Present Agricultural Practices Research Articles

Hydromorphology and land use at different spatial scales: expectations in a changing climate scenario for medium-sized rivers of the Western Italian Alps

The study presents an investigation of the relationships between hydromorphological features and land use in two medium-sized Italian Alpine catchments. The South European River Habitat Survey (SE_RHS) method was applied in the collection of hydromorphological data. Five different spatial scales ranging from catchment to site scale were considered for the quantification of land use. Separate Principal Component Analyses for grouped data sets were run on hydromorphological variables related to different spatial scales and the type of information provided. The analyses demonstrated that the most important gradients are related to channel stability. Unstable river reaches, characterized by a significant presence of unvegetated bars, were predominantly related to natural land use. On the contrary, more stable river reaches, characterized by the presence of vegetated bars, were found to be related to anthropogenic land use. High turbulence flow types appeared to be associated with urban and industrial land use. The climate scenario predicts a general increase in temperature, a slight decrease in precipitation, a more dynamic discharge regime and an increase in extreme events, all of which may produce considerable modifications to present agricultural and river management practices. A conceptual model based on the situation observed in the studied catchments is presented, that can be used to infer possible land use changes, during climate variation, in areas adjacent to rivers.

The status of ravine-like incisions in the dry valleys of the Pays de Thelle (Paris basin, France)

In the Pays de Thelle, France, ravines often cut the bottom of local chalk dry valleys. Morphometric and sedimentological analyses are used in an attempt to reconstruct the palaeoenvironments during the morphodynamic evolution of these small dry valleys. As in other Paris basin districts, the dry valleys were formed during periglacial Quaternary periods. However, some of the ravines look like fluvial incisions that have began since the Subboreal and result more from recent uplift of the Bray anticline than from human activities alone. Present agricultural practices, which are not in accordance with respect for the environment, contribute to the surface runoff that produces muddy floods along the dry valleys, but they are not thought to be the cause of the ravines.

Nature and Properties of Some Cultivated Entisols Under Peach Orchards

Entisols have developed from Quaternary deposits in northwestern Turkey under xeric moisture and thermic temperature regimes. The morphological features and physico-chemical properties of ten soil profiles representing the major Entisols under Mediterranean climate in northwestern Turkey were studied. These soils show a similar variation in morphological, physical, and chemical properties as a result of similar parent material, topography, climate, and vegetation. Entisols were developed in the 700 mm precipitation zone. These soils occur in nearly flat areas and are characterized by being dry in summers and moist in winter months. It is believed that present agricultural practices are degrading Entisols in this area.

Managing radioactively contaminated land: implications for habitat diversity.

Radioactive contamination of agricultural land may necessitate long-term changes in food production systems, through application of selected countermeasures, in order to reduce the accumulation of radionuclides in food. We quantified the impact of selected countermeasures on habitat diversity, using the hypothetical case of two agricultural areas in Finland. The management scenarios studied were conversions from grassland to cereal production and from grassland and crop production to afforestation. The two study sites differed with respect to present agricultural production: one being predominantly cereal production and seminatural grasslands, while the other was dominated by intensive grass and dairy production. Some of the management scenarios are expected to affect landscape structures and habitat diversity. These potential changes were assessed using a spatial pattern analysis program in connection with geographic information systems. The studied landscape changes resulted in a more monotonous landscape structure compared to the present management, by increasing the mean habitat patch size, reducing the total habitat edge length and reducing the overall habitat diversity calculated by the Shannon diversity index. The degree of change was dependent on the present agricultural management practice in the case study sites. Where dairy production was predominant, the landscape structure changes were mostly due to conversion of intensive pastures and grasslands to cereal production. In the area dominated by cereal production and seminatural grasslands, the greatest predicted impacts resulted from afforestation of meadows and pastures. The studied management changes are predicted to reduce biodiversity at the species level as well as diminishing species-rich habitats. This study has predicted prominent side effects in habitat diversity resulting from application of management scenarios. These potential long-term impacts should be considered by decision-makers when planning future strategies in the event of radionuclide deposition.

Nature and properties of mollisols in a semiarid region in northern Jordan

Mollisols have developed from Quaternary deposits in northern Jordan under xeric moisture and thermic temperature regimes. The morphological features and physico‐chemical properties of three Pedons representing the major Mollisols in the arid and semiarid region in northwestern Jordan were studied. The studied soils show a wide variation in their morphological, physical, and chemical properties as a result of differences in mean annual precipitation, vegetation, and topography. Mollisols were well developed in the 450 mm precipitation zone. Also, they are confined to areas of steep slopes. These areas are either uncultivated or under tree crops They are characterized by being dry for periods in summers, but are moist in winter months. It is believed that present agricultural practices are degrading Mollisols into mollic intergrades.

Livestock and landscape

Abstract This short discussion considers the role that livestock play in the creation and dilution of landscape coherences. Using the example of the cattle breeds found in the British Isles, it argues that variations in breed types are an important but neglected part of the landscape. Selected examples are discussed and it is contended that cattle represent significant cultural aspects of the landscape. It is also acknowledged that variations in regional cattle types reflect the impact of past and present agricultural practice on the landscape. Consequently, the paper suggests that types of breeds should also be taken into account when considering policy measures to conserve the appearance of local landscapes. The paper concludes by calling for a more systematic study of local livestock.

Does our lack of vision threaten the viability of the reconstruction of disturbed ecosystems?

There is widespread acceptance that in the extensive wheat-sheep zone of Australia, development for agriculture and associated changes to ecological processes have resulted in major problems of loss of species, land degradation and potential decreases in agricultural productivity. Present agricultural practices are not sustainable. There has been a range of responses to these changes, from community action through Landcare and revegetation projects, to legislative action. Unfortunately, these responses and the actions that follow, are usually carried out without any long-term context or any clear understanding of what we want our agricultural landscapes to look like in 150?200 years. While phrases such as "achieve the conservation of biological diversity through the adoption of ecologically sustainable agricultural practices" are being widely used, they will never become reality without the development of a vision of what we as a society want these landscapes to look like and how we want them to function. As a matter of urgency, we should develop a collective vision for the future of our agricultural landscapes and use that vision to provide the framework to integrate conservation of the biota with management for agricultural production, while addressing the environmental problems we face now or which may arise as we adapt management to changing environmental conditions.

Claiming the high ground: Sherpas, subsistence, and environmental change in the highest Himalaya

Stanley Stevens brings a new historical perspective to his study of a subsistence society in ever-increasing contact with the outside world. The Khumbu Sherpas, famous for their mountaineering exploits, have frequently been depicted as victims of the world's highest-altitude tourist boom. But has the flow of outsiders to Mt Everest and the heights of Nepal in fact destroyed a stable, finely-balanced relationship between the Sherpas and their environment? Steven's innovative use of oral history and cultural ecology suggests that tourism is not the watershed circumstance many have considered it to be. Drawing on extensive interviews and data gathered during three years of fieldwork, he documents the Sherpas' ingenious adaptation to high-altitude conditions, their past and present agricultural, pastoral, trade and forest management practices, and their own perspectives on the environmental history of their homeland.

Bryophytes in perennially moist forests of Papua New Guinea: ecological orientation and predictions of disturbance effects

Water relations of bryophytes must be understood along at least four dimensions: hydration/dehydration frequency; hydration duration; dehydration duration; degree of water loss. All these are biomass-dependent functions such that large colonies of bryophytes may maintain hydration longer than smaller colonies. The spread of a bryophyte colony allows lateral movement of capillary water; contiguous clones will thus allow lateral conduction of that water. In contrast, separated tufts or cushions may store water but will contribute very little to its transfer over the surface of the phorophyte. Many of the tropical rainforests of New Guinea have a larger mass of epiphytic bryophytes than any temperate forest. The primary effect of disturbance in these forests is a reduction in bryomass, presumably due to desiccation because of increased insolation and wind movement. The reduction of bryomass will decrease water and mineral retention in the bryophyte clones; and the reduction in the size of those clones will reduce their contiguity and thus interfere with bryophyte-mediatcd water and mineral transfer. Disturbance may alter bryophyte species frequency but, under present agricultural and forestry practices in New Guinea, I have seen no evidence of significant loss of bryophyte species.

Groundwater in Deccan basalts of the Betwa Basin, India

Jointing, resulting from cooling and from movement, is common in the upper part of each basalt flow while the original crust of the flow was itself broken and jointed. The joints were often filled subsequently either with clay produced by weathering or by mineralization from silica- and lime-rich groundwater but where not obliterated they provide much of the permeability of the Deccan basalts, the rest being provided by the present-day weathering mantle. While quite distant correlation of lava flows can be made, particularly with the help of natural gamma and resistivity logging, there is little continuity of water-bearing levels, a yielding horizon in one well being essentially barren in another only tens of metres away. The aquifers have transmissivities of 50–500 m 2/day but they are very local and prolonged pumping always gives evidence of this in falling water levels. The regional transmissivity is only 4 m 2/day. Storativity is thought to be 10 −5. If drilling is stopped at 60 m the yield expectation is 175 m 3/day per well; deeper drilling gives expectation of only 5 m 3/day per 10 m of drilling. These are averages: in fact of the thirty holes drilled, eight gave negligible yield; in five of the nine holes which met aquifers deeper than 60 m the water was unsuitable for irrigation. Because of poor recharge and low storativity the deep aquifers do not offer much replenishable yield. The shallow aquifer is a bit better and full development of its resources will provide 50 mm to be used between the end of one monsoon and the start of the next. Of the 50, 30 mm is presently lost to baseflow during September and October, immediately following the monsoon and before the winter crop is planted. With present agricultural practice this 30 mm will continue to run to waste and only the remaining 20 mm is available for irrigation. Half of this is already pumped from open wells or from the rivers.

Ant foraging activity in tropical agro-ecosystems

The potential role of ants as biological control agents has been investigated in Mexican tropical agro-ecosystems. Ant predation is compared among plots planted in corn, bean, squash polycultures; bean and corn monocultures; and fallow fields. A second treatment, length of time of field cultivation, was also tested for each planting regime. All plot treatments reflect present agricultural practices in Mexico. Effectiveness of ant predation in each plot is measured experimentally as the rate of bait removal by ants. Bait removal by ants is significantly different among polycultures cultivated for various lengths of time. Bait removal is significantly different in old polycultures compared with the second-growth area suggesting that a select subset of the ant community may colonize polycultures. Since there are differences in ant foraging activity, it should be possible to enhance the effectiveness of ant predation in these agro-ecosystems.

Plant Physiology and some aspects of future agriculture.

From considerations of solar energy conversion data it is suggested that the total area required for feeding the entire human population of the world according to present agricultural practices and nutritional standards is relatively small, being about 2000 x 2000 km. This area includes roads etc. and that needed for crop production would be only 25% of this figure. The author proposes that agricultural production may benefit from the setting up, in various parts of the world, of 3000 units each about 30 x 40 km in area and devoted to a limited number of crops and served by its own research station. Some consequences of this suggestion are discussed.-F.A.S. (Abstract retrieved from CAB Abstracts by CABI’s permission)

CONSERVATION OF SOIL MOISTURE IN DRY LAND FARMING'

In tracts where irrigation works are few, either due to the geographical situation of the place or to the want of sufficient finance to undertake major irrigation works-either productive or protective -rainfall is ipso-facto the limiting factor in successful crop produc- tion. Such tracts as suffer from this initial disability of a geogra- phical disadvantage and handicap, must needs depend on Nature, to send forth her timely showers on parched up lands and crops. To this class, may be assigned the districts of Bellary, Anantapur, Cuddapah and Kurnool-and portions of Guntur and Nellore. The first four districts verily form the 'Famine zone of the Madras Presidency and the scope of this article is to show how best an agrarian calamity can be averted by improving the present agricultural practices and by the application of suitable methods for the conservation of soil moisture. It has come to pass-as evidenced from the statistics at our dis- posal that crop failure as a result of inadequate rainfall, is a matter of common occurrence and a normal crop has been purely an acci- dental achievement.