-30

人类戊型肝炎(hepatitis E,HE)是由戊型肝炎病毒HEV(hepatitis Evirus,HEV)引起的一种急性传染病,是发展中国家的一种主要传染性疾病,呈地方流行性或散发,怀孕妇女尤其是妊娠末三个月的孕妇感染  相似文献