The impact of organic amendments on soil properties under mediterranean climatic conditions

Soil erosion and unsustainable land use produce adverse effects on SOC content. Soil management techniques and corrections can be applied for soil recovery, especially, with afforestaion purposes. This study presents the short term effects on the application of different treatments on soil properties for soil included in several sets of closed plots located in the experimental area of Pinarillo (Nerja, Spain). The analysed soil properties were: PH, EC, organic carbon, total nitrogen and total carbon. In order to verify possible differences, we applied the test of Mann-Whitney U in corroboration with the previous homogeneity test of variance.

Impact of HydroPolymers on the soil biological components in mediterranean drylands

Soil degradation affects more than 52 million ha of land in counties of the European Union. This problem is particularly serious in Mediterranean areas, where the effects of anthropogenic activities (tillage on slopes, deforestation, and pasture production) add to problems caused by prolonged periods of drought and intense and irregular rainfall. Soil microbiota can be used as an indicator of the soil healthy in degraded areas. This is because soil microbiota participates in the cycle elements and in the organic matter decomposition. All this helps to the young plants establishment and in long term protect the soils against the erosion. During dry periods in the Mediterranean areas, the lack of water entering the soil matrix leads to a loss of soil microbiological activity and it turns into a lower soil production capabilities. Under these conditions, the aim of this study was to evaluate the positive effect on soil biological components produced by an hydro absorbent polymer (Terracottem). The aim of the experiment was to evaluate the impact assessment of an hydropolymer (Terracottem) on the soil biological components. An experimental flowerpot layout was established in June 2015 and 12 variants with different amount of Terracottem were applied as follow: i) 3.0 kg.m3 ; ii) 1.5 kg.m3 and; iii) 0 kg.m3. In all the variants were tested the further additives: a) 1% of glucose, b) 50 kg N.ha-1 of Mineral nitrogen, c) 1% of Glucose + 50 kg N.ha-1 of Mineral nitrogen d) control (no additive). According to natural conditions, humidity have been kept at 15% in all the variants. During four weeks, mineral nitrogen leaching and soil respiration have been measured in each flowerplot. Respiration has been quantified four times every time while moistening containers and alkaline soda lime has been used as a sorbent. The amount of CO 2 increase has been measured with the sorbent. Leaching of mineral nitrogen has been quantified by ion exchange resins (IER). IER pouches have been placed on the bottom of each container, and after completion of the experiment mineral nitrogen leaching has been evaluated by distillation and titration method. Results from respiration have shown statistically significant differences between the variants. According to control, soil with polymers have shown significant difference when comparing respiration with independence of the additive used. CO 2 production in the first week has exceeded the sum of the outputs of the following weeks. Mineral nitrogen leaching measurement has shown statistically significant differences. The lowest leaching has been occurred in control variant, while the highest in variant containing only the addition of mineral nitrogen. Research results may conclude that the biological part of the test soil is not limited by a lack of components, the only thing that suppresses its activity is the lack of moisture. After moistening it leads to a rapid growth of soil activity, without causing the nutrients loss. Besides, Terracottem has affected soil activity neither positively nor negatively, but it considers being a suitable tool for reducing the drought impact in arid and semi-arid areas.

Improved salinity management for the Nebine / Mungallala / Wallam catchment

The low stream salinity naturally in the Nebine-Mungallala Catchment, extent of vegetation retention, relatively low rainfall and high evaporation indicates that there is a relatively low risk of rising shallow groundwater tables in the catchment. Scalding caused by wind and water erosion exposing highly saline sub-soils is a more important regional issue, such as in the Homeboin area. Local salinisation associated with evaporation of bore water from free flowing bore drains and bores is also an important land degradation issue particularly in the lower Nebine, Wallam and Mungallala Creeks. The replacement of free flowing artesian bores and bore drains with capped bores and piped water systems under the Great Artesian Basin bore rehabilitation program is addressing local salinisation and scalding in the vicinity of bore drains and preventing the discharge of saline bore water to streams. Three principles for the prevention and control of salinity in the Nebine Mungallala catchment have been identified in this review: • Avoid salinity through avoiding scalds – i.e. not exposing the near-surface salt in landscape through land degradation; • Riparian zone management: Scalding often occurs within 200m or so of watering lines. Natural drainage lines are most likely to be overstocked, and thus have potential for scalding. Scalding begins when vegetation is removed, and without that binding cover, wind and water erosion exposes the subsoil; and • Monitoring of exposed or grazed soil areas. Based on the findings of the study, we make the following recommendations: 1. Undertake a geotechnical study of existing maps and other data to help identify and target areas most at risk of rising water tables causing salinity. Selected monitoring should then be established using piezometers as an early warning system. 2. SW NRM should financially support scald reclamation activity through its various funding programs. However, for this to have any validity in the overall management of salinity risk, it is critical that such funding require the landholder to undertake a salinity hazard/risk assessment of his/her holding. 3. A staged approach to funding may be appropriate. In the first instance, it would be reasonable to commence funding some pilot scald reclamation work with a view to further developing and piloting the farm hazard/risk assessment tools, and exploring how subsequent grazing management strategies could be incorporated within other extension and management activities. Once the details of the necessary farm level activities have been more clearly defined, and following the outcomes of the geotechnical review recommended above, a more comprehensive funding package could be rolled out to priority areas. 4. We recommend that best-practice grazing management training currently on offer should be enhanced with information about salinity risk in scald-prone areas, and ways of minimising the likelihood of scald formation. 5. We recommend that course material be developed for local students in Years 6 and 7, and that arrangements be made with local schools to present this information. Given the constraints of existing syllabi, we envisage that negotiations may have to be undertaken with the Department of Education in order for this material to be permitted to be used. We have contact with key people who could help in this if required. 6. We recommend that SW NRM continue to support existing extension activities such as Grazing Land Management and the Monitoring Made Easy tools. These aids should be able to be easily expanding to incorporate techniques for monitoring, addressing and preventing salinity and scalding. At the time of writing staff of SW NRM were actively involved in this process. It is important that these activities are adequately resourced to facilitate the uptake by landholders of the perception that salinity is an issue that needs to be addressed as part of everyday management. 7. We recommend that SW NRM consider investing in the development and deployment of a scenario-modelling learning support tool as part of the awareness raising and education activities. Secondary salinity is a dynamic process that results from ongoing human activity which mobilises and/or exposes salt occurring naturally in the landscape. Time scales can be short to very long, and the benefits of management actions can similarly have immediate or very long time frames. One way to help explain the dynamics of these processes is through scenario modelling.

Phosphorus as a limiting factor on sustainable greywater irrigation

Water reuse through greywater irrigation has been adopted worldwide and has been proposed as a potential sustainable solution to increased water demands. Despite widespread adoption there is limited domestic knowledge of greywater reuse, there is no pressure to produce lowlevel phosphorus products and current guidelines and legislation, such as those in Australia, may be inadequate due to the lack of long-term data to provide a sound scientific basis. Research has clearly identified phosphorus as a potential environmental risk to waterways from many forms of irrigation. To assess the sustainability of greywater irrigation, this study compared four residential lots that had been irrigated with greywater for four years and adjacent non-irrigated lots that acted as controls. Each lot was monitored for the volume of greywater applied and selected physic-chemical water quality parameters and soil chemistry profiles were analysed. The non-irrigated soil profiles showed low levels of phosphorus and were used as controls. The Mechlich3 Phosphorus ratio (M3PSR) and Phosphate Environmental Risk Index (PERI) were used to determine the environmental risk of phosphorus leaching from the irrigated soils. Soil phosphorus concentrations were compared to theoretical greywater irrigation loadings. The measured phosphorus soil concentrations and the estimated greywater loadings were of similar magnitude. Sustainable greywater reuse is possible; however incorrect use and/or a lack of understanding of how household products affect greywater can result in phosphorus posing a significant risk to the environment.

水稻木质素在土壤中的降解及其效应

本论文主要以化感水稻PI312777和非化感水稻辽粳-9木质素为试验材料，通过土壤添加实验，分析水稻木质素降解产生的酚酸种类与含量，评价其降解产物对稗草及微生物的影响；同时测定水稻不同生育时期稻田土壤中酚酸种类和含量的变化。结果表明： (1)木质素降解过程中会释放多种酚酸，各酚酸含量变化显著。随着木质素的降解，释放出的酚酸含量呈现先升高再降低的趋势。木质素降解产生的酚酸含量的变化与其是否来自化感水稻品种无关，而与木质素的浓度有关。 (2)木质素对稗草产生显著抑制效果，且抑制程度与木质素的浓度呈负相关关系。木质素对稗草的抑制程度随培养时间呈现增强-减弱-增加的变化趋势。木质素对稗草的影响与其来源的水稻品种特性无关。 (3)培养到第四周木质素对细菌和放线菌产生显著抑制活性，并且对细菌和放线菌抑制效应随培养时间增加而减弱。木质素对细菌和放线菌的影响与其来源的水稻品种和浓度无关。在整个共培养时间内，木质素对真菌种群数量产生显著的影响。在其培养的前30天，随培养时间增加其促进作用增强，而后促进作用减弱。木质素的添加量及其来源的水稻品种均对真菌的种群数量产生显著影响。 (4)田间条件下，土壤中酚酸的含量随水稻生育期和品种的不同而存在显著差异。水稻幼苗期田间土壤中酚酸的含量较多，成熟期最少。而三种土壤游离态酚酸—香草酸、4-香豆酸和阿魏酸在水稻不同生育时期田间土壤中的含量变化不大。生测显示,田间土壤中的游离酚酸含量在水稻整个生育时期都低于酚酸对稗草生长的抑制浓度。稻田土壤中的酚酸含量与水稻品种及生育时期无关。

土壤侵蚀退化研究进展

从土壤物理退化、化学退化和生物学退化等3个方面回顾了国内外的土壤退化过程研究的历史与现状，全面总结了国内外在土壤侵蚀退化形成的过程、机理、影响因素以及评价土壤退化的指标方法等方面的最新研究进展，最后提出了土壤退化过程和防治方法研究中存在的主要问题，并从多学科交叉的角度和土壤侵蚀退化机理研究及定量动态监测角度来展望土壤侵蚀退化研究的进一步发展方向。

黄土高原土壤干层初步研究

在详细描述土壤干层现象和类型的基础上 ,分析了土壤干层的成因 ,即低降水高蒸发、水土流失、植被类型选择失当、群落生产力过高和群落密度过大等 ,指出土壤干层的危害主要表现为使局部小气候环境趋于旱化、土地退化、植被生长衰退、天然下种更新不良及加大造林难度等 ,最后提出了缓解土壤干层对黄土高原生态环境的恢复和重建的意义和重要性。

喀斯特丘原区石漠化过程中土壤退化的表征与分析——以清镇王家寨小流域为例

喀斯特石漠化问题是贵州省乃至整个西南地区最大的生态环境问题，对当地的经济发展和人类生存造成极大障碍，虽然石漠化问题日益受到重视，但生态建设超前、基础研究落后却是不争的事实。石漠化过程中土壤性质变化、人为干扰方式对土壤质量的影响、土壤——植被系统的关联退化是石漠化研究中非常重要的基础理论，可作为石漠化等级划分的参考，也是石漠化治理及生态恢复的重要依据。本文以王家寨小流域为研究区域，对喀斯特石漠化过程中土壤、植被的退化进行定量分析研究，以找出石漠化过程中土壤质量演变的规律以及人为干扰对其产生的影响，初步探讨了土壤——植被系统的退化特征及其协变关系，分析了坡位等流域内部影响因素对土壤质量退化的影响，并采用土壤退化指数对其进行评价，取得了以下几点认识： （1）研究区内土壤基本特征为：土层浅薄，剖面层次分化不明显，土壤呈中性至微碱性反应，CEC及盐基饱和度较高，有机质、氮素含量丰富，C/N较低，供氮潜力高，土壤营养元素较为丰富，但P、K、Na相对不足。 （2）石漠化过程中，土壤容重变大，孔隙度降低，土壤质地粘重，水稳性大团聚体减少，小团聚体相对增加；土壤有机质流失，全N含量降低，土壤中易于移动的营养元素，如P、K、Na、Ca、Mg等含量随石漠化程度加深而降低，难于移动的元素，如Fe、Mn、Cu等则表现出增加的趋势，土壤pH及CEC也基本呈降低趋势，土壤养分有效性降低，各元素有效态含量均下降，仅有效Mn例外。 （3）土壤剖面构型多为A—D，A—C型，也有少数已形成较为明显的心土层。土体A层营养状况相对较好。石漠化过程中，粘粒含量增加，尤其在土体中下部聚集更为明显，地球化学性质相对活跃的元素在土壤上、下层含量均降低，流失量上层大于下层，而相对较稳定的元素聚集量下层大于上层，土壤表层CEC降低，下层升高，有效Mn含量增加，有效铁含量仅在土壤下层增加，其他元素均降低。 （4）石漠化过程中土壤理化性质恶化与植被退化相互促进、互为因果，形成一种相互反馈的恶性循环。随石漠化程度加深，植被演替趋势为乔→草灌→灌草→稀疏灌草，其特征主要表现为：植被覆盖度较低，群落结构简单，富N、Ca、Mg，缺P、K、Na。通过对比及相关性分析，得出植物生长的主要限制因子为P、K、Na、Mn、Zn。 （5）石漠化经过一定时期发展，地势较平坦的区域易形成黄色石灰土，其理化性质介于石灰土与黄壤之间，随石漠化发展土壤性质的变化规律也更为明显；而地势陡峭，地形崎岖的区域则易在负地形中残留土壤形成年轻的黑色石灰土，其理化性质较好，剖面没有黄色石灰土分化明显，土壤性质也差异极大，因而在石漠化等级划分及综合治理上应予以区分，不应一概而论。 （6）筛选出土壤退让评价指标并赋予权重，主要包括平均土厚、有机质、全氮、pH、CEC、容重、密度、颗粒组成、水稳性团聚体、全磷、全钠、全钙、全镁、全铜、碱解氮、速效钾、有效铁、有效铜、有效锌等。评价结果显示土壤退化与石漠化发展具有同步性，其中化学性质的退化较物理性质明显，仅石漠化初期表现出相对较强的物理性质退化。轻度至中度是土壤退化最敏感的阶段，退化最为强烈，应予以重点防治。 （7）不同的人为干扰方式对土壤质量产生的影响不同，开垦和放牧作用下的土壤较为粘重，容重、密度都较樵采作用下的土壤大。通过退化评价指数可知，开垦和放牧影响下的土壤退化最为严重，主要表现为开垦、放牧后土壤养分的大量消耗和流失，土壤化学性质的变异引起土壤质量强烈恶化，而樵采和火烧则在一定程度上通过改善土壤的化学性质使退化延缓，因而土壤质量相对较好。 （8）小流域的研究方法虽然可以排除各种外在因素影响，但却无法排除流域内的影响因素，如坡位、坡度、坡向、坡形等。研究结果显示坡位对土壤密度、容积含水率、气相率、水稳性团聚体、C/N、元素全量及有效态含量都有一定影响。土壤退化指数显示土壤退化程度上坡>中坡>下坡。

The Application of Geophysics to a Number of Threats to Irish Soils

In its 2002 Communication "Towards a Thematic Strategy on Soil Protection" (COM 2002, 179), the Commission identified the main threats to which soils in the EU are confronted. More recently, the EU published a Thematic Strategy for Soil Protection (COM 2006, 231) as well as a proposal for a Soil Framework Directive (COM 2006, 232). The proposed directive, if implemented, will require states to identify a number of specific soil degradation processes that have occurred or are likely to occur in the near future. This project applies a number of recent geophysical developments, in addition to a range of traditional approaches, to a number of areas of Irish concern to Thematic Strategy for Soil Protection and the proposed Soil Framework Directive.

Sustainable Watershed Management: Illusion or Reality? A case of Kerala State in India

Soil erosion is more detrimental and affects the chemical, physical and biological properties of the soil. Degradation of soil and water resources is a worldwide problem. Over the next two decades, it is expected that the world will need 17% more water to grow food for the increasing population in developing countries and that total water use will increase by 40%. The total land area subjected to human-induced soil degradation is estimated as 20 x 106 (km)2 Hence conservation of soil and water is essential for the subsistence of life. This can be made possible through sustainable watershed management. This thesis aims at investigating the condition under which sustainable watershed management is possible in Kerala, in South India. The research has been carried out in three stages. In the first stage a conceptual framework is formulated (Chapter 3) based on the relevant literature (Chapter 2) in the field of watershed management. In the second stage this framework is applied to two existing case studies in Kerala State (Chapter 4). In the third stage, the methodology is used to test out geo textile innovation (Chapter 5) in two field experiments (Chapter 6).

Modelling of global crop production and resulting N2O emissions

Landwirtschaft spielt eine zentrale Rolle im Erdsystem. Sie trägt durch die Emission von CO2, CH4 und N2O zum Treibhauseffekt bei, kann Bodendegradation und Eutrophierung verursachen, regionale Wasserkreisläufe verändern und wird außerdem stark vom Klimawandel betroffen sein. Da all diese Prozesse durch die zugrunde liegenden Nährstoff- und Wasserflüsse eng miteinander verknüpft sind, sollten sie in einem konsistenten Modellansatz betrachtet werden. Dennoch haben Datenmangel und ungenügendes Prozessverständnis dies bis vor kurzem auf der globalen Skala verhindert. In dieser Arbeit wird die erste Version eines solchen konsistenten globalen Modellansatzes präsentiert, wobei der Schwerpunkt auf der Simulation landwirtschaftlicher Erträge und den resultierenden N2O-Emissionen liegt. Der Grund für diese Schwerpunktsetzung liegt darin, dass die korrekte Abbildung des Pflanzenwachstums eine essentielle Voraussetzung für die Simulation aller anderen Prozesse ist. Des weiteren sind aktuelle und potentielle landwirtschaftliche Erträge wichtige treibende Kräfte für Landnutzungsänderungen und werden stark vom Klimawandel betroffen sein. Den zweiten Schwerpunkt bildet die Abschätzung landwirtschaftlicher N2O-Emissionen, da bislang kein prozessbasiertes N2O-Modell auf der globalen Skala eingesetzt wurde. Als Grundlage für die globale Modellierung wurde das bestehende Agrarökosystemmodell Daycent gewählt. Neben der Schaffung der Simulationsumgebung wurden zunächst die benötigten globalen Datensätze für Bodenparameter, Klima und landwirtschaftliche Bewirtschaftung zusammengestellt. Da für Pflanzzeitpunkte bislang keine globale Datenbasis zur Verfügung steht, und diese sich mit dem Klimawandel ändern werden, wurde eine Routine zur Berechnung von Pflanzzeitpunkten entwickelt. Die Ergebnisse zeigen eine gute Übereinstimmung mit Anbaukalendern der FAO, die für einige Feldfrüchte und Länder verfügbar sind. Danach wurde das Daycent-Modell für die Ertragsberechnung von Weizen, Reis, Mais, Soja, Hirse, Hülsenfrüchten, Kartoffel, Cassava und Baumwolle parametrisiert und kalibriert. Die Simulationsergebnisse zeigen, dass Daycent die wichtigsten Klima-, Boden- und Bewirtschaftungseffekte auf die Ertragsbildung korrekt abbildet. Berechnete Länderdurchschnitte stimmen gut mit Daten der FAO überein (R2 = 0.66 für Weizen, Reis und Mais; R2 = 0.32 für Soja), und räumliche Ertragsmuster entsprechen weitgehend der beobachteten Verteilung von Feldfrüchten und subnationalen Statistiken. Vor der Modellierung landwirtschaftlicher N2O-Emissionen mit dem Daycent-Modell stand eine statistische Analyse von N2O-und NO-Emissionsmessungen aus natürlichen und landwirtschaftlichen Ökosystemen. Die als signifikant identifizierten Parameter für N2O (Düngemenge, Bodenkohlenstoffgehalt, Boden-pH, Textur, Feldfrucht, Düngersorte) und NO (Düngemenge, Bodenstickstoffgehalt, Klima) entsprechen weitgehend den Ergebnissen einer früheren Analyse. Für Emissionen aus Böden unter natürlicher Vegetation, für die es bislang keine solche statistische Untersuchung gab, haben Bodenkohlenstoffgehalt, Boden-pH, Lagerungsdichte, Drainierung und Vegetationstyp einen signifikanten Einfluss auf die N2O-Emissionen, während NO-Emissionen signifikant von Bodenkohlenstoffgehalt und Vegetationstyp abhängen. Basierend auf den daraus entwickelten statistischen Modellen betragen die globalen Emissionen aus Ackerböden 3.3 Tg N/y für N2O, und 1.4 Tg N/y für NO. Solche statistischen Modelle sind nützlich, um Abschätzungen und Unsicherheitsbereiche von N2O- und NO-Emissionen basierend auf einer Vielzahl von Messungen zu berechnen. Die Dynamik des Bodenstickstoffs, insbesondere beeinflusst durch Pflanzenwachstum, Klimawandel und Landnutzungsänderung, kann allerdings nur durch die Anwendung von prozessorientierten Modellen berücksichtigt werden. Zur Modellierung von N2O-Emissionen mit dem Daycent-Modell wurde zunächst dessen Spurengasmodul durch eine detailliertere Berechnung von Nitrifikation und Denitrifikation und die Berücksichtigung von Frost-Auftau-Emissionen weiterentwickelt. Diese überarbeitete Modellversion wurde dann an N2O-Emissionsmessungen unter verschiedenen Klimaten und Feldfrüchten getestet. Sowohl die Dynamik als auch die Gesamtsummen der N2O-Emissionen werden befriedigend abgebildet, wobei die Modelleffizienz für monatliche Mittelwerte zwischen 0.1 und 0.66 für die meisten Standorte liegt. Basierend auf der überarbeiteten Modellversion wurden die N2O-Emissionen für die zuvor parametrisierten Feldfrüchte berechnet. Emissionsraten und feldfruchtspezifische Unterschiede stimmen weitgehend mit Literaturangaben überein. Düngemittelinduzierte Emissionen, die momentan vom IPCC mit 1.25 +/- 1% der eingesetzten Düngemenge abgeschätzt werden, reichen von 0.77% (Reis) bis 2.76% (Mais). Die Summe der berechneten Emissionen aus landwirtschaftlichen Böden beträgt für die Mitte der 1990er Jahre 2.1 Tg N2O-N/y, was mit den Abschätzungen aus anderen Studien übereinstimmt.

Shifting cultivation and forest resources in Nagaland, N.-E. India

Die vorliegende Studie befasst sich mit der Ressourcennachhaltigkeit der traditionellen, auf Wanderfeldbau beruhenden Subsistenzwirtschaft in zwei Dörfern (Hongphoy und Minyakshu) in Nagaland im Nordosten Indiens. Hierbei werden die Cerealien Produktion, der Feuerholz Konsum und auch die Folgen der intensivierten Bewirtschaftung (Forstdegradation und Bodenverarmung) im Hinblick auf das Bevölkerungswachstum diskutiert. Während das traditionelle System des Wanderfeldbaus (Jhum) seit Jahrzehnten die Bedürfnisse der ehemals kopfjagenden Stämme Nagalands erfüllte, ergab unsere Studie durch Interviews und Feldaufnahmen in 2004 und 2005, dass die steigende Nachfrage einer wachsenden Bevölkerung nach Cerealien und Feuerholz als wichtigste Ressourcen der Subsistenzwirtschaft zu einer verkürzten Brachezeit und letztlich der Degradation von Naturressourcen geführt hat: Pro Hektar Ernten sind reduziert und der Zuwachs der Holzvorräte auf den Feldern kann durch die verkürzten Bracheperioden nicht mehr die Feuerholz Nachfrage decken. Eine Nahrungsmittelknappheit wurde durch die Gegenüberstellung des Energiebedarfs einer Person und die jährlichen pro-Kopf Erntemengen und unter Berücksichtigung des Zukaufs von Reis reflektiert: In Hongphoy ergab dies ein Defizit auf Dorfebene von 130 Tonnen Reis, in Minyakshu von 480 Tonnen, die nicht durch Ernten gedeckt werden konnten. Diese Nahrungsmittelknappheit erweist sich vor allem vor dem Hintergrund eines Bevölkerungswachstums von 6.7% und marginalen Einkünften als problematisch. Für fünf verschiedene Waldformationen (zwei Brachewälder, zwei Dorfwälder und ein Naturwald) wurden die unterschiedliche Artenzusammensetzung (Diversität) und Bestandesvolumina durch Forstinventuren beschrieben. Der dem Bestandesvolumen der Brachewälder gegenübergestellte pro-Kopf Feuerholz Bedarf ergab ein jährliches Defizit von 1,81m³ in Hongphoy und 0.05m³ in Minyakshu. Der Unterschied dieses Defizits zwischen beiden Dörfern wurde in einer abweichenden Bestandesstruktur (Dominanz der N2 fixierenden Baumart Alnus nepalensis in den Brachewäldern Minyakshus) begründet. Über den erhobenen Feuerholzbedarf wurde ein theoretischer pro-Kopf Flächenbedarf an Brachewald errechnet, der nötig wäre um den gesamten Feuerholz Bedarf innerhalb des Wanderfeldbau Systems zu decken. Das daraus resultierende Defizit wurde mit den Feuerholzvolumina der Dorfwälder und des verbliebenen Naturwalds gegenüber gestellt. Hieraus ergibt sich die Bedeutung der Feuerholzernte und des Wanderfeldbau als Ursache für die fortschreitende Entwaldung und Forstdegradation in Nagaland. Mit Hilfe dieser Informationen und aktuellen Angaben zum Bevölkerungswachstum werden die Ergebnisse anhand einschlägiger Literatur diskutiert und letztendlich die Nachhaltigkeit und Tragfähigkeit des Wanderfeldbau Systems in dieser Region bestimmt. Mögliche Verbesserungsstrategien um der zunehmenden Ressourcendegradation zu begegnen, werden andiskutiert.

Effects of activated charcoal and quebracho tannins on the turnover of goat manure in irrigated organic agriculture of the subtropics

Agriculture in semi-arid and arid regions is constantly gaining importance for the security of the nutrition of humankind because of the rapid population growth. At the same time, especially these regions are more and more endangered by soil degradation, limited resources and extreme climatic conditions. One way to retain soil fertility under these conditions in the long run is to increase the soil organic matter. Thus, a two-year field experiment was conducted to test the efficiency of activated charcoal and quebracho tannin extract as stabilizers of soil organic matter on a sandy soil low in nutrients in Northern Oman. Both activated charcoal and quebracho tannin extract were either fed to goats and after defecation applied to the soil or directly applied to the soil in combination with dried goat manure. Regardless of the application method, both additives reduced decomposition of soil-applied organic matter and thus stabilized and increased soil organic carbon. The nutrient release from goat manure was altered by the application of activated charcoal and quebracho tannin extract as well, however, nutrient release was not always slowed down. While activated charcoal fed to goats, was more effective in stabilising soil organic matter and in reducing nutrient release than mixing it, for quebracho tannin extract the opposite was the case. Moreover, the efficiency of the additives was influenced by the cultivated crop (sweet corn and radish), leading to unexplained interactions. The reduced nutrient release caused by the stabilization of the organic matter might be the reason for the reduced yields for sweet corn caused by the application of manure amended with activated charcoal and quebracho tannin extract. Radish, on the other hand, was only inhibited by the presence of quebracho tannin extract but not by activated charcoal. This might be caused by a possible allelopathic effect of tannins on crops. To understand the mechanisms behind the changes in manure, in the soil, in the mineralisation and the plant development and to resolve detrimental effects, further research as recommended in this dissertation is necessary. Particularly in developing countries poor in resources and capital, feeding charcoal or tannins to animals and using their faeces as manure may be promising to increase soil fertility, sequester carbon and reduce nutrient losses, when yield reductions can be resolved.

The role of organic farming for food security: local nexus with a global view

A convergence of factors has made food security one of the most important global issues. It has been the core concept of the Milan Expo 2015, whose title, Feeding the Planet, Energy for Life, embodied the challenge to provide the world’s growing population with a sustainable, secure supply of safe, nutritious, and affordable high-quality food using less land with lower inputs. Meeting the food security agenda using current agricultural production techniques cannot be achieved without serious degradation to the environment, including soil degradation, loss of biodiversity and climate change. Organic farming is seen as a solution to the challenge of sustainable food production, as it provides more nutritious food, with less or no pesticide residues and lower use of inputs. A limit of organic farming is its restricted capability of producing food compared to conventional agriculture, thus being an inefficient approach to food production and to food security. The authors maintain, on the basis of a scientific literature review, that organic soils tend to retain the physical, chemical and biological properties over the long term, while maintaining stable levels of productivity and thereby ensuring long-term food production and safety. Furthermore, the productivity gap of organic crops may be worked out by further investment in research and in particular into diversification techniques. Moreover, strong scientific evidence indicates that organic agricultural systems deliver greater ecosystem services and social benefits.

Environment, resource sustainability and sustainable behaviour: exploring perceptions of students in South West Victoria

The movement toward a sustainable future has begun in many parts of the world, as the seriousness of the environmental problems faced by the planet become more widely recognised. Waste reduction, improved efficiency of energy use, water saving devices and changes in modes of transport are the first steps in the transition to a sustainable future. The students of today will be the decision makers of tomorrow and, thus, can have a significant effect on future development and the environmental
impacts of that development. If students today are to become active participants in the environmental decision-making process, education for sustainability becomes a key component in ensuring sustainable futures. There is a need to establish data describing students’ attitudes toward environmental and resource sustainability issues so that challenges to implementing sustainable development policy can be better recognised. The aims of this study were to identify the perceptions of students in
the south west region of Victoria regarding environment and resource sustainability, and to identify their level of participation in sustainable behaviours. A survey of students has found that global environmental issues perceived by students as being in urgent need of attention were access to freshwater, loss of tropical rainforest and exhaustion of natural resources. At the local level the most urgent issues identified were water pollution, salinization and soil degradation, and clearing of native vegetation. Students perceive that Australians are overusing natural resources. They indicated particular concern for the sustainability of fossil fuels, water, coastal environments and fisheries resources. The results of this study indicate that students are responding to concerns for the environment and resource sustainability by embracing some forms of sustainable behaviour. However, as educators we need to ensure that
the link is made between environment and resource sustainability and the implementation of policies that will further encourage sustainable behaviour.