Browsing by Author "de Jong, E."
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Item Application of Saskatoon's de-watered sewage sludge to agricultural land(1991-02-21) Cowell, L.E.; de Jong, E.Item Assessing rainfall erosion risk in southern Saskatchewan from daily rainfall records(1989-02-16) Bullock, P.R.; de Jong, E.A mean annual rainfall erosion index (R1daily) calculated from daily rainfall records satisfactorily compared with the mean annual erosion index (R) calculated using the more accepted method with hourly rainfall records. An R1daily contour map of Southern Saskatchewan was constructed from a greater number of weather stations keeping daily rainfall records compared to the R contour map constructed from very few stations that keep hourly rainfall records. It was concluded that the R1daily contour map provided a more reliable assessment of rainfall erosion potential than the R contour map because the former distinguished local areas with high values and interpolation of rainfall risk involved much shorter distances between point measurements. Since significant erosion requires a combination of rainfall detachment as well as runoff, a runoff model that operated from daily climatic records was used to determine which days with rainfall also produced runoff. The runoff model was run for 62 stations in southern Saskatchewan and only days that produced runoff were included in the annual erosion index total. This effective erosion index (Reff) varied from 3.4 to 83.9 % of R1daily and was particularly sensitive to soil texture. Heavy-textured soils were, on average, more than four times as susceptible to water erosion than light-textured soils. It should be noted that the analysis does not include the effects of slope length and steepness, the crop canopy nor soil erodibility.Item Cultivation and landscape position effects on soil structure and related soil physical properties(1993-02-25) Cutts, M.I.; de Jong, E.Soil physical properties were evaluated at three sites (one native and two cultivated) in an area of hummocky terrain. The native site possessed the most favorable physical conditions and some of the soil physical properties at the native site displayed a spatial pattern related to their landscape position. Cultivation resulted in a deterioration of soil physical properties, while a spatial pattern was found to be: (i) not present, (ii) created, or (iii) maintained as length of cultivation was increased.Item Eco-physiological response to fertility and landform for spring wheat under rainfed environment in hummocky terrain, Saskatchewan, Canada(1993-02-25) Liu, W.Z.; de Jong, E.; Cowell, L.E.; Pennock, D.J.The experiment was made throughout the 1992 growing season on upper and lower slope positions at a site near Lanigan, Saskatchewan. Soil water reserves to 120 cm on the footslope was 38% more than on the shoulder at the beginning of the growing period, and the difference decreased gradually with wheat growth, Soil temperature on the lower slope at both the 50 cm depth and 100 cm depth was higher than on the upper slope before mid-July, whereas the opposite was true afterwards. Latent evaporation on the shoulder was higher than on the footslope. Significant differences occurred between slope positions as well as between fertilizer treatments for both the development of leaf area indices and for the accumulation of above ground biomass. Throughout the growing season, leaf water potentials indicated a high level of stress occurred in all treatments, with the shoulder position exhibiting the greatest stress. No significant difference of leaf water potential occurred between fertilizer treatments. Fertilizer application increased both total and grain yields, and raised water use efficiency, on both slope positions. The effect of the amount of precipitation in flowering-filling stage on harvest indices was enhanced with fertilizer application.Item The effect of fall stubble management on over-winter recharge and grain yield(1985-02-19) Kachanoski, R.G.; de Jong, E.; Rennie, D.A.Item The effect of traditional versus innovative farming(1982-02-18) Grevers, M.C.J.; de Jong, E.Item The effect of variable and uniform N-fertilizer application rates on grain yield(1985-02-19) Kachanoski, R.G.; Voroney, R.P.; de Jong, E.; Rennie, D.A.Item Effective rooting depth of mustard under dryland conditions(1993-02-25) Dharmasri, L.C.; de Jong, E.; Cowell, L.E.We conducted a field study to investigate the effective rooting depth of mustard (Brassicajuncea L. Coss.). The data on effective depth of root water extraction and root distribution are needed in understanding and modelling root-soil-water interactions and to use in soil water balance estimations. Data was collected from upper and lower slope positions in a mustard field. Soil water content was determined using neutron moderation (10- to 120-cm profile). Soil water content- time curves were used to identify the effective depths of root water depletion ("effective rooting depth"). Root distribution and the maximum rooting depth were measured with the trench profile method. For both slope positions maximum water depletion depths were deeper than the actual rooting depth at the early growth stage. This may be due to the upward water migration. Maximum rooting depth for mustard reached up to 150 cm at upper slope position but the effective rooting depth was found around 120 cm. This may be due to low rooting density at the bottom of the root zone at upper slope. At the lower slope, water depletion depth reached 100 em only for a short duration and was usually around 60-80 cm.Item Effects of erosion on soil quality and productivity of a field near Saskatoon(1989-02-16) de Jong, E.; Martz, L.W.Soil erosion has been identified as a major contributor to soil degradation on the Prairies. An 84 ha cultivated watershed near Saskatoon was selected to study the variability in erosion and deposition. 137Cs deposited mainly in the early 1960's was used as a tracer for soil movement. Soil erosion ranged from 35 t/ha/yr in small tributaries to the main channel, to 4 t/ha/yr or less on upper slope areas which occupied 60 % of the area. High rates of soil deposition were found in. upland depressions and in the main channel. The net soil loss from the basin was 2340 t or about 1 t/ha/yr. Seventy to 80% of the lost soil was retained ahead of a dam in the coulee leaving the field. It is estimated that the eroding areas of the field (approximately 77 ha) suffered an organic C loss of 275 t from the early 1960's to mid 1980's. Preliminary estimates indicate that about 215 t of organic C were deposited in the upland depressions and the main channel inside the field boundaries. Estimates of the organic C trapped in the coulee are in the order of 50 to 90 t. Further sampling will be needed to resolve the discrepancy between estimates of organic C lost from the field, and organic C trapped, in the coulee. Based on approximate relationships between soil depth and yield potential, it is expected that the production of about one quarter of the eroding area is adversely affected by erosion when other growing conditions are good.Item Effects of mature shelterbelts on microclimate and crop yield(1990-02-22) Kowalchuk, T.E.; de Jong, E.A study was conducted at Conquest, Saskatchewan, to assess the effects of mature caragana (Caragana arborescens Lams.) shelterbelts on soil moisture, potential evaporation, wind speed, and crop yield. Snow trap near the shelterbelts increased spring soil moisture contents, in the immediate area near the shelterbelts, by as much as 25 % above average field values. Potential evaporation and and wind speed between the belts was reduced by as much as 23 and 36 %, respectively. However, increased spring moisture, reduced evaporation and wind speed failed to produce significant yield differences as a function of distance from the shelterbelts. Severe moisture stress was the main factor limiting crop yield at the study site.Item Effects of soil management on denitrification(1988-02-19) Kirkland, J.A.; de Jong, E.Item Effects of soil redistribution on landscape patterns of organic carbon(2000-02-22) Dyck, M.F.; Pennock, D.J.; de Jong, E.Soil organic carbon (SOC) is important to soil productivity and is an important part of the global carbon cycle. Soil redistribution within hummocky landscapes has also resulted in SOC redistribution. Soil loss estimates using 137Cs techniques and SOC levels were measured on a 7x7 grid with a 100m sampling interval on a quarter section approximately 30 km east of Saskatoon. The quarter section has been under crop-fallow management for at least 50 years. 137Cs and SOC were also measured on a 5x6 grid (25m sampling interval) at a nearby native site as a reference for soil loss calculations. At the cultivated site, 34 out of the 49 sampling points had experience net erosion since 137Cs fallout (1960), 13 out of the 49 points were depositional, while 137Cs levels at the remaining two points were close to reference levels. A net soil loss of 7 Mg ha-’ yr“ was calculated based on the mean 137Cs concentration of the entire quarter section. Soil loss displayed a landscape pattern with footslope elements being areas of deposition and shoulder, backslope and level elements being eroded. SOC patterns followed soil loss patterns with depositional areas (footslopes) having higher levels of SOC than eroded areas. SOC that is not mineralized is redistributed within the landscape and concentrated into a relatively small area. As as a result, SOC levels over most of the quarter have been decreased substantially, indicating that there may be potential to sequester carbon over a larger area if management practices are changed.Item Growth and water use of irrigated and dryland lentils and wheat(1988-02-19) Livingston, N.J.; van Kessel, C.; de Jong, E.Lentils are becoming an increasingly more important crop in Saskatchewan with over 230,000 ha planted in 1987. A large part of this acreage was in the Brown Soil Zone. To date lentil water relations and adaptation to water deficits are largely undescribed. This study was initiated to determine the drought tolerance characteristics of lentils and to compare them to those of wheat growing under the same weather conditions. Dryland lentils exhibited considerable drought tolerance with large changes in osmotic potential in response to increasing soil water deficits. Despite maintaining high levels of turgor, values of stomatal conductance were very low. This behaviour enabled leaves to maintain high relative water contents and survive an extensive dry period. In contrast wheat displayed little drought tolerance. Consequently throughout the growing season the rates of dry land to irrigated above-ground dry matter was consistently higher for lentils than for wheat and at final harvest was 0. 71 and 0.41 for the two crops, respectively. Wheat and lentils had similar water use efficiencies, but lentils used more water because of their greater dry matter production. Very high dry matter production in irrigated lentils did not translocate into high grain yields.Item Irrigation with sewage effluent: nutrient inputs and its effect on crop quality(1976-02-11) Stewart, J.W.B.; de Jong, E.Item Irrigation with sewage effluent: the salt balance(1976-02-11) de Jong, E.Item Long term solute transport at the Laura site(2000-02-22) Dyck, M.F.; de Jong, E.; Kachanoski, R.G.Deep drainage in semi-arid environments such as the Canadian prairies may have significant implications for the subsurface movement of non-point source agricultural chemicals. Surface applied conservative tracers such as chloride can be used as indicators of long term water fluxes in semi-arid environments. In 1966, potassium chloride was applied to an Elstow soil approximately 50 km west of Saskatoon near the town of Laura. Chloride concentration profiles indicate quick movement of the majority of the applied chloride to depths of 150 to 200 cm in the first four years after application with very little movement occurring 4 to 28 years after application. Concentration profiles, however, reveal that small amounts of chloride have been leached below depths of 150 to 200 cm, and deep drainage fluxes below 150 to 200 cm are less than 0.1 cm/year. Deep drainage fluxes in concave lower slope positions are approximately 70% greater than the upper slope positions. Although small, deep drainage fluxes may be environmentally significant. The effects of topography have significant implications for the placement of manure and other agricultural chemicals.Item Management induced changes in aggregate stability in three different soil types(1997-02-20) Publicover, M.; de Jong, E.Poor aggregation reduces infiltration, increases runoff, and causes serious water erosion in many areas. These factors (especially reduced infiltration in the semi-arid prairie) influence soil/crop quality. Aggregate stability was assessed on cultivated and uncultivated fields in southern Saskatchewan. Three different landscape positions in three parent material types were evaluated. The relative importance of some of the mechanisms causing soil aggregate breakdown in the cultivated sites were also investigated. It was found that different mechanisms were important at different sites, however, landscape position had no influence. This paper will focus on the factors affecting soil aggregation at the three sites studied.Item Quantifying denitrification on a field-scale in hummocky terrain(1989-02-16) Elliott, J.A.; de Jong, E.Down-slope and cross-slope curvature and elevation were used to identify nine landscape elements for a slough-focused basin in hummocky terrain near Hafford, Saskatchewan. Denitrification was measured at monthly intervals from April to October in 1986, 1987, and 1988. The measured values were interpolated to daily values using a simple soil moisture budget and a regression model relating denitrification to moisture content and air temperature. The model predicted denitrification well except in 1987, the fallow year, when the denitrification flush due to substrate availability was underestimated. Annual denitrification was higher in 1987 than in either 1986 or 1988 when wheat and canola, respectively, were grown. Low-lying and convergent elements had greater denitrification than diverging elements or those higher in the landscape. The relative abundance of the landscape elements was used to extend the denitrification predicted for the landscape elements to the whole field.Item Rates of soil redistribution associated with Soil Zones and slope classes in southern Saskatchewan(1990-02-22) Pennock, D.J.; de Jong, E.Using 137Cs redistribution techniques we examined the relationship between mean rates of soil redistribution and average slope characteristics at twenty-one areas in the Brown, Dark Brown, and Black Chernozem Soil Zones of southern Saskatchewan. Net soil losses averaged 5.8 t ha-1 yr-1 for areas with mean gradients between 0 and 1.5°, 7.8 t ha-1 yr-1 for areas with mean gradients between 1.0 and 3°, and 11.3 t ha-1 yr-1 for areas with mean gradients between 3.5 and 8.5°. For all three slope classes, the highest rates of soil loss were found in the Dark Brown soil zone and the lowest rates in the Black Soil Zone. Net soil loss alone was, however, an inadequate indicator of the rate of loss within the areas because a considerable proportion of eroded soil was deposited within the confines of the study areas.Item Short term effect of breaking and cultivation on properties of an Oxbow landscape(1992-02-20) Anderson, R.F.; Pennock, D.J.; Anderson, D.W.; de Jong, E.Changes in soil quality over the first six years of cultivation were studied for an Oxbow landscape dominated by Black Chernozems. Bulk density at shoulder, footslope, and level landforms was found to increase by 15-20 % from 1985 to 1988 and by 3-4 % from 1988 to 1991. Similarly, organic carbon concentration declined by 17-37 % and 0-10 %, respectively, over the same periods. These results demonstrate that cultivation of virgin land has an almost immediate impact on soil quality. 137Cesium measurements indicated that appreciable soil erosion has not occurred in this landscape since cultivation began.