Impact of soil and water conservation measuren on catchment hydrological response: a case in north Ethiopia

Impact studies of catchment management in the developing world rarely include detailed hydrological components. Here, changes in the hydrological response of a 200-ha catchment in north Ethiopia are investigated. The management included various soil and water conservation measures such as the construction of dry masonry stone bunds and check dams, the abandonment of post-harvest grazing, and the establishment of woody vegetation. Measurements at the catchment outlet indicated a runoff depth of 5 mm or a runoff coefficient (RC) of 1·6% in the rainy season of 2006. Combined with runoff measurements at plot scale, this allowed calculating the runoff curve number (CN) for various land uses and land management techniques. The pre-implementation runoff depth was then predicted using the CN values and a ponding adjustment factor, representing the abstraction of runoff induced by the 242 check dams in gullies. Using the 2006 rainfall depths, the runoff depth for the 2000 land management situation was predicted to be 26·5mm(RCD 8%), in line with current RCs of nearby catchments. Monitoring of the ground water level indicated a rise after catchment management. The yearly rise in water table after the onset of the rains (ΔT) relative to the water surplus (WS) over the same period increased between 2002-2003 (ΔT/WS D 3·4) and 2006 (ΔT/WS >11·1). Emerging wells and irrigation are other indicators for improved water supply in the managed catchment. Cropped fields in the gullies indicate that farmers are less frightened for the destructive effects of flash floods. Due to increased soil water content, the crop growing period is prolonged. It can be concluded that this catchment management has resulted in a higher infiltration rate and a reduction of direct runoff volume by 81% which has had a positive influence on the catchment water balance. © 2010 John Wiley & Sons, Ltd

Influence of time and level of urea application on seed production of paspalum plicatulum at mt cotton, south-eastern queensland

Five levels of urea were applied as single or split dressings in early summer, at floral initiation(about Febraury 14), or at inflorescence exsertion to Paspalumplicatulum cv. Rodds Bay grown in rows on ared-yellow podzolic soil.All components of seed yield-tiller density, tiller fertility, raceme number and seed number, and seed size-were influenced by external nitrogen supply. The effects of adequate nitrogen supply during onedevelopment phase usually persisted subsequently when differences in plant nitrogen concentration haddisappeared. Nitrogen applications during the vegetative and floral initiation stages were most influential.The efficiency of response varied from 5.6 kg additional crude seed produced per kg N at the 50 kg N ha level to 1.2 at the 400 kg N ha -' level. High levels of urea (200 or 400 kg N ha - I)induced lodging and poor recovery of seed at harvest during a wet year, accentuated moisture stress during a dry year, but improved seed viability

Managing forage and turf‐type bahiagrass for seed production

Bahiagrass (Paspalum notatum Flüggé) is the most extensively cultivated perennial warm-season grass in the southeastern United States for pasture, utility turf, cover cropping, and soil stabilization. The University of Florida Institute of Food and Agricultural Sciences bahiagrass breeding program has recently selected several improved forage- and dwarf-turf-type tetraploid breeding lines. However, seed production andseed quality quantification is needed before proposing any of these lines for cultivar release. The objectives of this study were (a) to evaluate seed production in seven tetraploid bahiagrass breeding lines (two forage-type apomictic hybrids, and five turftype facultative apomicts) and the cultivar ?Argentine?, and (b) to determine the optimum management practices (defoliation timing [May, June] and N rate [0, 60, and 120 kg N ha−1]) to increase seed yield and quality. Six seed traits were evaluated during 2 yr (first and second production year) under a randomized complete block design in a strip-split-plot arrangement with three replications. Eight genotypes (main plot), two defoliation timings (subplot), and three N fertilization rates (sub-subplot)were tested. All breeding lines produced viable seed comparable with Argentine,although some of them exhibited very low reproductive efficiency. Nitrogen fertilization improved seed yield by increasing inflorescence density but did not affect seed quality traits. Defoliation in May produced greater seed yield, whereas defoliation in June resulted in greater seed quality, especially for turf-type genotypes. The information generated in this study will guide cultivar release(s) and will be used to develop targeted recommendation practices for seed production in the species.Fil: Rios, Esteban Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; Argentina. University of Florida; Estados UnidosFil: Zilli, Alex Leonel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Kenworthy, Kevin E.. University of Florida; Estados UnidosFil: Mackowiak, Cheryl. University of Florida; Estados UnidosFil: Quesenberry, Kenneth. University of Florida; Estados UnidosFil: Blount, Ann. University of Florida; Estados Unido