Spatial variability of boron availability in canola

Non-Peer ReviewedThe spatial variability of hot water soluble boron (HWS-B) and yield responses of canola to B fertilization was assessed at sites in the Grey soil Zone using a linear sampling transect. At each site, 128 soil samples were taken at 3-meter intervals and analyzed for HWS-B, physical and chemical soil properties. Results indicate that the organic matter content, particularly in acidic soils, strongly influenced HWS-B content. To a lesser extent, soil pH and texture also contributed to HWS-B variability. On the alkaline site, apparent yield increases to foliar B were correlated to soil pH in a positive and significant manner. The HWS-B test failed to predict the yield responses to B fertilization. In the year of the study eat and drought stress occurred during a period when canola is most sensitive to a B deficiency (flowering) and also may have contributed to the yield increases. Results of a geostatistical analysis, known as wavelet analysis, revealed that at spatial scales > 50m, variability in HWS-B content is significant. Therefore, significant responses to B fertilization may not be detected with the traditional random complete block design

Assessing microbial communities in transplanted soils after 21 years

Non-Peer Reviewe

Root-associated bacterial communities in flax (Linum usitatissimum) and their response to arbuscular mycorrhizal (AM) inoculation

Non-Peer Reviewe

Mobility of copper fertilizers in soils

Non-Peer ReviewedDue to its cationic nature, Cu mobility is assumed to be very limited in Prairie soils, which are dominated by negatively charged constituents (McLaren et al., 1983). Clay and organic matter are major sources of these negatively charged surfaces. Root interception, therefore, plays an important role in plant uptake of Cu. Normally, where Cu fertilizer applications are required to correct a deficiency, proximity to growing roots is considered essential (Gilkes and Sadleir, 1979). Incorporation of surface broadcast copper sulphate (CuSO4) has been an effective practice. However, over the past decade, there has been a significant shift towards less tillage and an increased awareness of other products and methods of application. Chelating agents are added to nutrient solutions to increase the solubility of metal cations. Metal chelates are characterized by the formation of more than one bond between the metal and functional groups of the complexing agent, forming a ring structure incorporating the metal ion. One of the most common chelating agents used for this application is EDTA (ethylene diamine triacetic acid). The relatively high stability of this product in chemical reactions is seen as an advantage for maintaining the availability of the nutrient. The objective of this experiment was to identify the relative mobility of Cu, using two fertilizer products, namely, CuSO4 (salt) and Cu-EDTA (chelate)

Microbial community structure in long-term no-till and intensive-till soils

Non-Peer ReviewedConversion from intensive tillage (IT) to no-till (NT) management creates an altered habitat for soil microorganisms. We utilized four long-term tillage experiments in Saskatchewan and Alberta to compare NT and IT microbial communities. Microbial abundance increased at the soil surface (0- to 5-cm depth) in NT vs. IT soils. Differences were much less pronounced or negligible at the 5- to 10-cm and 10- to 15-cm depths. Despite increased biomass of fungi and bacteria in NT surface soils no significant shift in the relative proportion of individual groups of organisms within the community was observed. Similarly, analysis of bacterial DNA fingerprints indicated that while microbial community clusters in the 0- to 5-cm depth increment were different than those at greater depth, there was no significant effect of tillage. Our results demonstrate that depth was a stronger determinant of microbial community structure than tillage management

Optimizing productivity in organic farming systems through variation of seeding density for field peas and lentils

Non-Peer Reviewe

Copper fertilization of wheat on soils with marginal copper levels

Non-Peer ReviewedCopper (Cu) is the micronutrient most often deficient in Saskatchewan. Fertilizer placement is an important consideration, particularly in minimum tillage systems, because Cu is generally thought of as immobile in soil. Several new products and methods of application have become available since the last local research was completed in the mid-eighties. This study was conducted to identify relative effectiveness, as indicated by response of hard red spring wheat (Triticum aestivum L. cv. AC Barrie) to a variety of Cu fertilization strategies on mineral soils having low levels of available Cu. Field experiments at five Saskatchewan sites over three years compared the effect of Cu treatment on wheat yield, tissue and grain Cu concentration, thousand kernel weight and grain Cu accumulation. The ranking of Cu fertilization method from most to least effective, was: foliar Cu (sulphonate) at Feekes 6 or 10 > broadcast and incorporated Cu sulphate at 5.5 kg ha-1 or 11 kg ha-1 > broadcast Cu sulphate with no incorporation. Broadcast Cu oxysulphate was ineffective, particularly without incorporation. Seed placed Cu sulphate or oxysulphate were also ineffective. Where Cu deficiencies are confirmed, foliar application of Cu products are recommended for response of wheat within the year of application

Growth and nitrogen fixation of field pea and lentil as influenced by herbicides: a three year field study

Non-Peer ReviewedA three-year field study was conducted in the Dark Brown and Black Soil Zones of Saskatchewan to assess the effects of trifluralin (Treflan ), metribuzin (Sencor), MCPB (Tropotox), and sethoxydim (Poast) on growth and symbiotic nitrogen fixation of field pea (Pisum sativum cv. Trapper) and lentil (Lens culinaris cv. Eston). Herbicides were applied at Saskatchewan recommended field rates and twice the recommended field rates. Treflan, Sencor, and Poast did not adversely affect plant growth or nitrogen fixation potential of field pea and lentil when applied at recommended field rates. Similarly, application of MCPB at the recommended rate did not adversely affect field pea under normal growing conditions. In some instances, herbicide application at the recommended rate was observed to have a stimulatory effect on growth and nitrogen fixation. In contrast, at application rates in excess of those currently recommended in Saskatchewan, or when plants were severely stressed by unfavorable growing conditions such as poor soil moisture, plant growth, yield, nodulation, and nitrogen fixation were adversely effected by herbicides. These effects were not consistent nor were they predictable. MCPB is not registered for use in lentil and, when applied in this crop, often resulted in reduced nitrogen fixation and seed yield. In all cases, data suggest that reductions in the nitrogen fixation potential were due to indirect effects of herbicide application on plant growth rather than to direct effects on nodulation and nitrogenase activity

Impact of in-crop and soil residual herbicides on effective nitrogen fixation in field pea (Pisum sativum L.) and chickpea (Cicer arietinum L.)

Non-Peer ReviewedA three-year project was initiated in 2004 to examine the effects of residual herbicides and registered “in-crop” herbicides, both soil and foliar applied, on N fixation and consequent yield of field peas and chickpeas. Inoculation strategies were examined to determine if inoculant formulation (i.e., peat powder versus granular inoculant) influences the degree to which herbicides can affect N fixation. This research is ongoing and thus all results are considered preliminary. Preliminary results in field pea, suggest that where herbicides had a negative effect on N fixation, the effects occurred at relatively early growth stages (i.e., soon after herbicide application) and were typically overcome at later growth stages. In addition, granular inoculants were associated with increased N fixation as compared to peat powder inoculants, and may have mitigated any negative herbicide effects. Chickpea incurred damage from the herbicides and all treatments had significantly less N fixation than the control. In general, results suggest that N fixation may be compromised if herbicides cause significant plant damage; however, improved weed control associated with herbicide application may counter the negative impact on early N fixation