Y. T. Gan

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...

Optimum plant population density for chickpea and dry pea in a semiarid environment

Chickpea (Cicer arietinum L.), an annual grain legume, is being broadly included in cereal-based cropping systems throughout the semiarid Canadian prairies, but information on optimum plant population density (PPD) has not been developed for this region. This study, which was conducted from 1998 to 2000 in southwestern Saskatchewan, determined the effect of PPD on field emergence, seed yield and quality, and harvestability of kabuli and desi chickpea compared with dry pea (Pisum sativum L.). Seed yields of all legumes increased with increasing PPD when the crops were grown on conventional summerfallow. The PPD that produced the highest seed yields ranged from 40 to 45 plants m-2 for kabuli chickpea, from 45 to 50 plants m-2 for desi chickpea, and from 75 to 80 plants m-2 for dry pea. When the legumes were grown on wheat stubble, the PPD that gained optimum seed yield ranged from 35 to 40 plants m-2 for kabuli chickpea, from 40 to 45 plants m-2 for desi chickpea, and from 65 to 70 plants m-2 for dry pea. T...

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...

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...

Seedling emergence, pod development, and seed yields of chickpea and dry pea in a semiarid environment

Chickpea (Cicer arietinum L.), an annual legume, has recently been introduced to western Canada, and is being rapidly adopted in the semiarid prairies, but little information exists on the crop establishment and agronomic management. A field study was conducted from 1998 to 2000 in southwestern Saskatchewan to determine effect of planting dates on seedling emergence, pod development, and seed yields for two market classes of chickpea (i.e., small- and large-seeded) compared to dry pea (Pisum sativum L.). The early-planted chickpea required 8 more days to emerge than late-planted chickpea. Averaged over the two planting dates, small-seeded chickpea required 103 heat units (base 5°C) to emerge compared to 110 for large-seeded chickpea and 97 for dry pea. Compared to the respective late-planting, the reproductive period (flowering to maturity) was 4 d longer for the early-planted chickpea, allowing the plants to use 49 (or 9%) more accumulated heat units. Consequently, the early-planted chickpea produced 17%...

Effect of formulation and placement of Mesorhizobium inoculants for chickpea in the semiarid Canadian prairies

The use of bacterial inoculants can increase root nodulation and the seed yield of annual legumes. A six site-year study was conducted to determine the effect of formulations (peat-based powder vs. granules) and placement in the soil (seed-row vs. side-band) of Mesorhizobium inoculants on plant establishment and seed yield of chickpea (Cicer arietinum L.) in the semiarid Canadian prairies. Two market classes of chickpea, namely desi and kabuli, were grown on silt loam and heavy clay soils in southwestern Saskatchewan from 1999 to 2002. Inoculation reduced plant population by 10% for desi chickpea, but had no effect on kabuli chickpea. However, the use of inoculant increased seed yield by an average of 35% for desi chickpea and 7% for kabuli chickpea. On the heavy clay, soil inoculation increased seed yield by 16% for desi and 9% for kabuli compared with seed inoculation, whereas the yield increase due to soil inoculation, over seed inoculation, was 3% when the crops were grown on the silt loam. Granular i...

Response of kabuli chickpea to seed size and planting depth

The use of small seed can reduce the production costs of kabuli chickpea (Cicer arietinum L.) 15 to 25% by reducing the amount of seed needed per unit area, but little is known about the effects of seed size on stand establishment, plant growth, and seed yield in semiarid environments. We conducted a field study in southwest Saskatchewan from 1998 to 2000 and determined the chickpea responses to seed size under different planting depths. Crops grown from small (7.1–9.0 mm) diameter seed required the same number of days to emerge (16.7 d) and mature (106 d) as those from large (9.1–11.0 mm) diameter seed. There were no differences in plant establishment, shoot dry weight, pod production, or seed yield between the two seed sizes when planted at a 50-mm depth. However, the small-seeded crop produced 7% lower plant stand, 4% lower seed yield, and 3% less seed 1799-mm diameter compared to the large-seeded crop when planted at a 100-mm depth (P < 0.05). Large-seed ed chickpea plants were 20 mm (4%) taller, and ...

Response of lentil to microbial inoculation and low rates of fertilization in the semiarid Canadian prairies

The use of microbial inoculation may increase nodulation and seed yield of annual legumes. A study was conducted to determine the effect of formulations (seedapplied powder vs. soil-applied granular inoculants), placement of granular inoculants in soils (applied in the seed-row vs. sidebanded), and low rates of fertilizers in comparison to P-solubilizing microbes Penicillium bilaii on plant establishment, maturity, and seed yield of lentil (Lens culinaris Medik.) in the semiarid Canadian prairies. Green lentil was grown on a silt loam and a heavy clay soil in southwestern Saskatchewan from 1999 to 2002. Inoculated lentil with Rhizobium increased seed yield by 45% averaged across all 6 site-years. Granular soil inoculants increased lentil seed yield by 19% over seed-applied inoculants. Placement of soil inoculants in the seed row or side-bands produced similar results. On the silt loam soil, the use of rhizobial inoculants increased lentil seed yield by 15%, while the yield increase was 70% on the heavy cl...

Interrelationships among yield components of chickpea in semiarid environments

Chickpea (Cicer arietinum L.) seed yield can be increased by identifying and managing the key yield components. A field study was conducted in southwestern Saskatchewan in 1999 and 2000 to determine the direct and indirect effects of various yield components on chickpea seed yield . Both desi- and kabuli-chickpea were planted at the target plant populations of 20, 30, 40, and 50 plants m-2 on conventional summerfallow (CS) and no-till wheat stubble (NT). Path coefficient analyses revealed that seed yield for both chickpea classes largely depended upon pods m-2 and seed weight, with the kabuli crop having higher coefficient values than the desi. These relationships were stronger when the pulses were grown on CS than on NT. Seeds pod-1 had a negative effect on seed yield for the kabuli crop, but this negative effect was counterbalanced by a strong, positive effect of seed weight on seed yield. The total pod production of the desi crop depended on plants m-2 more than on pods plant-1, whereas the pod product...