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This digital document is a journal article from Agriculture, Ecosystems and Environment, published by Elsevier in 2006. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

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Non-selective chemical control of crop pests disrupts beneficial insects and spiders. For Australian cotton crops, a beneficial disruption index (BDI) has been developed that ranks the impact of different insecticides on beneficial arthropods. To evaluate this index as a measure of natural enemy disruption, the abundance of beneficial arthropods was monitored in ten conventional and nine INGARD^(R) Bt cotton fields on ten commercial farms during the 2001-2002 season. Beneficial insects were more abundant in those fields subjected to a more selective insecticide regime (low BDI) than in fields that received broad-spectrum insecticide treatments (high BDI). However spider abundance did not change in relation to insecticide regime. Family composition of spider communities was affected by BDI and crop type (Bt or conventional), whereas family composition of insect communities only showed a trend to be affected by BDI and crop type. This difference may indicate that insects are more uniformly affected by the BDI than spiders. The beneficial disruption index is an effective measure of insecticide impacts on beneficial insects in Australian cotton crops. ... Read more

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This second publication in the "AWLAE" series on HIV/AIDS and agriculture in sub-Saharan Africa discusses the gender dimension of HIV/AIDS impact at household and community level. It does so in using the threefold typology of gender specific constraints, gender intensified disadvantages and gender imposed constraints. Special foci of attention include the implications of gender constraints for food security in rural settings, where women are the main producers of food crops as well as the main caregivers; and how cultural norms determine the different options open to women in contrast to men in mitigating the effects of the epidemic. This last point provides the link to the last publication in the series, which discusses agricultural mitigation strategies in the context of HIV/AIDS as a challenge to human development. The text is followed by an annotated bibliography. ... Read more

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This digital document is a journal article from Agriculture, Ecosystems and Environment, published by Elsevier in 2007. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

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Simple risk assessment tools for agricultural phosphorus (P) losses, like the P index, have been developed in the U.S.A. and in some European countries. Despite its popularity, there have been surprisingly few studies, which try to test the index close to the field scale. For Norway, the P index approach comprises the risk related to both the source of P (soil P status, amount of fertilizer and manure as well as method of application, plant P release by freezing and P balance) and the risk related to transport of P (erosion, flooding, surface runoff, contributing distance, modified connectivity, soil profile, subsurface drainage). In this paper, we have applied the Norwegian P index to farmer fields within a small agricultural catchment, the Skuterud catchment (450ha), in southeastern Norway. The Norwegian P index was tested for two agricultural fields (0.3-0.4ha) and nine subcatchments (6-65ha). Total P concentrations in runoff from the 11 study areas were measured during the year from May 2001 to April 2002. Results from the testing showed that the Norwegian P index described 66% of the variation in measured relative total P concentration for fields and subcatchments included in this study. Additionally, the P index was able to detect fields and subcatchments with the highest measured P concentrations. Results also showed that the source factor contributed most to the variation between fields and hence were important for the identification of high-risk areas in Skuterud catchment. It was found that the soil P status described 66% of the variation in the source factor. Among the transport variables, it was found that both erosion risk and contributing distance had an important influence on the transport factor. Overall, the study illustrated the potential of the P index to detect areas with the highest risk of P loss. ... Read more

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This publication is the first in a three part series on HIV/AIDS and agriculture in sub-Saharan Africa with the overall objective of providing a resource base on issues of rural development in a broad sense in the times of HIV/AIDS. This first book discusses the impact of the epidemic as it has emerged over the last decades at different levels of the agricultural sector, namely the farming system level, the livelihood level, and the household level. In a further step, impact on the agricultural estate sector as well as pastoralism is discussed. One overarching issue that emerges is the importance of gender attributes to adequately understand and address HIV/AIDS impact - the topic at the centre of the second part of the series. The text ends with a discussion of HIV/AIDS in relation to other shocks that befall rural livelihoods. It is followed by an annotated bibliography. ... Read more

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This digital document is a journal article from Agriculture, Ecosystems and Environment, published by Elsevier in 2005. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

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In Ethiopia land degradation in the forms of soil erosion and declining soil fertility are serious challenges to agricultural productivity and economic growth. Despite the general recognition of the threat from land degradation on agricultural productivity, few studies have been made to quantify the extent, rate and process of soil fertility depletion under various land use systems and management practices in the country. In this study we assessed soil chemical and physical property responses to deforestation and subsequent cultivation along a chronosequence of closely located farmlands of different ages (7, 10, 26, 34 and 53 years) since conversion from a tropical dry Afromontane natural forest in Ethiopia. These properties were compared with soil properties under an adjacent natural forest. The changes were used as indicators to evaluate the sustainability of the farm management. All the soils in the study were Mollic Andosols/Humic Haplustands. Soil bulk density (gcm^-^3) in the 0-10 and 10-20cm soil layers increased significantly while percent pore space decreased significantly in a continuum with increasing cultivation period. Soil C and total N contents (gkg^-^1) in the 0-10cm soil layer declined significantly and exponentially with increasing years under cultivation. However, in the 10-20cm soil layer both soil C and total N on the farmlands were significantly higher until after 34 years of continuous cultivation compared to the same soil layer under the natural forest. Consequently, the soil C stock (gm^-^2) of the upper 0.20m mineral soil was not significantly lower on the farmlands until after 26 years of continuous cultivation compared to the natural forest soil. Available P and K (mgkg^-^1) in the 0-10cm layer were higher in the soils of the farmlands throughout the 53 years of continuous cultivation compared to the soil under the natural forest. Exchangeable Ca, CEC and base saturation in the 0-10cm soil layer declined more or less throughout the cultivation period while in the 10-20cm soil layer they followed the patterns of soil C of that depth. Generally, the magnitudes and rates of degradation of the soil properties following conversion and subsequent cultivation were lower than expected for a low input tropical farming system as the one investigated. Nevertheless, almost all soil quality attributes showed overall declining trends in the long perspective. This continuous decline, albeit slowly, in soil quality with increasing cultivation period indicated that the present land management is not sustainable. Therefore, improved management is imperative to sustain the soil quality and maintain long-term productivity of the farmlands. ... Read more

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This digital document is a journal article from Agriculture, Ecosystems and Environment, published by Elsevier in 2006. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

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Soil organic matter is an effective indicator of soil resource condition that reflects functional traits such as aggregation and infiltration and plays a critical role in sustaining production and ecosystem services in agricultural landscapes. Agricultural practices typically reduce soil carbon through the action of soil disturbance and mineralization. In the Brigalow (Acacia harpophylla) landscape we studied, soil carbon levels in pellic vertisols were significantly lower in the agricultural matrix of cropping and grasslands than in remnant Brigalow vegetation. There was no detectable gradient of soil carbon across Brigalow/matrix boundaries. Uncultivated grasslands showed significantly higher carbon levels than currently and previously cultivated grasslands. Regenerating grasslands showed no significant recovery of soil carbon over 15 years. Total, organic and labile soil carbon fractions were used to indicate different aspects of soil function, with the more active (labile) components reacting more sensitively to changes in land management. The carbon management index (CMI) was used to combine the active and passive components of soil carbon to provide a sensitive indicator of the rate of change of carbon dynamics in response to changes in land management at local-scales. A landscape CMI (CMI"L) was developed using a combination of soil samples and GIS-derived spatial data and is proposed as a potentially useful tool for modelling soil carbon dynamics in agro-ecosystems at local and landscape scales. ... Read more

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This digital document is a journal article from Agriculture, Ecosystems and Environment, published by Elsevier in 2007. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

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The soil quality concept provides a tool to help quantify the combined biological, chemical and physical response of soil to crop management practices. Our objective was to quantify effects of 10 fertilizer and farm yard manure (FYM) treatments applied for 31 years to a rotation that included maize (Zea mays), pearl millet (Pennisetum americanum), wheat (Triticum aestivum) and cowpea (Vigna unguiculata) on an Inceptisol at the Indian Agricultural Research Institute in New Delhi, India. A soil quality index (SQI) based on six soil functions (i.e. the soil's ability to: accommodate water entry, facilitate water movement and storage, resist surface degradation, resist biochemical degradation, supply plant nutrients and sustain crop productivity) was derived for each treatment using bulk density, water retention, pH, electrical conductivity (EC), plant-available nutrients, soil organic matter (SOM), microbial biomass, soil enzymes and crop yield. SQI ratings ranged from 0.552 (unfertilized control) to 0.838 for the combined NPK fertilizer plus manure treatment. Comparisons among treatments indicated that SQI increases associated with the combined (NPK+manure) treatment were distributed as follows: N (7.1% increase), P (7.8%), K (14.4%), Zn (4.8%) and manure (15%). The control (-11.4%) and N alone (-5.1%) resulted in degradation compared to a reference soil (no fertilizer/manure, no crop), and NP alone or sub-optimal rates of NPK were on the verge of degradation. Hand weeding and sulphur application had no measurable effect on SQI. High K fixing capacity was a limiting factor for these soils, even when FYM was applied. The lower SQI rating associated with N or NP-only treatments suggests that two of the most common fertilizer management practices in India may not be sustainable. The SQI was calculated without the weighting factors too, which revealed that the weighting factors did not affect the relative ranks of individual treatments. ... Read more

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This digital document is a journal article from Agriculture, Ecosystems and Environment, published by Elsevier in 2005. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

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Maize is the main grain crop grown in the highlands of sub-Saharan Africa, on a broad range of soil fertility and management conditions. Important yield variability has been reported at different scales, reflecting the intensity and spatial distribution of growth-limiting and growth-reducing factors. Maize yield estimation represents a valuable tool to assess within-farm variability in soil fertility through crop performance. The objective of this study was to develop mathematical relationships between plant morphological attributes and grain yield of tropical maize genotypes, based on plant allometric characteristics. These models were used to estimate maize yields and the estimates were validated against independent data collected from experimental and farmers' fields in western Kenya. Three commercial hybrids and three local varieties were considered. Multiple linear regression models including plant height and either ear length or ear diameter as explanatory variables, and simple linear regressions including only plant height, were the most accurate to estimate both total aboveground biomass and grain dry matter yields per plant (r^2: 0.76-0.91). Average values for the harvest index ranged between 0.34 and 0.42, varying with the total aboveground biomass produced per plant. Yield estimations on ground area basis for farmers' fields were acceptably accurate. Plant height measurements can be easily taken at any moment after maize flowering and used in simple models to estimate maize yield. This approach proved also a valuable tool to discuss yield variability with farmers. ... Read more

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This digital document is a journal article from Agriculture, Ecosystems and Environment, published by Elsevier in 2004. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

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This work aims to determine variations in cover crop, bare soil and tree areas in olive (Olea europaea L.) groves as affected by the season based on aerial photographs and estimated vegetation indexes. Conventional-colour and colour-infrared aerial photographs were taken in spring and summer on three olive farms of 75-100ha, from a plane at 1525m above the ground. Images (scale 1:10,000) were digitized, georeferenced and processed. Twenty-six selected vegetation indexes were assayed for land-use discrimination. Early summer was the most suitable time to distinguish between cover crops and olive trees. Conventional-colour was more adequate and economic than infrared photography. Indexes based on blue and red wavelength reflectivity values divided by combinations of several reflectivity values were suitable for cover crop and olive tree discrimination. Selected vegetation indexes allowed for the cover crop areas to be estimated at 32.50% of the 100.5ha total farm surface, with an estimated accuracy of 91.9+/-1.4%. ... Read more

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This digital document is a journal article from Agriculture, Ecosystems and Environment, published by Elsevier in 2005. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

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Wheat (Triticum aestivum L.) and corn (Zea mays L.) rotation system is important for food security in the Loess Plateau of China. Grain yield and water-use efficiency (WUE: grain yield per unit of water consumed) trends, and changes in soil properties during a 24-year fertilization experiment in Pingliang, Gansu, China, were recorded. Mean yields of wheat for the 16 years started in 1981 ranged from 1.29tha^-^1 for the unfertilized plots (CK) to 4.71tha^-^1 for the plots that received manure (M) annually with inorganic nitrogen (N) and phosphorus (P) fertilizers (MNP). Corn yields for the 6 years started in 1979 averaged 2.29 and 5.61tha^-^1 in the same treatments. Yields and WUEs declined significantly with lapse of time except CK and MNP for wheat. Wheat yields with the N and M declined at rate of 77 and 81kgha^-^1year^-^1, but the decline of 57kgha^-^1year^-^1 for NP was similar to that of 61ha^-^1year^-^1 for straw with N annually and P every second year (SNP). Likewise, the corn yields and WUEs declined from 160 to 250kgha^-^1year^-^1 and from 0.01 to 0.03kgm^-^3year^-^1 among treatments, respectively. These declines were likely to loss of soil fertility and gradual dry weather. Yields were significantly correlated with seasonal evapotranspiration with slopes ranging from 0.5 to 1.27kgm^-^3 for wheat and from 1.15 to 2.03kgm^-^3 for corn. Soil organic carbon (SOC), total N (TN), and total P (TP) gradually built up with time except the CK, in which TN and TP remained unchanged but SOC and available P (AP) decreased. Soil AP decreased in the N. Soil available K declined rapidly without straw or manure. Balanced fertilization should be encouraged to ensure sustainable productivity in this intensive cropping system. The greatest SOC increases of about 160mgha^-^1year^-^1 occurred in the SNP and MNP, suggesting that long-term additions of organic materials to soil could increase soil water-holding capacity which, in return, improves water availability to plants and arrests yield declines, and decrease CO"2 emission from agricultural soils and sustain land productivity. ... Read more

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Book Content
The book provides a good guide on the indicators for sustainability for persons involved in land use. ... Read more

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This digital document is a journal article from Remote Sensing of Environment, published by Elsevier in 2005. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

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Information on the area and spatial distribution of paddy rice fields is needed for trace gas emission estimates, management of water resources, and food security. Paddy rice fields are characterized by an initial period of flooding and transplanting, during which period open canopy (a mixture of surface water and rice crops) exists. The Moderate Resolution Imaging Spectroradiometer (MODIS) sensor onboard the NASA EOS Terra satellite has visible, near infrared and shortwave infrared bands; and therefore, a number of vegetation indices can be calculated, including Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI) and Land Surface Water Index (LSWI) that is sensitive to leaf water and soil moisture. In this study, we developed a paddy rice mapping algorithm that uses time series of three vegetation indices (LSWI, EVI, and NDVI) derived from MODIS images to identify that initial period of flooding and transplanting in paddy rice fields, based on the sensitivity of LSWI to the increased surface moisture during the period of flooding and rice transplanting. We ran the algorithm to map paddy rice fields in 13 provinces of southern China, using the 8-day composite MODIS Surface Reflectance products (500-m spatial resolution) in 2002. The resultant MODIS-derived paddy rice map was evaluated, using the National Land Cover Dataset (1:100,000 scale) derived from analysis of Landsat ETM+ images in 1999/2000. There were reasonable agreements in area estimates of paddy rice fields between the MODIS-derived map and the Landsat-based dataset at the provincial and county levels. The results of this study indicated that the MODIS-based paddy rice mapping algorithm could potentially be applied at large spatial scales to monitor paddy rice agriculture on a timely and frequent basis. ... Read more

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This digital document is a journal article from Remote Sensing of Environment, published by Elsevier in . The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

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In this paper, we developed a new geospatial database of paddy rice agriculture for 13 countries in South and Southeast Asia. These countries have ~30% of the world population and ~2/3 of the total rice land area in the world. We used 8-day composite images (500-m spatial resolution) in 2002 from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor onboard the NASA EOS Terra satellite. Paddy rice fields are characterized by an initial period of flooding and transplanting, during which period a mixture of surface water and rice seedlings exists. We applied a paddy rice mapping algorithm that uses a time series of MODIS-derived vegetation indices to identify the initial period of flooding and transplanting in paddy rice fields, based on the increased surface moisture. The resultant MODIS-derived paddy rice map was compared to national agricultural statistical data at national and subnational levels. Area estimates of paddy rice were highly correlated at the national level and positively correlated at the subnational levels, although the agreement at the national level was much stronger. Discrepancies in rice area between the MODIS-derived and statistical datasets in some countries can be largely attributed to: (1) the statistical dataset is a sown area estimate (includes multiple cropping practices); (2) failure of the 500-m resolution MODIS-based algorithm in identifying small patches of paddy rice fields, primarily in areas where topography restricts field sizes; and (3) contamination by cloud. While further testing is needed, these results demonstrate the potential of the MODIS-based algorithm to generate updated datasets of paddy rice agriculture on a timely basis. The resultant geospatial database on the area and spatial distribution of paddy rice is useful for irrigation, food security, and trace gas emission estimates in those countries. ... Read more

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The main purpose of this work is to identify the most valuable literature sources concerned with rural energy in the Third World. The annotated bibliography provides critical reviews of more than 150 sources and lists 50 others. Two introductory chapters identify a number of important themes related to the understanding of the energy needs of rural people and the organization of the process of technical change needed to generate energy conversion technologies suitable for rural application. The bibliography is unique in focusing on the social science (rather than the technical or scientific) aspects of the rural energy problem. ... Read more

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Discusses a wide range of print and electronic media to locate hard to find documents, navigate poorly indexed subjects, and investigate specific research topics and subcategories. ... Read more