Effects of millet stover residue (0,500, and 2000 kg ha-') on wind erosion and surface soil properties were determined from 1991 to 1993 at the ICRISAT Sahelian Center in Niger, West Africa. Soil flux 0.1 m above the ground was significantly reduced with 2000 kg ha-' residue but not with 500 kg ha-'. Topographic measurements indicated that soil removed from the soil surface was less with either residue level than in the control. After 2 y, the soil surface (O-0.01 m) of both residue treatments had less coarse sand than the control, but more fine sand and clay, more organic carbon and an increased cation exchange capacity. The organic-C content of blown material was greater than that of surface soil. An amount of 500 kg ha-' residue can be considered useful for soil conservation, but 2000 kg ha-' are required for a significant reduction of soil flux caused during severe wind erosion events.
Forces driving the initiation of watershed management activities in Alabama have ranged from top‐down, agency‐led initiatives to bottom‐up, citizen‐led initiatives. A number of watershed projects in Alabama were examined including three NPS projects funded by U.S. EPA grants and a more comprehensive locally‐initiated watershed management authority. Watershed projects were categorized into four different models. Factors which produced significant differences in the development and utilization of social capital and local capacities for watershed management were investigated. The success of watershed management initiatives was examined qualitatively and appears to correlate with a number of social factors. These factors include the extent of stakeholder involvement, the availability of social capital in the watershed, and the presence of a real or perceived water resource concern or problem. Both short term project success and the longer term prognosis for continued watershed management activities seems to depend most upon the amount of social capital in the watershed. Two major changes in resource management programs and organizations could lead to increased focus on and support for local watershed management initiatives. These are reorganization of resource management agencies around watershed units, and assignment of at least one staff person in each watershed unit to watershed management.
S c o p e of t h e j o u r n a l Agricukural and Forest Meteorology is an international journal for the publication of articles and reviews in the interdisciplinary fields of meteorology and plant, animal and soil sciences as applied to heat, mass and momentum transfer in agriculture, forestry or natural ecosystems. Articles must appeal to an international audience. Emphasis is on basic and applied scientific research to problems in agriculture, forestry and natural ecosystems. Theoretical models should always be tested against experimental data. Typical topics include radiation transfer in plant canopies, evapotranspiration, energy transfer, air turbulence i n and above plant canopies, forest-fire/weather interactions, pollutant fluxes to vegetation in the field and enclosures, trace gas fluxes in man-made and natural ecosystems, climatology of plant distributions, glasshouse energy balances and climatology, animal biometeorology. Special issues devoted to single topics, conference proceedings and comprehensive reviews are also published. P u b l i c a t i o n schedule a n d s u b s c r i p t i o n i n f o r m a t i o n Agricultural and Forest Meteorology will have flve volumes in 1993. The subscript~on for 1993 1000 A€ Amsterdam). Annual subscription price in the USA US $1 003 (subject t o change). including air speed delivery. Application t o mail st second class postage rate is pendin at Jamaica,
Pearl millet [Pennisetum gluucum (L.) R. Br.] is grown worldwide in areas affected by wind erosion, but no data on associated damage to millet are available. Laboratory wind tunnel experiments were conducted to determine the kind and extent of damage to millet caused by wind, sandblasting, and burial. In Exp. 1, millet was exposed for 15 min to wind (8, 11, or 14 m s-') or wind + sand (8.3, 25.0, or 41.7 g ,-I-I sand abrader flux) at 8 and/or 16 d after emergence (DAE). Viable leaf area, leaf net photosynthesis, and NO3 content were measured through 21 DAE and dry matter production through 57 DAE. In Exp. 2, millet was seeded as three single seeds or in tufts, exposed to 25 g m-I s-' sand flux for 15 min at the 1-, 2-, or 3-leaf stage, and then manually covered by 15 mm sand. Survival was monitored weekly; dry matter was determined 70 DAE. In Exp. 1, survival was uniformly 100%. Wind alone or low sand flux had no effect on viable leaf area. High sand flux decreased viable leaf area by 74% at 2 d after the 8-DAE exposure and 42% at 5 d after the 16-DAE exposure. Photosynthesis of the remaining leaf area was reduced up to 88% immediately after exposure compared with the control, and NO3 content of sandblasted millet was increased up to six times. Dry weight was reduced 40% at 21 DAE by the highest sand flux, but 9.7% at 57 DAE. In Exp. 2, burial decreased millet survival and dry weight. Buried tufts had a higher survival rate and 35% more dry weight than buried single plants. Millet buried at the 1-leaf stage had 28% higher survival than plants treated later. Sandblasting reduced dry matter of buried millet only. Regression analyses between calculated total kinetic effects and growth parameters showed low ? values. Millet can survive short-term sandblasting at any growth stage, but growth is reduced by strong sand flux, a sequence of wind erosion events during early growth, or by combinations of abrasion with burial by blown sand. s IND EROSION affects 430 million hectares worldwide, w o r 897 o of the susceptible dryland areas (UNEP, 1992).
Effects of three levels of millet stover residue (0, 500, and 2000 kg ha-') on establishment and growth of pearl millet (Pennisetum glaucum (L.) R.Br) were determined in a wind-erosion-affected area in Niger, West Africa, during 1991 and 1992. The extent of millet seedlings buried by blown soil in plots with 500 kg ha-' residues was similar to that of control plots. A residue amount of 2000 kg ha-' reduced the extent of covered millet, but did not provide complete protection during severe sand storms. Partial covering of millet seedlings by blown soil decreased biomass yields compared to uncovered millet. Grain production, averaged over two years, was about 500 kg ha-' for the control, 570 kg ha-' with 500 kg ha-' residue, and 730 kg ha-' with 2000 kg ha-' residue. Increased yields were caused by both wind erosion protection and direct growth stimulating effects of residue. Stover yields for all treatments in both years were less than 2000 kg ha-' and thus insufficient to sustain the levels required for protection of crops against wind erosion damages. An increase in dry matter left in the field or the implementation of alternative wind erosion control measures is needed for sustainable crop production in wind-erosion-affected areas.
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