• Authors:
    • Turkington, T. K.
    • Johnston, A. M.
    • Harker, K. N.
    • Clayton, G. W.
    • O'Donovan, J. T.
    • Kutcher, H. R.
    • Stevenson, F. C.
  • Source: Canadian Journal of Plant Science
  • Volume: 85
  • Issue: 1
  • Year: 2005
  • Summary: A field experiment was conducted at Lacombe and Beaverlodge, AB, and Melfort, SK, in 1999 and 2000 to evaluate the effect of seed placement and herbicide application timing on productivity of a general purpose (AC Lacombe) and hull-less (Falcon) barley (Hordeum vulgare L.) cultivars. Barley plant density was often less and dockage greater when seed was spread in a 20-cm band with 28-cm sweeps spaced 23 cm apart compared to seeding in distinct rows with hoe openers spaced 23 or 30 cm apart. Method of seed placement had little effect on barley grain yield or yield was significantly lower with the sweep compared to the distinct rows. Herbicide application timing effects were variable for barley grain yield. Grain yield was often greater and dockage less when herbicides were applied at the one- to two- or three- to four-leaf stage of barley compared to the five- to six-leaf stage. Method of seed placement did not influence barley responses to time of herbicide application with either cultivar. Barley silage yield was mainly higher with the distinct 23-cm row spacing than with the other seed placement methods. Herbicide application timing did not affect silage yield.
  • Authors:
    • Peterson, G. A.
    • Westfall, D. G.
    • Ortega, R. A.
  • Source: Communications in Soil Science and Plant Analysis
  • Volume: 36
  • Issue: 19/20
  • Year: 2005
  • Summary: In the West Central Great Plains of the United States, no-till management has allowed for increased cropping intensity under dryland conditions. This, in turn, has affected the carbon (C) and nitrogen (N) mineralization dynamics of these systems. In this region, moisture stress increases from north to south due to an increase in evapotranspiration (ET), resulting in a climatic gradient that affects cropping system management. The objectives of this study were to determine the interaction of cropping system intensification and climatic gradient (ET) on C and N mineralization and to determine if the presence or absence of crop residue on the soil surface affects C and net N mineralization. Two cropping systems, winter wheat-fallow (WF) ( Triticum aestivium L.) and winter wheat-corn (sorghum)-millet-fallow (WCMF) [ Zea mays (L.), Sorghum bicolor (L.) Moench, Panicum milaceum (L.)] were studied at three locations across this aforementioned ET gradient. The treatments had been in place for 8 yrs prior to sampling in the study. These results showed that the more intense cropping system (WCMF) had a higher laboratory C mineralization rate at two of the three locations, which the study concluded resulted from larger residue biomass additions and larger quantities of surface residue and soil residue at these locations (Soil residue is defined as recognizable crop residue in the soil that is retained on a 0.6 mm screen). However, no differences in N mineralization occurred. This is most likely due to more N immobilization under WCMF as compared to WF. Presence or absence of crop residue on the surface of undisturbed soil cores during incubation affected potential C and net N mineralization more than either cropping system or location. Soil cores with the surface residue intact mineralized as much as 270% more C than the same soils where the surface crop residue had been removed. In laboratory studies evaluating the relative differences in cropping systems effects on C and N mineralization, the retention of crop residue on the soil surface may more accurately access the cropping system effects.
  • Authors:
    • Alakukku, L.
    • Pietola, L.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 108
  • Issue: 2
  • Year: 2005
  • Summary: Roots are an important sink for photoassimilates and carbon input to soil. Here the root growth and biomass of different spring sown annuals was determined to estimate the shoot:root (S:R) ratios and carbon inputs in the typical Nordic agroecosystem. The data, collected in southern Finland, present evidence for large difference in root growth dynamics and biomass input between spring oilseed rape (Brassica rapa L) and annual ryegrass (Lolium multiflorum Lam. var. italicum) whereas the rooting of spring sown barley (Hordeum vulgare) and oats (Avena sativa) was related. The four crops were sown at the same time in a field with a fine sand soil (Eutric Cambisol) with good nutrient and water supply. During one growing season, root growth was determined 12 times to a soil depth of 50 cm by using a minirhizotron-micro-video camera technology. At anthesis, root biomass and morphological parameters were measured to 60 cm soil depth at 5 cm intervals, with destructive soil sampling and image analysis of washed roots. The root growth rate of oilseed rape was clearly faster and that of rye grass slower compared with the other crops. At anthesis, the average total root dry biomass (0-60 cm) was 160 g for barley, 260 g for oats, 340 g for ryegrass, and 110 g m(-3) for oilseed rape. Also, the root length density and surface area of oilseed rape was less than that of other crops. Most of the biomass (59-80%) was accumulated the upper 20 cm of the soil. Shoot to root ratios (at anthesis for the seed crops) of 7.1, 4.4, 4.2 and 2.5 for barley, oats, oilseed rape, and ryegrass respectively, could be used for an approximation to estimate the amount of root biomass left in the 0-60 cm soil layer under Nordic long day conditions. In contrast to the seed crops, the root growth rate and density of ryegrass was high in the late season. Thus, ryegrass would be an efficient catch crop after harvest of cereals. (c) 2005 Elsevier B.V. All rights reserved.
  • Authors:
    • Mattsson, L.
    • Andren, O.
    • Roing, K.
  • Source: Acta Agriculturae Scandinavica Section B, Soil and Plant Science
  • Volume: 55
  • Issue: 1
  • Year: 2005
  • Summary: Estimates of soil N mineralization capacity and the factors that control the rates are necessary for optimal N management. Long-term field experiments can be used to measure how different management options affect the amount and quality of soil organic matter (SOM) - the substrate for N mineralization. Net N mineralization was estimated in a pot experiment as N uptake by ryegrass ( Lolium perenne) grown in pots with soils from 30 Swedish long-term field fertility experimental treatments ( 16 - 40 years). The long-term management effects of cereal and ley rotations, crop residue removal and return and inorganic N application on ryegrass N uptake were investigated and related to soil organic carbon (SOC) content. Total plant N uptake during three months varied between 9 and 27 mg N kg(-1) ( 23 - 67 kg N ha(-1)) and increased with SOC concentration and previous application levels of inorganic N. Soil from crop rotations with ley mineralized about 50% more N than soil from crop rotations with only cereals. Plant N uptake and SOC were not significantly affected by crop residue return.
  • Authors:
    • Abou-Alaiw, W.
    • Al-Abed, D.
    • Zhang, S. L.
    • Parani, M.
    • Chennareddy, S.
    • Sairam, R.
    • Goldman, S.
  • Source: In Vitro Cellular & Developmental Biology - Plant
  • Volume: 41
  • Issue: 4
  • Year: 2005
  • Summary: The development of robust plant regeneration technology in cereals, dicots and ornamentals that is in turn coupled to a high-frequency DNA transfer technology is reported. Transgenic cereals that include maize, Tripsacum, sorghum, Festuca and Lolium, in addition to dicots that include soybean, cotton and various ornamentals such as petunia, begonia, and geranium have been produced following either somatic embryogenesis or direct organogenesis independent of genotype. Coupled with these regeneration protocols, we have also identified several interesting genes and promoters for incorporation into various crops and ornamentals. In addition, the phenomenon of direct in vitro flowering from cotyledonary nodes in soybean is described. In in vitro flowering, the formation of a plant body is suppressed and the cells of the cotyledonary node produce complete flowers from which fertile seed is recovered. This in vitro flowering technology serves as a complementary tool to chloroplast transformation for developing a new transgenic pollen containment strategy for crop species. Recently, the center has undertaken to screen the expression response of the 24 000 Arabidopsis genes to nitric oxide. This signaling molecule upregulated 342 genes and downregulated 80 genes. The object here was to identify a population of promoters that can be manipulated by using a signaling molecule. In addition, in keeping with the mission of enhancing greenhouse profitability for North West Ohio growers, we cloned a number of genes responsive for disease resistance from ornamentals that play an important role in disease management and abiotic stress. We have constructed a plant transformation vector with CBF3 gene under the rd29A promoter for engineering cold and freezing tolerance in petunia. Leaf discs of Petunia * hybrida v26 were used for Agrobacterium-mediated transformation, and 44 hygromycin-resistant T0 plants were obtained. The presence of CBF3 gene was confirmed in all the transgenic plants by PCR and Southern analyses.
  • Authors:
    • Gyuricza, C.
    • Bencsik, K.
    • Ujj, A.
    • Singh, M. K.
  • Source: Cereal Research Communications
  • Volume: 33
  • Issue: 1
  • Year: 2005
  • Authors:
    • Sturny, W. G.
    • Ramseier, L.
    • Chervet, A.
    • Tschannen, S.
  • Source: Revue Suisse d'Agriculture
  • Volume: 12
  • Issue: 5
  • Year: 2005
  • Summary: Over the last ten years, conventional plough tillage has been compared to no-tillage on six crop rotation plots in the long-term field trial Oberacker at the Inforama Ruetti in Zollikofen, Switzerland. The deep cambisol of the trial plots contains 15% clay and 3% organic matter. The absence of tillage operations in no-tillage makes a more complex strategy for weed control necessary. Options such as a balanced crop rotation, permanent soil cover, adapted crop residue management and immediate seeding of subsequent crops are used alongside chemical, mechanical, and thermal strategies of weed control. Land use is sustainable in the no-tillage system: No-tilled soil has a higher structural stability and load capacity while being markedly less prone to erosion; less machine usage and traffic reduce (fuel) costs. After seven years of no-tillage, continuous release of soil-borne nitrogen leads to crop yields and qualities at least equal to those obtained with conventional tillage. Two challenges remain only partly solved: (a) the greater dependence on herbicides such as glyphosate and (b) the greater risk of mycotoxin formation in no-tilled winter cereal crops that follow maize. Remedies include adaptations of the crop rotation, chopping of residual maize straw/stalks and cropping of cereal varieties less susceptible to fusarium. In conclusion, no-tillage contributes substantially to maintaining soil fertility on a long-term basis.
  • Authors:
    • Mehuys, G. R.
    • Madramootoo, C. A.
    • Burgess, M. S. E.
    • Mehdi, B. B.
    • Dam, R. F.
    • Callum, I. R.
  • Source: Soil & Tillage Research
  • Volume: 84
  • Issue: 1
  • Year: 2005
  • Summary: Different tillage and residue practices could potentially lead to significant differences in both crop production and soil properties, especially if both practices are implemented over a long time period and on continuous monoculture corn (Zea mays L.). The objective of this research was to determine how differing tillage practices and corn residues affected soil bulk density, corn emergence rates and crop yields over an 11-year period. The experimental site consisted of three tillage practices (no-till, NT; reduced tillage, RT; and conventional tillage, CT) and two residue practices (with grain corn residue, R; without residue (corn crop harvested for silage), NR). Bulk density was 10% higher in NT (1.37 Mg m(-3)) than in CT (1.23 Mg m(-3)), particularly at the 0-0.10 m depth. Spring corn emergence in NTR was slower by 14-63% than all other treatments in 1992-1994. In 1996, corn emergence in the NTR treatment was 18-30% slower, and NTNR was 5-30% faster than all other treatments. No-till with residue (NTR) possibly had the slowest overall emergence due to the higher surface residue cover (8.5 Mg ha(-1) in 1996) and higher bulk density (1.37 Mg m(-3) over the 11 years). Long-term mean dry matter corn yields were not affected by tillage and residue practices during the course of this study; rather climatic-related differences seemed to have a greater influence on the variation in dry matter yields. The long-term cropping of corn under different tillage and residue practices can change bulk density in the surface soil layer, vary the corn emergence without affecting yields, and produce comparable yields between all the tillage and residue practices. (C) 2004 Elsevier B.V. All rights reserved.
  • Authors:
    • Shea, K. L.
    • Gregory, M. M.
    • Bakko, E. B.
  • Source: Renewable Agriculture and Food Systems
  • Volume: 20
  • Issue: 2
  • Year: 2005
  • Summary: We compared soil characteristics, runoff water quantity and nutrient fluxes, energy use and productivity of three farm types in an unusually dry farming season: conventional (continuous corn and deep tillage), rotation (5-year corn-soybean-oats/ alfalfa-alfalfa-alfalfa rotation with tillage 2/5 years) and no-till (corn-soybean with no cultivation). Soil organic matter content was highest on the rotation farm, followed by the no-till farm, and lowest on the conventional farm. Nitrate content of the soil did not differ significantly among the three farms, although the conventional farm had a much higher input of fertilizer nitrogen. Soil penetrometer resistance was lower and percent soil moisture was higher in the no-till and rotation systems compared to the conventional farm. Soil macroinvertebrate abundance and diversity were highest on the no-till farm, followed by the rotation farm. No invertebrates were found in the soil of the conventional farm. The conventional farm had the highest runoff volume per cm rain and higher nitrogen (N) loss in runoff when compared to the rotation and no-till farms, as well as a higher phosphorus (P) flux in comparison to the no-till farm. These results indicate that perennial close-seeded crops (such as alfalfa) used in crop rotations, as well as plant residue left on the surface of no-till fields, can enhance soil organic content and decrease runoff. The lower soil penetrometer resistance and higher soil moisture on the rotation and no-till farms show that conservation tillage can increase soil aggregation and water infiltration, both of which prevent erosion. Furthermore, crop rotation, and particularly no-till, promote diverse invertebrate populations, which play an important role in maintaining nutrient cycling and soil structure. Crop rotation and no-till agriculture are less fossil-fuel intensive than conventional agriculture, due to decreased use of fertilizers, pesticides and fuel. In this unusually dry year they provided superior corn and soybean yields, most likely due to higher soil moisture as a result of greater water infiltration and retention associated with cover crops (rotation farm) and crop residue (no-till farm).
  • Authors:
    • Halvorson, A. D.
    • DeVuyst, E. A.
  • Source: Agronomy Journal
  • Volume: 96
  • Issue: 1
  • Year: 2004
  • Summary: Annualized yields with more intensive cropping (IQ systems tend to be greater than those of spring wheat-fallow (SW-F); however, little economic comparison information is available. The long-term (12 yr) effects of tillage system and N fertilization on the economic returns from two dryland cropping systems in North Dakota were evaluated. An IC rotation [spring wheat (Triticum aestivum L.)winter wheat (T. aestivum L.)-sunflower (Helianthus annuus L.)] and a SW-F rotation were studied. Tillage systems included conventional till (CT), minimum till (MT), and no-till (NT). Nitrogen rates were 34, 67, and 101 kg N ha(-1) for the IC system and 0, 22, and 45 kg N ha(-1) for the SW-F system. Annual precipitation ranged from 206 to 655 mm, averaging 422 mm over 12 yr. The IC system generated higher profits than the SW-F system, but the IC profits were more variable. Within the IC system, MT generated higher profits than corresponding N treatments under CT and NT, but MT profits were more variable. Of the N rates evaluated, the largest N rates generated the largest profits. The dryland IC system with MT and NT was more profitable than the best SW-F system using CT for this location. Stochastic dominance analyses revealed that the SW-F system and IC system CT treatments were economically inefficient when compared with the IC system with MT and NT.