Dark Brown Soil Zones Research Articles

The potential of growing soybean in Saskatchewan and its irrigation water needs under climate change scenarios—a modelling study

The soybean industry in Canada is seeking opportunities to expand cultivation due to economic and environmental benefits of growing soybean. Climate projections indicate that soybean expansion into Saskatchewan would be possible with the increases in the available crop heat units under a future warmer climate; however, crop water availability could limit yields. Using a crop growth model, we simulated soybean yields within the Canadian Regional Agricultural Model regions in Saskatchewan for the near-term (2030s), mid-term (2050s), and distant future (2070s) periods under different climate scenarios. Soybean yields were simulated without water stress (potential yield), with water stress (rainfed yield), and under full and partial irrigation scenarios. Irrigation water needs were estimated under the irrigation scenarios and irrigation water availability was discussed. Our results suggest that reasonable and likely more profitable yields (∼2000–2500 kg ha−1) can be achieved under rainfed conditions in the Black soil zone neighbouring Manitoba but soybean production would be less favourable in the Dark Brown soil zone and least favourable in the Brown soil zone. Northeastern regions in the Black soil zone were found to be suitable for growing soybean cultivars in the maturity group (MG) 0 in the distant future and MG 00 in the mid-term under the medium–high greenhouse gas emission scenarios. Soybean would still not be suitable in the northwestern region. Our results indicate that regions in central Saskatchewan requiring 120–170 mm of irrigation are more likely to benefit from the proposed Lake Diefenbaker Irrigation Projects in the future.

Performance and Economic Evaluation of Low-Lignin Alfalfa ‘Hi-Gest® 360’ in Saskatchewan Canada

A three-year (2018–2020) study was conducted in Lanigan (Thin Black soil zone) and Saskatoon (Dark Brown soil zone), SK Canada to compare low-lignin alfalfa (Medicago sativa) cv. Hi-Gest® 360 (HiGest) with alfalfa- cv. AC Grazeland (Grazeland) in monoculture and binary mixtures with hybrid bromegrass (HBG; cv. AC Success) for forage yield, nutrient profile, and establishment costs. Field plots were seeded in August 2017. Stands were harvested at three maturity stages of alfalfa (1 = 10% bloom; 2 = 40% bloom; and 3 = 100% bloom). Compared to Grazeland, HiGest alfalfa yielded 25% less in Saskatoon in monoculture, but no difference was found in Lanigan. Averaged across two sites, HiGest had 8.6% less acid detergent lignin (6.51 vs. 5.95%) and 10.3% greater in vitro neutral detergent fiber digestibility (42.7 vs. 38.7% of neutral detergent fiber). In the binary mixtures, however, differences in yield and quality between the two alfalfas were negligible. The stand establishment costs averaged 300 Canadian dollar (CAD) ha−1, 205 CAD ha−1, 260 CAD ha−1, and 303 CAD ha−1 for HiGest, Grazeland, Grazeland-HBG, and HiGest-HBG, respectively. Hi-Gest® 360 alfalfa could provide higher digestible nutrients when it was used as a monoculture and could maintain quality better into later maturing stages. However, the higher seed price, and no actual advantage in mixtures may delay its adoption.

Evaluation of Alfalfa and Grass Species in Binary and Complex Mixtures on Performance under Soil Salinity Conditions

The effect of synergies between saline-tolerant grass and legume species grown in saline soil, on yield, quality, composition, persistence, and weed suppression was studied in 2019–2021 in a moderately saline soil located in the dark brown soil zone near Saskatoon, Saskatchewan, Canada. ‘Halo’ alfalfa (ALF), a salt-tolerant cultivar of alfalfa, was seeded in binary mixtures with ‘Revenue’ slender wheatgrass (ALF-SWG), ‘Garrison’ creeping meadow foxtail (ALF-CMF), and ‘Radisson’ smooth bromegrass (ALF-SBG). A complex mixture (quaternary) with all three grasses was also included. Four replicated treatments (n = 4) were randomly allocated to 6.2 × 1.2 m plots in spring 2019. The binary mixtures had similar or slightly better stand establishment compared to the quaternary mixture over the two years (83.3 vs. 76.9%), the quaternary stand showed greater (p = 0.01) establishment in Yr 2 than in Yr 1 (85 vs. 68.8%). There was high weed infestation in all the stands, but ALF-SWG had less weed infestation (23.8 vs. 44.1%) than ALF-CMF, especially in Yr 2 (p = 0.05). There were no significant differences among mixtures in yield, nutritional composition, and nutrient uptake. The ALF-CMF and ALF-SWG binary mixtures had 9 to 23% greater mean total DMY than the other mixtures in the moderately saline soil. The cost of establishing forage mixtures on unproductive saline land can be up to 89% recovered after only two years. The results suggested that binary mixtures of ‘Halo’ alfalfa with ‘Revenue’ slender wheatgrass or ‘Garrison’ creeping meadow foxtail could be reasonable alternatives for adequate forage production and quality, high N-use efficiency, and ultimately livestock gain per hectare, as well as for controlling soil salinity and improving soil fertility in this saline area in the dark brown soil zone.

Evaluation of New Fall Rye Cultivar ‘Bono’ in Single and Double Cropping Systems

A new fall rye (FR, Secale cereale L.) cv. Bono was investigated as a novel cropping option in Saskatchewan, Canada. In this study, the performance of Bono was compared to Hazlet FR, and both cultivars were compared to winter triticale (WT, Triticosecale Wittm.) cv. Pika in single cropping (SC) or in double cropping (DC) systems with spring barley (Hordeum vulgare L.) was evaluated in the Dark Brown soil zone, 2019–2021. Five replicated (n = 4) treatments were: (i) BonoFR; (ii) HazletFR; (iii) PikaWT; (iv) Barley–BonoFR; and (v) Barley–HazletFR. The first crop of barley was harvested at soft dough stage, followed by the second crop of FR seeded in the same year and harvested between flag leaf to heading emergence the following summer for greenfeed hay. Bono did not differ (p > 0.05) in DMY (1.2 Mg ha−1) or nutritive value from Hazlet, however, both FRs differed (p = 0.01) from WT by higher nitrogen use efficiency (NUE, 41.0 vs. 33.7) and NDF (541.8 vs. 479.3 g kg–1), but lower CP (155.3 vs. 187.1 g kg–1). Double cropping barley with fall ryes increased total DMY, nutrients yield per ha, and minerals uptake by up to 83% and NUE by 35.3%. In conclusion, Bono fall rye could be an equal quality alternative to Hazlet, although the current higher seed price may delay its adoption.

Modelling the climate change in regional crop production efficiency in Canada: based on the super-efficiency SBM model and DEA window analysis

This study aims to capture the spatial and time influence of climate change on crop production efficiency (CPE) using the SE-SBM model combined with DEA window analysis. The model is validated with the data from 1976 to 2016 in Saskatchewan, one of the three Canadian prairie provinces. By categorising Saskatchewan into three regions: black soil zone, dark brown soil zone, and brown soil zone, differences are analysed between CPE without considering climate change and CPE under climate change. We find that CPE under climate change is significantly larger than CPE without consideration of climate change, and the positive influence of temperature fluctuations during the growth period on CPE is more important than that of humidity fluctuations, and the beneficial impact of average humidity on CPE is significantly greater than that of average temperature.

PSXI-15 Evaluation of low-lignin alfalfa ‘Hi-Gest® 360’ on the Canadian prairies: productivity, nutrient profile, and rumen degradation kinetics

Abstract The study was conducted at Saskatoon, SK, Canada in the Dark Brown soil zone (52°07′N,106°38′W), to compare low-lignin Hi-Gest®360 alfalfa (Hi-Gest; Medicago sativa L.) to a conventional alfalfa (AC Grazeland) under two cutting regimes. Each cultivar was seeded in 2017 as both a monoculture and binary mixture (binary; Hi-Gest+HB and Grazeland+HB) with AC Success hybrid bromegrass (HB). Plot size was 1.2m×6m with 4 rows. Three years (2018–2020) result suggested that the first cut DMY was 1695±241 and 2151±276 kg/ha for the Hi-Gest and Grazeland, respectively. Hi-Gest had greater (P < 0.05) TDN (68.4 vs. 66.6%, DM basis), NEm (1.7 vs. 1.6 Mcal/kg), IVNDFD48: (42.9 vs. 37.8%), but lower second cut DMY (1288 vs. 1560 kg/ha), ADF (26.3 vs. 28.7%), NDF (34.7 vs. 36.6%), compared to AC Grazeland. Under two cutting, Hi-Gest was numerically lower in total DMY (2983 vs. 3712 kg/ha; P = 0.114) relative to Grazeland. In first cut forage, Hi-Gest also was numerically lower in ADL (5.9 vs. 6.5%; P = 0.57) relative to AC Grazeland. Hi-Gest was similar (P = 0.15) with AC Grazeland in effectively degradable dry matter (EDDM; 622 g/kg DM), effectively degradable CP (EDCP; 689 g/kg CP). Hi-Gest alfalfa had greater (P = 0.05) effectively degradable neutral detergent fiber (EDNDF; 19% more; 340 vs. 285 g/kg NDF) relative to AC Grazeland alfalfa. In binary system, Hi-Gest+HB had (P = 0.02) greater EDCP (12% more; 526 vs. 468 g/kg CP), and numerically greater EDNDF (4.4% more; 259 vs. 248 g/kg NDF; P = 0.10) but had similar EDDM (409 g/kg DM) relative to Grazeland+HB mixture. Each percentage unit increase in alfalfa ADL concentration decreased EDNDF by 2.3 percentage units (EDNDF, % NDF = 46.0–2.93×ADL, % DM, r2=0.26, P < 0.01). Although Hi-Gest yielded less (~25% less) than AC Grazeland, Hi-Gest had greater nutritive value compared to AC Grazeland; differed little for yield and quality in binary mixture, suggesting Hi-Gest can be a viable alternative legume for western Canadian prairies.

Early fungicide treatment reduces blackleg on canola but yield benefit is realized only on susceptible cultivars under high disease pressure

Blackleg [Leptosphaeria maculans (Desm.) Ces. & de Not.] is the most widespread disease of canola (Brassica napus L.) on the Canadian prairies. It has a noticeably increased incidence in recent years possibly due to shifts in the pathogen population and erosion in cultivar resistance. This study was conducted to assess foliar-applied fungicides for mitigating the risk of blackleg. Field trials were conducted at five locations in the Black or Dark-Brown Soil Zones for four years using the susceptible canola ‘Westar’. The fungicides pyraclostrobin (Headline®), azoxystrobin (Quadris®), propiconazole (Tilt®), and azoxystrobin + propiconazole (Quilt®) were applied at the 2–4 leaf stage against early infection. For comparisons, pyraclostrobin was also applied at bolting of ‘Westar’ and at the 2–4 leaf stage of two resistant cultivars (‘43E01’, ‘45H29’). These early treatments, except propiconazole, significantly reduced the mean disease incidence (MDI) and disease severity index (DSI) on ‘Westar’, relative to untreated control, reducing the impact of disease on yield by 16.5–26.9%. Late application of pyraclostrobin at bolting was ineffective. Two-application treatments, with pyraclostrobin at the 2–4 leaf stage and propiconazole at the bolting stage, or vice versa, provided no further efficacy or yield benefit relative to the early application of pyraclostrobin alone. None of the treatments showed substantial disease reduction or yield benefit in two low-disease station years (MDI <30%). On the resistant cultivars, pyraclostrobin reduced MDI and DSI, but showed no yield benefit. As resistant canola cultivars are used commonly on the prairies, a routine application of foliar fungicide is not recommended.

CDC Plava oilseed flax

CDC Plava oilseed flax (Linum usitatissimum L.), registered in 2015 by the Crop Development Centre, University of Saskatchewan, Saskatoon, SK, Canada, is targeted to the shorter growing season and the Dark Brown, Black, Grey, and Dark Grey soil zones of the northern prairies. This cultivar has a high seed yield (106%) compared with cultivar CDC Bethune and a medium maturity rating equal to Prairie Thunder. It has medium oil content (47.0%), α-linolenic acid content (57.8%), seed size (6.1 g 1000-seed weight), and good lodging resistance. It is resistant to North American races of rust caused by Melampsora lini (Ehrenb.) Thüm. and moderately resistant to wilt caused by Fusarium oxysporum Schltdl. f. sp. lini (Bolley) W.C. Snyder &amp; H.N. Hansen.

Annual ryegrass and Festulolium as companion crops in the establishment of perennial forage crops

Annual companion crops are often used in new seedings of perennial forages in western Canada. Fast-establishing grass species that do not overwinter in this region have potential as companion crops to increase seeding year yields without reducing perennial forage establishment. Trials were seeded in two different years at Saskatoon and Melfort, SK, in the Dark Brown and Black soil zones, respectively. Crested wheatgrass [Agropyron cristatum (L.) Gaertn.], meadow bromegrass (Bromus riparius Rehm.), and alfalfa (Medicago sativa L.) were seeded in pure stands and mixtures with or without an annual ryegrass (Lolium multiflorum Lam.) or Festulolium (Lolium × Festuca) companion crop at two seeding rates. Forage dry matter yield in the establishment year was increased with annual ryegrass companion crops compared with no companion crop regardless of seeding rate, but was increased only with the higher rate of Festulolium at Saskatoon. Despite using low companion crop seeding rates, stand densities of most of the perennial forage stands were lower than with no companion crop at Saskatoon, but in Melfort, most stand densities did not differ. The annual ryegrass companion crop reduced yields the year after seeding at both sites, while the Festulolium also reduced yields, but not at Melfort for the lower companion crop seeding rate. Dry matter yields were usually not different between companion and no companion crop treatments in the second year after seeding and for 3-yr total yields. The use of these companion crops increased the percentage of the 3-yr total yield produced in the seeding year.

Influence of crop residues and nitrogen fertilizer on soil water repellency and soil hydrophobicity under long-term no-till

Crop residues and N fertilizer under no-till may increase soil water repellency (SWR) and soil hydrophobicity, but few studies have examined these two treatment factors and their interaction. A laboratory study was conducted using a long-term (since 1999) field experiment on a clay loam soil to determine the effect of three crop residues and two N fertilizer levels on SWR and soil hydrophobicity under no-till within the Dark Brown soil zone of the semi-arid Canadian prairies. The three residue treatments were residues removed from soil (Rx0), residues returned to soil (Rx1), and residues supplemented to soil (Rx2). The two fertilizer N treatments were 0 (N0) and 45 kg N ha−1 (N1). Surface (0–10 cm) soil samples were taken in the spring of 2017 after 17 yr. Laboratory measurements were conducted on air-dried and sieved (&lt;2 mm) soil to determine SWR using the repellency index method (RI), soil organic C, hydrophobic CH and hydrophilic CO functional groups, and soil hydrophobicity (CH/CO ratio). Mean RI values ranged from 2.19 to 2.75, indicating subcritical (RI &gt; 1.95) SWR. Similar (P &gt; 0.05) RI values were found for the three residue and two N fertilizer treatments, but the trend was for greater RI with increased residue addition (by 12%–26%) and N fertilizer (by 8%). Soil hydrophobicity was significantly greater by 47%–82% for straw returned or supplemented than straw removed treatments, and by 33% for fertilized than unfertilized treatments. Overall, greater residues and N fertilizer had no effect on SWR, but significantly increased soil hydrophobicity.

Response of Soybean and Lentil to a Seed-Row Placed Starter Nitrogen-Phosphorus Fertilizer Blend in a Brown Chernozem in South-Central Saskatchewan

Soybean and lentil are important legume crops in southern Saskatchewan (SK) that can supply the majority of their nitrogen (N) requirement through biological N fixation (BNF). However, the onset of BNF can be slow in cold; dry prairie soils and a small amount of seed-row placed fertilizer containing both N and phosphorus (P) may benefit the crop. Nevertheless, high rates of fertilizer in close proximity to the seed can also cause injury. This study was conducted to determine the response of lentil and soybean to a starter N-P fertilizer blend applied in the seed-row. A farm field located at the boundary of the Brown and Dark Brown soil zones in south-central Saskatchewan was selected to evaluate the effect of seed-row placed N-P fertilizer blend: 50% Urea + 50% mono-ammonium phosphate (MAP) applied at 0, 10, 20 and 30 kg N and P2O5 ha-1 on emergence, yield, and nutrient uptake. The proportion of nitrogen derived from fixation (ndff) was determined in the soybean using N-15 dilution technique. The rate of 10 kg N and P2O5 ha-1 was found to be the rate that did not significantly reduce emergence, stand count or proportion of N derived from fixation, and was sufficient to maximize yield, N and P uptake for both soybean and lentil under field conditions. Rates higher than 10 kg N ha-1 in the seed row as starter 28-26-0 blend reduced emergence and decreased the proportion of ndff.

Evaluation of Low Heat Unit Corn Hybrids Compared to Barley for Forage Yield and Quality on the Canadian Prairies

Corn (Zea mays L.) production is expanding in the prairie region of western Canada. The objectives of this study were to compare three new low heat unit corn hybrids to barley (Hordeum vulgare L.) for forage yield, nutrient profile, and total nutrient production. The study was conducted at 4 sites (Evansburg and Fairview, Alberta; Melfort and Scott, Saskatchewan) with different soil characteristics (Gray Luvisolic, Grey Wooded, Dark Brown, and Black soil zones) over three consecutive years (2012-2014). At each site, annually, 16 plots (2.4×7.2 m) were randomly assigned to one of four forage crops (corn:Monsanto DKC26-25, Hyland 2D093, Pioneer P7443R; barley: cv. AC Ranger) in a replicated (n = 4) trial. Number of cobs per plant was not different (p = 0.23) between corn hybrids averaging 1.22 ± 0.32/plant (mean ± sd). Forage yield among the corn hybrids was negligible (p &gt; 0.05), but the corn hybrids exhibited 40% higher yield (p &lt; 0.05; avg. 11.3 ± 3.6 t/ha on DM basis) compared to barley (avg. 6.7 ± 1.7 t/ha). Corn hybrids were lower (p &lt; 0.05) in CP content [7.6 ± 1.4% versus (vs.) 12.4 ± 0.1%] than barley. No difference was observed between the 4 forage crops in TDN content (68.2 ± 2.8% DM).Study results suggestthat new cool-season corn hybrids can produce high quality forage to meet the nutrient requirements of grazing beef cows in mid- and late-stage pregnancy.New corn hybrids may be suitable alternatives for winter grazing strategies since forage harvest costs would be eliminated.

Quantifying Optimal Rates of Litter Retention to Maximize Annual Net Primary Productivity on Mixed-Grass Prairie

Optimal rates of litter retention for maximizing annual aboveground net primary productivity (ANPP) were investigated in native mixed-grass rangelands in Saskatchewan, Canada. The study was conducted on 18 independent study sites on brown and dark brown Chernozem (Mollisol) soils during the 2011 and 2012 growing seasons. Each site contained 30 treatment plots with two control plots and 28 treatment plots receiving between 1 and 2 290 g/m2 of added plant litter sourced from a reference site. Soil moisture values were recorded for each plot in May, June, and July, while forb, graminoid, and total ANPP were harvested at the end of the growing season. Soil moisture-litter relationships were driven by weather patterns with significant differences between years. Graminoid ANPP-litter relationships were nonlinear with peaks in productivity between 54 and 412 g/m2 of litter mass in the brown soil zone and between 27 and 157 g/m2 of litter mass in the dark brown soil zone. Forb ANPP was highest at the lowest litter masses and was not significantly influenced by study year or soil zone. The recommended litter retention rates in provincial range health assessment guidelines are accurate for the dark brown soil zone but are lower than the levels identified here for the more arid brown soil zone.

Will summer fallow re-emerge in the Dark Brown soil zone of the Canadian Prairie as a response to net return risk?

We assessed the extent to which summer fallow in the Dark Brown soil zone is likely to return as a response to net return (NR) risk. An economic model was used to identify, delineate, and quantify ...

Unsaturated water flux at mid and lower slope positions within an inclined landscape of the Dark Brown soil zone in southern Alberta

Miller, J. J. and Chanasyk, A. S. 2015. Unsaturated water flux at mid and lower slope positions within an inclined landscape of the Dark Brown soil zone in southern Alberta. Can. J. Soil Sci. 95: 27–36. Little research has quantified vertical-unsaturated water flux below the root zone for mid and lower slope positions within inclined, low-relief, and longer-slope landscapes of the Dark Brown soil zone of the Canadian prairies. We measured soil moisture (0.23–1.22 m) in the field at mid and lower slope positions in southern Alberta from May to October in 1985 and 1986. Undisturbed soil cores were taken from soil horizons and saturated hydraulic conductivity and soil moisture retention were determined in the laboratory. Vertical-unsaturated water flux below the root zone was calculated between 1.07 and 1.22 m depths below ground surface using the hydraulic gradient method. Water fluxes for the 2 yr ranged from &lt;10−11 to 10−10 m s−1 at the mid slope position, and from &lt;10−11 m s−1 to 10−9 m s−1 at the lower slope position, and were consistent with some other studies. Cumulative water flux was dominantly downward (−2.2 to −3.4 mm) at the mid slope position and this flow direction was consistent with this Orthic Dark Brown Chernozemic soil that was located in a “recharge area”. Cumulative water flux was dominantly upward at the lower slope position in 1985 (1.4 mm) and dominantly downward but of very low magnitude in 1986 (−0.1 mm), and this flow direction was consistent with this saline Gleyed Regosol and “saline seep”. Cumulative water fluxes as a percentage of annual precipitation were 0.8 to 1.8% at the mid slope position and 0.3 to 0.5% at the lower slope position.

Litter accumulation drives grassland plant community composition and functional diversity via leaf traits

Direct physical interference from litter is an important mechanism driving changes in the diversity and composition of plant communities dominated by perennial species. While the consequences of litter for species diversity and composition are well known, the mechanisms shaping how litter acts as a filter on leaf and shoot functional traits to alter community structure and functional diversity remain unclear. These questions were examined using a large field experiment in native mixed-grass prairie grasslands in the brown and dark brown soil zones in central Saskatchewan, Canada. Litter additions ranging from 0 to 2,290 g m−2 were applied to plots in a response surface design, and responses including community structure, above-ground functional diversity, and community-weighted mean values for leaf functional traits were measured. Species richness, functional richness, and functional dispersion declined with increasing litter mass, but functional evenness increased. Community composition became more variable because increased litter acted as a filter on the perennial species previously present in the plots; the remaining species in a given plot were the most litter-tolerant subset of the original community in the plot. Increased litter mass affected graminoid and forb species differently. Increased litter mass selected for graminoid species characterized by greater height, leaf area, specific leaf area (SLA), leaf thickness, and leaf tissue density. In contrast, increased litter selected for forb species characterized by larger, thicker leaves, lower SLA, and lower leaf tissue density. Forbs with cauline leaves were also selected for over acaulescent growth forms. Physical interference by litter likely reduces grassland diversity and alters species composition in diverse grassland communities by forcing convergence in community trait structure, but not convergence in species composition.

跨地带土壤置换的实验研究

When people did ecological restoration,it was very difficult to achieve the trans-regional soil replacement. Basalt platform is distributed around the Changbai Mountain Nature Reserve. The intrazonality soil( i. e. baijiang soil,peat soil and meadow soil) in the temperate humid climate zone is developed widely on basalt platform,howerer,the zonality soil such as dark brown earth is rare. The mountain brown coniferous forest soil,baijiang soil,peat soil and meadow soil are not in the same physical geographic zone,and there are significant differences in their physical and chemical properties,thus, it is not easy to complete soil replacement directly. In this zone,we could use the synthesis soil which is artificially synthesized with baijiang soil,peat soil and meadow soil to instead of the mountain brown coniferous forest soil. In this study,the baijiang soil,peat soil and meadow soil in the dark brown soil zone in the temperate broadleaved-coniferous mixed forest were used as raw materials,and the mountain brown coniferous forest soil in cold temperate zone in Changbai Mountain Nature Reserve was used as replacement object. Firstly,we completed soil synthesis taking the imitates the natural prototype principle,and then,conducted the experimental research on trans-regional soil replacement and plant growth. The results showed that the differences of soils were significant in the distribution of the content of every soil grain size group( %),humus layer thickness( 10—20 cm),pH( 5. 9—7. 5),and the available nitrogen( N) content( 57. 8—100. 7 g / kg) in the mountain brown coniferous forest soil zone. The limited factors of plant growth were humus layer thickness,pH,and available N content of mountain brown coniferous forest soil. Plant growth condition was better as the humus layer thickness was 40cm,pH was 7. 0 and available N content was 80 mg / kg which were the inflection point value of the mountain brown coniferous forest soil limited factors. Therefore,the inflection point value of the mountain brown coniferous forest soil limited factor was a key to synthesis soil,and it was the basis for physical and chemical indicators of synthesis soil. There were more gravel but less silt and clay on surface soil of the mountain brown coniferous forest soil,the soil texture is gravelly sandy loam. Soil texture of meadow soil was sandy loam soil. There were less gravel but more silt and clay on surface soil of soil texture of baijiang soil,and peat soil was loam. The mountain brown coniferous forest soil and the peat soil were more abundant in organic matter content,however,the baijiang soil and the meadow soil were low. The pH of the mountain brown coniferous forest soil was higher than that of baijiang soil,peat soil and meadow soil. Total N was more abundant in the mountain brown coniferous forest soil than that of other types of soils,but the available N was lower in surface soil of the mountain brown coniferous forest soil. The total and available potassium was the most abundant nutrient in the mountain brown coniferous forest soil. There was no significant different in the total and available phosphorus for the four types of soils. In Changbai Mountain,the mixed soil was made of a quarter of peat soil,a quarter of meadow soil and a half of baijiang soil and the its soil layer thickness was kept about 40 cm,then the pH of the mixed soil was adjusted to neutral by lime. It was the most reasonable solution for replacing the mountain brown coniferous forest soil since the vegetation restoration effect was best and the cost was the lowest to produce the mixed soil.

Continuous Cropping and Moist Deep Convection on the Canadian Prairies

Summerfallow is cropland that is purposely kept out of production during a growing season to conserve soil moisture. On the Canadian Prairies, a trend to continuous cropping with a reduction in summerfallow began after the summerfallow area peaked in 1976. This study examined the impact of this land-use change on convective available potential energy (CAPE), a necessary but not sufficient condition for moist deep convection. All else being equal, an increase in CAPE increases the probability-of-occurrence of convective clouds and their intensity if they occur. Representative Bowen ratios for the Black, Dark Brown, and Brown soil zones were determined for 1976: the maximum summerfallow year, 2001: our baseline year, and 20xx: a hypothetical year with the maximum-possible annual crop area. Average mid-growing-season Bowen ratios and noon solar radiation were used to estimate the reduction in the lifted index (LI) from land-use weighted evapotranspiration in each study year. LI is an index of CAPE, and a reduction in LI indicates an increase in CAPE. The largest reductions in LI were found for the Black soil zone. They were −1.61 ± 0.18, −1.77 ± 0.14 and −1.89 ± 0.16 in 1976, 2001 and 20xx, respectively. These results suggest that, all else being equal, the probability-of-occurrence of moist deep convection in the Black soil zone was lower in 1976 than in the base year 2001, and it will be higher in 20xx when the annual crop area reaches a maximum. The trend to continuous cropping had less impact in the drier Dark Brown and Brown soil zones.

Distribution and Relative Abundance of Richardson’s Ground Squirrels, &lt;em&gt;Urocitellus richardsonii&lt;/em&gt;, According to Soil Zones and Vegetation Height in Saskatchewan During a Drought Period

Richardson’s Ground Squirrels (Urocitellus richardsonii) prefer to establish their burrow systems in fields with shorter vegetation and good visibility. Between 2001 and 2009, warm weather and low precipitation, creating ideal environmental conditions for this species, were common throughout Saskatchewan. We therefore hypothesized that Richardson’s Ground Squirrels would be abundant throughout the agricultural region of the province and would be relatively more abundant in fields with shorter vegetation. In May and June 2008, we selected a total of 36 study plots of 0.49 ha each in 12 randomly selected rural municipalities in the Brown, Dark Brown, Black, and Gray soil zones. Using visual counts of Richardson’s Ground Squirrels and counts of burrow entrances, we found that Richardson’s Ground Squirrels were abundant across the agricultural region of the province, but densities of Richardson’s Ground Squirrels and densities of burrow entrances were generally higher in the drier Brown soil zone than in the other soil zones. In 2009 and 2010, in a study of the effect of vegetation height on the abundance of Richardson’s Ground Squirrels in the Brown soil zone, we found that densities of burrow entrances in five study plots with vegetation ≥15 cm in height were significantly (P &lt; 0.05) lower than densities recorded in five adjacent study plots with vegetation &lt;15 cm in height. Our findings warrant more studies on Richardson’s Ground Squirrels inhabiting fields with short and tall vegetation to determine whether differences in population densities are due to differences in birth and death rates or immigration and emigration.

Estimating changes of residual soil nitrogen in Chernozemic soils in Canada

Yang, J. Y., Huffman, T., Drury, C. F., Yang, X. M., De Jong, R. and Campbell, C. A. 2012. Estimating changes of residual soil nitrogen in Chernozemic soils in Canada. Can. J. Soil Sci. 92: 481–491. Chernozemic soils (Mollisols) account for approximately 68% of total farmland in the prairies and 54% of farmland in Canada. Although many field studies have focused on the importance of N in Chernozemic soils, few modelling studies have been conducted to examine the risk of N contamination to the environment The objective of this research was to estimate temporal and spatial changes in residual soil nitrogen (RSN) on Chernozemic soils at the 1:1 million regional scale. An annual N budget was developed for the study area for the period 1981 to 2006, using the Canadian Agricultural Nitrogen Budget (CANB v3.0) model. The difference between N inputs and outputs is considered RSN, which is defined as the inorganic N left in the soil after harvest. Average RSN levels in the sub-humid Black and Dark Gray Chernozemic soils increased from 7–9 kg N ha−1in 1981 to 20–23 kg N ha−1in 2006. Changes in RSN were much less pronounced in the arid and semi-arid Brown and Dark Brown soil zones, where average values increased from approximately 1 kg N ha−1to 4–7 kg N ha−1over 25 yr. Commercial fertilizer, manure and biological N2fixation were the three main sources of the increased N inputs. Drought conditions also contributed to the surplus of N in some years by reducing crop growth and thus the amount of N removed in grain and forage crops. In Chernozemic soils, more careful use of chemical fertilizer N, improved manure N management and greater use of legume-cereal rotations are recommended as methods to maintain soil fertility and reduce nitrogen loss to the environment.