Evaluation of technologies for sequestering carbon in agricultural land by using organic filter underdrains

Technology for storing carbon in the subsoil of agricultural land using organic filter materials in underdrains was evaluated as an activity for sequestering CO₂ to mitigate global warming. First, the quantity of carbon remaining in wood chips and rice husks in underdrains was determined over 11 years after construction. Moreover, the quantity of CO₂ emissions from the construction of two underdrain types was calculated. Then, a survey was conducted to investigate the effect on greenhouse gas emissions of the filter material. The results indicate that greenhouse gas emissions would not increase. The quantity of storage carbon in the wood chip filter material of underdrains during their 15-year service life was estimated to be 6.76 tCO₂eq ha⁻¹. Rice husks, in contrast, were found ineffective in storing carbon. Therefore, the selection of the filter material for underdrains is important. The value of storage carbon in the wood chip filter material is similar to the amount of carbon sequestered by no-till farming, which is now being implemented as a global warming countermeasure based on soil management in agricultural land.

     

Enhancing soil organic carbon,particulate organic carbon and microbial biomass in semi-arid rangeland using pasture enclosures

Background

Rehabilitation of degraded rangelands through the establishment of enclosures (fencing grazing lands) is believed to improve soil quality and livelihoods, and enhance the sustainability of rangelands. Grazing dominated enclosure (GDE) and contractual grazing enclosure (CGE) are the common enclosure management systems in West Pokot County, Kenya. Under CGE, a farmer owning few animals leases the enclosure to households with relatively more livestock, while GDE is where the livestock utilizing the enclosure are purely owned by the farmer. Livestock management in both systems is via the free-range system. This study evaluated the effect of enclosure management on total soil organic carbon (SOC), particulate organic carbon (POC) and microbial biomass carbon (MBC) and nitrogen (MBN) as key indicators of soil degradation at 0–40 cm depth. The two enclosure systems were selected based on three age classes (3–10, 11–20 and >?20 years since establishment) (n?=?3). The adjacent open grazing area (OGR) was used as a reference (n?=?9).

Results

Relative to OGR, the pasture enclosures significantly decreased soil bulk density and increased the concentrations of total organic C, POC, MBC and MBN compared to the degraded OGR (P?<?0.001). Significantly higher concentrations of POC and MBC was recorded in GDE than CGE (P?=?0.01). The POC accounted for 24.5–29.5% of the total SOC. MBC concentrations ranged from 32.05?±?7.25 to 96.63?±?5.31 µg C g^?1 of soil in all grazing systems, and was positively correlated with total SOC and POC (P?<?0.001). The proportional increase in POC and MBC was higher in GDE (56.6 and 30.5% respectively) compared to CGE (39.2 and 13.9% for POC and MBC respectively).

Conclusions

This study demonstrated that controlling livestock grazing through the establishment of pasture enclosures is the key strategy to enhance total SOC, POC, MBC, and MBN in degraded rangelands; a precondition for improving soil quality. Therefore, the establishment of enclosures is an effective restoration approach to restore degraded soils in semi-arid rangelands.

     

Evaluation of the water-quality dynamics in a eutrophic agricultural pond by using a one-box ecosystem model considering several algal groups

The Okubo pond is an agricultural pond located in the Itoshima area of Fukuoka Prefecture, Japan. It was constructed for irrigating a nearby cultivated area. A monitoring program from August 11 to November 26, 2008, suggested the risk of eutrophication in the water body. The high total nitrogen concentration (1.34 mg/l), high total phosphorus concentration (0.06 mg/l) and extreme oxygen depletion (2 mg/l on 5 November 2008) exceeded the Japanese standards for paddy irrigation water. Furthermore, luxuriant algal blooming in October indicated a hypereutrophic status according to the OECD (1982) criteria. In this study, a one-box ecosystem model was developed to obtain an insight into the seasonal variations in the algal concentrations and chemical components of the Okubo pond with the aims of protecting its aquatic ecosystem and maintaining its water quality. The model was based on a completely mixed system and included 12 water-quality indices: green algae, blue-green algae, diatoms and dinoflagellates, cryptophytes, zooplankton, particulate organic matter, dissolved organic matter, phosphate–phosphorus, ammonia–nitrogen, nitrite–nitrogen, nitrate–nitrogen, and dissolved oxygen. The monitoring data were used to verify the model simulation. Model evaluation suggested good agreement between the predicted and the observed data for the seasonal variations in the algal, nutrient, and dissolved oxygen concentrations. To determine the sensitivity of the model parameters, a sensitivity analysis was conducted leading to the conclusion that the optimal temperature, growth rate, and respiratory rate of the four algal groups, especially the ideal temperature for blue-green and green algae are the most influential factors determining the variability affecting the model inference. From the model simulation, the water temperature and nutrient concentration were considered to be the key limiting factors controlling alternative algal blooms in this period.     

Evaluation of land suitability for Moringa oleifera tree cultivation by using Geospatial technology: The case of Dhidhessa Catchment,Abay Basin,Ethiopia

Land suitability analysis of Moringa oleifera tree cultivation is important to enhance its product, as the demand for this tree for medicinal values and food sources is increasing worldwide. Therefore, this study aimed to assess suitable land for Moringa oleifera tree cultivation by using the integration of multi-criteria evaluation with geospatial technologies in the Dhidhessa catchment, western Ethiopia. Five parameters, namely: slope, land use and land cover(LULC), soil texture, land surface ...     

Modelling pasture management practices for soil organic carbon gain in livestock systems

Our ability to develop strategies to mitigate climate change includes an understanding of, and our capacity to predict soil organic carbon (SOC) dynamics in livestock systems. Here we assess the capability of the Sustainable Grazing System (SGS) Pasture Model for predicting pasture growth (elongated wheatgrass, Thinopyrum ponticum) and SOC accumulation in different environments and under a range of pasture management practices in hydrohalomorphic soils located in South-eastern Buenos Aires Province, Argentina. After Model calibration, aerial net primary productivity (ANPP) and TSOC content under two grazing intensities (7.5 and 11 cm post-grazing target heights) and two N fertilization levels (0 and 100 kg N ha⁻¹ yr⁻¹) were simulated over a 10 year-period. The SGS Pasture Model predicted 87% of the observed ANPP, with observed and predicted ANPPs averaging 1.46 and 1.42 Mg ha⁻¹ yr⁻¹, respectively. There were differences in simulated ANPP between fertilized and unfertilized treatments both at high and low grazing intensities for the last year of the period. Total SOC contents from the modelling showed differences between high (83.7 to 84.2 Mg ha⁻¹) and low (86.8 to 87.5 Mg ha⁻¹) grazing intensities, with treatments receiving N also showing higher carbon stocks. The positive effect of reduced grazing intensity on soil carbon was explained by an increased input of aerial and subterranean dry matter into the soil. Sensitivity analysis showed that SGS is a robust model, capable of performing effectively under a variety of conditions. Hence, it can be used for exploring management practices to mitigate the impact of livestock systems on emissions and SOC stocks.     

气相色谱法测定茶青中有机氯农药残留量

对茶青中六六六和滴滴涕共八种异构体的残留量进行测定,与同地点成品茶叶农药残留量相比较基本无差异。本法检测限为>0.15ng/g,回收率为78.8%-102.0%,相对标准偏差<10.0%。     

Characterizing nitrogen use efficiency in natural and agricultural ecosystems to improve the performance of cereal crops in low-input and organic agricultural systems

Low-input and organic farming systems have notable differences in nitrogen (N) sources, cycling and management strategies compared to conventional systems with high inputs of synthetic N fertilizer. In low-input and organic systems, there is greater reliance on complex rotations including annual and perennial crops, organic N sources, and internal N cycling that more closely mimic natural systems. These differences in farming system practices fundamentally affect N availability and N use efficiency (NUE) and could impact crop traits and breeding strategies required to optimize NUE. We assess genetic and environmental factors that could assist breeders in improving crop performance in low-input and organic farming systems by examining NUE in natural and agricultural ecosystems. Crop plants have often been bred for high N productivity, while plants adapted to low N ecosystems often have lower productivity and higher levels of internal N conservation. Breeders can potentially combine N productivity and N conservation through the use of elite and wild germplasm. Beneficial genetic traits include the ability to maintain photosynthesis and N uptake under N stress and the ability to extract soil N at low concentrations, perhaps through beneficial associations with soil microorganisms. In addition, breeding for specific adaptation to climactic and management practices so that crop uptake patterns match N availability patterns, while minimizing pathways of N loss, will be critical to improving NUE.     

A decision support system for agricultural drought management using risk assessment

Since predicted changes in climate will modify temperature and rainfall patterns, there are concerns about the potential impacts of these changes on agricultural drought and agricultural water resources management. An agricultural drought is influenced by several factors such as rainfall, soil characteristics, crops, and reservoir water supply and may be defined as the imbalance of water circulation in paddy and water environments. In particular, soil moisture and water supply for reservoir demand are the most direct and important indicators of agricultural drought events. In the past, conventional drought management approaches based on climatic and meteorological observations have been the primary tools used for measuring drought severity. Because of the spatial and temporal variability and multiple impacts of drought, it is necessary to improve tools to determine the onset, severity, spatial extent, and end of the drought conditions. Improved and available data for mapping and monitoring of this phenomenon are also needed. Effective and efficient drought management can be achieved through drought monitoring based on the ability to assess current conditions and provide improved tools to adapt and mitigate the impacts of future changes. In this article, a methodology is developed to support the risk-based decision-making process involved in agricultural drought management using the following four strategies: drought assessment and monitoring, drought forecast and outlook, drought countermeasures, and drought records management.     

Production of activated carbon from organic by-products from the alcoholic beverage industry: Surface area and hardness optimization by using the response surface methodology

The ability of activated carbon to remove pollutants from water in packed column systems is dependent on granular material with mechanical strength sufficient to avoid attrition caused by stream flow. Therefore, an appropriate balance between surface area and hardness is essential when using activated carbon in real systems. The purpose of this research is to determine the optimal production conditions that generate activated carbon with adequate physical properties to be used in packed systems from agave bagasse, a waste product from the mezcal industries in Mexico. Activated carbons were produced by chemical activation (ZnCl₂ or H₃PO₄). Response surface methodology (RSM) was used to evaluate the effect of the activation temperature (250-550 °C), activation time (0-50 min), and the concentration of activating agent (0.2-1.4; g activating agent/g bagasse) on both surface area and hardness. The production conditions that generated optimal characteristics in the activated carbon were 392 °C, 1.02 g activating agent/g bagasse and 23.8 min for H₃PO₄ activated samples and 456 °C, 1.08 g activating agent/g bagasse and 23.8 min for ZnCl₂ activated samples. The surface area and hardness of the activated carbon produced from bagasse under these conditions were similar to activated commercial carbons (surface area > 800 m²/g and hardness > 85%).     

Multiple use of plants: Studies on selenium incorporation in some agricultural species for the production of organic selenium compounds

The technique of spraying plants with inorganic forms of selenium can be employed for phytochemical production of organic selenium compounds. Fractionation of the plant material makes it possible to produce a highly concentrated and well defined selenium supplement with potential use in animal and human nutrition. The fractionation also gives opportunities to combine production of organic selenium compounds with other products, for example plant fibres. Multiple use of plants can contribute to a more efficient utilization of land area (in comparison to monocultures solely adapted to food production). It also gives the opportunity to develop systems suitable for long term fixation of carbon, as long as the plant material is not reoxidised to carbon dioxide. Plant fibres could provide raw material for the production of paper or building materials in combination with the production of organic selenium compounds preferentially accumulated in another fraction of the processed plant.     

Evaluation of hair-dyeing by using Rubus coreanus Miquel sludge

Hydro-extraction, enrichment by evaporation, and freeze drying processes were sequentially carried out to extract the colorants from the Rubus coreanus Miquel sludge which was supplied as the waste of the traditional wine process. The dyeing on to human hair was performed at some pH values by using the commercial condition; 0.4 g of human hair, 100 % (on the weight of hair) of the powder of colorants, liquor ratio 1:5, 40 °C and 30 min. The extract was evaluated by UV-vis spectroscopy, antioxidant property (DPPH radical scavenging activity) and antimicrobial activity measurements. Color of the extract in aqueous solution was red at pH 2, violet at intermediate pH condition, and brown at pH 9. Color properties and colorfastness to light and washing were also analyzed for the hair samples dyed with the extract. With the variation of pH, the color of dyed hair was observed mostly BG-RP at pH 2-5 and then changed to YR-GY at pH>6. For the dyed hair samples, light colorfastness was relatively good; the rating 3 was maintained up to 40 hrs. The rating of wash colorfastness was remained 3 for 25 cycles. Results of color analysis and fastness tests confirmed that the colorants from the Rubus coreanus Miquel were successfully applied to hair-dyeing.     

Exploring remotely sensed technologies for monitoring wheat potassium and phosphorus using field spectroscopy

Given the importance of potassium (K) and phosphorus (P) contents to wheat yield and grain quality, and the very little experience that has been gained on nutritional monitoring of other than nitrogen using remotely sensed technologies, a study was undertaken to explore the possibility of identifying these mineral stresses using spectral data. Canopy spectra and biophysical data were collected from commercial and experimental fields in India and Israel. Traditional and newly developed vegetation indices, together with Partial Least Squares (PLS) regression models, were calculated in order to predict potassium and phosphorus contents from the wheat canopy spectral data. Results show that the application of PLS and specific narrow bands vegetation indices reached significant levels of accuracy in the retrieval of K and P levels, in comparison to traditional broad band indices. Additionally, it was observed that a significant improvement is obtained when the mineral total content is considered instead of the relative content. Therefore it was suggested that the biomass should also be retrieved from the spectral data. Finally, as very different crop conditions were included in this study, it was possible to confirm that the level of accuracy in the retrieval of K and P levels is related to the quality and variability of the data used for calibrating the models.     

Evaluation of land use change and groundwater use impact on stream drying phenomena using a grid-based continuous hydrologic model

The effect of land use change on drying streams was evaluated using a grid-based continuous hydrological model (PGA-CC). For a drying stream-progressed watershed (398.8 km²), the model was calibrated and validated using 7 years (2005–2011) of streamflow data at the watershed outlet with an average Nash–Sutcliffe model efficiency of 0.71. Based on the model simulation results for 36 years (1976 to 2011), both land use change and climate change decreased the 10-day minimum flow by 0.16 m³/s and increased the day counts below the annual average by 40.6 days/year. These changes resulted from the 8.7 % increase in urban area, 1.43-fold increase in groundwater use, and 1.1 °C temperature increase during the 36-year period. From the distributed results of the model, we identified the drying stream location and progression. The spring and winter seasons were relatively strongly affected, and drying streams were identified in more urbanized areas with greater groundwater use.     

Evaluation of activated carbon fiber applied in supercapacitor electrodes

This study uses rayon woven fabrics as the raw material for activated carbon fabrics (ACFs), which were manufactured by oxidation, carbonization and activation engineering in a continuous semi-open high-temperature furnace. First, the activated carbon fabrics are prepared under two specific manufacturing conditions with different production rates and flow rates of steam activation at 1000 °C. Then the electrochemical prosperities of the ACFs are evaluated by a three-electrode device. The experimental results show that the BET specific surface area and electrical capacitance are higher with a lower production rate. Moreover, the steam activator higher flow rate under the proposed approach. ACFs with a 2332.1 m²/g specific surface area and 78.7 % mesopore ratio result in a higher electronic conductivity of 430.4 F/g at the low rate charge (5 mV/s) and with 60 % capacitance retention during the high-speed charging-discharging process (100 mV/s).     

Soil organic carbon stocks in verges and urban areas of Flanders, Belgium

Soil organic carbon (SOC) stocks in different terrestrial ecosystems have already been calculated. However, SOC stocks of grassy verges and grass‐covered urban areas have never been reported. In this study the total grass‐covered area of verges and urban areas in different agro‐pedological regions of Flanders, Belgium was calculated and SOC stocks estimated. The total grassy area of verges along roads, waterways and railways was calculated to be 18 027 ha, 9530 ha for gardens and parks and 2360 ha for recreations areas. Total SOC stock for grass‐covered verges, extrapolated to a depth of 1 m, was estimated to be 3520 kt SOC. Total SOC stock for grassy vegetation in urban areas was 1738 kt SOC. These total SOC stocks equate, respectively, to 0·10 and 0·05 of the total SOC stock in Flemish grassland.     

Reduction in numbers of the wild rabbit (Oryctolagus cuniculus) due to changes in agricultural practices and land use

Rabbits were collected each month over a 9-year period from a farm in Eastern Scotland. Parts of the study area of c. 500 ha were improved over the 9-year period and the impact of these changes on the numbers and distribution of rabbits collected was monitored. The removal of favoured habitats significantly reduced rabbit numbers in the more intensively farmed areas and reduced the chances of these areas being recolonized. It is suggested that, because of its long-term benefits, habitat manipulation should be considered when devising rabbit control programmes. The patchy distribution of the resurgence of rabbit numbers since myxomatosis in Great Britain may be explained in part by the rate with which land improvements have been introduced in different parts of the country.     

秩次分析法评价国家芝麻区试品种的产量性能

利用秩次分析法,对参加２００５和２００６年度国家区域试验的１７个芝麻品种的产量表现进行了分析。在 方差分析的基础上,通过对品种的秩次值、环境区分指数、秩次均方等统计数的计算,比较了品种的高产性和稳产 性。结果表明,在参试的１７个品种中驻０３Ｊ－３、６１２０和００－５１０１３具有最好的高产性和稳产性,与实际情况相符, 这些品种已经通过国家品种审定。秩次法能够客观、准确的评价参试品种的优劣,具有较高的应用价值。     

Model of resalinization by capillary rise in reclaimed land

Paddy and Water Environment - Large areas of reclaimed land have recently been required to be developed as environmentally friendly centers of vegetation, such as dryland fields for cultivation of...     

水稻机插秧农机与农艺配套技术探讨

为探索水稻机械化插秧农艺配套技术 ,减轻农民劳动强度 ,提高工效 ,推进水稻生产机械化进程 ,实现水稻生产省工、节本、增效的目标 ,２００１年我们对水稻机械化插秧配套技术进行了认真的探讨和尝试 ,取得了可喜的成果。一、机插秧质量与效率ＰＦ４５５Ｓ步行式插秧机 ,单程插幅１２０ｃｍ ,４行并列 ,平均行距３０ｃｍ(固定 ) ,株距调节幅度１１～１４ｃｍ ,田间实插株距平均为１１．１ｃｍ。理论上每６６７ｍ２应插２万穴 ,田间实查１．８２万穴。机插秧质量受秧苗质量、水层深度、整地、机械性能等各方面的影响而不同 ,本次插秧漏插率５…