How the Soil Moves Upward in the Olive Orchards of NW Syria: Sustainability Analysis of a Local Innovation

This paper analyses a local innovation in response to intense soil degradation in olive orchards of north‐west Syria. Farmers developed a practice consisting of quarrying red clayey soil in valley bottoms and applying this soil to hillslope olive orchards with heavily degraded calcareous soils. A biophysical, economic and social analysis of the practice of soil application identified the opportunities and risks of this innovative soil management technique. On the basis of a pairwise comparison of nine adjacent treated and nontreated orchard plots, soil applications were found to increase soil depth by 36%, soil water availability by 28% and total available soil nutrients: potassium (+45%), nitrogen (+12%) and phosphorus (+6%). Olive yield increased by about 40%. A cost–benefit analysis found this practice to be economically viable within a large geographical area, and farmers scored the practice higher than alternative methods. A socio‐economic analysis revealed its widespread adoption among different farmer types. The positive results of soil applications at the farm level explain its fast adoption. However, potential risks – including the further depletion of soil resources and the transfer of soil‐borne diseases – limit the long‐term sustainability of this locally developed practice. Copyright © 2013 John Wiley & Sons, Ltd.     

Suitability of enzyme activities for the monitoring of soil quality improvement in organic agricultural systems

There is growing interest in the applications of soil enzymes as early indicators of soil quality change under contrasting agricultural management practices. However, despite there being an abundant literature on this subject, most comparative assessments have been based on a limited number of experimental farms and, therefore, conclusions are not as robust as desired. In this study, we compare 18 pairs of organic and neighbouring conventional olive orchards in southern Spain. These sites were selected to allow the definition of the relative contributions of site-landscape features, soil type, and time since organic accreditation and tillage intensity, on the soil quality. Soils were analysed for physico-chemical properties, the activities of dehydrogenase, β-glucosidase, arylsulphatase, acid and alkaline phosphatase, and potential nitrification. The geometric mean of the assayed enzymes (GMea) was validated with an independently performed Principal Component Analysis (PCA), and used as a combined soil quality index. The effects of tillage intensity and time since organic accreditation on the improvement of soil quality were also evaluated within the subset of organic farms. Overall for the 18 sites, contrasted management practices did not differ in their impact on basic soil physico-chemical properties, except for loss of on ignition and available inorganic N which were higher and lower in organic farms, respectively. Organic management resulted in significantly higher soil enzyme activities. However, differences were not significant in some of the paired comparisons when considered individually. This highlights the need for extensive comparative assessment, as in this study, to draw clear conclusions concerning the changes to soil quality under sustainable management practices. The GMea was significantly correlated with the first axis of the PCA and shown to be appropriate for condensing the set of soil enzyme values to a sole numerical value. Soil quality changes in organic versus conventional farms, as measured by the GMea, ranged from −23% to 97%, and was highly dependent on time since organic accreditation (r = 0.88; P < 0.01). On the other hand, tillage intensity clearly tended to delay any progress in soil quality in the organic farms.     

Analysis of the effects of soil management on runoff generation in olive orchards using a physically based model.

Abstract. A numerical model that incorporates the spatial variability of infiltration, surface storage and resistance to overland flow was developed, calibrated and validated for olive orchards. The model reproduced accurately amounts of runoff used in validation, and predicted runoff in olive orchards managed in different ways, in line with published results. The model was used to analyse the runoff generation in a virtual, 180 m length, 5% steep, olive grove, using 54 different scenarios which combined three different soil types, two tree canopy sizes and nine soil management techniques (four tillage scenarios: freshly or degraded tillage with and without a compacted plough layer; no-till, and four cover crops in strips differing in width and plant density). The results of the numerical experiment showed that no-till had the highest runoff coefficient, while a dense cover crop had the lowest. Recently tilled soils also exhibited some of the lowest runoff coefficients. The effects of increasing soil cover due to a greater tree canopy on runoff were significant and caused by the greater area of high infiltration beneath the canopy. Effects of tree canopy size were less important than the impact of soil management practices on runoff.     

典型黑土区坡耕地退化程度诊断与评价

为了对黑土区坡耕地退化程度进行全面、综合、客观的诊断与评价,通过文献计量法和频度分析法对国内外耕地退化评价文献内的高频指标进行了统计分析,建立了适用于东北典型黑土区坡耕地退化程度诊断与评价的指标体系(TIS)。同时以拜泉县为研究区域,通过聚类分析建立了土壤退化程度诊断与评价最小指标集(MIS)。结果表明:(1)TIS共包括物理、化学、生物和侵蚀特征因子4类共11项指标:腐殖质层厚度、黏粒含量、有机质含量、pH值、坡度、垄坡角、沟壑密度、容重、水稳性大团聚体含量、土壤阳离子交换量和作物产量,其中前6项指标组成了MIS。(2)研究区未退化土壤占12%,轻度退化土壤占12%,中度及以上退化土壤占76%。坡度可能是影响研究区土壤退化的主要因素之一,坡度与垄坡角之间存在协同关系。此外,施用农药、化肥以及连作导致土壤酸化问题突出。     

三江源区草地退化与人工恢复对土壤理化性状的影响

以三江源区不同退化程度的天然草地及不同恢复年限的人工草地为研究对象,系统分析土壤理化性质随取样深度的动态变化。结果表明:(1)人工草地土壤含水量及全氮、全钾、全磷、速效钾、速效磷的含量随恢复年限均表现出先减小后增大的"V"形变化趋势;(2)随着退化程度增加,退化草地土壤中含水量逐渐降低,全氮、全钾、有机质、速效钾含量未表现出逐渐降低趋势,而草地的裸斑面积、土壤及养分的流失量逐渐增加;(3)人工草地及退化草地土壤中全氮、速效钾、有机质含量均随着取样深度增加而逐渐降低,草地恢复年限和退化程度基本不影响养分在土壤中的空间分布;(4)人工草地建设使退化草地有机质、全氮、全钾的含量增加,尤其有利于0-4cm的土壤养分增加。因而,人工草地建设可以作为三江源区退化草地土壤恢复的措施之一。     

A simple bioindication method to discriminate olive orchard management types using the soil arthropod fauna

Bioindication has proved to be a useful tool to evaluate the state of conservation of an ecosystem based on the living organisms it contains, and thus many studies have used arthropods as bioindicators. In the cultivation of olive (Olea europaea L.), several management methods are employed, from organic production to conventional intensive farming. This study uses arthropod fauna as a means of discriminating between management types and takes into account the features of sampling methods and the data set used in order to make the discriminant method more effective.A total of 15 olive orchards were considered under three types of management (organic production, conventional non-tillage, and traditional conventional farming). During the summer of 2007, sampling was undertaken fortnightly using pitfall traps in the interior (under the canopy) as well as exterior (in the orchards lanes) soil. The samples were identified to the order level or taxonomic categories easiest to recognise, and two datasets were built (“management type” and “organic/non-organic”). A Linear Discriminant Analysis (LDA) was applied with cross validation by the leave-one-out (LOO) method, for all the scenarios analysed.The olive orchards under organic management registered greater abundance, diversity, and richness of orders. Also, significant differences between management types were detected with respect to the main groups, particularly between organic and non-organic. Formicidae and Coleoptera predominated in the interior and exterior soil, respectively. The soil-arthropod community considered at the order level proved useful to discriminate between management types, especially between organic and non-organic approaches. In light of the results, sampling of the interior soil and the use of the set of orders that significantly differ in the test of mean differences are suggested in order to optimise the discriminant analysis. In this way, classification accuracy reaches 100%, and 99% using cross validation with LOO.     

Contrasted Impact of Land Abandonment on Soil Erosion in Mediterranean Agriculture Fields

Abandonment of agricultural land results in on-and off-site consequences for the ecosystem. In this study, 105 rainfall simulations were carried out in agriculture lands of the Mediterranean belt in Spain(vineyards in Málaga, almond orchards in Murcia, and orange and olive orchards in Valencia) and in paired abandoned lands to assess the impact of land abandonment on soil and water losses. After abandonment, soil detachment decreased drastically in the olive and orange orchards, while vineyards did not show any difference and almond orchards registered higher erosion rates after the abandonment. Terraced orchards of oranges and olives recovered a dense vegetation cover after the abandonment, while the sloping terrain of almond orchards and vineyards enhanced the development of crusts and rills and a negligible vegetation cover resulted in high erosion rates. The contrasted responses to land abandonment in Mediterranean agricultural lands suggest that land abandonment should be programmed and managed with soil erosion control strategies for some years to avoid land degradation.     

Cattle manure and inorganic nitrogen fertilizer application effects on soil hydraulic properties and maize yield of two soils of Murewa district,Zimbabwe

This study set out to determine the effects of cattle manure and inorganic N‐fertilizer application on the hydraulic properties and maize yield of a clay and sandy soil in a smallholder farming area of Zimbabwe. Four fields classified as homefields (HF: more fertile and closer to homesteads) and outfields (OF: less fertile and further from the homesteads) were selected on clay and sandy soil. They were subjected to four treatments, control (no fertility amendment), 5, 15 and 25 t/ha cattle manure + 100 kg/ha N (as ammonium nitrate) for 7 years. A two‐way randomized complete block design was used with fertility and field type as the two factors. Clay soil hydraulic properties, which included density of macropores with a diameter >300 μm, unsaturated hydraulic conductivity, steady‐state infiltration rate, moisture retention under low suction and maize grain yield, were significantly improved (P < 0.05) by fertility management compared with the control and were generally comparable between the HF and OF. Fertility management significantly improved maize grain yield on sandy soils but did not enhance hydraulic parameters, thereby indicating poor responsiveness in structural build‐up. On the other hand, significantly different hydraulic parameters between the sandy soil HF and OF suggested effects of other factors not related to soil fertility and field type treatments. We therefore concluded that application of a high rate (25 t/ha) of cattle manure and inorganic N‐fertilizer is beneficial for fertility restoration to the degraded OFs with associated comparable hydraulic properties on HFs and OFs on clay soil, unlike on sandy soil.     

Olive Husk Compost Improves the Quality of Intensively Cultivated Agricultural Soils

Organic amendments improve the quality of degraded cultivated agricultural soils. In this work, we examined the impact of an olive husk compost (OHC) on quality‐related physical, chemical and biochemical properties of intensively managed greenhouse soil. To this end, a completely randomized block experiment involving a single factor and two treatments (viz., annual application of OHC at 30 Mg ha⁻¹ or no application) with three replications was used for 5 years. The effect of the compost was studied at two soil depths (0–10 and 10–25 cm) and two positions relative to crop rows (viz., on rows and between rows). Application of OHC increased soil organic matter (SOM) content, which is consistent with the low degradation rate of the compost in soil and confirms its usefulness as a source of organic C for soil. Increased SOM content resulted in decreased bulk density, and also in increased porosity and available water in the soil. The amendment was also an effective source of nutrients, particularly N, P, K and Ca, the last of which contributed to decrease exchangeable Na levels in the soil surface layer. The compost increased the activity of all enzymes studied except urease. This result can be ascribed to increased microbial activity, the presence of enzymes in the compost and their stabilization by organic matter and clay in the soil. Dehydrogenase and phosphatase were the individual enzyme activities in the soil, which were correlated with the largest number of soil properties favourably affected by OHC. Copyright © 2015 John Wiley & Sons, Ltd.     

渭北不同园龄苹果园土壤团聚体状况及演变趋势研究

为了探索果业生产和果园管理措施对土壤质量的影响,选取了渭北旱源苹果主产区彬县10a幼龄和21a老龄苹果园0~40 cm土壤为研究对象,以农田为对照,采用干筛法和湿筛法研究了不同种植年限果园土壤团聚状况与演变趋势。结果表明:渭北地区土壤机械稳定性团聚体以0.25 mm微团聚体为优势级别,仅0~20 cm处随园龄递增果园土壤团聚化趋势较为明显,0.25 mm土壤团聚体含量(DSAC0.25)、平均重量直径(MWD)和几何平均直径(GMD)均显著增大,团聚体分形维数(D)递减,但是,10~0.25 mm和5~1 mm最有价值团聚体和团聚体系数(KCTP)均在递减。渭北土壤水稳性团聚组成中约60%为0.25 mm微团聚体,在0~30 cm处土壤水稳性团聚体的MWD、GMD和WSAC0.25呈现为农田(对照CK)10a果园21a果园,随园龄递增有明显增大趋势。0.25 mm团聚体的破坏率(PAD0.25)随园龄增加显著增大,递增幅度随土层深度增加而递减。相关分析表明,土壤总有机碳(TOC)、颗粒态有机碳(POC)与机械稳定性团聚体各项指标呈极显著相关,土壤碳酸钙含量、黏粒含量与水稳定团聚体多项指标呈极显著相关,PAD0.25与土壤理化性质呈显著相关。研究表明,果树种植在表观上明显提高了渭北地区表层0~20 cm土壤机械稳定性大团聚体数量,增强了土壤抗风蚀能力,但却显著降低了土壤团聚体的农艺质量及其稳定性,果园土壤团聚体的农艺质量显著退化与有机物及碳酸钙含量递减有着直接关系。     

退化演替对高山草地植被和土壤理化特性影响

[目的]分析3种不同草地退化阶段(轻度退化,中度退化和重度退化)草地植被和土壤理化特性的变化规律,为类似区域退化草地植被恢复提供有效途径。[方法]野外植被调查、土壤取样和室内分析。[结果]草地退化不同阶段草地植物群落组成和物种多样性均有差异,退化对草地土壤理化特性有明显影响。重度退化草地土壤容重显著高于轻度退化草地(p0.05)。轻度和中度退化样地0—10cm土壤空隙度显著高于重度退化草地。重度退化草地的土壤有机质、全碳、全钾、全磷和有效钾均明显小于轻度退化草地(p0.05),但土壤pH值和有效氮含量没有显著变化。[结论]高山草地退化演替对该区土壤物理特性具有显著影响。     

Spatial variability of soil organic carbon stock in an olive orchard at catchment scale in Southern Spain

Orchards have a high potential for carbon sequestration. However, little research is available on the spatial variability at catchment scale and on the difference between the tree area and the lanes. We analyzed theik spatial variability of soil organic carbon stock, SOC_stock at 90 cm depth in an 8-ha catchment in Southern Spain with olives on a vertic soil. Results showed higher soil organic carbon concentration, SOC, in the tree area as compared to the lane up to 60 cm depth, but its impact on SOC_stock was negligible since it was compensated by the higher soil bulk density in the lane. SOC at different depths was correlated with that in the top 0–5 cm. The overall SOC_stock of the orchard was 4.14 kg m⁻², ranging between 1.8 and 6.0 kg m⁻². This SOC_stock is in the mid-lower range of values reported for olive orchards, measured at smaller scale, and similar to those other intensive field crops and agroforestry under comparable rainfall conditions. The spatial variability in SOC_stock was correlated to several geomorphological variables: elevation, cumulative upstream area, topographic wetness index, sediment transport index, and tillage erosion. Differences in SOC and SOC_stock are driven by the sediment redistribution downslope, mainly by tillage erosion, and higher soil water availability in lower areas allowing higher biomass production. These topographic indexes and the correlation between SOC in the topsoil and SOC_stock up to 90 cm should be further explored in other typology of olive orchards for facilitating the mapping of SOC_stock.     

Soil phosphorus status of organic farming in Flanders: an overview and comparison with the conventional management

Abstract. A number of organic farms in Flanders were sampled to investigate the general phosphorus (P) status and degree of P saturation (P_sat) of the soils. Where possible, the soil P status was compared to that in conventional agriculture and related to farm characteristics: agricultural land use, soil texture, fertilization intensity and time since conversion. Generally, the P status of the organic farms was high, and similar to that of conventional farms in Flanders, which is due to the restricted time since conversion to organic farming on most farms. The average soil P_sat was slightly lower (37%) than the average value for East Flanders (39%) taken over the soil profile to 90 cm. However, a large proportion of the field areas on organic farms still had a P_sat greater than 30% (critical P_sat value), which may be an indication that P saturation will continue to be a problem for these farms.     

Evaluating the impact of soil management on soil loss in olive orchards

Abstract. The effects of soil management on soil losses from olive plantations in southern Spain were evaluated using the Revised Universal Soil Loss Equation (RUSLE), a review of published experiments, and preliminary results of an on-going field trial. Experimental data were used to parameterize the RUSLE for olive orchards under various soil management regimes. The predictions agreed qualitatively with the data available, and the model provided a simple way to assess the effects of soil management on erosion. Our results showed that no-tillage caused the greatest soil loss, while cover crops showed the least. Tillage and planting following contours proved only partially effective and did not reduce soil erosion as much as protective crops. One scenario studied suggests that, on slight to moderate slopes, land transformed from row crops to olive orchards may remain below the maximum tolerable soil erosion limit, if a cover crop is included between the trees. A scenario for marginal olive orchards located on steep slopes suggests that effective erosion control could only be achieved with a cover crop system that would have the side-effect of reducing the yield of rain-fed olives. Quantifying the effects of soil management on soil erosion in olive orchards is uncertain because very few experimental results are available. Further research that monitors soil loss in carefully selected long-term experiments at different scales and follows the changes in key soil parameters is urgently required to develop effective erosion control policies.     

桂西北环境移民示范区柑橘园土壤营养探析

对桂西北环境移民示范区柑橘园土壤营养状况测定结果表明 ,该区柑橘园有机质含量丰富 ,全N、全P偏低 ,水解氮、有效磷基本适宜 ,K素缺乏 ,pH偏酸性 ;且主要土壤养分变异系数均 >16 % ,土壤 pH变异系数为4 .4 % ;不同产量级柑橘园土壤养分差异主要表现于水解氮和速效钾含量 ,丰产园水解氮和速效钾含量分别为10 6 .4 6mg/kg和 76 .2 1mg/kg ,低产园分别为 96 .88mg/kg和 5 9.83mg/kg且显著低于丰产园 ,水解氮和速效钾与柑橘产量分别呈极显著和显著相关。并提出果园土壤水解氮、速效钾丰缺指标。     

土壤养分状况系统研究法在蕉园土壤上的应用研究

采用实验室分析、吸附试验和温网室盆栽试验相结合的诊断程序,以香蕉为指示作物,对广州市番禺区3种蕉园土壤的养分限制因子进行了系统诊断.结果表明:广州市番禺区3种蕉园土壤均缺N,减N处理产量分别比最佳处理(OPT)下降59.7%、46.7%和55.1%,减产极显著.番禺东涌蕉园与灵山蕉园土壤K、Mg含量偏低,B丰富;万顷沙蕉园土壤P、K含量较缺乏;3种土壤中的Ca与Fe含量充足,Mn含量较充足.     

Assessment of deforestation impact on soil erosion in loess formation using 137Cs method (case study: Golestan Province,Iran)

Golestan, a province in the North-East of Iran, is characterized by high coverage of loess deposits. Since 1963, the area has experienced approximately 200,000 ha deforestation due to land-use changes in agriculture and increasing demand for wood. Approximately, 110,000 ha of the clear-cut lands are under dry-farming, mainly for wheat cropping, and about 86,000 ha have been reforested. This IAEA funded project is the first attempt to use nuclear techniques in the East of Hircanian Forest for determination of on-site impacts of deforestation due to two land-use changes (i.e. dry farming and reforestation). Practicing long-term dry-farming led to 60% soil losses with a mean rate of 2 mm per year. The net erosion rate of croplands on loess deposits in the study area was 32.27 t ha⁻¹ yr⁻¹. Reforestation, cultivation of even-aged Cypress trees since 1993, showed 13 to 60 percent effectiveness in soil conservation. Dry-farming land use resulted in the loss of 95 t ha⁻¹ soil organic carbon (SOC) stock at a mean rate of 1.7 t ha⁻¹ over 54 years. Cultivating Cypress trees successfully restored the SOC content by 100% compared with the SOC in original forests. The conversion of dry-farming lands to orchards of olive trees since 2004, brought more income for farmers but were less effective in soil conservation because of low canopy cover of olive trees. Our data provide key information and guidance for land users and decision-makers about implementing strategic and sustainable conservation practices to restore degraded land.     

退化草地土壤农化性状与微生物区系研究

通过对三种退化程度不同的草地土壤农化性状与微生物区系进行研究，结果表明，草地退化后，其土壤肥力水平、土壤微生物数量和微生物种类有随退化程度增高而下降的趋势；退化草地存在不同的程度的营养元素比例失调，表现为少氮、缺磷、富钾和高有机质含量，且退化程度接近的草地间，在土壤微生物区系和农化性状有部分类似的特征。     

Soil properties in organic olive groves compared with that in natural areas in a mountainous landscape in southern Spain

This study evaluates soil properties in organically managed olive groves and natural zones in a mountainous area of Andalusia, Spain. Two soil types (Eutric Regosol and Eutric Cambisol) and the most common soil management methods (tillage and two intensities of grazing) were studied. Both soil types in the groves had values not much lower than those in the natural areas. Average (±SE) values in the groves were 1.58 ± 0.71% for organic carbon, 323 ± 98 g kg^?1 for macroaggregate stability, 1.11 ± 0.16 g cm^?3 for bulk density, 3.5 ± 1.6 mm h^?1 for saturated hydraulic conductivity and 1209 ± 716 mg CO₂ kg^?1 for soil respiration. Overall, these values tended to be lower in the tilled compared with that in the grazed groves. The average phosphorus soil content (5.83 ± 5.22 mg kg^?1) was low for olive production and within adequate ranges for N (0.12 ± 0.05%) and K (142 ± 81 mg kg^?1). Soil erosion was high in the tilled groves (35.5 ± 18.2 t ha^?1 year^?1) with soil loss correlating with indicators of soil degradation such as organic carbon content and water stable macroaggregates. In the grazed groves, soil loss was moderate with no clear indications of soil degradation. Overall, there was significant farm‐to‐farm variability within the same soil and land management systems. Olive production had a moderate effect on soil degradation compared with natural areas and olive cultivation could be sustained in future if cover crop soil management replaced tillage, especially in the most sloping areas.     

Geoinformation evaluation of soil resource potential for horticulture in Krasnodar region and the Republic of Adygea

A geoinformation database for assessing soil resource potential for horticulture in Krasnodar region and Adygea has been developed. The results of geoinformation analysis indicate that only 55–60% of soils in these regions are suitable for growing horticultural crops without limitations; about 35–40% of the total soil area is unsuitable for horticultural purposes. For plum trees, the area of unsuitable soils is somewhat lower than for other horticultural crops. Geographically, the areas of soils suitable and unsuitable for horticulture are close to one another. The thickness of the loose earthy soil material, the gravel content, the degree of salinization, the soil texture, and the degree of soil hydromorphism are the major soil properties imposing considerable limitations for the development of fruit-growing industry in the studied regions. The highest portions of soils suitable for horticulture are found in Eiskii, Kushchevskii, Krylovskii, Shcherbinovskii, and Novokubanskii districts of Krasnodar region. The development of horticulture in Tuapsinskii, Slavyanskii, and Primorsko-Akhtarskii districts is limited because of the unsuitability of soils for this purpose. About 8% of the existing orchards are found on soils recognized as unsuitable for horticulture, and only about 20% of the existing orchards are found on soils suitable for fruit growing without limitations. About 70% of the existing fruit orchards are located on degraded soils or on soils with certain limitations for horticulture. The profitability of fruit orchards on such soils is lower than that of the orchards planted on soils without limitations for horticulture. This information is necessary for the adequate economic evaluation of the degree of soil degradation.