紫外法测定红土壤中的硝态氮

根据硝态氮(硝酸盐氮和亚硝酸盐氮)在紫外区具有强烈吸收的特征,采用国产751G型紫外分光光度计对吉安市红土壤中的硝态氮含量进行测定。经过对500份不同地点种植农作物的土样进行测定分析,结果表明,此法相对其他方法具有操作简便、测定范围宽、干扰因素少、精密度和准确度高等优点。

G45双通高速公路红壤土边坡生物绿化关键技术研究

G45双辽一通辽高速公路沙化严重,必须进行生物绿化。针对该公路边坡红壤土的特性,提出了边坡生物绿化工程的设计原则、设计思路和具体方案,可为同类工程提供参考与借鉴。

Fluxes of soil carbon dioxide,nitrous oxide and firedamp in broad-leaved/Korean pine forest

To understand influence of litters on the emission/absorption of CO2, N2O and CH4 in broadleaved/Korean pine forest in Changbai Mountain, fluxes of soil CO2, N2O and CH4 were measured by closed static chamber technique, from Sept 3, 2002 to Oct 30, 2003 in two types of soil ecosystems, of which one was covered with litters on the surface soil, and the other had no litters. The results showed that litters had significant influences on CO2, N2O and CH4 fluxes (p<0.05). Their diurnal change patterns of plot with litters and litter-free plot were similar, and they all showed emission/absorption peak at 18:00. The diurnal change fluxes of CO2 and N2O of plot with litters were significantly higher than those of the litter-free plot, while the diurnal flux of CH4 of plot with litters was lower than that of litter-free plot. The fluxes of CO2, N2O, and CH4 showed the similar seasonal patternsfor both plots. The fluxes of CO2, CH4 showed their peak fluxes in June, but the fluxes of N2O showed its peak emissions in August. The annual fluxes of CO2 and N2O of plot with litters were significantly higher than those of the litter-free plot, while the annual flux of CH4 of plot with litters was lower than that of litter-free plot. Keywords Flux - CO2, N2O and CH4 - Seasonal variation - Diurnal variation CLC number S718.5 Document code A Foundation item: The study was supported by innovation research project of Institute of Appiied Ecology, Chinese Academy of Sciences (SCXZD0101-02) and National Natural Science Foundation of China (30271068)Bigraphy: XIAO Dong-mei (1979-), female, master of Institute of Applied Ecology. Chinese Academy of Sciences, Shenyang 110016. P. R. China.Responsible editor: Song Funan

The contribution of root respiration of Pinus koraiensis seedlings to total soil respiration under elevated CO_2 concentrations

The impacts of elevated atmospheric CO2 concentrations (500 靘olmol-1and 700 靘olmol-1) on total soil respiration and the contribution of root respiration of Pinus koraiensis seedlings were investigated from May to October in 2003 at the Research Station of Changbai Mountain Forest Ecosystems, Chinese Academy of Sciences, Jilin Province, China. After four growing seasons in top-open chambers exposed to elevated CO2, the total soil respiration and roots respiration of Pinus koraiensis seedlings were measured by a LI-6400-09 soil CO2 flux chamber. Three PVC cylinders in each chamber were inserted about 30 cm into the soil in-stantaneously to terminate the supply of current photosynthates from the tree canopy to roots for separating the root respiration from total soil respiration. Soil respirations both inside and outside of the cylinders were measured on June 16, August 20 and October 8, respectively. The results indicated that: there was a marked diurnal change in air temperature and soil temperature at depth of 5 cm on June 16, the maximum of soil temperature at depth of 5 cm lagged behind that of air temperature, no differences in temperature between treatments were found (P>0.05). The total soil respiration and soil respiration with roots severed showed strong diurnal and seasonal patterns. There was marked difference in total soil respiration and soil respiration with roots severed between treatments (P<0.01); Mean total soil respiration and contribution of root under different treatments were 3.26, 4.78 and 1.47 靘olm 2s-1, 11.5%, 43.1% and 27.9% on June 16, August 20 and October 8, respectively.

Topsoil phosphorus signature in five forest types along an urban-suburban-rural gradient in Nanchang, southern China

Conversions from rural to urban land uses have the potential to greatly modify soil phosphorus （P） levels. Soils in shrubs, Masson pine forest, conifer and broadleaf mixed forest, evergreen broadleaved forest and bamboo forest in the mid-subtropical region along an urban-rural gradient in Nanchang City, southern China, were analyzed for total P and P fractions using the modified Hedley P sequential fractionation method. Results show that the topsoil total P and total exactable P concentrations were significantly higher in the urban area （0.71 g·kg^-1 and 378.50 mg·kg^-1, respectively） than in the suburban （0.30 g·kg^-1 and 150.74 mg·kg^-1, respectively） and rural areas （0.31 g·kg^-1 and 147.38 mg·kg^-1, respectively） （p〈0.05）. Among the five P fractions of resin-P, NaHCO3-P NaOH-P, Sonication-P and HCI-P, the relative abundance of HCl-P in urban forest soils （36%） was the highest and also significantly higher than in suburban （8%） and rural soils （6%）, while NaOH-P was the dominant form in suburban （41%） and rural soils （50%）. Phosphorus accumulation in the urban soils could affect the cycle of P in urban forest systems, particularly the HCl-P fraction that might rapidly enrich aquatic systems in urban areas.

Effects of Long-term Fertilization on Fertility of Lateritic Red Loam Paddy

The change rules of the fertility of red soil paddy under the long-term different fertilization were investigated, and the reasonable fertilization mode to improve the fertility of red soil paddy was discussed. There were eight treatments in the experiment, which were CK （no fertilizer）, N1 （N of 60 kg/hm2）, N2 （N of 120 kg/hm2）, N1P1 （P2O5 of 30 kg/hm2）, N2P1 and N2P2 （P2O5 of 60 kg/hm2）, N2P2K1 （K2O of 45 kg/hm2） and N2P2K2 （K2O of 90 kg/hm2）. All treatments were applied with composted cow dung as the base fertilizer, and each season 50% of the straws were returned to the field. The content of organic matter, nitrogen, phosphorous and potassium in red soil paddy was observed continuously for ten years and their correlation was also analyzed. Under cow manure and straw return to field, organic matter content of different treatments was positively correlated to year. After ten years, organic matter content of surface soil rose by 2.5 g/kg averagely with an annual increase of 0.25 g/kg. Total nitrogen content and organic matter content of different treatments presented similar variation trend. Total nitrogen content rose by 0.35 g/kg averagely with an annual increase of 0.035 g/kg. Among all the treatments, N2P2K1 and N2P2K2 showed the biggest increase, which went up by 0.052 and 0.48 g/kg, respectively. Phosphorous-free treatments （CK, N1, N2） had steady phosphorous content with irregular changes of different years. Total phosphorous content of phosphorous treatments increased year by year. Total phosphorous content of N1P1 and N2P1 rose by 0.008 g/kg every year. The increment range of total phosphorous content of N2P2, N2P2K1 and N2P2K2 was 0.012 -0.013 g/kg annually. Available phosphorous content varied vastly among different treatments. Available phosphorous content of organic fertilizer treatments basically remained stable with irregular changes of different years. Available phosphorous content of organic fertilizer with phosphate fertilizer treatments rose year by year. Available phosphorous content of N1P1 and N2P1 rose approximately by 0.8 mg/kg. Available phosphorous content of N2P2, N2P2K1 and N2P2K2 rose approximately by 1.4 -1.6 mg/kg annually. Potassium fertilizer amount greatly affected total potassium content. Total potassium content of no-potassium treatments （CK, N1, N2, N1P1, N2P1 and N2P2） remained the same. Total potassium content of N2P2K markedly increased year by year, which was 0.014 g/kg annually. Rapid available potassium content of no-potassium treatments （CK, N1, N2, N1P1, N2P1 and N2P2） showed a decreasing trend. With phosphate fertilizer, rapid available potassium content of N2P2K1 and N2P2K2 remained the same or increased year by year. The change trend of slow available potassium content and rapid available potassium content resembled. Rational allocation of organic fertilizer, nitrogenous fertilizer, phosphate fertilizer and potassium fertilizer can significantly improve soil fertility and economic benefits. Balanced fertilization is an effective measure for soil fertility improvement as it＇s shown that nutrients of surface soil accumulate annually.

Characteristics of Soil Porosity and Changes of Soil Water Content in Eucalyptus Plantation

Objective] This study almed to investigate the characteristics of soiI total porosity （STP） and various factors affecting soiI water content （SWC） in eucalyptus pIantation （EP）, thereby providing references for soiI water utiIization in eucalyptus pIanting in the red soiI hiI y region of South China. [Method] In the same cIimatic region, soiI sampIes were coI ected from surface soiI Iayer （A）, iI uvial horizon （B） and parent material horizon （C） in the upper sIope, middIe sIope and Iower sIope of eucalyptus pIantation, native forest and pine forest, respectiveIy, to determine the soiI porosity and soiI water content and analyze changes and various infIuencing factors of soiI water content in horizontal and vertical direction. [Result] Average soiI porosity in eucalyptus pIantation, native forest and pine forest was 45.9%, 41.4%and 55.3%, respectiveIy; soiI water content in these three forest stands was 13.3%, 13.4% and 15.5%, respectiveIy. In addition, soiI water content in these three forest stands exhibited no significant differences （P＆gt;0.05） among different soiI profiIes and sIope positions, but soiI water content in surface soiI Iayer varied significantIy （P＆lt;0.05） among different forest stands; in the horizontal direction, soiI water content exerted an extremeIy significant positive correIation with total coverage. [Conclusion] Total coverage of canopy Iayer, herb and Iitter Iayer is one of the most critical fac-tors affecting the changes of soiI water content in surface soiI Iayer of forest stands.

Isolation and Identification of Soil Actinobacteria from Mangrove forest in Beihai,Guangxi Province

[Objective] The aim was to identify the species diversity of Actinomycetes from Mangrove forest in Beihai,Guangxi Province. [Method] 10 strains of typical Actinomycetes were isolated from Mangrove forest soil,and the Actinomycetes genomic DNA was successful extracted. 16S rDNA was amplified by PCR and sequenced by Sanger dideoxy sequencing method. [Result] All the sequences were blasted in genbank,eight strains belonged to the genus of Streptomyces (80%),and two strains belonged to the genus of Nocardiopsis (20%). [Conclusion] There are many different Actinomycetes species in Mangrove forest soil samples in Beihai,Guangxi Province.

一年生黑麦草种植与利用

黑麦草（指多花黑麦草）为禾本科一年生植物,适应性广。再生力强,鲜草品质好,产量高,是越年生草本牧草,一般生长期为1至2年。须根发达,基部丛生,株高90至130厘米。叶长而较宽,叶色深绿而有光泽,呈弧形披垂。黑麦草喜温和湿润气候,肥沃土壤,也适宜黏土壤和红土壤,土壤最适宜pH值为6至7。

德庆县高良镇富富笋＂铺＂出致富路

德庆县高良镇是德庆县第一大镇，那里多山地丘陵，遍地都是富含铁元素的红土壤，是富笋生长的“温床”。这里的农民利用得天独厚的自然条件，种植出纯天然绿色产品——富笋，走上了致富增收路。近日上午，记者前往了解他们的致富经。

Effects of N,P and K Fertilizers on Growth of Clover Nitrogen-fixing Rhizobia and Soil Fertility after Plantation

In order to develop organic rice and increase paddy soil fertility by cloverorganic rice rotation, the effects of N, P and K fertilizers on growth of clover nitrogen-fixing rhizobia and soil fertility after plantation were investigated, thereby providing certain reference for reasonable cultivation of clover and improvement of soil fertility. A two-year experiment was conducted from 2012 to 2013. The clover was cultivated after rice every year, and different levels of N, P and K fertilizers were applied before winter. In the treatment group, no fertilizer was applied. The effects of different fertilizers and different application amounts on clover yield, nitrogen-fixing rhizobia quantity, nitrogen-fixing rhizobia weight and soil fertility after plantation were analyzed. The results showed that the application of N, P and K fertilizers in the early stage had significantly effect on the growth of clover. When the application amount of N fertilizer was 75 kg/hm^2（N 46%）, the clover yield, nitrogen-fixing rhizobia quantity and nitrogen-fixing rhizobia weight were highest. The soil nitrogen content after plantation increased with the increase of the application amount of N fertilizer, while the P and K content decreased and then increased with the increased application amounts. Soil available P content increased with the increased application amounts of N and P fertilizers, but it did not change significantly with the increased application amount of K fertilizer. Soil available K content increased first and then decreased with the increased application amounts of N and P fertilizers.When the application amounts of N and P fertilizers were 150（N 46%） and 300（P_2O_5 12%） kg/hm^2, soil available K content reached the maximum. Soil organic matter content increased with the increased application amounts of N, P and K fertilizers. Therefore, in the cultivation of clover, appropriate application of N, P and K fertilizers in the early stage can improve clover yield and soil fertility.

Crop Yield and Soil Responses to Long-Term Fertilization on a Red Soil in Southern China

A 15-year fertilization experiment with different applications of inorganic N,P and K fertilizers and farmyard manure (M)was conducted to study the yield and soil responses to long-term fertilization at Qiyang,Hunan Province,China. Average grain yields of wheat and corn(1 672 and 5 111 kg ha-1,respectively)for the treatment NPKM were significantly higher than those(405 and 310 kg ha-1)of the unfertilized control and single inorganic fertilizer treatments.Compared with the corresponding initial values of the experiment,all treatments showed a yield decline of 9 to 111 kg ha-1 year-1 in wheat and 35 to 260 kg ha-1 year-1 in corn,respectively,and a significant pH decline of 0.07 to 0.12 pH year?1,except for the treatments PK and NPKM.After long-term fertilization,the soil organic C,soil available P,exchangeable Ca2+ and Mg2+and available Cu2+and Zn2+contents were higher in the treatment NPKM than in the treatments applied with inorganic fertilizer only.Compared to the treatment NPK,the treatment NPKM,where manure partially replaced inorganic N,had a positive impact on arresting the decline of soil pH.This improved grain yields of wheat and corn, suggesting that application of NPK fertilizer in combination with farmyard manure is important to maintain soil fertility and buffering capacity in red soil.

GIS-Based Red Soil Resources Classification andEvaluation

A small scale red soil resources information system (RSRIS) with applied mathematical models wasdeveloped and applied in red soil resources (RSR) classification and evaluation, taking Zhejiang Province,a typical distribution area of red soil, as the study area. Computer-aided overlay was conducted to classifyRSR types. The evaluation was carried out by using three methods, i.e., index summation, square root ofindex multiplication and fuzzy comprehensive assessment, with almost identical results. The result of indexsummation could represent the basic qualitative condition of RSR, that of square root of index multiplicationreflected the real condition of RSR qualitative rank, while fuzzy comprehensive assessment could satisfactorilyhandle the relationship between the evaluation factors and the qualitative rank of RSR, and therefore it is afeasible method for RSR evaluation.

Effect of Different Vegetation Systems on Soil Erosion and Soil Nutrients in Red Soil Region of Southeastern China

The effect of different vegetation systems including bamboo plantation (BP), forest ecosystem (CF),citrus orchard (Ctr) and farmland (FL) on erosion and nutrients of red soil were investigated in hilly region of southeastern China to find effective control measures for soil erosion. The results showed that all the vegetation systems could significantly reduce soil erosion and nutrient losses compared to bare land (Br).The ability of different vegetation systems to conserve soil and water was in the order of Ctr ＞ BP ＞ CF ＞ FL ＞ Br. Vegetation could also improve soil fertility. The soil organic matter, total N and total P contents were much higher in all the vegetation systems than in bare land, especially for the top soils. Vegetation systems improved soil physical properties remarkably. Compared to the bare land, soil organic matter, TP,TK and available K, especially soil microbial biomass C, N and P, increased under all the vegetation covers.However, they were still much lower than expected, thus these biological measurements are still needed to be carried out continuously.

Comparative Study on Rain Splash Erosion of Representative Soils in China

As the first event of soil erosion, rain splash erosion supplies materials for subsequent transportation and en-trainment. The Loess Plateau, the southern hilly region and the Northeast China are subject to serious soil and water loss; however, the characteristics of rain splash erosion in those regions are still unclear. The objectives of the study are to ana-lyze the characteristics of splash erosion on loess soil, red soil, purple soil and black soil, and to discuss the relationship between splash erosion and soil properties. Soil samples spatially distributed in the abovementioned regions were col-lected and underwent simulated rainfalls at a high intensity of 1.2mm/min, lasting for 5, 10, 15, and 20min, respectively. Rain splash and soil crust development were analyzed. It shows that black soil sample from Heilongjiang Province corre-sponds to the minimum splash erosion amount because it has high aggregate content, aggregate stability and organic mat-ter content. Loess soil sample from Inner Mongolia corresponds to the maximum splash erosion amount because it has high content of sand particles. Loess soil sample from Shanxi Province has relatively lower splash erosion amount be-cause it has high silt particle content and low aggregate stability easily to be disrupted under rainfalls with high intensity. Although aggregate contents of red soil and purple soil samples from Hubei and Guangdong provinces are high, the sta-bility is weak and prone to be disrupted, so the splash erosion amount is medium. Splash rate which fluctuates over time is observed because soil crust development follows a cycling processes of formation and disruption. In addition, there are two locations of soil crust development, one appears at the surface, and the other occurs at the subsurface.

Effect of Anions on Toxicity of Cadmium Applied to Microbial Biomass in Red Soil

A laboratory incubation experiment was conducted to elucidate the effects of associated anions on toxicity of cadmium applied to microbial biomass in the red soil. Cadmium was applied at six different levels, i.e., 0 (background), 5, 15, 30, 60 and 100 μg-1 soil in the form of either cadmium acetate or cadmium chloride.Application of cadmium as cadmium acetate markedly reduced the soil microbial biomass carbon compared to cadmium applied as cadmium chloride at all the tested levels. Similarly, organic carbon to biomass carbon ratio in the soil was markedly increased by increasing the level of the cadmium in the soil as cadmium acetate,while the change was much smaller in the case of cadmium chloride at the same cadmium levels. The results suggested that due consideration should be given to the source of cadmium while deciding the cadmium levels in experiments.

Effect of land use on microbial biomass－C, －N and －P in red soils

Eleven red soils varying in land use and fertility status were used to examine the effect of land use on microbial biomass C, N and P. Microbial biomass C in the red soils ranged from about 68 mg C/kg to 225 mg C/kg, which is generally lower than that reported from other types of soil, probably because of low organic matter and high acidity in the red soils. Land use had considerable effects on the amounts of soil C mic . The C mic was the lowest in eroded fallow land, followed by woodland, tea garden, citrus grove and fallow grassland, and the highest in vegetable and paddy fields. There was significant correlation between C mic and organic matter content, suggesting that the influence of land use on C mic is mainly related to the input and accumulation of organic matter. Microbial biomass N in the soils ranged from 12.1 Nmg/kg to 31.7 Nmg/kg and was also affected by land use. The change of N mic with land use was similar to that of C mic . The microbial C/N ratio ranged from 5.2 to 9.9 and averaged 7.6. The N mic was significantly correlated with soil total N and available N. Microbial biomass P in the soils ranged from 4.5 mg P/kg to 52.3 mg P/kg. The microbial C/P ratio was in the range of 4-23. The P mic was relatively less affected by land use due to differences in fertilization practices for various land use systems.

Effect of Nitrogen Fertilizers on Movement and Transformation of Phosphorus in an Acid Soil

The effects of two different nitrogen fertilizers （urea and NH4C1） with monocalcium phosphate （MCP） on the movement and transformation of fertilizer P in soil microsites along with soil pH changes at different distances from the fertilizer application site were studied in an incubation experiment. A highly acidic red soil （Ultisol, pH 4.57） from south China with MCP fertilizer alone or in combination with NH4C1 or urea was added to the surface of soil cylinders and packed in wax blocks. After 7 and 28 days, the extraction and analysis of each 2 mm layer from the interface of the soil and fertilizer showed that added NH4C1 or urea did not change the movement distance of fertilizer P. However, P transformation was significantly affected （P 〈 0.05）. After 7 days, at 0-8 mm distance from the fertilizer site the addition of urea significantly decreased the water-extractable P concentration; however, after 28 days the effect of N addition had disappeared. Also,at limited distances close to the fertilizer site NH4Cl application with MCP significantly increased acid-extractable P and available P, while with the addition of urea they significantly decreased. Compared with application of MCP alone,addition of urea significantly increased soil pH in fertilizer microsites, whereas the addition of NH4Cl significantly decreased soil pH.