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1.
Soil quality is important in measuring sustainable land‐use and soil‐management practices. It is usually assessed by evaluating important physical, chemical, and biological soil properties. For this study, a site‐specific 22 variables representing pertinent soil (0–10 cm) and groundwater properties were selected as potential soil‐quality indicators in a coastal salt‐affected farmland of E China. To investigate the role of groundwater in soil‐quality assessment, we designed two sets of minimum data sets (MDSs). Minimum data set 1 (MDS1) had inputs of the 19 soil chemical and physical properties whereas MDS2 was based on the 22 soil and groundwater properties. Using principal‐component analysis, discriminant analysis, and soil‐quality‐index (SQI) model, we demonstrated the procedures of MDS selection, indicator normalization, and integration of MDS into SQI value for soils used for the two cropping systems. Results indicated selection of SOCD, AK, and ρb as MDS1 indicators but MDS2 indicators included SOM, SOCD, Cl, Na, WTg, and ECg. These were found to be the most effective discriminators between the two cropping systems. Available K (AK) made greatest contribution to SQI using MDS1 indicators, however, WTg, ECg, and Cl were the greatest contributors to the SQI for MDS2. Contribution of SOCD to SQI was severely inhibited in cotton–barley rotation system while ECg and WTg contributions to SQI were inhibited in rice–rape rotation system. In general, cotton–barley rotation system had a better soil quality over rice–rape rotation system as the former had higher SQI values than the latter for both MDSs. Crop parameters did also exhibit significant relationship with the SQI values using MDS2 but it was not significant for MDS1. Our results suggest that in addition to soil chemical, physical, and biological indicators, groundwater properties particularly the WTg and ECg are also important for assessing soil quality in an intensively farmed coastal area.  相似文献   

2.
The soils in the hot semi-arid tropical (SAT) regions generally have low organic matter and nutrient reserves. Soil-management problems in these soils primarily occur because of poor physical conditions and inadequate drainage through excess runoff, finally resulting in poor crop growth. Hence, the present investigation was conducted to study the long-term impact of conjunctive nutrient use treatments on soil quality indicators and soil quality indices under three cropping systems: (i) sole soybean, (ii) soybean + maize, and (iii) sole maize cropping systems at the Indore Centre of the All-India Coordinated Research Project for Dryland Agriculture (AICRPDA) using Navjot and JS-335 as cultivars of maize and soybean, respectively. In 2005, the soil quality assessment study under this experiment was undertaken after 8 years of experimentation. Soil quality assessment was done by identifying the key indicators using principal component analysis (PCA) and linear scoring technique (LST). Soil quality indices (SQI) and relative soil quality indices (RSQI) were also computed. Results revealed that most of the soil quality parameters were significantly influenced by the conjunctive nutrient management treatments. The common key indicators that emerged in all the treatments were pH, organic carbon (OC), exchangeable magnesium (Mg), available zinc (Zn), copper (Cu), manganese (Mn), and boron (B). The soil quality indices across the management treatments under sole maize system varied from 1.70 to 2.40 and application of 20 kg nitrogen (N) (compost) + 20 kg N through urea as top dressing emerged as a one of the most superior treatments with SQI value of 2.40. The soil quality indices in maize + soybean system varied from 1.12 to 1.47 and application of 20 kg N (compost) + 20 kg N through urea + azotobacter at 2 kg ha?1 proved to be significant with the greatest SQI value of 1.47. In the case of the sole soybean system, the SQI varied from 1.21 to 1.61. After considering all the systems together, the average best performance SQI score (ABP-SQI score) was computed, which varied from 1.14 to 1.56. The greatest value was recorded in the treatment with 20 kg N (compost) + 20 kg N (gliricidia) + 10 kg N (urea). The quantitative relationship developed in this study between mean soybean and maize yields (Y) and RSQI values (X), irrespective of the management treatments, could be quite useful to predict the yield quantitatively with respect to a given change in key indicators for these rainfed Vertisols.  相似文献   

3.
Soil quality in rice (Oryza sativa L.)–wheat (Triticum aestivum L.) cropping systems is governed primarily by the tillage practices used to fulfill the contrasting soil physical and hydrological requirements of the two crops. The objective of this study was to develop a soil quality index (SQI) based on bulk density (BD), penetration resistance (PR), water stable aggregates (WSA) and soil organic matter (OM) to evaluate this important cropping system on a Vertisol in India. Regression analysis between crop yield and SQI values for various tillage and crop residue management treatments indicated SQI values of 0.84–0.92, 0.88–0.93 and 0.86–0.92 were optimum for rice, wheat and the combined system (rice + wheat), respectively. The maximum yields for rice and wheat were 5806 and 1825 kg ha−1 occurred at SQI values of 0.85 and 0.99, respectively. Using zero tillage (ZT) for wheat had a positive effect on soil quality regardless of the treatments used for rice. Regression analyses to predict sustainability of the various tillage and crop residue treatments showed that as puddling intensity for rice increased, sustainability without returning crop residues decreased from 6 to 1 years. When residue was returned, the time for sustainable productivity increased from 6 to 15 years for direct seeded rice, 5 to 11 years with low-intensity puddling (P1) and 1 to 8 years for high-intensity (P2) puddling. For sustainability and productivity, the best practice for this or similar Vertisols in India would be direct seeding of rice with conventional tillage and residues returned.  相似文献   

4.
It is desirable to develop an objective Soil Quality Index (SQI) to guide sustainable agronomic intensification, thereby promoting socio‐economic well‐being. This study pioneers the use of Ward's cluster and principal component regression methods to evaluate soil homogeneity and construct a SQI (expressed as %). Field data were acquired from five different sites within Ohio, USA, that were under no‐till (NT), conventional till (CT) management and natural vegetation (NV) land use. Soil pH, carbon/nitrogen (C/N) ratio, nitrate and soil organic carbon (SOC) concentrations were identified as primary drivers of soil quality. Based on Ward's cluster method, the soil properties of croplands were not significantly different from those under NV land use. However, SQI ranked surface soils under CT management as higher in quality than NV and NT managed soils, respectively. The coefficient of determination (R2) between SQI and corn (Zea mays L.) and soya bean [Glycine max (L.) Merr.] yields was 0.7 and 0.9, respectively, implying this SQI effectively relates soil properties, a function of anthropogenic land management practices, with crop yields. In future, time series analyses will be used to assess SQI versus crop yield dynamics, with key socio‐economic and climate variables.  相似文献   

5.
The application of conservative agricultural practices such as crop rotation, shallow tillage, and organic fertilizer could usefully sustain crop yield and increase soil fertility, thus playing an important role in the sustainable agriculture. This study was conducted to determine the effects of conservative agronomic practices on yield and quality of wheat. The effects of these practices on soil fertility were further investigated in this four-year study (2005–2008). Two cropping systems, durum wheat in continuous cropping, and in two-year rotation with leguminous crops, were investigated at Foggia (Southern Italy) in rain-fed conditions. Within each cropping system, two levels of crop management were compared: i) conventional, characterized by a higher soil tillage management and mineral fertilizers application; ii) conservative, with a lower soil tillage management and organic-mineral fertilizers. The seasonal weather greatly affected the wheat yield and quality, inducing lower production in years that were characterized by unfavorable climatic conditions. This trend was found when the conventional treatment was applied, both in continuous cropping and rotations. The effects of cropping systems and crop management pointed out the positive role played by the leguminous crops (common vetch and chickpea) in crop rotation. This introduction improved wheat yield in rotation (6.47% compared to the continuous cropping), improved grain protein content (5.88%), and reduced the productive gap between conventional and conservative treatments (9.24 and 14.14% of the wheat in rotation and continuous cropping, respectively). Conversely, the effects of cropping systems and crop management on soil fertility were not very high, since the differences found at the end of the study in total nitrogen values were poor. However, total organic carbon (16.04 and 17.58% for cropping system and crop management, respectively) and available phosphorus values (11.30 and 7.43%) depend on root organic matter contribution, plant biomass residues, and fertilizations. The suitable crop rotation and the sustainable crop management appear important agronomical practices to improve yield and quality of wheat, and may reduce the environmental risks resulting from conventional intensive cropping systems.  相似文献   

6.
Soil‐quality assessment provides a tool for evaluating the sustainability of alternative soil‐management practices. Understanding the effects of the long‐term use of chemical fertilizers on soil quality is essential for sustaining soil productivity. The cumulative effect of a 17‐y‐old chemical‐fertilizer application on integrated soil quality was investigated in the surface (0–15 cm) and subsurface (15–30 cm) soils of a soy–broomcorn–millet cropping system with an experiment design of two factors with three levels for each factor. The treatments were N0P0, N0P1, N0P2, N1P0, N1P1 (local farmer' fertilization strategy), N1P2, N2P0, N2P1, N2P2, and a control NF. The objectives were to describe and quantify the effect of continuous applications of chemical fertilizer through soil‐quality index (SQI) and attempt to offer an efficient and appropriate nutrient‐supply strategy for the local region. Following 17 y of chemical fertilization, the SQI increased markedly in the studied soil layers, and soil chemical indicators changed more significantly than physical properties. The soil‐quality indicators in the surface soil layer were more variable and sensitive to fertilizer application than the subsurface layer. The indicators that sensitively responded to long‐term fertilization could be classified into three types: soil‐fertility indicators (soil organic matter [SOM], total P, and available N), soil‐texture indicators (clay, silt), and soil‐structure indicators (bulk density, mean weight diameter [MWD]). The simplified indicators (SOM, sand, available N, bulk density, and total P in the surface soil and SOM, MWD, and silt content in the subsurface soil) preferably reflected the status of the integrated soil quality as influenced by continuous fertilization. Among the fertilized treatments, the combined‐fertilizer treatments maintained a higher SQI than the single‐fertilizer treatments in the surface and subsurface soils. The N1P2 treatment maintained the highest SQI in both soil layers, followed by N1P1 treatment. However, for the slope cropland, given the relative costs, soil resource, and environmental protection, the traditional treatment of N1P1 may be the optimal fertilizer treatment in the local region.  相似文献   

7.
Cover crops are important components of a sustainable crop production system. They can be planted with plantation crops such as cacao, coffee, banana, rubber, and oil palm or in rotation with cash crops. Their use in a cropping system is mainly beneficial for soil and water conservation, recycling of nutrients, control of pests and improved microbiological activities. However, beneficial effects depend on the selection of appropriate cover crops and their management. Hence, understanding their agronomy and physiology is fundamental for their use in sustainable cropping systems. Growth and development of a crop (physiological aspects) is determined genetically as well as influenced by environmental variables. This information can be useful in improving production of these crops and, consequently, their incorporation in farming systems, wherever it is possible. There are hundreds of tropical cover crops and, therefore, it is not possible to include all of them in one article. Hence, selected cereals and legumes are included.  相似文献   

8.
Widespread yield stagnation and productivity declines in the rice–rice cropping system have been reported and many of the associated issues are related to soil quality. A long‐term experimental study was initiated in 1969 to assess the impact of continuous cultivation of rice as a single crop grown in wet as well as dry seasons using varying levels of chemical fertilizer and manure applications on soil quality indicators (physical, chemical and biological), a sustainable yield index (SYI) and a soil quality index (SQI). The treatments comprised chemical fertilizers and farmyard manure (FYM) either alone or in combination viz. control, N, NP, NK, NPK, FYM, N+FYM, NP+FYM, NK+FYM and NPK+FYM, laid out in a randomized complete block design with three replications. Soil samples were collected after the wet season rice harvest in 2010 and were analysed for physical, chemical and biological indicators of soil quality. A SYI based on long‐term yield data and SQI using principal component analysis (PCA) and nonlinear scoring functions were calculated. Application of NPK fertilizers in combination with FYM significantly increased the average grain yield of rice in both wet and dry seasons and enhanced the sustainability of the system compared to the control and plots in receipt of fertilizers. The SYI for the control was higher in the wet season than in the dry one, whereas the reverse was true for NPK+FYM treatment. The value of the dimensionless SQI varied from 1.46 in the control plot to 3.78 in the NPK+FYM one. A greater SYI and SQI in the NPK+FYM treatment demonstrated the importance of using a chemical fertilizer in combination with FYM. For the six soil quality indicators selected as a minimum data set (MDS), the contribution of DTPA‐Zn, available‐N and soil organic carbon to the SQI was substantial ranging from 59.4 to 85.7 per cent in NPK+FYM and control plots, respectively. Thus, these soil parameters could be used to monitor soil quality in a subhumid tropical rice–rice system.  相似文献   

9.
中国东北农田土壤质量评价的最小数据集选择   总被引：2，自引：0，他引：2  
Soil quality assessment provides a tool for agriculture managers and policy makers to gain a better understanding of how various agricultural systems afect soil resources.Soil quality of Hailun County,a typical soybean (Glycine max L.Merill) growing area located in Northeast China,was evaluated using soil quality index(SQI)methods.Each SQI was computed using a minimum data set(MDS) selected using principal components analysis(PCA)as a data reduction technique.Eight MDS indicators were selected from 20 physical and chemical soil measurements.The MDS accounted for 74.9% of the total variance in the total data set(TDS).The SQI values for 88 soil samples were evaluated with linear scoring techniques and various weight methods.The results showed that SQI values correlated well with soybean yield (r=0.658**) when indicators in MDS were weighted by the regression coefcient computed for each yield and index.Stepwise regression between yield and principal components (PCs) indicated that available boron(AvB),available phosphorus (AvP),available potassium (AvK),available iron (AvFe) and texture were the main factors limiting soybean yield.The method used to select an MDS could not only appropriately assess soil quality but also be used as a powerful tool for soil nutrient diagnosis at the regional level.  相似文献   

10.

Purpose

Soil quality (SQ), a measure of the sustainability of land use and soil management practices, can be assessed by indicators including soil physical, chemical, and biological properties. Our primary objectives were to investigate the influence of consecutive cultivation and different crop rotation systems on individual SQ indicators and to examine the impact of rotation systems on SQ using soil quality index (SQI) model.

Materials and methods

A site-specific selection of 17 potential SQ indicators representing soil chemical and physical attributes (0–10 cm) and groundwater features on 60 sampling locations and 10 representative soil profiles was chosen in a typical coastal newly reclaimed farmland of north Jiangsu Province, China. Using ANOVA analysis, the crop rotation effect was analyzed by comparing SQ indicators between rice/rape rotation soil and cotton/barley rotation soil. An overall SQI was calculated to examine whether plant biomass indices exactly responded to the SQI value.

Results and discussion

Results indicated that cultivation had significant effect on some soil profile characteristics, including SOM, SOCD, AP, CEC, AK, ECe, and I f. Crop rotation systems also had significant influence on some SQ indicators. Compared with cotton/barley rotation soil, rice/rape rotation soil was characterized by higher organic matter, undifferentiated nutrient storage and salinity/alkalinity, lower water accommodation and infiltration, and adverse groundwater conditions. Cotton/barley rotation had higher SQI values over rice/rape rotation (0.523 vs. 0.422). SQ indicators of SARe, ECe, and WTg contributed the most to the overall SQI value for each rotation system. Plant biomass indices significantly correlated with the SQI values for both rotation systems, suggesting that the SQI values essentially reflected the status of SQ.

Conclusions

Such results allowed us to conclude that cotton/barley rotation system contributed more to the improvement of SQ than rice/rape rotation system in coastal farming area. Also, we suggested SOCD, AK, ρ b, WTg, and ECg as the minimum data set for SQ assessment, as they had potential in discriminating the effect of rotation systems on SQ between the rotation systems used here.  相似文献   

11.
利用非线性评价模型对28a双季稻种植下连续冬种绿肥对土壤质量的影响进行量化,以农业部衡阳红壤环境重点野外科学观测基地长期冬种绿肥稻田为平台,分析了28a冬种不同绿肥的红壤性水稻土质量的变化情况,选择土壤容重(BD)、最大持水量(MWHC)、孔隙度(POR)、标准化平均重量直径(MNWD)、pH、阳离子交换量(CEC)、有效养分、土壤有机质(SOM)、微生物生物量碳(MBC)、土壤酶和作物生产力等项目作为评价指标,并根据不同指标所具有的功能归纳为:抗物理退化,养分供应和贮藏,抗生物化学退化和保持作物生产力的能力,以这4项功能为基础划分土壤质量指数(SQI)。冬种绿肥处理条件下土壤抗物理退化、土壤养分供应和贮藏、抗生物化学退化和保持作物生产力的功能都明显强于冬闲处理。稻-稻-黑麦草(R-R-RG)处理土壤抗物理退化功能最强;稻-稻-紫云英(R-R-MV)处理土壤养分供应和贮藏功能最强;抗生物化学退化功能,R-R-MV处理和稻-稻-油菜(R-R-RP)处理最强;R-R-RP处理保持作物生产力功能最强。4个处理的SQI等级范围为0.552(稻-稻-冬闲(R-R-WF)处理)到0.632(R-R-MV处理),R-R-MV处理的SQI值和土壤功能等级最高,3个冬种绿肥处理都明显高于冬闲处理。长期冬种绿肥翻压能明显地改善红壤性水稻土质量。  相似文献   

12.
Land use changes and soil management can potentially alter soil quality. A study was conducted to assess the long‐term (>20 years) effects of perennial trees (PT), vegetable crops (VC), rice–wheat (RW) system, sewage‐irrigated fields (SF), maize–wheat (MW) system and uncultivated soils (US) on soil quality. Soil physical quality parameters were significantly affected only in the SF system when compared with the US soil, particularly for bulk density (BD 1·51 Mg m−3 in SF vs. 1·34 in US). Among chemical parameters, electrical conductivity was high in SF, and soil nutrients (N, P, K, S, Zn, Fe, Cu and Mn) were well above the critical limits of deficiency in all the systems. Soil parameters were integrated into soil quality indices (SQIs) by unscreened transformation and principal component analysis (PCA). SQI observed under each system were compared with the US to assess the degree of degradation. Mean SQI differences showed that PT (+16·02 per cent), VC (+4·80 per cent), RW (+10·04 per cent), and MW (+11·30 per cent) are aggrading, whereas SF (−2·06 per cent) is degrading with respect to the reference soil (US). Adoption of MW system proved to be better than traditional RW; and in general agricultural crops have a significant advantage than VC, in terms of maintaining soil quality. Sewage irrigation is not a sustainable practice and long‐term use may degrade the soil. Among the SQIs, PCA with nonlinear scoring function (NLSF) based SQI was effective in judging land degradation due to soil quality changes as affected by long‐term land use and soil management practices. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

13.
This study was conducted in Chinchura-Mogra and Polba-Dapur Blocks of Hugli District, West Bengal to determine the changes in cropping systems on water-retention characteristics (WRC) and available water capacity (AWC) and their relations with other soil properties. In the present study, three sites contained adjacent cropping systems of banana and mango orchard, paddy–paddy, and paddy–potato–vegetables were selected. Soil samples were collected from depths of 0–30 and 30–60 cm in three representative sites of each cropping system with three replications guided by land use and soil map of study area. Analysis of variance was performed to compare the impact of cropping systems on available water content and water-retention characteristics. The mean clay content was greater both on the surface (61.70%) and in the subsurface (55.06%) in the soils under the paddy–paddy cropping system than banana and mango orchard and paddy–potato–vegetable cropping systems. Paddy–potato–vegetables cropping system (0.55%) has lower soil organic carbon compared to the banana and mango orchard (0.63 %) and paddy–paddy cropping system (0.65%) at 0–30 cm deep, whereas no significant difference in soil organic carbon was recorded in 30–60 cm deep. The results of available water capacity indicated that paddy–paddy cropping system recorded lower available water capacity at both ranges of depth. Available water capacity is significantly positively correlated with silt and organic carbon. The results of water-retention studies indicated that 75 and 85% of available water was removed from the soil of paddy–potato–vegetable cropping system by 0.5 M Pa at 0–30 and 30–60 cm deep, respectively, whereas only 56–62% of available water was removed by 0.5 M Pa in the other two systems. The results show that the paddy–potato–vegetable cropping system is more vulnerable to moisture stress during drought periods.  相似文献   

14.
Surveys on land use dynamics were conducted over a 3-year period along various toposequences in benchmark inland valley watersheds of the Ashanti region, Ghana. Six typical land use systems were selected for more detailed studies, Le., primary forest (PF), cacao farm (CP), fallow (Fallow), mixed cropping (MC), and lowland rice-based systems including both traditional rice (TR) and sawah{ft1} (paddy)-based rice farming (Sawah). Topsoil samples (0-20 cm) and samples of leaves and bark of various plants were collected from these land use systems for nutrient characterization using laboratory analyses. The remaining primary and secondary forests cover only a patchy area, accounting for less than 20%, in forest reserves and surrounding areas. Cacao farms were developed both in the upland areas, middle slopes, and lowland areas, which occupied about 20% of the watershed. Lowland rice farming is estimated to account for about 10% of the watershed. Oil palm cultivation is also common in the lowland areas. The remaining land use systems were mostly fallow and mixed cropping of maize, cocoyam, cassava, and plantain. Plant leaves of various species in the lowland traditional rice area showed higher concentrations of phosphorus and potassium but lower calcium and strontium concentrations than those of the leaves in the upland surveyed plots, especially, the forest area. Nitrogen, sulfur, magnesium, and the other mineral elements, however, did not show any clear differences among the six land use systems. Bark samples tended to exhibit lower concentrations of nitrogen, phosphorus, sulfur, magnesium, sodium, silicon, aluminum, iron, manganese, and copper but higher concentrations of calcium and strontium. Cacao leaves showed silicon-accumulator characteristics and the magnesium concentration was high too. Cacao bark contained potassium and zinc in appreciable amounts in compared to the leaves. Topsoil samples of the primary forest and cacao farms in the upland areas showed higher levels of TC, TN, exchangeable Ca and Mg, and eCEC while the levels of available P showed a rather reverse trend compared to the lowland traditional and sawah rice plots. Topsoil samples of the fallow and mixed cropping plots at upland and fringe sites showed intermediate levels. The pH at the mixed cropping site was the lowest. These general fertility trends along upland and lowland topo-sequences were different from those of monsoon Asia and Japan. With the implementation of the sawah rice-based farming system, the inland valleys could contribute to the enhancement of sustainable food production in the country.  相似文献   

15.
【目的】 探讨不同生物质炭施用量对连作黄瓜根区土壤环境的作用效果,为用生物质炭修复黄瓜连作土壤以及在农业中的推广应用提供科学依据。 【方法】 以如皋市农业科学研究所大棚示范区为试验基地,一次性向设施农田土壤中添加0 (CK)、5 (C1)、10 (C2)、20 (C3)、30 (C4)、40 (C5) t/hm2的生物质炭,通过连续两年温室定位试验,测定生物质炭施用后黄瓜连作根区土壤的物理性状、养分含量及酶活性的变化状况,采用土壤质量指数 (SQI) 评价不同生物质炭施用量对黄瓜连作两季后土壤质量的影响。 【结果】 随着生物质炭施用量的增加,第一季与第二季黄瓜根区土壤的理化性状变化趋势一致,具体表现为容重不断降低,土壤孔隙度、饱和含水量、田间持水量、饱和导水率、有效磷及有机质含量不断升高,且当生物质炭施用量为30 t/hm2(C4处理) 时,土壤中全氮、硝态氮和铵态氮含量最高。与CK相比,生物质炭的施用可以减少黄瓜根区土壤 < 0.25 mm粒径的微团聚体含量,而增加 > 0.25 mm粒径的大团聚体含量,土壤中0.25～0.5 mm和0.5～1 mm粒径的团聚体含量都在高施用量 (40 t/hm 2) 处理中达到最大值。生物质炭施用后的连续两季,黄瓜根区土壤中脲酶与过氧化氢酶活性均随生物质炭施用量的增加呈先增加后降低的趋势,其活性分别在生物质炭施用量为30 t/hm2和20 t/hm2时最大。当生物质炭施用量为30 t/hm2时,两季黄瓜产量都达到最高,分别为3.24 × 104 kg/hm2和6.18 × 104 kg/hm2。通过土壤质量指数 (SQI) 对生物质炭施用后两季黄瓜土壤质量进行评价可知,不同生物质炭施用水平下土壤质量指数依次为C4 > C5 > C3 > C2 > C1 > CK,相应的土壤质量指数分别为0.774、0.740、0.728、0.650、0.635、0.583。 【结论】 施用生物质炭对黄瓜连作田土壤的理化性状和酶活性均有显著影响,高施用量 (40 t/hm2) 条件下对土壤物理性状改善效果最好,当生物质炭施用量为30 t/hm2 (C4处理) 时对黄瓜连作根区土壤的养分含量提升效果最佳。SQI可以客观定量地评价生物质炭施用对连作黄瓜根区土壤质量的影响,其分析结果表明改善黄瓜连作土壤环境的最佳生物质炭施用量为30 t/hm2。   相似文献   

16.
Biodegradable plastic films are desirable alternatives to traditional black polyethylene plastic for use as mulches in agroecosystems. Efforts are ongoing to engineer biodegradable plastic mulches that could be incorporated into the soil at the end of the crop season, and decomposed by microorganisms, ultimately to CO2, H2O, and biomass. Whether changes in soil quality occur during or following biodegradation is unknown. An 18-month study evaluated the effects on soil quality following burial of four potentially biodegradable mulches and a no mulch control in high tunnel and open field tomato production systems across three geographically distinct locations (Knoxville, TN; Lubbock, TX; Mount Vernon, WA). The mulch treatments included: two starch-based mulches (BioAgri® Ag-Film and BioTelo Agri); one experimental 100% polylactic acid mulch (Spunbond-PLA-10); one cellulose-based mulch (WeedGuardPlus; positive control); and a negative control (no mulch). The soil management assessment framework (SMAF) was used to calculate a soil quality index (SQI) according to five dynamic soil properties: microbial biomass carbon, β-glucosidase, electrical conductivity, total organic carbon (TOC), and pH. Within the 18-month evaluation period, the effects of the biodegradable mulches on the SQI were minor, and dependent upon production system and time of incubation at all locations. In general, the SQI was higher in the high tunnel systems for some of the mulch treatments at Knoxville and Lubbock but the opposite was true at Mount Vernon. By the final sampling at 18 months, the SQI was lowest for WeedGuardPlus at Lubbock and Mount Vernon but at Knoxville, the WeedGuardPlus SQI was not significantly different from the no mulch control. Of the five SMAF indicators evaluated, soil microbial biomass and β-glucosidase activity were the most responsive to mulch and production systems, supporting the use of these variables as soil quality indicators for short-term changes due to this agricultural management practice.  相似文献   

17.
基于最小数据集的黄土高原矿区复垦土壤质量评价   总被引：7，自引：3，他引：4  
矿产开发影响了土壤质量,特别是在黄土高原生态脆弱地区。通过植被恢复能够改善矿区复垦土壤质量。为了揭示矿区复垦土壤质量在植被恢复过程中的变化,该文以黑岱沟矿区排土场不同恢复年限不同植被类型、未复垦地和周边自然植被恢复区为研究对象,选取21项理化生指标作为总数据集(totaldataset,TDS),运用主成分分析(principal component analysis,PCA)结合Norm值构建评价指标最小数据集(minimum data set,MDS),通过非线性(non-Linear,NL)和线性(linear,L)两种评价方法对研究区土壤质量进行了评价。研究表明:黄土高原北部典型矿区复垦土壤质量评价指标MDS包括粉粒百分比、有机质、速效磷、钠吸附比和微生物碳;2种评价方法下,植被恢复均对复垦土壤质量指数(soil quality index,SQI)有了显著提升(P 0.05),复垦20 a灌木SQI高于复垦10 a灌木SQI,复垦12 a草本SQI高于复垦20 a草本SQI,然而所有复垦土壤SQI均未达到自然植被恢复土壤SQI;由于非线性土壤质量评价方法(SQI-NL)具有更大的土壤质量指数变化区间和变异系数,此外,在SQI-NL和线性土壤质量(SQI-L)评价两种方法下,MDS和TDS之间决定系数分别为0.911和0.866,因此,非线性土壤质量评价方法在该区域具有更好的适用性,并且最小数据集能够较准确地进行土壤质量评价。  相似文献   

18.
土壤肥力质量评价及土壤肥力障碍因子分析,对于区域土壤利用和改良、指导农业生产结构布局具有重要意义。以江西省进贤县为研究区,通过水稻遥感解译测产,结合主成分分析进行土壤质量评价;采用综合指数法表征土壤肥力质量水平,分析该区域低肥力质量区域主要障碍因素,并进行障碍因子区划。结果表明,该地区土壤肥力质量评价的最小数据集(MDS)指标包括:有机质、阳离子交换量(CEC)、全钾(TK)、交换性钙(Ex.Ca)、容重、粉黏比;土壤质量综合指数与水稻产量相关系数达到0.73(p0.01),以当地水稻平均产量7.215 t hm~(-2)确定土壤质量综合指数阈值为0.65。分析得出,该地区影响土壤肥力的主要障碍包括有机质含量低和容重较大反映的低熟化度障碍、中量元素缺乏反映的酸化障碍、全钾含量低和高粉黏比反映的结构障碍等。根据障碍因素将研究区域划分为三大障碍区:东南部丘陵区主要障碍因子为酸化和土壤结构障碍;中西部低岗平原主要为土壤酸化障碍;北部滨湖区主要障碍为水稻土熟化程度低。通过对不同区域施行针对性改良措施有益于提高土壤肥力。  相似文献   

19.
为明确酚酸类物质在连作植烟土壤中的变化特征,探讨土壤主要环境因子对酚酸类物质的影响,以不同连作年限（4 a,6 a,8 a,14 a和16 a）植烟土壤为对象,研究了不同连作年限植烟土壤酚酸类物质、理化性状、酶活性和细菌多样性的变化特征,并利用Mantel Test分析了酚酸类物质与土壤主要环境因子的相关性。结果表明,随连作年限增加,土壤酚酸类物质和速效钾含量升高,pH、有机质含量、细菌菌群丰度和多样性降低,水解性氮和有效磷含量呈先降低后升高趋势,酶活性呈先升高后降低趋势。Mantel Test分析表明,土壤酚酸类物质含量与理化性状、酶活性和细菌丰度显著相关,且与理化性状相关性最高;不同酚酸类物质含量与土壤主要环境因子相关性存在差异,其中,对羟基苯甲酸和阔马酸与植烟土壤理化性状、酶活性以及细菌丰度的相关性最高。因此,在本试验条件下,连作植烟土壤酚酸类物质具有明显积累特征,植烟土壤环境恶化;酚酸类物质积累受理化性状、酶活性和细菌多样性影响,且理化性状影响最大;不同酚酸类物质受主要土壤环境因子的影响存在差异,其中对羟基苯甲酸和阔马酸积累所受影响最大。  相似文献   

20.
Rainfed Inceptisol soils, despite their agricultural potential, pose serious problems, including soil erosion, low fertility, nutrient imbalance, and low soil organic matter, and ultimately lead to poor soil quality. To address these constraints, two long-term experiments were initiated to study conservation agricultural practices, comprising conventional and low tillage as well as conjunctive use of organic and inorganic sources of nutrients in Inceptisol soils of Agra center of the All-India Coordinated Research Project for Dryland Agriculture (AICRPDA). The first experiment included tillage and nutrient-management practices, whereas the second studied only conjunctive nutrient-management practices. Both used pearl millet (Pennisetum americanum (L.) Linn) as test crop. These experiments were adopted for soil quality assessment studies at 4 and 8 years after their completion, respectively, at the Central Research Institute for Dryland Agriculture (CRIDA), Hyderabad, India. Soil quality assessment was done by identifying the key indicators using principal component analysis (PCA), linear scoring technique (LST), soil quality indices (SQI), and relative soil quality indices (RSQI). Results revealed that most of the soil quality parameters were significantly influenced by the management treatments in both the experiments. In experiment 1, soil quality indices varied from 0.86 to 1.08 across the treatments. Tillage as well as the nutrient-management treatments played a significant role in influencing the SQI. Among the tillage practices, low tillage with one interculture + weedicide application resulted in a greater soil quality index (0.98) followed by conventional tillage + one interculture (0.94), which was at par with low tillage + one interculture (0.93). Among the nutrient-management treatments, application of 100% organic sources of nutrients gave the greatest SQI of 1.05, whereas the other two practices of 50% nitrogen (N) (organic) + 50% (inorganic source) (0.92) and 100% N (inorganic source) (0.88) were statistically at par with each other. The various parameters that emerged as key soil quality indicators along with their percentage contributions toward SQI were organic carbon (17%), exchangeable calcium (Ca) (10%), available zinc (Zn) (9%), available copper (Cu) (6%), dehydrogenase assay (6%), microbial biomass carbon (25%) and mean weight diameter of soil aggregates (27%). In experiment 2, SQI varied from 2.33 to 3.47, and 50% urea + 50% farmyard manure (FYM) showed the greatest SQI of 3.47, which was at par with 100% RDF + 25 kg zinc sulfate (ZnSO4) (3.20). Under this set of treatments, the key soil quality indicators and their contributions to SQI were organic carbon (19%), available N (20%), exchangeable Ca (3%), available Zn (4%) and Cu (17%), labile carbon (20%), and mean weight diameter of soil aggregates (17%). The quantitative relationship established in this study between mean pearl millet yields (Y) and RSQI irrespective of the management treatments for both the experiments together could be quite useful to predict the yield quantitatively with respect to a given change in soil quality for these rainfed Inceptisols. The methodology used in this study is not only useful to these Inceptisols but can also be used for varying soil types, climate, and associated conditions elsewhere in the world.  相似文献   

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