连续化肥减量配施有机肥提升植烟土壤肥力质量的综合评价

为准确评价连续多年化肥减量配施有机肥料对烤烟产量及植烟土壤综合肥力质量的影响,探究植烟土壤质量提升与烤烟绿色优质协同的化肥减量有机替代技术。以长期定位试验的第7年数据为基础,运用因子分析法、相关系数法、内梅罗指数法,对不施肥(CK)、当地推荐常规施肥(100%化肥,CF)、化肥减量20%配施有机肥(OF)和配施生物有机肥(BIO)4个处理的土壤肥力质量进行综合评价,并采用随机森林回归分析,探讨各土壤单项肥力指标对烤烟产量的解释度。结果表明,在连续7年化肥减量20%条件下,配施有机肥和生物有机肥均能降低烤烟青枯病和黑胫病的发病率和病情指数,提高烤烟经济性状、产量可持续性与稳定性,提高植烟土壤养分含量和土壤肥力综合质量。随机森林分析表明,植烟土壤有效磷、碱解氮、全氮是影响烤烟产量的决定因素,其解释率分别为19.66%、15.38%、12.07%。在3种评价方法下,植烟土壤综合肥力指数IFI值均表现为BIO>OF>CF>CK,BIO和OF处理较CF处理分别提高23.03%~31.75%和4.92%~7.94%。3种评价方法的IFI值与烤烟相对产量均呈显著或极显著正相关关系,相关系数大小依次为内梅罗指数法(0.884)>因子分析法(0.867)>相关系数法(0.747)。因此,连续多年化肥减量配施不同有机肥具有提高植烟土壤综合肥力质量和烤烟产量及质量的持续效应,且以化肥减量20%配施生物有机肥的效果最优。

环神农架地区植烟土壤重金属评价及其富集特征

研究了环神农架地区主要植烟土壤91个耕层样品8种重金属元素Cr、Ni、Cu、Zn、As、Cd、Pb、Hg的水平,利用单因子和内梅罗污染指数法对该区土壤重金属环境质量状况进行了评价,并探讨了该区土壤重金属的富集特征。研究结果显示:环神农架地区土壤重金属元素含量存在较大变异,以Hg和Pb变异最大,变异系数分别为60.22%和59.78%,Ni元素变异最小,变异系数为17.81%。环神农架地区植烟土壤Cr、Cu、As、Cd、Pb、Hg含量均符合无公害生产产地标准,Ni和Zn元素分别有3个和2个样品超标,综合污染评价显示供试土壤分别有78%和22%处于清洁和尚清洁水平。以湖北省A层(0～20cm)土壤元素背景值为基准的研究结果表明,20世纪90年代以来,环神农架地区8种重金属均存在不同程度富集,而As、Pb、Zn、Cd、Ni富集更为明显。

我国煤炭开采和燃烧过程中的硫污染对土壤环境的影响

我国煤炭在开采和燃烧过程中形成的硫污染物主要是酸性矿井水和二氧化硫 ,由煤炭燃烧造成的硫的干湿沉降以及煤炭开采过程中形成的酸性矿井水使土壤的物理化学性质发生变化 ,从而对土壤造成严重的破坏。主要表现在造成土壤中可溶性硫酸盐的大幅度升高 ;引起土壤的pH值下降 ;植物营养元素特别是K、Na、Ca、Mg等产生淋失 ;活性铝溶出量增加 ;有毒重金属活化 ;抑制土壤酶的活性等方面。可以通过脱硫除尘、加强绿化、建立合理的工业布局、加入土壤改良剂等措施来减少硫污染物的排放量和改善其对土壤环境的影响 ,但总量控制是关键 。

Evaluation of soil nutrient status in poplar forest soil by soil nutrient systematic approach

A study was conducted to evaluate the soil nutrient status of poplar plantation by Soil Nutrient Systematic Approach (SNSA) in Jianghan Plain, Hubei Province, China. Soil physiochemical properties were analyzed in laboratory through collection soil samples of study site. Ten treatments of application different fertilizers were designed such as CK, optimum treatment (N, P, K, Zn), N(P, K, Zn), P(N, K, Zn), K(N, P, Zn), +Mg(N, P, K, Zn, Mg), Zn (N,P,K), +2P(N, 2P, K, Zn), +2K(N, P, 2K, Zn), and 2N+2P+2K(2N, 2P, 2K, Zn) for field experiment to test the effect on tree height, diameter (DBH) growth, and dry weight of poplar. The results showed that there was no significant difference in tree heights between treatments with different fertilizers, diameter growth of poplar trees in treatments of lack of N and Zn was significantly slower than that of trees in optimum treatment, and dry weight of poplar dropped significantly for treatment of CK as well as treatments without application N and Zn. It is concluded that N and Zn were main limiting factor for poplar growth. Results from laboratory analysis and field experiment were uniform per-fectly, which proved that SNSA was reliable in evaluating soil nutrient status of poplar plantation.

Characteristics and Evaluation of Soil Fertility in Sugarcane-producing Areas in Guangxi

[Objective] Soil fertility in Guangxi sugarcane-growing areas was evaluated to provide theoretical reference for sugarcane scientific planting and fertilization and further optimize evaluation system for soil fertility in Guangxi sugarcane-growing ar- eas. [Method] Nutrients of soil samples in 3 006 plots were measured, and fertility characters were evaluated based on the improved Nemerow composite index method. [Result] Soil in Guangxi sugarcane-growing area was sticky and acidic with an average pH value of 4.94. Available B was insufficient with an average content of 0.24 mg/kg. Exchangeable Mg was low with an average content of 62.34 mg/kg. Organic matter content was moderate. The contents of alkali N, rapidly available P, rapidly available K, available Cu, available Zn, available Mn and available Ca were moderate. However, unlike the soil in high-yield areas, there was unbalanced nutri- tion distribution. According to Nemerow integrated index method, soil fertility in sug- arcane-growing areas was grade lU, namely low fertility. The integrated fertility index was 0.56. Individual fertility indexes including rapid available Cu, rapidly available Zn, exchangeable Mg, available Mn, rapidly available manganese Mn and alkali N were at poor level. Other indexes were at medium or high level. [Conclusion] It could be concluded that soil fertility in Guangxi sugarcane-growing area was gener- ally low, The above-mentioned evaluation method could help to build a quantified and scientific soil fertility evaluation system and reduce the impacts of subjective factors during evaluation process.

Research Progress of Evaluation Index of Soil Moisture

In modern agriculture, accurate and effective measurements of soil water content lays foundation for promotion on precision irrigation technology and improvement on water use efficiency. The research reviewed soil moisture indices at home and abroad and classified the indices into two categories in order to make prediction on soil moisture and take measures. Specifically, single indices included precipitation index, soil moisture index, and crop drought index and overall indices included supply/demand water index of crops, overall water index, PDSI, crop water shortage index. Soil moisture index was analyzed in terms of advantages and disadvantages,as well as adaptability in agriculture, providing references for relieving and predicting adverse effects on agriculture and formulating scientific policies.

The Content of Pb Element and Environmental Quality Assessment in Latosol of Hainan Island

[Objective] To research the content of Pb element in latosol of Hainan island and to assess its environmental quality.[Method] Samples were selected for lab analysis.27 samples from different landforms of Hainan Island were selected（the same place was sampled for three times） to analyze the content of Pb in latosol of Hainan Island,study the spatial distribution feature of this element in latosol from different places and evaluate the content of Pb element in latosol of Hainan Island by geo-accumulation index.[Result] The content of Pb generally stays at high level in latosol of Hainan Island;however,the mean content of Pb in east Hainan is lower than the mean value of west Hainan;vertically,the mean content of Pb shows descending order from hills,mountainous area to plain;the pollution assessment result showed that latosol of Hainan Island was hardly polluted by Pb element and only its content in the latosol from middle,south area stays at high level.[Conclusion] The research provided scientific reference for constructing a national tropical modern agricultural base in Hainan as well as controlling Pb pollution.

Distribution Characteristic and Potential Ecological Risk Assessment of Heavy Metals in Latosol in the Western Area of Hainan Island

[Objective] The paper was to carry out ecological geochemical survey and ecological risk assessment on the heavy metals in latosol in western area of Hainan Island.[Method] The contents of six heavy metals including Cr,Cu,Zn,As,Cd and Pb in latosol in western area of Hainan Island were analyzed.Single-factor index method and Hakanson ecological risk index method were used to evaluate the integrated pollution effect of heavy metals in latosol.[Result] The average contents of Cr,Cu,Zn,As,Cd and Pb in latosol in western area of Hainan Island were 65.57,35.16,93.56,8.50,0.24 and 79.29 mg/kg,respectively.The major pollution factor of heavy metal was Pb.The sequence of influence factors of various heavy metals was PbCu = ZnCrAsCd.The potential ecological risk coefficient of various heavy metals was PbCdCuAsCrZn.The average value of potential ecological risk index（RI）was 45.14,belonging to low ecological risk range.[Conclusion] The heavy metal pollution in latosol in western area of Hainan Island belongs to slight pollution.

Overall Evaluation of Organic Paddy Soil Fertility

[Objective] The aim was to explore soil quality and fertility of organic rice fields in Daizhuang Village. [Method] The analysis was made based on soil samples from different areas where planting methods varied after harvest of organic rice. [Result] The content of organic matter improved generally in fields of organic rice in Daizhuang. Specifically, the contents of N, P and K were not high, and the contents of N and P declined in the fields with crop rotation of organic rice Astragalus sin# cus, but the content of K increased. [Conclusion] It is of great significance for soil fertility to develop and promote crop rotation of organic rice Astragalus sinicus, which also advances quality of organic rice.

Evaluation on Soil Heavy Metal Pollution of Agricultural Habitat Environment in Xi'an City

[Objective] This study aimed to understand and grasp the soil heavy metal pollution status of agricultural habitat environment in Xi＇an City. [Method] The soil heavy metal pollution status of pollution-free agricultural products-producing areas in 9 counties （districts） of Xi＇an City was investigated. A total of 609 soil samples were collected, and their Cd, Hg, As, Pb and Cr contents were determined. In addition, the heavy metal pollution status of the collected soil samples was evaluated by Nemerow index method. [Result] The pollution in Baqiao, Chang＇an; Gaoling, Lan- tian, Lintong and Yanliang was of grade I, belonging to clean level; the pollution in Hu County, Weiyang and Zhouzhi was of grade II, near the warning line, belong to relatively clean level. There was no large-area soil heavy metal pollution overall. The investigated areas could be used as production bases of pollution-free agricultural products and even high-quality agricultural products. However, the heavy met- als contents in some individual areas exceeded relevant soil environmental quality standards, and they should be avoided or forbidden during regional planning and selection of production area. [Conclusion] Soil heavy metal pollution of agricultural habitat environment in Xi＇an City is generally at good status. Targeting at the future development plan of Xi＇an City, feasible and scientific suggestions are put forward.

Evaluation on Fuzzy Variable Weight of Cultivated Land Fertility Based on GIS

[Objective] The modified variable weights based on constant weight and in- troduced theory of equalization function would better incorporate authentic index weights and make evaluation results of fertility more scientific. [Method] In Gaozhou City, the final weights of influential factors can be determined with the help of GIS and as per AHP and theory of variable weights. In addition, farmland fertility was e- valuated in an automatic and quantitative way and the spatial distribution pattern was analyzed as per fuzzy comprehensive evaluation. [Result] For farmlands at 58 505.027 8 hm2 in the city, farmlands from grade 1 to grade 8 account for 3.62%, 18.27%, 33.15%, 26.96%, 13.66%, 3.29%, 0.81% and 0.24%, respectively, which is in consistent with local condition. [Conclusion] These results have been applied di- rectly in test regions and constitute a rewarding exploration for fertility evaluation in South China.

Monitoring and Evaluation of Soil Changes Under Landuse of Different Patterns at a Small Regional Level in South China

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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.

Application of Immune Algorithm to Evaluation of Soil Resource Quality

Based on the geographic information system (GIS) technology, ArcInfo software was adopted to collect, process andanalyze spatial data of Guangdong Province for an evaluation of soil resource quality. The overlay analysis method wasused in combining evaluation factors of Guangdong soil resource quality to determine the evaluation units. Because ofits favorable convergent speed and its ability to search solutions, the immune algorithm was applied to the soil resourcequality evaluation model. At the same time, the evaluation results of this newly proposed method were compared to twoother methods: sum of index and fuzzy synthetic. The results indicated that the immune algorithm reflected the actualcondition of soil resource quality more exactly.

Evaluation of AMSR-E——Derived Soil Moisture over Northern China

In this study,the authors evaluated two re-motely sensed surface soil moisture datasets derived from the Advanced Microwave Scanning Radiometer of the Earth Observing System (AMSR-E) over northern China.The soil moisture datasets were derived from algorithms developed by the National Snow and Ice Data Center (NSIDC) and jointly developed by the Vrije Universiteit Amsterdam and NASA Goddard Space Flight Center (VUA-NASA).The NSIDC and VUA-NASA products were compared to in situ soil moisture data from nine enhanced coordinated observation stations.The VUA-NASA dataset presented a strong correlation with top layer in situ soil moisture observations,and the correla-tion coefficients ranged from 0.34 to 0.73 (p<0.01).The correlation coefficients decreased as the observed soil layer depth increased.The correlation coefficients be-tween the NSIDC retrievals and the top layer in situ ob-servations were between 0.10 and 0.62 (p<0.01).Fur-thermore,VUA-NASA soil moisture variations agreed well with in situ soil moisture dynamics and responded sensitively to precipitation events.In contrast,the NSIDC dataset failed to capture signals of soil moisture dynamics.The analyses demonstrated that the VUA-NASA product was capable of representing soil moisture conditions over northern China.

Assessing Soil Erosion Rates on Manually-Tilled Hillslopes in the Sichuan Hilly Basin Using ^(137)Cs and ^(210)Pb_(ex) Measurements

Purple soils are widely distributed in the Sichuan Hilly Basin and are highly susceptible to erosion, especially on the cultivated slopes. Quantitative assessment of the erosion rates is, however, difficult due to small size of the plots of the manually-tilled land, the complex land use, and steep hillslopes. ^137Cs and ^210Pbex （excess ^210Pb） tracing techniques were used to investigate the spatial pattern of soil erosion rates associated with slope-land under hoe tillage in Neijiang of the Sichuan Hilly Basin. The ^137Cs and ^210Pbex inventories at the top of the cultivated slope were extremely low, and the highest inventories were found at the bottom of the cultivated slope. By combining the erosion rates estimates provided by both ^137Cs and 21~Pbex measurements, the weighted mean net soil loss from the study slope was estimated to be 3 100 t km^-2 year^-1, which was significantly less than 6 930 t km^-2 year^-1 reported for runoff plots on a 10° cultivated slope at the Suining Station of Soil Erosion. The spatial pattern of soil erosion rates on the steep agricultural land showed that hoe tillage played an important role in soil redistribution along the slope. Also, traditional farming practices had a significant role in reducing soil loss, leading to a lower net erosion rate for the field.

Soil Quality Assessment Using Weighted Fuzzy Association Rules

Fuzzy association rules (FARs) can be powerful in assessing regional soil quality, a critical step prior to land planning and utilization; however, traditional FARs mined from soil quality database, ignoring the importance variability of the rules, can be redundant and far from optimal. In this study, we developed a method applying different weights to traditional FARs to improve accuracy of soil quality assessment. After the FARs for soil quality assessment were mined, redundant rules were eliminated according to whether the rules were significant or not in reducing the complexity of the soil quality assessment models and in improving the comprehensibility of FARs. The global weights, each representing the importance of a FAR in soil quality assessment, were then introduced and refined using a gradient descent optimization method. This method was applied to the assessment of soil resources conditions in Guangdong Province, China. The new approach had an accuracy of 87%, when 15 rules were mined, as compared with 76% from the traditional approach. The accuracy increased to 96% when 32 rules were mined, in contrast to 88% from the traditional approach. These results demonstrated an improved comprehensibility of FARs and a high accuracy of the proposed method.

Assessment on soil fertility of Dongting Lake wetland area (China) based on GIS and fuzzy evaluation

Using soil data of the Second National Field Survey,the soil fertility of wetland ecosystem of Dongting Lake was evaluated by using the technology of GIS and method of fuzzy evaluation.Integrated with the wetland actuality of Dongting Lake and particularity of paddy,seven factors (including soil organic matter,total nitrogen,total phosphorus,total potassium,available phosphorus,available potassium,and pH value),closely related with soil fertility,were chosen to establish the index system of synthetical evaluation.Based on the effect degree of each selected index on soil fertility,a judgment matrix was built,and the weight coefficient was determined by the method of correlation coefficient.Finally,under the support of the spatial analysis module of GIS (Geographic Information System),the spatial distribution properties of soil fertility in wetland ecosystem of Dongting Lake were studied.The results show that the soil fertility of Dongting Lake wetland ecosystem is not very good,and the area of type III and type IV achieves 69.8%.As a result,many countermeasures should be taken to improve the soil fertility.As for the spatial properties,the soil fertility level of central and west Dongting Lake is much higher than that of north and south part.The soil fertility of paddy field surpasses that of red soil,and the contents of soil organic matter and total nitrogen in paddy field are large.

Application of Projection Pursuit Evaluation Model Based on Real-Coded Accelerating Genetic Algorithm in Evaluating Wetland Soil Quality Variations in the Sanjiang Plain, China

A new technique of dimension reduction named projection pursuit is applied to model and evaluatewetland soil quality variations in the Sanjiang Plain, Helongjiang Province, China. By adopting the im-proved real-coded accelerating genetic algorithm (RAGA), the projection direction is optimized and multi-dimensional indexes are converted into low-dimensional space. Classification of wetland soils and evaluationof wetland soil quality variations are realized by pursuing optimum projection direction and projection func-tion value. Therefore, by adopting this new method, any possible human interference can be avoided andsound results can be achieved in researching quality changes and classification of wetland soils.

Evaluation of Soil Fertility Suitability of Yiliang Tobacco-growing Areas in Yunnan Province

[Objective]This study was conducted to evaluate the soil fertility in Yiliantobacco-growing areas of Hunan Province.[Method]The soil nutrient contents iseven tobacco-growing towns of Yiliang County,Yunnan Province were surveyefrom 2010 to 2013 and integrated soil fertility index（SFI value）was calculated tanalyze the soil fertility suitability in theses areas.[Result]The soil p H,contents oorganic matter,hydrolytic N,rapidly available K and available B were all at an appropriate level,while the contents of rapidly available P,available Mg,available Zand water-soluble Cl-were high.Among them,the contents of available P and water-soluble Cl-had great variation.Finally,the soil fertility suitability of Yiliang tobacco-growing areas was graded based on their SFI values.As a result,20%of thestobacco-growing areas were in Grade I,47.7%in Grade II,29.3%in Grade III1.5%in Grade IV and 1.5%in Grade V.The average SFI was 0.61.From 2010 t2013,the p H value and available Mg content reduced year by year,while the contents of organic matter,hydrolytic N,rapidly available P,rapidly available K,available Zn,available B and water-soluble Cl-were increased.