Development of a Soil N Test for Fertilizer Requirements for Wheat

Abstract

2 Optimal fertilizer nitrogen (N) rates result in economic yield levels and reduced pollution. A soil test for determining optimal fertilizer N rates for wheat has not been developed for Quebec, Canada, or many other parts of the world. Therefore, the objectives were to determine: 1) the relationship among soil nitrate (NO − 3 )-N, soil ammonium (NH + 4 )-N and N fertilizer on wheat yields; and 2) the soil sampling times and depths most highly correlated with yield response to soil NO − 3 -N and NH + 4 -N. In a three year research work, wet and dried soil samples of 0-to 30-and 30-to 60-cm depths from 20 wheat fields that received four rates of N fertilizer at seeding and postseeding (plants 15 cm tall) were analyzed for NH + 4 -N and NO − 3 -N using a quick-test (N-Trak) and a standard laboratory method. Wheat yield response to N fertilizer was limited, but strong to soil NO − 3 -N.

OPTIMAL N FERTILIZATION, USING TOTAL AND MINERAL N, AFFECTING CORN (ZEA MAYSL.) GRAIN N UPTAKE

“…Using different regression models, the best-fitted ones were selected and accordingly the regression parameters, which indicated the contribution of each model parameter to the amount of N absorbed by corn grain as well as the coefficients of determination, were calculated. According to the equations and the related coefficients of determination, postseeding is the most appropriate time to take the soil samples for N analysis, which is also in agreement with the results of our other experiments and the work of other researchers (Magdoff, 1991;Klapwyk and Ketterings, 2006;Miransari and Mackenzie, 2010, 2011a, 2011b. The other interesting point about the calculated equations is that in all equations most equation coefficients are in a similar range indicating the precision of the equations under different conditions for the evaluation of N dynamic in soil, its effects on corn grain uptake and eventual prediction of proper N fertilization.…”

“…A wide range of soil tests have been tested so far using soil and plant samples (Magdoff et al, 1984(Magdoff et al, , 1990Sainz Rozas et al, 2000;Klapwyk and Ketterings, 2006;Mackenzie, 2011a, 2011b). However, to our knowledge, there is limited data related to the use of corn grain N uptake as affected by soil total and mineral N to determine optimum N fertilization (Miransari and Mackenzie, 2010, 2011a, 2011b. Hence, in these three-year experiments using a wide range of soil types under corn, the amounts of N in the soil and corn grains were determined.…”

“…The response of different plant parameters was tested, including grain and straw yield of corn and wheat as well as grain N-uptake to the experimental treatments such as total and mineral N for planning appropriate fertilization strategies (Miransari and Mackenzie, 2010, 2011a, 2011b. For wheat, the N test indicated that sampling at seeding is the more appropriate time for the determination of proper N fertilization using both crop yield and grain N uptake.…”

Molecular cloning and functional analysis of two phosphate transporter genes from Rhizopogon luteolus and Leucocortinarius bulbiger, two ectomycorrhizal fungi of Pinus tabulaeformis

“…Plants, such as wheat, require at least 16 macro-and micronutrients for their growth and reproduction (Miransari and Mackenzie 2011); among these nutrients, phosphorus (P) is one of the limiting factors that influence forest productivity and crop yields. In addition, P is particularly important for plant water uptake.…”

The Role of Soil Microbes in Plant Nutrient Availability

“…AM fungi can also increase the uptake of different nutrients by their host plant through their extensive hyphal network. Although there are some signs indicating that AM fungi can affect the process of N uptake by the host plant through their extensive hyphal network and production of different compounds, the greater details have yet to be further investigated (Podile and Kishore, 2006;van Loon, 2007;Miransari, 2011b).…”