Plant production after defoliation of native, Northern Mixed Prairie on hummocky terrain in Saskatchewan

2010 ◽  
Vol 90 (4) ◽  
pp. 421-433 ◽  
Author(s):  
A. Pantel ◽  
J T Romo ◽  
Y. Bai

Resting plants after grazing is central to sustaining potential plant production. Growth of graminoids and forbs was determined for 3 yr after a single defoliation to 7.5 cm in May, June, July, August, September, October, November, or April on five different landform elements in the Northern Mixed Prairie. Green standing crop and cumulative green standing crop of forbs, graminoids, and their total varied with months of defoliation, landform elements, and years after defoliation. Green standing crop and cumulative green standing crop of forbs, graminoids, and their total was less than the control (P ≤ 0.05) on at least one of five landform elements until the second year after defoliation. This pattern of growth suggests the need to defer grazing for at least 1 yr after use to allow plants to regain their production potential. Plants defoliated early in the growing season recovered their production sooner or at the same time as those defoliated later in the growing season or when dormant. Generalizations that spring or early summer defoliation of native range reduces production and late summer or dormant season grazing has no effect on production warrants reconsideration where adequate rest is provided following a short period of grazing.Key words: Landform, landscape, primary production, rangeland, regrowth, standing crop


Author(s):  
T. Southgate

Variation in the abundance of Barleeia unifasciata is compared in several red algal species between June 1978 and June 1980 at Cooskeen Cove, Bantry Bay, Ireland. Population abundance in all algae varied seasonally, exhibiting a cycle of late-summer to autumn maxima, with winter to early summer minima. Greatest abundance was recorded in those algae which formed compact turf-like growths suitable for the entrapment of diatoms and detrital material and provided greatest shelter from wave-crash. Length frequency data showed the main recruitment period to be late June-October with a peak in August with juveniles present in all months of the year. Maximum life span was shown to be 2 years or more with only 15 % of the population surviving into the second year. Sexual development and reproductive cycle was determined for 0 + and 1 + animals. Mature males produced sperm continuously throughout the year. Not all 0 + females spawned in their first year. Summer spawning 0 + females exhibited reduced sexual activity in October and spawned again in the following summer. Some 1 + females spawned in winter and spring. Delayed sexual development in some individuals of both sexes was related to late hatching.



2021 ◽  
pp. 1-10
Author(s):  
Juming Zhang ◽  
Michael Richardson ◽  
Douglas Karcher ◽  
John McCalla ◽  
Jingwen Mai ◽  
...  

Many bermudagrass (Cynodon sp.) and zoysiagrass (Zoysia sp.) cultivars are not available as seed and are commonly planted vegetatively using sprigs, especially for sod production or in sand-based systems. Sprig planting is typically done in late spring or early summer, but this can result in an extended grow-in period and delay the use of the turf in the first growing season. The objective of this study was to determine if sprigs of bermudagrass and zoysiagrass could be planted earlier in the year, during the dormancy phase, to hasten establishment. A field study was carried out in Fayetteville, AR, in 2014 and 2016 using ‘Tifway’ hybrid bermudagrass (Cynodon dactylon × Cynodon transvaalensis) and ‘Meyer’ zoysiagrass (Zoysia japonica), and in Guangzhou, China, in 2015, using ‘Tifway’ hybrid bermudagrass and ‘Lanyin III’ zoysiagrass (Z. japonica). Sprigs were planted in March (dormant), May (spring) and July (summer) in Fayetteville, and in January (dormant), March (spring) and May (summer) in Guangzhou. Sprigging rates of 30, 60, and 90 m3·ha−1 were tested at both locations and across all planting dates. Bermudagrass was less affected by planting date, with dormant, spring or summer plantings effectively establishing full cover in the first growing season. Zoysiagrass that was sprigged in the dormant season was successfully established by the end of the first growing season while a full zoysiagrass cover was not achieved with either spring or summer plantings in Arkansas. Dormant sprigging reached full coverage as fast or faster than traditional spring or summer planting dates at both locations, indicating that bermudagrass and zoysiagrass establishment can be achieved earlier in the growing season using dormant sprigging methods.



2007 ◽  
Vol 60 ◽  
pp. 15-20
Author(s):  
K.R. Everett ◽  
O.E. Timudo-Torrevilla ◽  
J.T. Taylor ◽  
J. Yu

Control of preharvest summer rot in cv Royal Gala apple in the Waikato district during the 2006/2007 growing season was evaluated There were six treatments and an unsprayed control Three treatments investigated the effect of timing by applying tolyfluanid mancozeb captan and copper sequentially at 1014 day intervals in October and early November (spring) November and December (early summer) or January and February (late summer) The fourth treatment was two applications of carbendazim in early October (flowering) and there were two biological control treatments Bacillus subtilis QST713 and Serratia marcescens HR42 applied at 1014 day intervals from flowering (October) to harvest (February) Compared with the unsprayed treatment the most effective control was achieved by fungicide applications during either November/December or January/February Due to large variation in the data differences were not statistically significant but mean lesion diameter at final assessment for these treatments was 29 and 35 of controls respectively The other treatments did not control rots



2018 ◽  
Vol 15 (14) ◽  
pp. 4647-4660 ◽  
Author(s):  
Thomas J. Ryan-Keogh ◽  
Sandy J. Thomalla ◽  
Thato N. Mtshali ◽  
Natasha R. van Horsten ◽  
Hazel J. Little

Abstract. The seasonal and sub-seasonal dynamics of iron availability within the sub-Antarctic zone (SAZ; ∼40–45∘ S) play an important role in the distribution, biomass and productivity of the phytoplankton community. The variability in iron availability is due to an interplay between winter entrainment, diapycnal diffusion, storm-driven entrainment, atmospheric deposition, iron scavenging and iron recycling processes. Biological observations utilizing grow-out iron addition incubation experiments were performed at different stages of the seasonal cycle within the SAZ to determine whether iron availability at the time of sampling was sufficient to meet biological demands at different times of the growing season. Here we demonstrate that at the beginning of the growing season, there is sufficient iron to meet the demands of the phytoplankton community, but that as the growing season develops the mean iron concentrations in the mixed layer decrease and are insufficient to meet biological demand. Phytoplankton increase their photosynthetic efficiency and net growth rates following iron addition from midsummer to late summer, with no differences determined during early summer, suggestive of seasonal iron depletion and an insufficient resupply of iron to meet biological demand. The result of this is residual macronutrients at the end of the growing season and the prevalence of the high-nutrient low-chlorophyll (HNLC) condition. We conclude that despite the prolonged growing season characteristic of the SAZ, which can extend into late summer/early autumn, results nonetheless suggest that iron supply mechanisms are insufficient to maintain potential maximal growth and productivity throughout the season.



1976 ◽  
Vol 6 (4) ◽  
pp. 539-556 ◽  
Author(s):  
Melvin G. R. Cannell

The dynamics of terminal bud development on seven 3-year-old nursery-grown provenances of Pinuscontorta Dougl. were monitored by sampling buds at 1- to 3-weekly intervals during one growing season. Differences in rates of cataphyll initiation occurred which were analysed in terms of (a) the projected areas of the apical domes, which changed over the season, (b) the relative rates at which the apical domes expanded radially during a plastochrone (square millimetres per square millimetre), as shown by the extent to which the new cataphyll primordia receded away from the domes, and (c) the projected areas of the tissues used to form new cataphyll primordia. Component a was a measure of the size of the apical dome meristems and b was a measure of their rates of 'activity.' A model-matching method is described to measure b.Those provenances which produced most cataphylls during the growing season developed and maintained large apical domes (component a above). There were unexpectedly small provenance differences in the apical dome 'activity' in midsummer (component b defined above), although differences occurred in spring and autumn. Differences in the projected areas of the new cataphyll primordia (component c) were inversely related to cataphyll initiation rates. Apical dome tissue doubling times in midsummer were estimated to be less than 120 h, irrespective of provenance.Inland provenances had small but relatively 'active' apical domes in spring, but they produced cataphyll primordia as products of this growth rather than reinvesting in apical dome 'capital.' Consequently, their apical domes remained small. Coastal Alaskan provenances, on the other hand, developed large apical domes, but these domes ceased to be very 'active' after the end of August. The apical domes on south coastal provenances did not become 'active' until early summer, but their domes were relatively large even in spring, became much larger by late summer, and they remained 'active' until mid-September.Implications are noted regarding cross-breeding of complementary genotypes to increase needle production and height growth.



2018 ◽  
Author(s):  
Thomas J. Ryan-Keogh ◽  
Sandy J. Thomalla ◽  
Thato N. Mtshali ◽  
Natasha R. van Horsten ◽  
Hazel Little

Abstract. The seasonal and sub-seasonal dynamics of iron availability within the sub-Antarctic zone (SAZ, ~ 40–45° S) play an important role in the distribution, biomass and productivity of the phytoplankton community. The variability in iron availability is due to an interplay between winter entrainment, diapycnal diffusion, storm-driven entrainment, iron scavenging and iron recycling processes. Biological observations utilising grow-out iron addition incubation experiments were performed at different stages of the seasonal cycle within the SAZ to determine the importance of these supply mechanisms. Here we demonstrate that at the beginning of the growing season there is sufficient iron to meet the demands of the phytoplankton community, but as the growing season develops the supply mechanisms fail to meet this demand. Phytoplankton increase their photosynthetic efficiency and net growth rates following iron addition from mid to late summer, with no differences determined during early summer; suggestive of seasonal iron depletion and low iron resupply. The result of which is residual macronutrients at the end of the growing season, and the prevalence of the high-nutrient low-chlorophyll (HNLC) condition. We conclude that despite the prolonged growing season characteristic of the sub-Antarctic zone, which can extend into late summer/early autumn, the results suggest that the iron supply mechanisms are insufficient to maintain potential maximal growth and productivity throughout the season.



HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 531D-531 ◽  
Author(s):  
Greg L. Davis ◽  
Julie Schimelfenig

Public interest in installing landscapes for reduced maintenance remains high. While availability and specification of native and/or adapted landscape plants such as wildflowers and prairie grasses increase, establishment, management, and expectations of such plantings are not well understood. Our objectives in this study were to measure temporal changes of mixed prairie wildflower plantings under various management regimes and to determine consumer expectations and preferences in these plantings. Nine combinations of wildflowers and prairie grasses were planted in June 1997 at the John Seaton Anderson Turfgrass and Ornamental Research Area, Univ. of Nebraska Agricultural Research Development Center near Mead. On-site surveys were conducted during the Festival of Color, a popular outreach event that occurs annually in September at the site. In 1997 and 1998, the festival attracted more than 9000 and 10,500 participants, respectively, of which 750 completed the survey. To determine preferences for planting compositions, plot desirability ratios were calculated from scaled responses. In 1997, respondents preferred the planting composed of only annuals by a ratio of 5.8: 1 (rated desirable vs. undesirable). This result changed dramatically by the second year, in which the desirability ratio for annuals was 0.3: 1, while that of the combination of perennials and annuals was 11.2: 1. Our plant population density and flowering data validate consumers' preference for abundant color. In late summer of the establishment year (1997), the percentage of the plant population in full bloom was highest in the planting of annuals alone as expected and in 1998 was lowest in the annuals.



1982 ◽  
Vol 60 (7) ◽  
pp. 1647-1659 ◽  
Author(s):  
R. G. Randall ◽  
U. Paim

The production rate of juvenile Atlantic salmon (Salmo salar) was estimated at four sites in two tributary streams of the Miramichi River, New Brunswick, during the period September 1976 to October 1978. Annual production ranged between 0.27 and 5.12 g∙m−2∙year−1. Growth was largely restricted to a 4-month period in early summer. Among the four sites, age 0+ salmon attained a mean weight of between 0.95 and 3.50 g by the end of their first growing season (September) and densities in July ranged between 0.3 and 3.1 fry∙m−2∙Age 1+ parr grew to mean weights between 4.95 and 12.45 g by September, and June–July densities ranged between 0.03 and 0.6 parr∙m−2. Marking information indicated that most parr remained in the study sites from July to September, but larger proportions of migrant parr were recorded in October. Production during summer was directly and positively related to initial population densities. Production rates at these sites were lower than most other recorded values for juvenile Atlantic salmon. Biomass of salmon may have been below the carrying capacity of the environment at all four sites.



1983 ◽  
Vol 7 (2) ◽  
pp. 76-81
Author(s):  
R. C. Schmidtling

Abstract Fertilizers were applied at different dates during the growing season to orchard ramets of loblolly (Pinus taeda L), slash (Pinus elliottii Engelm. var. elliottii), shortleaf (Pinus echinata Mill.), and Virginia pines (Pinus virginiana Mill.) to determine optimum time to enhance flowering. Depending on species, female flowering was increased by applications in mid- to late summer. Male flowering was increased most by applications in early summer.



1952 ◽  
Vol 3 (2) ◽  
pp. 148 ◽  
Author(s):  
RC Rossiter

The results of a grazing trial with Merino wether sheep on perennial veldt grass with subterranean clover are presented. During the four years 1944-45 to 1947-48 total pasture production under continuous grazing was almost identical with that under rotational grazing (one week's grazing followed by five weeks' rest). No consistent treatment differences were observed in sheep body-weight trends. In each year the weights increased during the growing season, remained stationary during early summer, and declined in late summer. The contribution of the perennial grass (Ehrharta calycina Sm.) declined rapidly with time, though more so under continuous grazing. This was associated with an increase in the proportion of subterranean clover in the sward. The lack of persistence of Ehrharta calycina is attributed to selective grazing, together with susceptibility to drastic defoliation. Alternative schemes for the use of this grass, involving restricted winter grazing, are suggested.



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