scholarly journals Simulation of grass sward dry matter yield in Slovenia using the LINGRA-N model

2017 ◽  
pp. 44-56 ◽  
Author(s):  
Tjaša Pogačar ◽  
Lučka Kajfež Bogataj

Calibration and validation of the LINGRA-N model were performed using herbage dry matter (DM) yield data from field studies conducted at three locations in Slovenia. Calibration was done by minimising root mean square error (RMSE) and validation by using RMSE and Willmott’s index of agreement (dw). Calibration of LINGRA-N was not successful for the experiment conducted on permanent grassland in Ljubljana in the period 1974-1993 (RMSE% = 14%, dw = 0.37). Better results were obtained for grass monocultures in Jablje (J) and Rakičan (R) in the period 1998– 2013, with the best fit for cocksfoot (Dactylis glomerata L.; RMSE% = 12%, dw = 0.84). Fifty-year simulations were performed for cocksfoot (J-DG) and timothy grass (Phleum pratense L.) in Jablje (J-PP) and perennial ryegrass (Lolium perenne L.) in Jablje (J-LP) and Rakičan. Outliers with very low simulated herbage DM yield were detected only in the second half of the study period and were associated with drought and/or high maximum air temperatures. A time series analysis of annual potential yield values showed a statistically significant (P=0.05) negative trend for J-LP (–24 kg DM ha–1year–1) and J-PP (–29 kg DM ha–1year–1). A change in the variability of the reduction factor for crop growth due to drought was already noticeable.

2013 ◽  
Vol 40 (2) ◽  
pp. 115-119 ◽  
Author(s):  
Eric P. Prostko ◽  
Theodore M. Webster ◽  
Michael W. Marshall ◽  
Ramon G. Leon ◽  
Timothy L. Grey ◽  
...  

ABSTRACT Field studies were conducted at 13 locations across the US peanut belt during 2010–2012 to evaluate peanut response to postemergence applications of glufosinate. Glufosinate was applied at 0, 41, 82, 164, 328 and 656 g ai/ha 30, 60, and 90 days after planting (DAP). There was a significant interaction for peanut yield between application time and glufosinate rate; peanut yield data were regressed on rate of glufosinate and fit to a log-logistic dose response curve by application timing. At 30 DAP, peanut yield ranged from 16 to 92% of the non-treated control, with glufosinate at 266 g/ha causing an estimated 50% reduction in yield (Y50). At 60 DAP, peanut yield ranged from 16 to 82% of the nontreated control, with Y50  =  266 g/ha of glufosinate. Peanut yield when glufosinate was applied at 90 DAP ranged from 20 to 78% of the non-treated control; Y50  =  187 g/ha of glufosinate, which was lower than that at 30 DAP and indicated greater peanut sensitivity. Peanut plants treated at 30 DAP had more time to recover from glufosinate injury at the lower rates and/or were in a less susceptible stage of growth relative to 90 DAP. These data provide peanut growers across the US with an estimate of potential yield losses associated with mis-application, off-target movement, or sprayer contamination of glufosinate.


Author(s):  
Jiří Skládanka

The work was carried out to study the influence of additional sowing and differentiated systems of use in the summer period on the production of grass sward in the autumn and winter period. An additional sowing of Festuca arundinacea and Festulolium was made into the grass stand with dominating Festuca rubra, Taraxacum officinale, Agropyron repens, Dactylis glomerata, Trisetum flavescens, Agrostis stolonifera and Phleum pratense. In summer (preparatory cut), the grass stand was utilized in June, July and August. In the autumn (main use), it was utilized in November, December and January. The additional sowing, the preparatory cut and the main use were monitored for their influence on the yield of dry matter. Another assessment was made of the share of Festuca arundinacea and Festulolium in the harvested herbage. In June 2001, the share of additionally sown herb species in the harvested herbage did not exceed 2%. However, their proportion increased to more than 20% in four years of the study. In the summer period, the additional sowing did not show any significant effect on dry matter yields. The additionally sown herb species exhibited a pronounced dominance in November. The shares of Festuca arundinacea and Festulolium in the harvested herbage were 80.1% and 71.3%, respectively. Yields from the additionally sown grass stands were higher from the third year of the study (by 1.07–1.26 t.ha–1) than those from the grass stand with no additional sowing (0.66–0.97 t.ha–1) the variance being insignificant. In the autumn and in winter, a significant decrease (P < 0.05) was seen in yields from the grass stand utilized until the beginning of August and the yields further decreased with the proceeding winter.


2011 ◽  
Vol 50 (No. 6) ◽  
pp. 277-282 ◽  
Author(s):  
N. Lemežienė ◽  
J. Kanapeckas ◽  
P. Tarakanovas ◽  
S. Nekrošas

An average dry matter yield structure (three cuts per growing season) in relation to agronomically valuable characteristics of six forage grass species and a year of herbage utilization was studied over the period of 1989&ndash;2002 in Lithuania. The most productive species of the first cut of two years of herbage utilization were Phleum pratense (P &lt; 0.01) and Festulolium hybrids (P &lt; 0.05) (average dry matter yield were 7.42 and 6.66 t/ha, respectively), moderately productive &ndash; Festuca pratensis, Dactylis glomerata and Lolium perenne (5.58, 5.42 and 5.20 t/ha), significantly lower (P &lt; 0.01) yielding was Poa pratensis (4.19 t/ha). During two years of herbage utilization Dactylis glomerata produced significantly (P &lt; 0.01) higher dry matter yield of aftermath &ndash; 7.30 t/ha. Other grass species were ranked in the following order: Festulolium hybrids 5.85 t/ha, Festuca pratensis 4.94 t/ha, Poa pratensis 4.57 t/ha, Lolium perenne 4.48 t/ha, and Phleum pratense 3.92 t/ha. Dactylis glomerata and Poa pratensis distinguished by the highest aftermath percent in the structure of the annual dry matter yield (57.7 and 52.2%). Phleum pratense formed an especially poor aftermath &ndash; only 34.6%. An average annual dry matter yield data analysis of two years of herbage utilization over the period of 1989&ndash;2002 showed that Dactylis glomerata and Festulolium hybrids were most productive (P &lt; 0.01) species.


1985 ◽  
Vol 65 (3) ◽  
pp. 787-791
Author(s):  
H. A. BURITY ◽  
B. E. COULMAN ◽  
M. A. FARIS

A greenhouse experiment has shown that total nitrogenase activity of alfalfa (Medicago sativa L.) is not significantly affected when grown in association with timothy (Phleum pratense L.), smooth bromegrass (Bromus inermis Leyss) or orchardgrass (Dactylis glomerata L.) except after initial harvest when decreased alfalfa activity was associated with smooth bromegrass or orchardgrass. It was concluded that mixed cultures of alfalfa with timothy, smooth bromegrass or orchardgrass have no effect on alfalfa N2 fixation. The results also suggest the occurrence of N transference from alfalfa to associated grasses. It is speculated that this transfer is not primarily due to the death of roots and nodule tissue (after harvest), but involves some degree of N excretion during the period before initial harvest.Key words: Alfalfa-grass mixtures, N2-fixation, nodule activity, N-transference


1983 ◽  
Vol 63 (1) ◽  
pp. 267-276 ◽  
Author(s):  
R. L. NICHOLS ◽  
R. A. PETERS

Birdsfoot trefoil (Lotus corniculatus L. ’Viking’) was seeded directly into a predominantly orchardgrass (Dactylis glomerata L.) sward following overall or banded applications of paraquat (1,1′-dimethyl-4, 4′-bipyridinium ion, as dichloride salt) or glyphosate [N-(phosphonomethyl)glycine, as isopropylamine salt] to determine the degree of sward control necessary for stand establishment without tillage. Effects of the herbicide treatments and the seeding on botanical composition and dry matter production were determined by a vertical intercept technique and by hand separations of harvests into botanical components. Trefoil establishment was proportional to the degree of sward control during the seeding year. Little trefoil was established by direct seeding without herbicides. The banded herbicide treatments were less effective than overall herbicide applications for trefoil establishment. Trefoil yield obtained following overall application of paraquat was approximately 65% of that obtained following overall glyphosate treatment.Key words: Dactylis glomerata, glyphosate, Lotus corniculatus, herbicide, no-tillage, paraquat


2011 ◽  
Vol 59 (1) ◽  
pp. 13-22
Author(s):  
Z. Varga-Haszonits ◽  
E. Enzsölné Gerencsér ◽  
Z. Lantos ◽  
Z. Varga

The temporal and spatial variability of soil moisture, evapotranspiration and water use were investigated for winter barley. Evaluations were carried out on a database containing meteorological and yield data from 15 stations. The spatial distribution of soil moisture, evapotranspiration and water use efficiency (WUE) was evaluated from 1951 to 2000 and the moisture conditions during the growth period of winter barley were investigated. The water supply was found to be favourable, since the average values of soil moisture remained above the lower limit of favourable water content throughout the growth period, except for September–December and May–June. The actual evapotranspiration tended to be close to the potential evapotranspiration, so the water supplies were favourable throughout the vegetation period. The calculated values of WUE showed an increasing trend from 1960 to 1990, but the lower level of agricultural inputs caused a decline after 1990. The average values of WUE varied between 0.87 and 1.09 g/kg in different counties, with higher values in the northern part of the Great Hungarian Plain. The potential yield of winter barley can be calculated from the maximum value of WUE. Except in the cooler northern and western parts of the country, the potential yield of winter barley, based on the water supply, could exceed 10 t/ha.


1988 ◽  
Vol 68 (4) ◽  
pp. 1121-1129 ◽  
Author(s):  
W. N. MASON ◽  
P. M. FLIPOT

Five timothy (Phleum pratense L.) cultivars, Clair, Champ, Milton, Climax and Bounty, were harvested at first flower stage during 2 consecutive years and in the regrowth for 1 yr. The forages were each offered as hay to 15 young rams to evaluate voluntary intake. Five animals were used to determine initial harvest dry matter digestibility. The cultivars varied significantly in voluntary intake at first flower stage. The highest intake (g kg−0.75 d−1) averaged for the years was obtained in the early cultivar Champ (65.9), which was 10% more than that of the medium-late cultivar Climax. The cultivars did not differ significantly in dry matter digestibility. In the regrowth, the relative intakes of the cultivars were essentially reversed from that of the initial harvest. The voluntary intake was substantially higher but the differences among forages were less marked. Climax regrowth voluntary intake was higher (P < 0.05) than all cultivars, except Bounty. A 15% range in digestible dry matter intake was present among cultivars. The ranking of the culivars for digestible dry matter was different than for dry matter yield. Key words: Timothy, Phleum pratense L., voluntary intake, dry matter digestibility


1970 ◽  
Vol 50 (6) ◽  
pp. 685-691 ◽  
Author(s):  
J. R. LESSARD ◽  
M. HIDIROGLOU ◽  
R. B. CARSON ◽  
J. M. WAUTHY

Each of the species birdsfoot trefoil (Lotus corniculatus L.), timothy (Phleum pratense L.), bromegrass (Bromus inermis Leyss.), orchardgrass (Dactylis glomerata L.), reed canarygrass (Phalaris arundinacea L.) and creeping red fescue (Festuca rubra L.) was grown in the field on 10 plots sampled at weekly intervals in rotation from June 13. Each plot was resampled after 6 weeks and all samples were analyzed for copper, molybdenum and sulfur. In most species, levels of Cu and Mo were highest in the early samplings and decreased with advancing maturity. Second-cut samples tended to be higher in Cu, Mo and S than first-cut samples. The S content was more uniform in the first cycle but increased considerably in the second cycle, especially in reed canarygrass. The ranges in Cu content were 7.4 to 14.1 ppm for birdsfoot trefoil and 3.7 to 11.4 ppm for the grasses. Mo ranged from 1.9 to 8.1 ppm in birdsfoot trefoil and from 1.0 to 6.5 ppm in the grasses. The overall range in S content was from 0.14 to 0.95%. The mineral composition of the crops is discussed in relation to the requirement of ruminants for these three elements.


2018 ◽  
Vol 32 (5) ◽  
pp. 586-591
Author(s):  
Samuel J. McGowen ◽  
Katherine M. Jennings ◽  
Sushila Chaudhari ◽  
David W. Monks ◽  
Jonathan R. Schultheis ◽  
...  

AbstractField studies were conducted in North Carolina to determine the critical period for Palmer amaranth control (CPPAC) in pickling cucumber. In removal treatments (REM), emerged Palmer amaranth were allowed to compete with cucumber for 14, 21, 28, or 35 d after sowing (DAS) in 2014 and 14, 21, 35, or 42 DAS in 2015, and cucumber was kept weed-free for the remainder of the season. In the establishment treatments (EST), cucumber was maintained free of Palmer amaranth by hand removal until 14, 21, 28, or 35 DAS in 2014 and until 14, 21, 35, or 42 DAS in 2015; after this, Palmer amaranth was allowed to establish and compete with the cucumber for the remainder of the season. The beginning and end of the CPPAC, based on 5% loss of marketable yield, was determined by fitting log-logistic and Gompertz equations to the relative yield data representing REM and EST, respectively. Season-long competition by Palmer amaranth reduced pickling cucumber yield by 45% to 98% and 88% to 98% during 2014 and 2015, respectively. When cucumber was planted on April 25, 2015, the CPPAC ranged from 570 to 1,002 heat units (HU), which corresponded to 32 to 49 DAS. However, when cucumber planting was delayed 2 to 4 wk (May 7 and May 21, 2014 and May 4, 2015), the CPPAC lasted from 100 to 918 HU (7 to 44 DAS). This research suggested that planting pickling cucumber as early as possible during the season may help to reduce competition by Palmer amaranth and delay the beginning of the CPPAC.


Sign in / Sign up

Export Citation Format

Share Document