摘要:

AbstractThe attitudes of farmers in the New England region of Australia are internally consistent in some cases, but in others seem inconsistent. Cluster analysis and discriminant analysis indicate that even internally inconsistent respondents can be divided into definable categories, and differences in response patterns relate significantly to other variables such as business structure, commodities being produced, attitudes to external influences in decision‐making and to conservation generally. The results suggest that for policy‐oriented research on attitudes to complex environmental issues, analysis should take account of data which do not necessarily conform to the requirements for unidimensional scale construction, but which can usefully be interpreted by analysing respondent clust

ISSN:1085-3278    

DOI:10.1002/ldr.3400050302

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractSalinization/alkalization and waterlogging have rendered a sizeable area of India's arable lands unproductive. These highly dynamic phenomena can be studied using remote sensing data collected at regular intervals. Landsat Multi‐spectral Scanner data of 28 February 1975 and 9 March 1990 were interpreted visually to derive information about the spatial extent and distribution of salt‐affected soils. A significant decrease in the area of salt‐affected soils was noted over this period, which can be attributed to reclamation efforts by government agencies and farmers. On a large scale, i.e. 1:50000, the waterlogged area could also be mapped using a Landsat Thematic Mapper false‐colour composit

ISSN:1085-3278    

DOI:10.1002/ldr.3400050303

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractMany of the soils in Santa Cruz Department, Bolivia, are degraded by serious weed infestation, subsoil compaction, and low organic matter and nitrogen contents. Fallow periods with cover crops are frequently used to recuperate the fertility of degraded soils, but little information exists on the desired characteristics of cover crops for this purpose. The aim of this study was to describe those characteristics, believed to be most relevant to the rehabilitation of degraded soils in Santa Cruz, of 14 cover crops, which included three grasses, nine legumes, and two winter cover crops sown after summer soybean (Glycine max). The cover crop characteristics, evaluated over two years, were ease of establishment, competitiveness against weeds, tolerance to drought, dry matter production and nutrient contents of the above‐and below‐ground residues, nodulation, rooting density and root diameters. The three grasses Tobiata (Panicum maximumvar. Tobiatd), Centenario (Panicum maximumvar. Centenario) and Brizantha (Brachiaria brizantha) appeared to be the most promising for increasing soil organic matter contents, and the three grasses and groundnuts (Arachis hypogaea)/pigeon pea (Cajanus cajan) for the recuperation of subsoil structure. Mucuna deeringiana and Lablab (Dolichos lablab) were the most promising for increasing soil N status. All of these cover crops competed successfully with we

ISSN:1085-3278    

DOI:10.1002/ldr.3400050304

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractMapping and monitoring of land degradation processes such as soil erosion has become an important task for both agricultural and environmental planners. The potential of using SPOT‐HRV data for assessing the types of soil erosion and land degradation is obvious. The spectral information and the spatial resolution of the multispectral data allow a high accuracy in local mapping and rapid regional assessment.In Basilicata, southern Italy, spectral mixture modelling (end‐member techniques) has been applied to extract relevant information for assessing soil erosion. This method allows an estimate of the proportion of surface cover types (end‐members) within the pixel. From the data sets average spectral responses were extracted for growing vegetation, non‐green sclerophylous vegetation mixed with dry grasses and bare soil. Using these spectra as end‐members in the model, it was possible to decompose the spectral information of all pixels into the three surface components, giving the percentage cover of the three types within every pixel. Classification of the pixels according to the percentage of surface cover or bare soil allows an assessment of erosion or ero

ISSN:1085-3278    

DOI:10.1002/ldr.3400050305

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractThe development of appropriate technologies for the judicious use of India's 8.11 million ha of salt‐affected lands would give increased food, fodder and fuelwood production. A sizeable portion of the salt‐affected lands of the Indo‐Gangetic plain have been reclaimed through chemical amendments and are being commercially used for arable farming. However, large areas of salt‐affected common lands, village and government lands and waste lands near cities, along railway tracks and roads do not have any productive use. Owing to their sparse vegetative cover such lands are vulnerable to further degradation and can be a source of runoff causing floods, especially where cows congregate. Research at the Central Soil Salinity Research Institute, Karnal has generated agroforestry techniques which could enable the economic exploitation of such marginal lands. This paper deals with various aspects of these techniques, which have been applied to over 50 000 ha by 1994.Based on eight to ten years of growth and biomass figures, the most salt‐tolerant woody species identified were:Prosopis juliflora, Acacia nilotica, Casuarina equisetifolia, Tamarix articulata, Leptochloa fusca(a palatable forage grass which was found to be a promising primary colonizer of salt lands). Agronomic practices for the successful establishment of trees such as planting methods, amendment use, irrigation, spacing and lopping schedules are discussed.A Prosopis juliflora‐leptochloa fuscasilvipastoral model was found to be excellent for fuelwood and forage production and for the amelioration of high pH soils. This system, when followed for little more than four years, reclaims alkali soils to such an extent that normal agriculture crops such asTrifolium alexandrinumand T.resupinatumcan be grown successfully. A ridge‐trench system of tree planting was found to be helpful in alkali soils, thein siturainwater conservation it led to assisting biomass production.Eucalyptus tereticornis, Populus deltoides and Tectona grandisbased agroforestry were promising for reclaimed salt‐affected lands. The short‐ and long‐term effects of various tree plantations on the physicochemical properties of the soil and on soil‐water relations are also discussed. Agroforestry options for the development of salt‐affected lands found in various agroclimatic zone

ISSN:1085-3278    

DOI:10.1002/ldr.3400050306

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

ISSN:1085-3278    

DOI:10.1002/ldr.3400050307

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

ISSN:1085-3278    

DOI:10.1002/ldr.3400050308

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

ISSN:1085-3278    

DOI:10.1002/ldr.3400050301

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY