scholarly journals Seasonal dynamics and primary production of the flora in a winter rye field in Finland

1991 ◽  
Vol 63 (2) ◽  
pp. 115-130
Author(s):  
Päivi Halinen ◽  
Mikko Raatikainen
Keyword(s):  
Primary Production ◽  
Dominant Species ◽  
Seed Storage ◽  
Ground Vegetation ◽  
Winter Rye ◽  
Total Production ◽  
Weed Seed ◽  
Harvesting Method ◽  
Winter Annual ◽  
Plough Layer

The total weed seed storage in the plough layer of 20 cm was 93 965 seeds/m2, of which 36 taxa were defined. The proportion of seeds of annual and winter annual species in soil was 89.6 %. The number of rye seeds emerging in autumn was 614 per m2 and weeds 224 per m2. The total number of weeds was 381/ m2 when the calculation was based on the time of maximal appearance. 0.3 % of the total amount of weeds emerged. Rye and Elymus repens were the dominant species in the above-ground vegetation, whereas the biomass of the other weeds remained poorly developed because of marked shading from these two. The maximum biomass of the living above-ground vegetation, 614 g/m2, was achieved in the middle of August (12. VIII). Net above-ground primary production, measured by the harvesting method, was 664 g/m2 · year and underground production 190 g/m2 · year, giving a total production of vegetation and detritus of 854 g/ m2 · year. The net efficiency of the primary producers was 0.7 %.

Net Primary Production and Carbon Stocks for Subarctic Mesic–Dry Tundras with Contrasting Microtopography, Altitude, and Dominant Species

Ecosystems ◽  
2009 ◽  
Vol 12 (5) ◽  
pp. 760-776 ◽  
Author(s):  
Matteo Campioli ◽  
Anders Michelsen ◽  
Andreas Demey ◽  
Annemie Vermeulen ◽  
Roeland Samson ◽  
...  
Keyword(s):  
Primary Production ◽  
Dominant Species ◽  
Net Primary Production ◽  
Carbon Stocks

New and regenerated primary production in a productive reservoir ecosystem

2010 ◽  
Vol 67 (2) ◽  
pp. 278-287 ◽  
Author(s):  
Leah M. Domine ◽  
Michael J. Vanni ◽  
William H. Renwick
Keyword(s):  
Primary Production ◽  
Euphotic Zone ◽  
Gizzard Shad ◽  
Phytoplankton Production ◽  
Total Production ◽  
Relative Importance ◽  
Dorosoma Cepedianum ◽  
New Production ◽  
Total Primary Production ◽  
The Difference

The concept of new and regenerated production has been used extensively in marine ecosystems but rarely in freshwaters. We assessed the relative importance of new and regenerated phosphorus (P) in sustaining phytoplankton production in Acton Lake, a eutrophic reservoir located in southwestern Ohio, USA. Sources of nutrients to the euphotic zone, including watershed loading, fluxes from sediments, and excretion by sediment-feeding fish (gizzard shad, Dorosoma cepedianum ), were considered sources of new P input that support new primary production and were quantified over the course of a growing season. Regenerated production was estimated by the difference between new and total primary production. New production represented 32%–53% of total primary production, whereas regenerated production represented 47%–68% of total primary production. P excretion by gizzard shad supplied 45%–74% of new P and 24% of P required for total production. In summary, fluxes of P from the watershed and those from sediment-feeding fish need to be considered in strategies to reduce eutrophication in reservoir ecosystems.

scholarly journals Primary production and seasonal dynamics of the flora and fauna of the field stratum in a reserved field in Middle Finland

1976 ◽  
Vol 48 (4) ◽  
pp. 363-385
Author(s):  
Timo Törmälä ◽  
Mikko Raatikainen
Keyword(s):  
Primary Production ◽  
Seasonal Dynamics ◽  
Net Primary Production ◽  
Dry Weight ◽  
Abundant Species ◽  
Aboveground Net Primary Production ◽  
Harvesting Method ◽  
Underground Biomass ◽  
The Mean ◽  
Seasonal Aspects

The underground biomass of a reserved field which had not been cultivated for three years, exceeded that of the aboveground living vegetation throughout the year. The mean amount of the aboveground detritus, including both loose litter and rooted nonliving parts of the vegetation, was in dry weight 300 g/m2. It was at its minimum end of June and early July. The aboveground net primary production measured by the harvesting method was 405—415 g/m2. year depending on the way of calculation, and the underground production was 343 g/m2. year. Seasonal dynamics of the green biomasses of 56 taxa could be studied and five groups were formed on the basis of the time and duration of the biomass maxima. Using Renkonen’s and Sorensen’s indices three seasonal aspects of the vegetation could be distinguished. The leafhoppers were divided into three phenological groups, and three seasonal aspects were formed. The vertebrate fauna was scarce in the study area. Shrews were the most abundant species and e.g. five Sorex isodon were trapped. During the period of maximum standing crops the herbivores amounted to 0.3 % of the green biomass. The higher the trophic level the later it reached the maximum.

scholarly journals Rolled Winter Rye and Hairy Vetch Cover Crops Lower Weed Density but Reduce Vegetable Yields in No-tillage Organic Production

HortScience ◽  
2011 ◽  
Vol 46 (3) ◽  
pp. 387-395 ◽  
Author(s):  
Matthew J. Leavitt ◽  
Craig C. Sheaffer ◽  
Donald L. Wyse ◽  
Deborah L. Allan
Keyword(s):  
Cover Crops ◽  
Cover Crop ◽  
Crop Yields ◽  
Organic Production ◽  
Bell Pepper ◽  
Winter Rye ◽  
No Tillage ◽  
Hairy Vetch ◽  
Weed Density ◽  
Winter Annual

Winter annual cover crops, winter rye (Secale cereale L.) and hairy vetch (Vicia villosa Roth), can reduce weed density and build soil quality in organic production systems. There is interest in integrating cover crops and reduced tillage with organic vegetable production, but few studies have been conducted in regions with short growing seasons and cool soils such as the upper Midwest. We evaluated no-tillage production of tomato (Solanum lycopersicum L.), zucchini (Cucurbita pepo L.), and bell pepper (Capsicum annuum L.) planted into winter rye, hairy vetch, and a winter rye/hairy vetch (WR/HV) mixture that were mechanically suppressed with a roller–crimper at two locations in Minnesota. Average marketable yields of tomato, zucchini, and bell pepper in the rolled cover crops were reduced 89%, 77%, and 92% in 2008 and 65%, 41%, and 79% in 2009, respectively, compared with a no-cover control. Winter rye and the WR/HV mixture reduced average annual weed density at St. Paul by 96% for 8 to 10 weeks after rolling (WAR) and hairy vetch mulch reduced weeds 80% for 2 to 8 WAR, whereas at Lamberton, there was no consistent effect of cover treatments on weed populations. Winter rye and the WR/HV mixture had higher average residue biomass (5.3 and 5.7 Mg·ha−1, respectively) than hairy vetch (3.0 Mg·ha−1) throughout the season. Soil growing degree-days (SGDD) were lower in cover crop treatments compared with the no-cover control, which could have delayed early vegetable growth and contributed to reduced yields. All cover crop mulches were associated with low levels of soil nitrogen (N) (less than 10 mg·kg−1 N) in the upper 15 cm. Rolled winter annual cover crops show promise for controlling annual weeds in organic no-tillage systems, but additional research is needed on methods to increase vegetable crop yields in rolled cover crops.

scholarly journals Winter Annual Rye Seeding Date Influence on Nitrogen Recovery and Ammonia Volatilization from Late Fall Surface-Applied Manure

Agronomy ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 931 ◽  
Author(s):  
Parisa Akbari ◽  
Stephen Herbert ◽  
Masoud Hashemi ◽  
Allen Barker ◽  
Omid Reza Zandvakili ◽  
...  
Keyword(s):  
Cover Crop ◽  
Ammonia Volatilization ◽  
Ammonia Emission ◽  
Winter Rye ◽  
Planting Dates ◽  
Manure Application ◽  
Late Fall ◽  
Winter Annual ◽  
Forage Rape ◽  
Fall Application

Dairy farmers in the northeast face challenges in the application of manure in fall and on-time planting of cool-season grasses to maximize recovery of residual N and nutrients released from fall applied manure. Ammonia emission from animal manure is a serious environmental concern and can be reduced if cover crop is integrated in the farming system. On-time planting of cover crops can reduce ammonia volatilization from fall, surface-applied manure, and prevents N loss to leaching. A two-year study was conducted in 2015 and 2016 to investigate if time of planting of winter annual rye (Secale cereale L.) along with late fall application of manure when air temperature is low can influence ammonia emission and preserve nitrogen (N) to meet the N requirement of forage rape. Three planting dates (16 September, 30 September, and 14 October) of rye cover crop with two manure application treatments including late-fall application and no manure were assessed for mitigating ammonia volatilization, and also yield and recovery of N by forage rape (Brassica napus L.). The highest rates of ammonia volatilization were detected in the first 24 hours after manure spreading regardless of the treatment. The result indicated that cover crop use significantly limited volatilization compared with no cover crop. The earliest planting date produced 3823 kg ha−1 dry matter of winter rye cover crop that was 16 and 35 percent higher than second and third dates of planting, respectively. The manured cover crop accumulated 132 kg N ha−1 when planted early. However, biomass yield of forage rape was more when planted after all cover crop treatments with manure application. Prior to forage planting, the nitrate-N content in all three soil depths (0–20, 20–40, and 40–60 cm) in the plots with manure was higher than plots with no manure. No significant differences in forage rape yield was detected among winter rye planting dates; however, forage rape planted after winter rye was higher than after no-cover crop. The results of this study suggest that when immediate incorporation of manure into soil is not feasible, establishing cover crop early and then applying manure in the late fall, is a practical management to limit nonpoint source pollution from ammonia loss.

scholarly journals Seed retention of winter annual grass weeds at winter wheat harvest maturity shows potential for harvest weed seed control

2019 ◽  
Vol 34 (2) ◽  
pp. 266-271 ◽  
Author(s):  
Neeta Soni ◽  
Scott J. Nissen ◽  
Philip Westra ◽  
Jason K. Norsworthy ◽  
Michael J. Walsh ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Great Plains ◽  
Downy Brome ◽  
Annual Grass ◽  
Weed Seed ◽  
Weed Species ◽  
Jointed Goatgrass ◽  
Seed Retention ◽  
Winter Annual ◽  
Feral Rye

AbstractDowny brome, feral rye, and jointed goatgrass are problematic winter annual grasses in central Great Plains winter wheat production. Integrated control strategies are needed to manage winter annual grasses and reduce selection pressure exerted on these weed populations by the limited herbicide options currently available. Harvest weed-seed control (HWSC) methods aim to remove or destroy weed seeds, thereby reducing seed-bank enrichment at crop harvest. An added advantage is the potential to reduce herbicide-resistant weed seeds that are more likely to be present at harvest, thereby providing a nonchemical resistance-management strategy. Our objective was to assess the potential for HWSC of winter annual grass weeds in winter wheat by measuring seed retention at harvest and destruction percentage in an impact mill. During 2015 and 2016, 40 wheat fields in eastern Colorado were sampled. Seed retention was quantified and compared per weed species by counting seed retained above the harvested fraction of the wheat upper canopy (15 cm and above), seed retained below 15 cm, and shattered seed on the soil surface at wheat harvest. A stand-mounted impact mill device was used to determine the percent seed destruction of grass weed species in processed wheat chaff. Averaged across both years, seed retention (±SE) was 75% ± 2.9%, 90% ± 1.7%, and 76% ± 4.3% for downy brome, feral rye, and jointed goatgrass, respectively. Seed retention was most variable for downy brome, because 59% of the samples had at least 75% seed retention, whereas the proportions for feral rye and jointed goatgrass samples with at least 75% seed retention were 93% and 70%, respectively. Weed seed destruction percentages were at least 98% for all three species. These results suggest HWSC could be implemented as an integrated strategy for winter annual grass management in central Great Plains winter wheat cropping systems.

Herbicides Reduce Seed Production in Reproductive-Stage Yellow Starthistle (Centaurea solstitialis)

2004 ◽  
Vol 18 (4) ◽  
pp. 1065-1071 ◽  
Author(s):  
Vanelle F. Carrithers ◽  
Cindy Talbott Roché ◽  
Dean R. Gaiser ◽  
Denise Horton ◽  
Celestine L. Duncan ◽  
...  
Keyword(s):  
Seed Production ◽  
Residual Activity ◽  
Centaurea Solstitialis ◽  
Viable Seed ◽  
Weed Seed ◽  
Yellow Starthistle ◽  
Spray Solution ◽  
Effective Reduction ◽  
Flower Stage ◽  
Winter Annual

Herbicides with residual activity more effectively control infestations of yellow starthistle, a facultative winter annual, because seed banks quickly furnish replacement plants after nonresidual herbicide treatments. Picloram has been applied to rosettes in fall or spring, but new infestations of yellow starthistle are often discovered when plants are more noticeable in bud or flower stages. Eradication, containment, and revegetation are facilitated if weed seed rain can be stopped. This study evaluated whether registered rates (0.14, 0.28, and 0.42 kg ae/ha) of picloram, alone and with 2,4-D at 1.12 kg ae/ha, can prevent seed production when applied to yellow starthistle at bud or flower stage. Picloram applied at bud stage curtailed both seed production and germination, reducing seed production by 42 to 86% and viability by 80 to 99%. Neither the picloram rate nor the addition of 2,4-D to the spray solution affected the percentage of nonviable seeds. The addition of 2,4-D further decreased germination of developed seeds only at the lowest picloram rate. At flower stage, picloram and 2,4-D neither killed mature plants nor consistently reduced the quantity and quality (viability) of seeds. Bud stage was the phenological limit for effective reduction of viable seed by picloram, which caused both bud abortion and lower seed germination.

Sign in / Sign up

Export Citation Format

Share Document