Browsing by Author "de Jong, R."
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Item Effect of cropping frequency, crop type, and fertilization on nitrate leaching in a semi-arid environment(2005-02-17) Zentner, R.P.; Selles, F.; Campbell, C.A.; De Jong, R.; Lemke, R.; McConkey, B.G.Item Effect of fallow frequency on soil water conservation in the semi-arid region of Saskatchewan(2008-03-28) Basnyat, P.; De Jong, R.; Zentner, R.P.; Campbell, C.A.; Cutforth, H.; Desjardins, R.The effects of fallow frequency on soil water conservation were quantified for a 40 yr (1967-2006) field experiment conducted on a medium textured Orthic Brown Chernozem (Aridic Haploboroll) in semiarid southwestern Saskatchewan, in which soil water contents were measured each year in early spring, shortly after harvest, and again just prior to freeze-up in the fall. The three treatments examined were continuous wheat (Triticum aestivum L.) (Cont W) and fallow-wheat (F-W), each receiving N and P fertilizer and Cont W receiving only P. On average, 36 % of the precipitation received during the fall and winter months for Cont W (N+P) was conserved in the soil. In the summer fallow system (F-W (N+P)) a greater proportion (42 %) of the precipitation was conserved during the first fall and winter. During the second overwinter period, only 6 % of the precipitation received was conserved in the F-W system compared to 44 % in the first overwinter period. Compared to the 36% of fall and wither precipitation conserved in Cont W (N+P), inadequate N fertility (Cont W (+P)) resulted in only 27 % of the precipitation being conserved during this period. We developed equations that will allow estimation of water conserved as a function of precipitation received between harvest and seeding for F-W and Cont W (N+P. Trends in grain yield were fairly closely correlated with growing season precipitation and potential evapotranspiration.Item Effect of fallow frequency, fertilizer, and available water on net N mineralization under wheat grown in the semi-arid Brown Soil Zone(2008-02-28) Zentner, R.P.; Campbell, C.A.; Basnyat, P.; De Jong, R.; Lemke, R.; Desjardins, R.Item Estimation of Canadian manure and fertilizer nitrogen application rates for crops at the soil polygon level using the CANB v2.0 model(2006-03-02) Yang, J.Y.; Huffman, T.; Drury, C.F.; De Jong, R.; Yang, X.M.; Liu, Y.C.In response to national environmental and climate change modeling projects such as agri-environmental indicators, greenhouse gases, carbon sequestration and policy scenarios, fertilizer N and manure nitrogen N application rates were estimated for individual crops at the Soil Landscapes of Canada (SLC) polygon scale (1:1 million). This database provides an estimate of the actual amount of N applied per crop and per hectare, based on provincial fertilization recommendations, manure production levels of each type of livestock and reported amounts of fertilizer sold. The database is being incorporated into ongoing programs related to Kyoto accounting of greenhouse gas emissions, environmental performance and policy formulation at Agriculture and Agri-Food Canada. A standardized Canadian Agricultural Nitrogen Budget (CANB v2.0) model was developed to calculate the agri-environmental indicators Residual Soil Nitrogen (RSN) and Indicator of Risk of Water Contamination by Nitrogen (IROWC-N). CANB is a national-level model that operates on 3500 SLC polygons using generalized soil, landscape, climate, and Census of Agriculture socioeconomic data. It is designed to provide a regional update on the soil N balance for each of the census years of 1981, 1986, 1991, 1996, 2001 and into the future. The database and model have the capability to calculate a number of different components of the nutrient balance, including the inputs of fertilizer N, manure N, biological N and atmospheric N and N the removals of N in the harvested proportion of the crop and via nitrogenous gas emissions. This paper describes the procedures to estimate fertilizer N and manure N inputs for each crop within each polygon. It includes: (i) the compilation of soil-specific N application rates from provincial extension guidelines, (ii) the calculation of total manure N production from animal numbers and excretion rates, (iii) the calculation of available manure N after storage and handling losses, and (iv) the recommended and adjusted nitrogen application rates. Adjustments were made to account for the amount of inorganic N in the manure applied to the various crops. The adjusted nitrogen rate data was also reconciled with the provincial fertilizer sales data.Item Nitrate leaching after 17 years in no-tilled crop rotations in southwestern Saskatchewan(2005-02-17) Selles, F.; Campbell, C.A.; Zentner, R.P.; De Jong, R.; Lemke, R.; McConkey, B.G.Item Nitrogen effects on water use efficiency in the semi-arid Canadian prairies(2011-03-15) Kröbel, R.; Lemke, R.L.; Campbell, C.A.; Zentner, R.P.; Steppuhn, H.; Desjardins, R.L.; De Jong, R.In the semiarid environment of the Canadian prairies, water is the main constraint to crop production. Few studies have examined the influence of fertilizer on water use efficiency (WUE) and fewer still have made comparisons on a cropping system basis. We assessed the impact of fertilizer N on WUE in a 39-year crop rotation experiment conducted on a Brown Chernozemic soil at Swift Current, Saskatchewan. The cropping systems included continuous wheat (Cont W) with N+P and P fertilizer alone, and a fallow-wheat-wheat (F-W-W) system with N+P and P only. All cropping systems were managed using conventional tillage practices. We developed an equation to asses WUE of the cropping systems that included water use during the fallow year. We also calculated precipitation use efficiency (PUE, i.e., yield/harvest-to-harvest precipitation). WUE and PUE values and fertilizer effects were greatest in the later third of the study period, due to the increase in recommended fertilizer N rates applied and the more favorable moisture conditions that prevailed. We converted PUE results into net return values ($ ha-1 mm-1 water) by assuming an average price over the 39-yr period and found that N fertilizer in the Cont W system earned an average return above fertilizer cost of $36.39 ha-1 yr-1 and $9.81 ha-1 yr-1in the F-W-W system.Item Test of Stanford-like N mineralization model with field-derived data(1986-02-20) Campbell, C.A.; Jame, Y.W.; de Jong, R.