Spatial variability of available nutrients in soil in nearly level fields in northeastern Saskatchewan

Non-Peer Reviewe

Factors affecting yield variations of various crops in north-eastern Saskatchewan

Non-Peer Reviewe

Формування субрегіонів як напрям підвищення конкурентоспроможності та інвестиційної активності території

Характерною особливістю регіону є виконання ним не тільки економічних, а й соціальних функцій. Саме тут криється принципова відмінність між різними ланками відтворювального процесу. Кінцева мета відтворювального процесу регіону – матеріальний добробут населення, покращення навколишнього середовища, створення нормальних умов для праці й відпочинку, можливостей духовного розвитку особи і т. п

Biomass accumulation and nutrient uptake of cereals at different growth stages in the parkland region of Saskatchewan

Non-Peer ReviewedField experiments were conducted with spring wheat (cv. AC Barrie - CWRS and cv. AC Taber - CPS), barley (cv. AC Oxbow - malt and cv. AC Lacombe - feed) and oats (cv. CDC Boyer or CDC Pacer) in 1998 and 1999 at Melfort, Saskatchewan, Canada, to determine biomass accumulation and nutrient uptake in cereal crops at different growth stages, and their relationship. All cereal crops followed a similar pattern of biomass and nutrient accumulation, which increased at early growth stages, reached at maximum and then decreased at late growth stages. Cereal crops usually reached their maximum biomass at late milk to full ripening stages (72-90 days after emergence), although some cultivars had a several days difference between the two years. Maximum biomass accumulation rate was 164-204 kg ha-1d-1 for wheat, 211-308 kg ha-1d-1 for barley and 185-217g ha-1d-1 for oats. Maximum uptake of nutrients usually occurred at beginning of flower to late milk (63-82 days after emergence) in both years. Maximum accumulation rate of N, P, K and S was 2.0-4.7, 0.3-0.4, 2.4-5.1 and 0.3-0.5 kg ha-1d-1 for wheat, 2.4-5.2, 0.3-0.5, 3.1-7.6 and 0.4-0.8 kg ha-1d-1 for barley, and 2.7-3.6, 0.3, 4.2-4.7 and 0.4-0.5 kg ha-1d-1 for oats, respectively. Both seed yield and nutrient uptake were lower in 1999 than in 1998, due to differences in weather conditions in the growing season in the two years. In summary, maximum nutrient accumulation rate occurred earlier than maximum biomass accumulation rate, and maximum nutrient uptake occurred earlier than maximum biomass. This indicates that in order to get high seed yields, there should be sufficient supply of nutrients to ensure higher nutrient uptake rate at tillering to stem elongation growth stage first, then a higher biomass accumulation rate at early to late boot growth stage, a greater nutrient uptake at beginning of flower to late milk growth stage, and a greater biomass at late milk to full ripening growth stage. This also suggests that sufficient supply of nutrients from soil/fertilizers at early growth stages is of great importance for high-yield crop production systems

Nitrogen fertilization improves quantity and quality of organic matter in a grassland soil

Non-Peer Reviewe

Biomass accumulation and nutrient uptake of oilseeds at different growth stages in the parkland region of Saskatchewan

Non-Peer ReviewedField experiments were conducted with canola (Brassica napus and B. rapa, cv. Quantum and Tobin), mustard (cv. AC Vulcan) and flax (cv. Norlin) in 1998 and 1999 at Melfort, Saskatchewan, Canada, to determine biomass and nutrient accumulation in oilseeds at different growth stages and their relationship to seed yield. In general, all oilseed crops followed a similar pattern in biomass accumulation and nutrient uptake, which increased at early growth stages, reached maximum and then decreased at late growth stages. Oilseed crops usually reached their maximum biomass at medium to end of pod forming growth stages (74-80 days after emergence), although Quest canola cultivar had a several day delay at early ripening stage (84 days after emergence) in 1998. Maximum biomass accumulation rate was 146-190 kg ha-1d-1 for canola, 158-182 kg ha-1d-1 for mustard and 174-189 kg ha-1d-1 for flax. Maximum nutrient uptake usually occurred at flowering to seed filling stage (59-85 days after emergence. Maximum nutrient uptake rate for N, P, K, S and B, respectively, was 2.3-4.5, 0.3-0.5, 2.5-5.7, 0.7-1.1 and 0.005-0.008 kg ha-1d-1 for canola, 2.3-3.9, 0.4-0.5, 2.6-4.9, 1.2-1.4 and 0.006-0.008 kg ha-1d-1 for mustard and 3.2-4.0, 0.3-0.4, 2.9-4.1, 0.3-0.5 and 0.004-0.009 kg ha-1d-1 for flax. Both seed yield and nutrient uptake in seed were lower in 1999 than in 1998, due to differences in weather conditions in the growing season in the two years. In summary, maximum nutrient accumulation rate occurred earlier than maximum biomass accumulation rate, and maximum nutrient uptake was earlier than maximum biomass. This indicates that in order to get high seed yields, there should be sufficient supply of nutrients to plants to ensure higher nutrient uptake rate at side shooting to bud forming stage, and then a greater biomass accumulation rate at early to late bud forming stage. This further suggests that adequate supply of nutrients from soil/fertilizers at early growth stages is of great importance for high-yield crop production systems

Biomass accumulation and nutrient uptake of pulses at different growth stages in the parkland region of Saskatchewan

Non-Peer ReviewedField experiments was conducted with pea (cv. Carnival and Swing), lentil (cv. Laird and CDC Milstone) and bean (cv. CDC Camino) in 1998 and 1999 at Melfort, Saskatchewan, Canada, to determine biomass and nutrient accumulation in pulses at different growth stage and their relationship to seed yield. Pulse crops followed a similar pattern in dry matter and nutrient accumulation, which increased at early growth stages, reached maximum and then decreased at late growth stages. Pulse crops usually reached their maximum biomass at medium pod forming to early seed filling stages (75-82 days after emergence). Maximum biomass accumulation rate was 175-215 kg ha-1d-1 for pea, 109-140 kg ha-1d-1 for lentil and 53 kg ha-1d-1 for bean. Maximum uptake of nutrients usually occurred at flowering to seed filling stages (59-85 days after emergence). Maximum accumulation rate of N, P, K and S, respectively, was 4.6-4.9, 0.4-0.5, 5.0-5.3 and 0.3 kg ha-1d-1 for pea, 2.4-3.8, 0.2-0.3, 2.0-3.4 and 0.2 kg ha-1d-1 for lentil and 1.1, 0.1, 1.5 and 0.1 kg ha-1d-1 for bean. Both seed yield and nutrient uptake in seed were lower in 1999 than in 1998, due to differences in weather conditions in the growing seasons in the two years. In summary, maximum nutrient accumulation rate occurred earlier than maximum biomass accumulation rate, and maximum nutrient uptake was earlier than maximum biomass. This indicates that in order to get high seed yields, there should be sufficient supply of nutrients to plants to ensure higher nutrient uptake rate at side shooting to bud forming stage, and then a greater biomass accumulation rate at early to late bud forming stage. This further suggests that adequate supply of nutrients from soil/fertilizers at early growth stages is of great importance for high-yield crop production systems

Effect of Na doping on flux pinning of YBa1.9Na0.1Cu3O7-d

We have prepared Na-doped YBa2Cu3Oy (YBa1.9Na0.1Cu3Oy +40mol%Y211) (YBNCO) and Na-free YBa2Cu3Oy (YBCO) samples by the Melt-Textured Growth (MTG) method to study the effect of doped Na ion on flux pinning. The ac susceptibility curves (acs) as well as the hysteresis loops were measured for the samples. Then the effective pinning energy (U(T,Hdc,J)), irreversibility line (Hirr(T)) and critical current density (jc(Hdc)) were determined, where T, Hdc and J are temperature, dc magnetic field and current density, respectively. We found that, with Na doping, the Hirr(T) line shifted to lower temperature while the Jc(Hdc) and U(T,Hdc,J) became smaller. It indicates that the Na ions play a negative role in the flux pinning of YBCO. The appearance of the second peak in the Jc(Hdc) curves and the enhancement of anisotropy in YBNCO further support this finding.Comment: 7 pages, 7figures. Submited to Physica.

Metastable behavior of vortex matter in the electronic transport processes of homogenous superconductors

We study numerically the effect of vortex pinning on the hysteresis voltage-temperature (V-T) loop of vortex matter. It is found that different types of the V-T loops result from different densities of vortex pinning center. An anticlockwise V-T loop is observed for the vortex system with dense pinning centers, whereas a clockwise V-T loop is brought about for vortices with dilute pinning centers. It is shown that the size of the V-T loop becomes smaller for lower experimental speed, higher magnetic field, or weak pinning strength. Our numerical observation is in good agreement with experiments