خيارات البحث
النتائج 91 - 100 من 142
[The sulfate-acidity relationship in precipitation]
1983
Toro E, P. (Chile Univ., Santiago (Chile). Facultad de Ciencias Fisicas y Matematicas)
[Effect of urban water discharge into a large-bedded fluvial current, Valdivia, 1983]
1983
Scoebitz, R. | Montes, L. (Universidad Austral de Chile, Valdivia (Chile). Facultad de Ciencias Veterinarias)
[Research advances on the influence of DDT on nitrogen fixation and forage seed germination in soils of Region 10]
1983
Romero, J. | Ruiz, V.M. | Urzua, H.
[Heavy metals in the Mapocho River]
1983
Gaslaschi P, G. | Vergara F, I. | Schalscha B, E. (Chile Univ., Santiago (Chile). Facultad de Ciencias Basicas y Farmaceuticas)
[Comparative study of some methods of cyanide analysis in water]
1983
Bastidas, M.E. | Tello Rosales, A.
[Monitoring and control of drinking water quality in the Metropolitan Region]
1983
Basunan Diaz, R. (Ministerio de Salud, Santiago (Chile))
[Acidity of rain waters in the Metropolitan Region and Region 5]
1983
Villaseca C, S. (Instituto de Investigaciones Agropecuarias, Santiago (Chile). Estacion Experimental La Platina)
Transport of ammonium- and nitrate-nitrogen in surface runoff from pasture as influenced by urea application النص الكامل
1983
Sharpley, A.N. | Syers, J.K. | Tillman, R.W.
The effect of a surface application of urea on the transport of N in surface runoff from permanent pasture in New Zealand was investigated under natural rainfall conditions. Maximum concentrations of NH4- N(3.6 mg l-1) and NO3-N(4.5 mg l-1) in surface runoff were attained 3 and 1 week, respectively, following urea application (60 kg N ha-1). Amounts of NH4-N, NO3-N, and total N transported in surface runoff from unfertilized (1.58, 0.52, and 4.73 kg ha-1 yr-1, respectively) and fertilized pasture (1.74, 1.09, and 8.96 kg ha-1 yr-1)were less than inputs in precipitation (2.09, 3.63, and 10.9 kg ha-1 yr-1), respectively. Amounts of NH4-N, NO3-N, and total N transported in surface runoff were only 0.3, 1.0, and 7.1 % of that applied. The mean annual concentration of NH4-N (0.9 mg l-1) in surface runoff from unfertilized pasture was above the recommended levels for drinking water (0.5 mg l-1) and the mean concentration of NO3-N (0.5 mg l-1) was greater than levels associated with accelerated cutrophication (0.3 mg l-1 ). The practicality of attaining or maintaining N concentrations in surface runoff from fertilized agricultural land below recommended levels is questioned.
اظهر المزيد [+] اقل [-][Pollution prevention methods in fast flowing rivers]
1983
Rozas Elgueta, E. (La Serena Univ., Santiago (Chile))
[Nuclear techniques in environmental pollution studies]
1983
Aravena, R. | Cortes, E. | Heresi, N. (Comision Chilena de Energia Nuclear, Santiago (Chile))
