The quandary of local people—Park relations in Nepal's Royal Chitwan National Park

This paper analyzes five major causes of park-people conflicts that have occurred in Nepal's Royal Chitwan National Park. The causes include illegal transactions of forest products from the park, livestock grazing in the park, illegal hunting and fishing, crop damage, and threats to human and animal life caused by wild animals from the park. The conflicts indicate a reciprocal relationship between the park and local people. They reflect the attitudes of local people and representatives of the park authority whose priorities and objectives largely diverge. The results show that people settled adjacent to the park are heavily dependent on its resources. Even in places where some, albeit few alternative sources exist, local people continue to trespass the park boundary as these sources are inadequate to ensure the fulfillment of local people's resource needs. Illegal transactions of resources continue throughout the year; however, they are less intense during summer due to flooding caused by the Rapti River, which forms the park boundary towards the northern section where this study is conducted. The frequency of local people's visits to the park is mainly determined by their age, distance between homesteads and park, and volume of crop loss caused by wild animals. Crop damage is the function of size of landholding, distance, and frequency of crop raid. Local people claim that they have no intention of letting their livestock graze in the park; however, the dense vegetation of the park attracts livestock grazing on riverbanks just outside the open park boundary. Many head of livestock are killed by carnivores of the park. Human casualties are mainly caused by sloth bear (Melursus ursinus), tiger (Panthera tigris), wild pig (Sug scrofa), and rhinoceros (Rhinoceros unicornis). There had been some earlier attempts to reconcile the conflicts by offering local people different kinds of compensations; however, these were unsuccessful measures. An integrated approach is essential if efforts to resolve the park-people conflicts are to succeed. The government is in the process of launching a project that aims to resolve the inherent problems with such an approach. Suggestions are made to incorporate some key elements, such as maintaining effective communication between various parties and the potential for wildlife conservation among local people.     

酸性降水和SO2复合污染对几种蔬菜影响的研究

应用开顶式熏气装置,以油菜、白菜、波菜、青茭和蕃茄为材料,分别暴露于模拟酸性降水(pH2.8~5.6)单一污染和模拟酸性降水与SO₂复合污染的环境,测定其生理代谢、生长和产量的反应。结果指出:酸性降水和SO₂复合处理对叶绿素含量,光合强度,叶片K+外渗,叶片含糖量和相对生长速率的影响大于单独酸性降水和SO₂处理,五种蔬菜在酸性降水(pH5.6~2.8)和SO₂(0.1ppm)复合处理下,减产6.0%~29.0%,表现为协同效应,比酸性降水和SO₂单独处理的危害更大。      

Air pollution impact assessment on agroecosystem and human health characterisation in the area surrounding the industrial settlement of Milazzo (Italy): a multidisciplinary approach

In order to evaluate the impact of atmospheric pollutants emitted by the industrial settlement of Milazzo (Italy) on agriculture, sulphur dioxide and ozone levels in air were monitored and the data were used to estimate yield losses of the most widespread cultures. Trace element concentrations in crops and soils were also detected and metabolic profiles of soil microbial communities were considered. Vibrio fischeri test was used to appraise airborne pollutant ecotoxicity and epidemiological studies on causes of death distribution were carried out to characterize health state of people living in the area. All the sampling points were selected in farms on the basis of a theoretical meteo-diffusive model of industrial air pollutants. Experimental SO₂ and O₃ values mainly exceeded the threshold established by Italian and EU regulations to protect vegetation and they correspond to estimated significant crop losses. Conversely toxic element residues in soils and in agroalimentary products were generally lower than the fixed values. SO₂ and O₃ concentrations, toxic element contents and ecotoxicity levels of airborne pollutants were not related only to industrial site emissions, while the fluctuations on metabolic profiles of soil microbial communities seem to agree with the predicted deposition of xenobiotic compounds from the industrial plants. The epidemiological study evidenced a better health state of populations living in the investigated area than in the Messina province and the Sicily region but, inside the area, males living in the municipalities closest to the industrial settlement exhibited a worst health state than those in the very far ones.     

Ethylenediurea (EDU): a research tool for assessment and verification of the effects of ground level ozone on plants under natural conditions

Ethylenediurea (EDU) has been widely used to prevent ozone (O₃) injury and crop losses in crop plants and growth reductions in forest trees. Successful use requires establishing a dose/response curve for EDU and the proposed plant in the absence of O₃ and in the presence of O₃ before initiating multiple applications to prevent O₃ injury. EDU can be used to verify foliar O₃ symptoms in the field, and to screen plants for sensitivity to O₃ under ambient conditions. Despite considerable research, the mode of action of EDU remains elusive. Additional research on the mode of action of EDU in suppressing O₃ injury in plants may also be helpful in understanding the mode of action of O₃ in causing injury in plants.     

Polychlorinated dibenzo-p-dioxins and dibenzofurans emissions from open burning of crop residues in China between 1997 and 2004

Annual emissions of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) from open burning of crop residues in each province of China mainland between 1997 and 2004 were estimated to be ranged from 1.38x10(3) to 1.52x10(3) g I-TEQ/yr, with the average of 1.50+/-0.08x10(3) g I-TEQ/yr, which contributed to approximately 10% approximately 20% of the total emissions in China. The PCDD/F emissions mainly occurred in the largest crop-producing provinces, especially in those of higher economic levels. The major sources of PCDD/F emissions from open burning in China were found to be cereal residues (i.e. rice, wheat, and corn), which accounted about 70% of the total emissions. Moreover, the first-order one-variable grey differential equation model (GM (1,1) model) for annual emissions of PCDD/Fs was established based on grey system theory. The GM (1,1) model was proved to be robust to predict the annual PCDD/F emissions from crop residue field burning in forthcoming years.     

A quantitative review of the effects of biochar application to soils on crop productivity using meta-analysis

Increased crop yield is a commonly reported benefit of adding biochar to soils. However, experimental results are variable and dependent on the experimental set-up, soil properties and conditions, while causative mechanisms are yet to be fully elucidated. A statistical meta-analysis was undertaken with the aim of evaluating the relationship between biochar and crop productivity (either yield or above-ground biomass). Results showed an overall small, but statistically significant, benefit of biochar application to soils on crop productivity, with a grand mean increase of 10%. However, the mean results for each analysis performed within the meta-analysis covered a wide range (from −28% to 39%). The greatest (positive) effects with regard to soil analyses were seen in acidic (14%) and neutral pH soils (13%), and in soils with a coarse (10%) or medium texture (13%). This suggests that two of the main mechanisms for yield increase may be a liming effect and an improved water holding capacity of the soil, along with improved crop nutrient availability. The greatest positive result was seen in biochar applications at a rate of 100 t ha⁻¹ (39%). Of the biochar feedstocks considered and in relation to crop productivity, poultry litter showed the strongest (significant) positive effect (28%), in contrast to biosolids, which were the only feedstock showing a statistically significant negative effect (−28%). However, many auxiliary data sets (i.e. information concerning co-variables) are incomplete and the full range of relevant soil types, as well as environmental and management conditions are yet to be investigated. Furthermore, only short-term studies limited to periods of 1 to 2 years are currently available. This paper highlights the need for a strategic research effort, to allow elucidation of mechanisms, differentiated by environmental and management factors and to include studies over longer time frames.     

Size distribution and chemical characteristics of particles from crop residue open burning in North China

Crop residue open burning is an important emission source of ambient particles in China. This study analyzed the particle emission characteristics of crop residue open burning through combustion experiments with a novel open combustion simulation device using three typical crop straws in north China (corn, wheat, and rice). Particle samples size ranging from 0.006–9.890 µm were collected by an Electrical Low Pressure Impactor plus, a high size-resolution instrument capable of dividing particles into 14 size stages. The size distributions of organic carbon (OC), elemental carbon (EC), water-soluble ions, and elements were analyzed, and source chemical profiles were constructed for PM_0.1, PM₁, PM_2.5, and PM₁₀. The number concentration of particles was concentrated in the Aiken nuclei mode (0.006–0.054 µm), accounting for 75% of the total number, whereas the mass concentration was concentrated in the accumulation mode (0.054–0.949 µm), accounting for 85.43% of the mass loading. OC, EC, Cl^?, and K(include total K and water-soluble K) were the major chemical components of the particles, whose mass percentage distributions differed from those of other components. These five main components exhibited a bell-shaped size distribution in the 0.006–9.890 µm range, whereas the other components exhibited a U-shaped distribution. Among the chemical profiles for PM_0.1–PM₁₀, OC was the most important component at 10–30%, followed by EC at 2%–8%. The proportions of K⁺, Cl^?, and K varied substantially in different experimental groups, ranging from 0–15%, and K⁺ and Cl^? were significantly correlated (r = 0.878, α = 0.000).     

Impact of industrial effluent on growth and yield of rice (Oryza sativa L.) in silty clay loam soil

Degradation of soil and water from discharge of untreated industrial effluent is alarming in Bangladesh. Therefore, buildup of heavy metals in soil from contaminated effluent, their entry into the food chain and effects on rice yield were quantified in a pot experiment. The treatments were comprised of 0, 25%, 50%, 75% and 100% industrial effluents applied as irrigation water. Effluents, initial soil, different parts of rice plants and post-harvest pot soil were analyzed for various elements, including heavy metals. Application of elevated levels of effluent contributed to increased heavy metals in pot soils and rice roots due to translocation effects, which were transferred to rice straw and grain. The results indicated that heavy metal toxicity may develop in soil because of contaminated effluent application. Heavy metals are not biodegradable, rather they accumulate in soils, and transfer of these metals from effluent to soil and plant cells was found to reduce the growth and development of rice plants and thereby contributed to lower yield. Moreover, a higher concentration of effluent caused heavy metal toxicity as well as reduction of growth and yield of rice, and in the long run a more aggravated situation may threaten human lives, which emphasizes the obligatory adoption of effluent treatment before its release to the environment, and regular monitoring by government agencies needs to be ensured.     

Modeling water and soil quality environmental impacts associated with bioenergy crop production and biomass removal in the Midwest USA

The removal of corn stover or production of herbaceous crops such as switchgrass (Panicum virgatum) or big bluestem (Andropogon gerardii) as feedstocks for bioenergy purposes has been shown to have significant benefits from an energy and climate change perspective. There is potential, however, to adversely impact water and soil quality, especially in the United States Corn Belt where stover removal predominantly occurs and possibly in other areas with herbaceous energy crops depending upon a number of geo-climatic and economic factors. The overall goal of this research was to provide a thorough and mechanistic understanding of the relationship between stover and herbaceous crop production management practices and resulting range of impacts on soil and water quality, with a focus on eastern Iowa, USA. Comparisons of the production of herbaceous bioenergy crops to continuous corn (Zea mays L.) and corn-soybean (Glycine max L.) rotations on five different soils representative of the region were performed. Indices for total nutrient (nitrogen and phosphorus) loss to surface water and groundwater, total soil loss due to water and wind erosion, and cumulative soil carbon loss were derived to assess long-term sustainability. The Agricultural Policy/Environmental eXtender (APEX) agroecosystem model was used to quantify the sustainability indices and to generate sufficient data to provide a greater understanding of variables that affect water and soil quality than previously possible. The results clearly show the superiority of herbaceous crop production from a soil and water quality perspective. They also show, however, that compared to traditional cropping systems (e.g., corn-soybean rotations with conventional tillage), soil and water quality degradation can be reduced under certain conditions at the same time stover is removed.     

From IBM to IPM: Using individual-based models to design the spatial arrangement of traps and crops in integrated pest management strategies

The development of alternative pest-control strategies based on the spatial design of cropping systems requires a thorough understanding of the spatial links between the pest and its environment. Mechanistic models, especially individual-based models (IBMs), are powerful tools for integrating key behaviours, such as habitat selection and dispersal, with spatial heterogeneity. In this paper, we used an IBM calibrated and evaluated from real data to represent the spatial dynamics of the banana weevil in relation to the cropping system. We considered crop fragmentation and mass trapping as tools for suppressing pest numbers. Our simulation results showed that manipulating crop residues in the area surrounding each pheromone trap greatly improved trap efficiency. For an intensive banana plantation in fallow, traps were most effective when situated at the transition zone between banana area and fallow so as to maximize the trapping of weevils escaping the fallow. The model also showed that weevil numbers decreased when fragmentation of banana plantations was reduced.