C. A. Campbell

Long-term assessment of management of an annual legume green manure crop for fallow replacement in the Brown soil zone

In the Brown soil zone of western Canada summerfallowing (F) is traditionally used to reduce the water deficit associated with cereal production, but frequent use of this practice results in soil degradation and reduces the N-supplying capacity of soils. Some scientists suggest that an annual legume green manure crop (LGM) could be used as a partial-fallow replacement to protect the soil against erosion and increase its N fertility, particularly when combined with a snow-trapping technique to replenish soil water used by the legume. We assessed this possibility by comparing yields, N economy, water use efficiency, and economic returns for hard red spring wheat (W) (Triticum aestivum L.) grown in rotation with Indianhead black lentil (Lens culinaris Medikus) green manure (i.e., LGM-W-W) vs. that obtained in a traditional F-W-W system. Further, we assessed whether a change in manage ment of the LGM crop (i.e., moving to earlier seeding and earlier turn-down) was advantageous to the overall performance of th...

Effects of crop rotations and fertilizer management on leaf spotting diseases of spring wheat in southwestern Saskatchewan

The objective of this study was to determine the effect of crop sequence, summerfallow frequency, and fertilizer application, on the severity of leaf spotting diseases of spring wheat (Triticum aestivum L.). In the field experiment examined, Pyrenophora tritici-repentis (Died.) Drechs. was the pathogen most commonly isolated from lesioned leaf tissue, followed by stagonospora blotch (Phaeosphaeria nodorum [E. Muller] Hedjaroude). The severity of leaf spots in wheat after fallow was greater than in monoculture continuous wheat, or in wheat after a noncereal crop. Percent area with leaf spots in wheat grown after wheat was higher than in wheat grown after flax (Linum usitatissimum L.) or lentil (Lens culinaris Medikus) in years with high disease pressure (1995 and 1996), but not in 1993 or 1994 when overall disease levels were low. Under soil N-deficient conditions, leaf spot levels increased in years with dry summers (1994 and 1996), whereas a P deficiency decreased leaf spot severity in years that had coo...

Long-term effect of cropping system and nitrogen and phosphorus fertilizer on production and nitrogen economy of grain crops in a Brown Chernozem

Assessment of the long-term impact of fertilizers and other management factors on crop production and environmental sustainability of cropping systems in the semi-arid Canadian prairies is needed. This paper discusses the long-term influence of N and P fertilizers on crop production, N uptake and water use of hard red spring wheat (Triticum aestivum L.), and the effect of the preceding crop type [flax (Linum usitatissimum L.) and fall rye (Secale cereale L.)] on wheat grown on a medium-textured, Orthic Brown Chernozem at Swift Current, Saskatchewan. We analysed 36 yr of results (1967–2002) from eight crop rotation-fertility treatments: viz., fallow-wheat receiving N and P (F-W, N + P), three F-W-W treatments fertilized with (i) N + P, (ii) P only, and (iii) N only; two other 3-yr mixed rotations with N + P (i) F-flax-W (F-Flx-W) and (ii) F-fall rye-W (F-Rye-W); and two continuous wheat rotations (Cont W), one receiving N + P and the other only P. Growing season weather conditions during the 36-yr period w...

Nitrogen contribution of field pea in annual cropping systems. 2. Total nitrogen benefit

The total nitrogen (N) benefit of field pea (Pisum sativum) to a succeeding non-legume crop was measured in a small plot experiment at Scott, Saskatchewan in the moist Dark Brown soil climatic zone, and in a small plot and landscape experiment near Melfort, Saskatchewan in the moist Black soil climatic zone from 1993 to 1995. The total N benefit was calculated as the difference in net N mineralized from soil plus N in the above- and below-ground crop residue between field pea and non-legume stubble-cropped plots over the growing season. Landscape slope position did not affect the total N benefit of field pea to a succeeding wheat crop, and preseeding tillage had an inconsistent effect on the total N benefit between years. The direct N benefit of field pea aboveground residue available to the succeeding crop in the landscape experiment was a minor component of the total N benefit, which averaged 25 kg N ha−1. The total N benefit was equivalent to the N residual effect, defined as the amount of fertilizer N...

Effect of crop rotations and fertilization on energy balance in typical production systems on the Canadian Prairies

Abstract Non-renewable energy inputs (both direct and indirect), metabolizable energy output and the energy efficiency of 10 spring wheat (Triticum aestivum L.) rotations were examined over an 18-year period on a loam soil in the Brown soil zone of the Canadian Prairies. The rotations, which were managed using conventional tillage methods, included a range of crops, cropping intensities, crop sequences and fertilizer practices. The results showed that the total energy input per unit of land was lowest for the traditional fallow-wheat (F-W) rotation (3482 MJ ha−1), intermediate (4470 MJ ha−1) for N- and P-fertilized fallow-wheat-wheat (F-W-W) and highest for N- and P-fertilized continuous wheat (7100 MJ Ha−1). Substituting flax (Linum usitatissimum L.) or rye (Secale cereale L.) for wheat in the rotations reduced total energy input by 3 to 8%, while withholding the application of either N or P fertilizer reduced total energy input by 16–37%. Liquid fuel for field operations and local product transport, and fertilizer (primarily N) were the major energy inputs; both increased with cropping intensity. Fuel accounted for 30–50% of the total energy input of the rotations. Fertilizer represented 15–49% of the total energy input and was of greater importance than fuel for the continuous crop rotations. Despite the high energy content in pesticides, they accounted for only 4–11% of the total energy input of the rotations. Metabolizable energy output displayed similar response patterns as total energy input reflecting the higher total annual grain yields as cropping intensity increased. For example, energy output averaged 12639 MJ ha−1 for F-W, 14641 MJ ha−1 for F-W-W and 17764 MJ ha−1 for continuous wheat. In contrast, the energy output to input ratios and the quantity of wheat produced unit−1 of energy input decreased with cropping intensity. The average energy output to input ratio for F-W was 3.6, or 262 kg of wheat GJ−1 of energy input, while those for F-W-W and continuous wheat were 3.3 and 2.6, or 240 and 191 kg of wheat GJ−1 of energy input, respectively. Rotations that included flax or cereal forage crops had the lowest energy efficiencies.

Root mass for oilseed and pulse crops: Growth and distribution in the soil profile

Crop roots transport water and nutrients to the plants, produce nutrients when they decompose in soil, and provide organic C to facilitate the process of C sequestration in the soil. Many studies on these subjects have been published for cereal crops, but little is known for oilseed and pulse crops. This study was conducted at Swift Current, Saskatchewan, in 2006 and 2007 to characterize the root growth and distribution profile in soil for selected oilseed and pulse crops. Three oilseed [canola (Brassica napus L.), mustard (Brassica juncea L.), flax (Linum usitatissimum L.)], three pulse crops [chickpea (Cicer arietinum L), dry pea (Pisum sativum L.) lentil (Lens culinaris Medik.)], and spring wheat (Triticum aestivum L.) were grown in 100 cm deep × 15 cm diameter lysimeters pushed into a silt loam soil. Crops were studied under rainfed and irrigated conditions. Lysimeters were removed from the field and sampled for above-ground (AG) and root mass at different depths at five growth stages. Root mass was h...

REGRESSION MODEL FOR PREDICTING YIELD OF HARD RED SPRING WHEAT GROWN ON STUBBLE IN THE SEMIARID PRAIRIE

Soil testing laboratories require predictive equations to make accurate fertilizer recommendations to cereal producers in the Canadian prairies. We used results from two 12-yr experiments (one studying snow management × fertilizer rates, and the other a tillage experiment), conducted on a medium-textured Orthic Brown Chernozem at Swift Current, Saskatchewan, to develop a regression model to estimate grain yield of hard red spring wheat (Triticum aestivum L.) grown on stubble. Stepwise regression, with backward elimination, was used to develop the relationship:Y = 1006 + 10.53 WU − 0.017 WU2 + 5.52 FN − 0.095 FN2 − 33.16 SN + 0.436 SN2 − (0.112 FN × SN) + (0.057 FN × WU) + (0.159 SN × WU) − 1.26 DD (R2 = 0.89, P = 0.001, n = 262)where Y = grain yield (kg ha−1), WU = estimated water use (mm), SN = soil test N (kg ha−1), FN = rate of fertilizer N (kg ha−1), and DD = degree days >5 °C (°C-days). Water use was available spring water in the 0- to 1.2-m depth plus 1 May to 31 July precipitation + irrigation, and...

Water use efficiency and water and nitrate distribution in soil in the semiarid prairie: Effect of crop type over 21 years

In the semiarid prairie, available water is the most limiting and nitrogen the second most limiting factor influencing crop production. Although numerous studies have been conducted on the effect of management practices on water use efficiency (WUE), most have concentrated on monoculture wheat, the major crop grown in the region. Even those studies dealing with other crop types have mostly been short-term in nature. But precipitation is so variable in amount and distribution that such an assessment is best conducted in long-term experiments. We used the results of a 21-yr experiment, conducted in the Brown soil zone at Swift Current, Saskatchewan, to determine the influence of crop type on WUE, and used the distribution of water and NO3-N in the soil, and N uptake by the crop to assist in interpreting these results. Four crop rotations were compared: summer fallow-wheat-wheat (F-W-W), F-flax-W (F-Flx-W), continuous wheat (Cont W) and wheat-lentil (W-Lent). All received N and P fertilizer based on soil tes...

Cropping frequency effects on yield of grain, straw, plant N, N balance and annual production of spring wheat in the semiarid prairie

Producers in the semiarid Canadian prairies practice frequent summerfallow to conserve water and reduce the risk of crop failure, but this practice promotes soil degradation. In contrast, annual cropping enhances soil quality but results in greater economic risk. We need to know what is the most suitable cropping frequency for this region. In 1985, based on results of the first 18 yr of a long-term crop rotation experiment being conducted on a medium-textured, Orthic Brown Chernozem at Swift Current, Saskatchewan, we modified the experiment to allow comparison of four cropping frequencies over the period 1985–2002. These were fallow-spring wheat (Triticum aestivum L.) (F-W), F-W-W, F-W-W-W-W-W, and continuous wheat (Cont W). All systems received recommended rates of N and P fertilizer. Growing season precipitation during the 1985–2002 period was 10% above average so that grain yields were also above average for this region. We assessed yields of grain, straw and N in aboveground plant parts, N concentrati...

Factors influencing grain N concentration of hard red spring wheat in the semiarid prairie

Prairie producers are now being rewarded with significant premiums for producing wheat (Triticum aestivum L.) of high protein concentration. We analyzed data from two 12-yr experiments conducted on a medium-textured Orthic Brown Chernozem at Swift Current, Saskatchewan, to determine and quantify factors influencing grain N concentration of hard red spring wheat grown on stubble land. Results of one of the 12-yr studies, a snow management × fertilizer N, zero-tillage experiment, showed that under hot, dry conditions, grain N concentration was very high and increased with moderate rates of fertilizer N (FN), then levelled off at higher rates of N. Under cool, wet conditions, grain N first decreased (due to N dilution by yield) then increased with further addition of FN. Under warm intermediate moisture conditions, grain N concentration increased at moderate rates in response to FN. Data for the two 12-yr experiments were pooled and multiple regression, with backward elimination, and stepwise selection used ...