Modelling interactions between scavenger behaviour and farming practices: Impacts on scavenger population and ecosystem service efficiency

Long term conservation of ecosystem services requires a deep understanding of their basic processes and the development of tools to assess the effects of human practices on their efficiency. As an example of recycling service, we focus on the consumption of livestock carcasses by obligate scavengers, taking the case of vultures which face a dramatic decline worldwide. We investigate whether maintaining this recycling service through individual feeding stations called light feeding stations in contrast to aggregated resource on heavy feeding stations can meet the double objectives of vulture conservation and service efficiency. We built a spatially explicit multi-agent model to investigate the long term effects of livestock farmers practices on both the recycling service efficiency for farmers and vulture population carrying capacity including: (i) carcass disposal practices that drive the quantity and spatial distribution of resources for vultures and (ii) temporal distribution of livestock mortality due to economic choices that drive the dynamics of resources for vultures. In addition, we examine various scenarios related to vulture feeding behaviour - i.e. central place vs. random foraging and contest vs. scramble intraspecific competition - that may play a role in the vulture carrying capacity and recycling service efficiency. When accounting for vulture central place foraging, we found that favouring the use of light feeding stations instead of heavy feeding station does not affect vulture population carrying capacity and increases the number of farmer for which vulture service is optimal. The increase of light feeding station users poorly affects the number of farmers for which vulture service is optimal in contrast to results obtained with a vulture random foraging behaviour. Both of the recycling service efficiency and the vulture carrying capacity vary with the kind of intraspecific competition and with the seasonal distribution of livestock mortality. Livestock mortality distributions with a seasonal peak of mortality result in a mismatch between vulture food requirement and farmers needs for carcass removal. Finally we raise several points on the relevance of light feeding stations as a sustainable management for vulture conservation and for the recycling service and discuss the potential implications of seasonal scarcity of resources due to farming economic constraints.     

On the choice of farm management practices after the reform of the Common Agricultural Policy in 2003

The Common Agricultural Policy (CAP) was fundamentally reformed in 2003. From 2005, farmers will receive decoupled income support payments instead of production premiums if basic standards for environment, food safety, animal health and welfare are met. Farmers are likely to adjust production and management practices to the new policy framework. We describe how this reform fits into the EU strategy of making agricultural production more environmentally friendly by concentrating on the financial aspects of the reforms. Using an agricultural sector model for Austria, we show that the reform will further decrease agricultural outputs, reduce farm inputs, lessen nitrogen surpluses and make environmentally friendly management practices more attractive for farmers.     

水肥管理对热带地区双季稻田CH4和N2O排放的影响

水稻土被广泛认为是甲烷（CH₄）和氧化亚氮（N₂O）主要排放源,深入研究不同水肥管理条件下热带地区双季稻田CH₄和N₂O的排放特征,对补充我国双季稻田温室气体排放研究的不足意义重大.本研究设置8个处理：常规灌溉-施磷钾肥（D-PK）、常规灌溉-施氮磷钾肥（D-NPK）、常规灌溉-施氮磷钾+有机肥（D-NPK+M）、常规灌溉-施有机肥（D-M）、长期淹水-施磷钾肥（F-PK）、长期淹水-施氮磷钾肥（F-NPK）、长期淹水-施氮磷钾+有机肥（F-NPK+M）和长期淹水-施有机肥（F-M）.采用密闭静态箱-气相色谱法测定双季稻田CH₄和N₂O排放量,测定水稻产量和估算全球增温潜势（GWP）及温室气体排放强度（GHGI）.结果表明：①早稻季和晚稻季CH₄累积排放量分别为10.3~78.9 kg·hm^-2和84.6~185.5 kg·hm^-2.与F-PK和F-NPK处理相比,早稻季F-NPK+M和F-M处理显著增加CH₄累积排放量.同一施肥条件下,长期淹水处理CH₄累积排放量高于常规灌溉处理.灌溉和施肥极显著影响早稻季CH₄累积排放量.②早稻季和晚稻季N₂O累积排放量分别为0.18~0.76 kg·hm^-2和0.15~0.58 kg·hm^-2.与F-PK处理相比,早稻季F-NPK处理N₂O累积排放量显著增加;与D-PK相比,D-NPK、D-NPK+M和D-M处理显著增加N₂O累积排放量.与F-PK相比,晚稻季长期淹水其它处理N₂O累积排放量显著增加;与D-PK处理相比,D-NPK和D-M处理N₂O累积排放量显著增加.施肥极显著影响早稻季N₂O排放;灌溉和施肥极显著影响晚稻季N₂O排放.③早稻和晚稻产量分别为7310.7~9402.4 kg·hm^-2和3902.8~7354.6 kg·hm^-2,且F-NPK和F-M处理下早稻产量显著高于F-PK和D-NPK、D-PK和D-NPK处理.与PK处理相比,同一灌溉条件下其余3种施肥处理均显著增加晚稻产量.早稻季GWP和GHGI分别为580.8~2818.5kg·hm^-2和0.08~0.30 kg·kg^-1.与F-PK处理相比,常规灌溉条件下早稻季各施肥处理间GWP无显著性差异;但长期淹水条件下F-NPK+M和F-M处理GWP均显著增加.早稻季F-NPK+M和F-M处理GHGI显著高于其它处理.晚稻季GWP和GHGI分别为3091.6~6334.2 kg·hm^-2和0.50~1.23 kg·kg^-1.灌溉显著影响早稻和晚稻季GWP和GHGI,施肥对晚稻季GWP和GHGI的影响不显著.④土壤NH₄⁺-N含量和5 cm土温均与CH₄排放呈极显著负相关,pH与CH₄排放呈极显著正相关,但与N₂O排放呈显著负相关.土壤NH₄⁺-N和NO₃^--N含量与N₂O排放呈极显著负相关.综合作物产量、GWP和GHGI考虑,D-NPK+M可推荐为当地最优的减排稳产的水肥管理模式.     

Accumulation and Chemical Fractionation of Heavy Metals in Andisols after a Different, 6-year Fertilization Management (8 pp)

Goal, Scope and Background Andisols are widespread in Japan and have some special properties such as high anion exchange capacity, low bulk density, and high organic matter content, which might influence the accumulation or chemical fractionation of heavy metals. However, few such data exist in Japanese andisols. The primary objective of this study was to investigate the distribution and chemical fractions of Cu, Zn, Ni, and Cr in the soil profiles and subsequently to assess their potential environmental hazard. Materials and Methods Soil samples were taken from a field experiment conducted on Japanese andisols, which had received either swine compost or chemical fertilizers for 6 years. Concentrations of Cu, Zn, Ni, and Cr were determined for all of the obtained extract solutions by ICP-AES. Results and Discussion Considerably higher total concentrations of Cu and Zn were observed in the top 20 cm layer of the compost-amended soil, relative to the unfertilized soil, while chemical fertilizers had little effect. Application of the swine compost increased the concentrations of Cu and Zn, but not Ni and Cr, in all fractions in the top 20 cm layer. The greatest increase in the organically bound fraction (OM) Cu and dilute acid-exchangeable fraction (DAEXCH) Zn was observed. This suggests that Cu and Zn are potentially bioavailable and mobile in the andisol profiles after 6-year consecutive applications of the swine compost. On the other hand, distribution of Cu, Zn, Ni and Cr among various soil fractions was generally unaffected by chemical fertilizers. Conclusions We observed that 6-year consecutive applications of the swine compost led to an increase in total metals of Cu and Zn, as well as their all-chemical fractions, in the top 20 cm soil layers. Potential hazard of heavy metals, especially of Cu and Zn, as a result of the use of swine compost on andisols, must be taken into account. Recommendations and Outlook The long-term effect of the accumulation of heavy metals, particularly Cu and Zn, in various plant tissues and soils, as well as their potential risk to surface water via runoff and groundwater via leaching, needs to be carefully considered. Further investigations in the long-term experiments are therefore necessary. - Abbreviations. EXCH, exchangeable fraction of metals; DAEXCH, dilute acid-exchangeable fraction of metals; FeMnOX, iron and manganese-oxide-bound fraction; OM, organically-bound fraction; RESD, residual fraction. COMPOST, SRNF, RANF, and CONTROL stand for compost (from swine wastes), slow-release nitrogen fertilizer (coated urea), readily available nitrogen fertilizer (including NH4-N, P, and K fertilizers), and no fertilizer application, respectively.     

State Forest Practice Regulatory Programs: An Approach to Implementing Ecosystem Management on Private Forest Lands in the United States

/ Implemented in the context of a long history ofintense public debate, forestry practices applied on private forest land areregulated in some form by 38 states. State regulatory activities can involvemany agencies implementing numerous regulatory laws, a single forestry agencyadministering a comprehensive regulatory program, or a combination of thetwo. Regulatory programs are designed to protect resources such as soils,water, wildlife, and scenic beauty. Program administration often involvesrule promulgation, harvest plan reviews, coordination of interagency reviews,and pre- and postharvest on-site inspections. Forest practice rules usuallyfocus on reforestation, forest roads, harvest procedures, and wildlifehabitat protection. Emerging regulatory trends include growth of multiagencyregulatory authority and associated jurisdictional conflicts, increasedtendencies to narrowly specify standards in statutes and rules, emergence ofcontingent regulations, growing sensitivity to processes enabling theadoption of new forest practice technologies and an ability to addresscumulative effects, interest in collaborative rule-making stemming fromheightened concern over legalization of administration processes, and growingconcern over the constitutional foundations for regulatory programs and thegovernment and private sector cost of implementing such programs.KEY WORDS: Ecosystem management; Forestry practices; Private landowners;Regulatory programs; State government     

SPRING RUNOFF AND DRAINAGE N AND P LOSSES FROM HOG-MANURED CORN1

ABSTRACT: A two-year study was conducted to assess the effect of hog manure on the losses of nitrogen and phosphorus in runoff and drainage from grain-corn (Zea mays L.) plots, and the importance of spring versus annual loads. Treatments consisted of mineral N-P-K fertilizer applied at rates of 152 kg N ha^-1, 35 kg P ha^-1, and 86 kg K ha^-1; and hog (Sus scrofa domestica L.) manure applied preplant or post-emergence (six-to-eight leaf stage), at 152 kg N ha^-1, 39 kg P ha^-1, and 112 kg K ha^-1. The plots were rototilled (7 cm depth) in spring to incorporate fertilizer and preplant hog manure, and fall chisel-plowed (15 cm depth) to incorporate chopped corn residues. They were arranged in a completely randomized plot design. Flow volumes and nutrient levels in runoff and drainage waters were monitored year round but occurred mainly during the snowmelt (March 25-April 9), and post.snowmelt (April 10-May 13) periods. Of the total amount of water lost during snowmelt, 90 percent was in runoff, while 92 percent occurred as drainage in the post-snowmelt period. Sixty-five percent of the total annual volume of water lost was lost during these two periods as runoff and drainage. Treatments did not affect the annual snowmelt or post-snowmelt N and P loads. Total annual loads averaged 8.0 kg TKN ha^-1, 1.8 kg NH₄-N ha^-1, 43 kg NO₃-N ha^-1, 0.4 kg TP ha^-1, and 0.15 kg PO₄-P ha^-1. Spring (snowmelt and ost-snowmelt) runoff and drainage loads averaged 2.9 kg TKN ha^-1, 1.2 kg NH₄-N ha^-1, 18 kg NO₃-N ha^-1, 0.25 kg TP ha^-1, and 0.04 kg PO₄-P ha^-1, which were 40 percent to 70 percent of the yearly nutrient loads. Therefore, the hog manure management systems examined were of no greater threat to the environment than mineral fertilizers. However, spring N and P losses do represent an important part of the annual nutrient loss budget, even with conservation practices.     

不同施肥处理对东北黑土温室气体排放的短期影响

以东北耕作黑土为对象,在25℃和60%最大持水量(WHC)条件下开展为期7 d的室内培养试验,研究了不同施肥处理对东北黑土温室气体排放的短期影响.结果表明,与不施肥对照处理相比,单施氮肥对土壤呼吸释放的CO_2没有影响,而在施用氮肥的基础上配施有机物料使得CO_2排放量提高了一个数量级,氮肥配施秸秆对CO_2排放的促进效果大于氮肥配施猪粪.短期培养时间内施用氮肥对N_2O排放没有显著影响,硝化作用是对照处理和单施氮肥处理土壤排放N_2O的主要过程.与单施氮肥处理相比,氮肥配施猪粪或秸秆显著促进了反硝化过程,使得N_2O排放量提高了两个数量级,氮肥配施秸秆处理的N_2O排放量显著大于氮肥配施猪粪处理.单施氮肥抑制了CH_4的排放,表现为对CH_4的微量吸收,而氮肥配施猪粪或秸秆则显著促进了CH_4的排放.     

长期施肥对不同深度稻田土壤碳氮水解酶活性的影响特征

与稻田土壤碳周转密切相关的酶活性是评价土壤肥力和肥料管理的重要指标.本研究选取秸秆还田(ST)、化肥(NPK)和不施肥(CK)的长期定位试验田,以10 cm的间距分段采集土壤剖面0~40 cm范围内的新鲜土样,利用96微孔酶标板荧光分析法,测定参与土壤碳氮转化过程关键酶β-1,4-葡萄糖苷酶(BG)和β-1,4-N-乙酰氨基葡萄糖苷酶(NAG)活性,探讨不同施肥措施对不同深层土壤酶活的影响.结果表明,相比不施肥的土壤,施用化肥和秸秆土壤的BG酶活性分别提高了35%~118%和55%~342%;NAG酶活性分别提高了9%~30%和102%~484%.同时,随着土层深度的增加,土壤酶活性逐渐降低,0~20 cm深层土壤酶活性显著高于20~40 cm深层土壤.在不同施肥措施中秸秆还田可高程度影响稻田深层土壤.RDA分析表明土壤碳氮含量主要与0~20 cm的土壤酶活性有显著的正相关关系,与20~40 cm的土壤酶活性呈负相关关系.综上所述,随着土壤深度增加土壤微生物量和土壤酶活性显著降低.长期施肥显著提高了不同深层土壤生物量和土壤酶活性,其中秸秆还田作用尤为突出.因此,合理的秸杆还田有利于改善稻田深层土壤肥力,优化农田土壤养分循环,为作物生长提供良好的土壤环境.     

Conservation practices in U.S. agriculture and their impact on carbon sequestration

Increase in the use of conservation practices byagriculture in the United States will enhance soilorganic carbon and potentially increase carbonsequestration. This, in turn, will decrease the netemission of carbon dioxide. A number of studies existthat calibrate the contribution of various individual,site-specific conservation practices on changes insoil organic carbon. There is a general absence,however, of a comprehensive effort to measureobjectively the contribution of these practicesincluding conservation tillage, the ConservationReserve Program, and conservation buffer strips to anchange in soil organic carbon. This paper fills thatvoid. After recounting the evolution of the use ofthe various conservation practices, it is estimatedthat organic carbon in the soil in 1998 in the UnitedStates attributable to these practices was about 12.2million metric tons. By 2008, there will be anincrease of about 25%. Given that there is asignificant potential for conservation practices tolead to an increase in carbon sequestration, there area number of policy options that can be pursued.     

Community Production Practices and Desertification in the Sahelo-Sudanian Region of Cameroon at the Turn of the Millennium

The Sahelo-Sudanian region of Cameroon extends over 10 million hectares. Varied flora and soil types, a complex mosaic of vegetation and plant communities and a diversified wild animal population are the major natural resources of this region. Desertification in the region can be related to two major known causes: a. short or long-term drought due to short-term or long-term climatic trends toward aridity; b. human activities which degrade the biological environment. Globally, humans generally have less effect on desertification than climatic change in the short run. The only strategy to fight against this situation particularly in the developing countries is to withdraw populations from the areas and to settle them elsewhere. However, most local or regional desertification processes in general, and in the Sahelo-Sudanian region in particular, are due to the misuse or unsound exploitation of natural resources by humans and their animals. Often, comprehension of the complexity of even small interactions between parameters affecting our local environment remains limited. Poor economic assessments of the long-term benefits of proper natural resource conservation and management increase the extent of the exploitation, in turn increasing the degradation process. Yet ecologically sound management of natural resources integrating indigenous knowledge and basic population interest and concern can secure restoration in several areas and sustained productivity of Sahelo-Sudanian lands.