Rye and grass cover crops can potentially intercept residual soil mineral nitrogen (SMN), reduce overwinter leaching, transfer SMN to next growing seasons and reduce the fertilizer need of subsequent crops. These aspects were studied for 6 years in continuous silage maize cv. LG 2080 production systems receiving 20-304 kg N/ha, on a sandy soil in the Netherlands. Rye cv. Admiraal and grass...... hiện toàn bộ
A review with 41 references including a detailed examination of models of the exchange process underlying these equations and a discussion of the assumptions inherent to these models and the ensuing limitations of the resulting equations. Some suggestions are made on the direction of future developments in this field. (Abstract retrieved from CAB Abstracts by CABI’s permission)
Tjisse Hiemstra, W.H. van Riemsdijk, M.G.M. Bruggenwert
Titration curves of a synthetic pure crystalline gibbsite suspension have been made at three NaCl levels. The synthesized gibbsite is characterized by TEM, TGA and X-ray diffraction. The overall BET surface area and the surface area of the edges of the hexagonal crystals are determined. The surface structure of gibbsite is discussed. The surface charge ( sigma 0)-pH data are analysed with ...... hiện toàn bộ
A study was made in 1987-89 of the wind protection provided by a sparse tree canopy in a savanna woodland (mainly Acacia tortilis) edge in N. Tanzania. Wind speeds were measured at two heights (1.0 and 2.5 m) along transects perpendicular to the prevailing wind; tree density ranged from 60 to 150 stems/ha. A simple model was formulated for average wind reduction within such canopies. Avera...... hiện toàn bộ
M.C.S. Wopereis, J. Ceuppens, Pascal Boivin, A. N'Diaye, Alioune Kane
Soil quality under irrigation in the Senegal River Valley may become affected by salinization (Delta) and alkalinization (Middle Valley) processes. The salinity status of 158 irrigated rice fields in the Delta was measured with an electromagnetic conductivity meter. Double-cropped fields (two rice crops per year on the same field) were least saline (average horizontal reading: 0.6 dS/m), f...... hiện toàn bộ
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