Investigations of alternative kale management: Production, regrowth and quality from different sowing and defoliation dates

2007 ◽  
pp. 29-33 ◽  
Author(s):  
H.E. Brown ◽  
S. Maley ◽  
D.R. Wilson
Keyword(s):  
Sowing Date ◽  
Linear Increase ◽  
Thermal Time ◽  
Total Production

Gruner kale showed a linear increase (8.0 kg DM/ha per °Cd) in biomass with sowings on 1 October, 3 November and 1 December producing 23, 19 and 17 t DM/ha (respectively) by the 29 May. Regrowth following mid season defoliation was slow (5.3 kg DM/ha per °Cd) reducing total production (relative to undefoliated) by 7.5 and 5.5 t DM/ha for treatments defoliated on the 29 January and 14 March, respectively. Keyworks: defoliation, kale, quality, regrowth, sowing date, thermal time, yield

Plant development of triticale cv. Lasko at different sowing dates

1998 ◽  
Vol 130 (3) ◽  
pp. 297-306 ◽  
Author(s):  
R. E. L. NAYLOR ◽  
J. SU
Keyword(s):  
Stem Elongation ◽  
Seedling Emergence ◽  
Sowing Date ◽  
Thermal Time ◽  
Development Stages ◽  
Leaf Emergence ◽  
Sowing Dates ◽  
Time Requirements ◽  
Leaf Appearance ◽  
Double Ridge

The progress of leaf emergence, external morphology and apical development stages were recorded in sowings of triticale (cv. Lasko) made from February to November 1990 at Aberdeen (57° N). Leaf appearance and the number of primordia were related to thermal time (above a base of 0°C) except when photoperiods were <c. 11 h. The thermal time per phyllochron varied between leaves and the combined times for all the phyllochrons at a particular sowing accounted for the apparent response of average phyllochron to sowing date. The thermal time requirements for progression to the double ridge stage, terminal spikelet stage, onset of stem elongation and anthesis were similar except where photoperiods of <11 h occurred. The rate of grain primordium production was constant when photoperiod had been increasing at seedling emergence but the rate was reduced when the seedling experienced shortening photoperiods at emergence.

The growth and activity of winter wheat roots in the field: the effect of sowing date and soil type on root growth of high-yielding crops

1984 ◽  
Vol 103 (1) ◽  
pp. 59-74 ◽  
Author(s):  
P. B. Barraclough ◽  
R. A. Leigh
Keyword(s):  
Winter Wheat ◽  
Root Growth ◽  
Grain Yield ◽  
Dry Weight ◽  
Sowing Date ◽  
Thermal Time ◽  
Regression Equations ◽  
Root Dry Weight ◽  
Significant Difference ◽  
Distribution Of Roots

SummaryThe effect of sowing date on root growth of high-yielding crops (8–1 It grain/ha, 85% D.M.) of winter wheat (Triticum aestivum L. cv. Hustler) was measured at Rothamsted and Woburn in 1980 and 1981. Roots were sampled by coring on five occasions and changes in root dry weight and length were determined. The average growth rate between March and June was about 1 g/m2/day (200 m/m2/day), over 5 times that measured between December and March. Increases in root weight or length with time were generally exponential to anthesis when the crops had 101–172 g root/m2 (20–32 km/m2). September-sown wheat had more root than October-sown wheat at all times, but whereas early differences in length were maintained throughout the season, root weights converged between March and June. Overall, there was no significant difference in root dry-matter production between sites at anthesis, but there was a substantial difference between years. Differences in root growth between crops were reduced by plotting the amount of root against either the number of days from sowing or accumulated thermal time. Using che latter, root growth between December and June was reasonably linear although there was some indication of a lag below 500 °C days. Regression equations obtained for the relationships between root growth and accumulated thermal time also fitted previously published data and may provide general descriptions of root growth with time.Roots of September-sown crops reached 1 m depth by December but those of October-sown crops were not detectable at this depth until April. For most crops the distribution of roots with depth was reasonably described by an exponential decay function, with over 50% of the roots in the top 20 cm of soil at all times. At Woburn in 1981, a plough-pan restricted roots to the upper soil horizons for most of the season but apparently had little effect on the total amount of root produced. For one of the experimental crops an empirical mathematical function describing the distribution of roots with depth and time is presented.Using the data from this and previously published studies, the relationship between grain yield and the amount of root at anthesis was investigated. Total root length was positively correlated with grain yield but nonetheless similarly yielding crops could have different-sized root systems. Total root dry weight was poorly correlated with grain yield.

GROUNDNUT GROWTH AND DEVELOPMENT IN CONTRASTING ENVIRONMENTS. 2. HEAT UNIT ACCUMULATION AND PHOTO-THERMAL EFFECTS ON HARVEST INDEX

1998 ◽  
Vol 34 (1) ◽  
pp. 113-124 ◽  
Author(s):  
M. J. BELL ◽  
G. C. WRIGHT
Keyword(s):  
Harvest Index ◽  
Growing Season ◽  
Sowing Date ◽  
Short Wave ◽  
Thermal Time ◽  
Dominant Factor ◽  
Published Data ◽  
Wide Range ◽  
Semi Arid ◽  
Subtropical Australia

When the same cultivars of groundnuts (Arachis hypogaea) were grown under a wide range of environmental conditions, temperature and irradiance played a major role in determining crop duration and partitioning of dry matter to pods, the latter assessed by harvest index. Utilizing published data for the Virginia groundnut cultivar Early Bunch under non-limiting conditions, we show that accumulation of thermal time using three cardinal temperatures (Tb=9 °C, To=29 °C and Tm=39 °C) has considerable potential for predicting crop maturity. In sixteen sowings ranging from the wet tropics in Indonesia to the elevated subtropics in Australia, harvest date for Early Bunch corresponded to the accumulation of 1808 (±23) degree-days after sowing. In all sowings except one in the semi-arid tropics, this value of thermal time was within eight calendar days of actual harvest maturity. Harvest index varied greatly with both location and sowing date, ranging from 0.31 (Indonesia) to 0.58 (subtropical Australia). Using total short-wave solar radiation incident during the growing season and calculated values of thermal time, the growing season for each sowing in each location was described in terms of a photo-thermal quotient (PTQ, MJ m−2 degree-day−1). Values for PTQ ranged from 0.99 (Indonesia) to 2.11 (subtropical Australia). Variation in harvest index could be explained largely by a curvilinear function of PTQ (R2=0.98), provided data were not confounded by the effects of photoperiod. In the semi-arid tropical environment, decreases in photoperiod associated with delayed sowing were the dominant factor controlling harvest index.

Prediction of ear emergence in winter wheats grown at Temora, New South Wales

1997 ◽  
Vol 48 (4) ◽  
pp. 433 ◽  
Author(s):  
L. D. J. Penrose
Keyword(s):  
New South ◽  
New South Wales ◽  
Sowing Date ◽  
Thermal Time ◽  
Yield Potential ◽  
Regression Equations ◽  
Sowing Time ◽  
Frost Risk ◽  
South Wales

This study examined factors that determine ear emergence in winter wheats grown at Temora, New South Wales. Three development factors were considered: degree of winter habit, response to photoperiod, and intrinsic earliness. The effect of winter habit was first examined by using 3 pairs of related wheats that differed for spring–winter habit. Wheats were sown under irrigation from mid February to June, for up to 4 consecutive years. Ear emergence was recorded in days of the year for ease of field interpretation, and in photo-thermal time to measure delay in development. Winter habit was found to delay ear emergence throughout this sowing range. Ear emergence was then studied in 23 winter wheats that as a group encompassed a broad range for each of the 3 development factors, and these winter wheats were grouped on the basis of combinations of development factors. Differences in ear emergence between these groups guided the construction and testing of regression equations that described ear emergence as a function of sowing date and of the 3 development factors. Many combinations of factors were associated with the time of ear emergence (i.e. 1 October) at Temora that best optimises the balance between frost risk and yield potential. Combinations of development factors also influenced the flexibility of sowing time for winter wheats grown at Temora. These findings may assist the breeding of new winter wheats that can be sown over a longer period than current winter cultivars.

Effects of sowing date, sowing density and nitrogen supply on leaf extension in spring barley

1989 ◽  
Vol 113 (3) ◽  
pp. 305-315 ◽  
Author(s):  
A. A. S. Maan ◽  
D. Wright ◽  
M. B. Alcock
Keyword(s):  
Leaf Area ◽  
Sowing Date ◽  
Nitrogen Supply ◽  
Extension Growth ◽  
Thermal Time ◽  
Extension Rate ◽  
Leaf Position ◽  
Main Shoot ◽  
N Supply ◽  
Leaf Extension

SUMMARYThree pot experiments were performed in unheated glasshouses at the University College of North Wales College Farm, Aber, Gwynedd in 1980–1983. Two experiments tested the effects of sowing date and N supply, the third sowing density and nitrogen supply. Extension growth of main-stem leaves was measured by ruler and expressed in thermal time units to allow comparisons between sowing dates. Rate and duration of leaf extension were determined from linear regressions of leaf length against thermal time.Increasing N supply increased leaf extension rate but had no significant effects on leaf extension duration. Leaf extension rate increased with leaf position on the main shoot, but decreased slightly in leaves extending at the time of stem elongation. Leaf extension duration also increased with leaf position on the main shoot and was related to mean temperature during the leaf extension phase. Plants sown in September were able to compensate for lower radiation receipts by having a faster rate and longer duration of leaf extension, by producing larger leaves with a greater specific lamina area and by partitioning a greater proportion of extension growth into lamina and less into sheaths. In plants sown in June, the largest leaf occurred at a lower stem node and leaves emerging later showed a strong response to N. It is suggested that this is attributable to earlier onset of internal competition for assimilates. Variation in leaf extension rate was the main factor influencing variation in final leaf area. There was a strong positive relationship between leaf extension rate and leaf N content.Increasing sowing density increased the area of the first four leaves on the main shoot and decreased that of later leaves, changes mainly associated with changes in leaf extension duration. It is concluded that progress in the modelling of leaf area expansion, light interception and dry matter production requires more information about how sowing date, sowing density and N supply interact to influence crop development and leaf growth.

A field study of the number of main shoot leaves in wheat in relation to vernalization and photoperiod

1992 ◽  
Vol 118 (3) ◽  
pp. 271-278 ◽  
Author(s):  
E. J. M. Kirby
Keyword(s):  
Field Experiments ◽  
Seedling Emergence ◽  
Wheat Plant ◽  
Sowing Date ◽  
Thermal Time ◽  
Model Function ◽  
Main Shoot ◽  
Leaf Emergence ◽  
Sowing Dates ◽  
Developmental Feature

SUMMARYThe number of leaves formed on the main shoot of a wheat plant is an important developmental feature, and a method of predicting this is essential for computer simulation of development.A model function was used to estimate vernalization from simulated sowing dates throughout a season. When expressed in terms of thermal time, it was estimated that a plant might be fully vernalized soon after seedling emergence or take up to about 1000 °Cd, depending on sowing date. When the simulated progress of vernalization was related to main shoot development (primordium initiation and leaf emergence) it was found that there were substantial differences between sowings in the rate of vernalization at comparable stages of apex development.A number of field experiments done in Britain from 1980 to 1984 with prominent commercial varieties, sown at various times from September to March, were analysed in terms of the thermal time to full vernalization and the photoperiod at the time of full vernalization, with vernalization simulated by the model function. In both winter and spring varieties, both of these variables significantly affected the number of main shoot leaves. Multiple linear regression using these two variables accounted for between 70 and 90% of the variance in leaf number, depending on variety.

scholarly journals Conyza bonariensis growth and development according to thermal time accumulation and photoperiod

2020 ◽  
Vol 55 ◽  
Author(s):  
Nereu Augusto Streck ◽  
Giliardi Dalazen ◽  
Anelise da Silva Lencina ◽  
Nelson Diehl Kruse ◽  
Michel Rocha da Silva ◽  
...  
Keyword(s):  
Plant Height ◽  
Growth And Development ◽  
Sowing Date ◽  
Thermal Time ◽  
Vegetative Stage ◽  
Development Stages ◽  
Conyza Bonariensis ◽  
Sowing Dates ◽  
Time Accumulation ◽  
Hairy Fleabane

Abstract: The objective of this work was to characterize the growth and development of hairy fleabane (Conyza bonariensis) according to thermal accumulation and photoperiod, at different sowing times, and to propose a scale representing the main plant development stages. The experiment was carried out with ten replicates in the 2011/2012 growing season. The sowing dates were: 05/31/2011, 07/04/2011, 08/03/2011, 09/09/2011, and 11/07/2011. Plant height (cm) and phenology were evaluated weekly. The duration of the different stages (days) and thermal time accumulation (°C day) were determined. The linear regression analysis showed that plant height was related to thermal time accumulation. Regardless of the sowing date, the vegetative stage had a longer duration (in days and in ºC day) than the reproductive stage. Sowing on 11/07/2011 promoted the shortening of the vegetative stage, and the rosette stage did not occur. Flowering was induced in the photoperiod between 12.5 and 13.5 hours of light, regardless of the sowing date. Slow growth was observed at lower temperature conditions, when plants accumulated 30.9 and 16.3°C day per centimeter of height for the 05/31/2011 and 11/07/2011 sowing dates, respectively. The phenology scale adequately predicts the development stages of hairy fleabane.

scholarly journals Seedling development and growth of white clover, caucasian clover and perennial ryegrass grown in field and controlled environments

2002 ◽  
pp. 197-204 ◽  
Author(s):  
A.D. Black ◽  
D.J. Moot ◽  
R.J. Lucas
Keyword(s):  
Perennial Ryegrass ◽  
White Clover ◽  
Sowing Date ◽  
Rapid Onset ◽  
Seedling Development ◽  
Thermal Time ◽  
Axillary Shoots ◽  
Sowing Dates ◽  
Environment Study ◽  
Controlled Environments

Autumn sowing on 4 February (SD1) and 31 March (SD2) 2000 was used to compare the establishment success of white and caucasian clovers sown with 0, 3, 6 or 12 kg seed/ha of perennial ryegrass. Total dry matter (DM) production from sowing to 3 October 2000 averaged 5770 and 3470 kg DM/ha for the two sowing dates, respectively. Clover species did not affect herbage production in monocultures which averaged 2610 kg DM/ha. The total DM increase from the addition of ryegrass was 87, 109 and 114% for 3, 6 and 12 kg/ha, respectively. On 3 October 2000, white clover content averaged 15% when sown with 3-12 kg/ha ryegrass on SD1 but less than 2% for SD2. Caucasian clover never exceeded 9% in either sowing and weed content was 2% when ryegrass was included for SD1 but 18% for SD2. A complimentary controlled environment study examined seedling development and growth of the three species. For each species the leaf appearance interval (phyllochron) in days differed across temperatures but was constant in thermal time at 94ºCd for white clover, 109ºCd for caucasian clover and 101ºCd for ryegrass. Axillary leaves and tillers of ryegrass first appeared after 375ºCd compared with 439ºCd for axillary leaves of white clover and 532ºCd for stolon initials. No secondary leaf development or rhizome initiation was detected in caucasian clover up to 774ºCd. At this time ryegrass seedling shoots were 635 mg/plant compared with 167 and 184 mg/plant for white and caucasian clovers, respectively. Thus, the success of ryegrass seedlings during autumn pasture establishment was explained by its high relative growth rate, and rapid onset of axillary leaf and tiller development compared with white and particularly caucasian clovers. Successful caucasian clover establishment is most likely to occur in the absence of either ryegrass or white clover. Keywords: axillary shoots, Lolium perenne, pasture establishment, phyllochron, sowing date, sowing rate, thermal time, Trifolium ambiguum, Trifolium repens

Temperature and Sowing Date Affect the Linear Increase of Sunflower Harvest Index

1907 ◽  
Vol 90 (3) ◽  
pp. 324-328 ◽  
Author(s):  
Michael P. Bange ◽  
Graeme L. Hammer ◽  
Kenneth G. Rickert
Keyword(s):  
Harvest Index ◽  
Sowing Date ◽  
Linear Increase

scholarly journals Optimum Sowing Dates for High-Yield Maize when Grown as Sole Crop in the North China Plain

Agronomy ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 198 ◽  
Author(s):  
Xuepeng Zhang ◽  
Jiali Cheng ◽  
Biao Wang ◽  
Peng Yan ◽  
Hongcui Dai ◽  
...  
Keyword(s):  
North China Plain ◽  
North China ◽  
Grain Filling ◽  
Maize Yield ◽  
Sowing Date ◽  
Thermal Time ◽  
High Yield ◽  
The North ◽  
The North China Plain ◽  
Sowing Dates

The maize sole cropping system solves problems related to ground water resource shortages and guarantees food security in the North China Plain. Using optimal sowing dates is an effective management practice for increasing maize yield. The goal of this study was to explore an optimum sowing date for high-yield maize. Six sowing dates (SDs) from early April to late June with intervals of 10 to 20 days between SD—SD1 (early April), SD2 (mid to late April), SD3 (early May), SD4 (mid to late May), SD5 (early June), SD6 (late June)—were applied from 2012 to 2017. The results showed that yield was correlated with the sowing date based on the thermal time before sowing (r = 0.62**), which was defined as the pre-thermal time (PTt), and that the yield was steadily maintained at a high level (>10,500 kg ha−1) when PTt was greater than 479 °C. To satisfy the growing degree-days required for maturity, maize needs to be sown before a PTt of 750 °C. Data analysis of the results from 2014, 2015, and 2017 revealed the following: i) Most of the grain-filling parameters of late-sown dates (SD4, SD5 and SD6) were better than those in early-sown dates (SD1, SD2, and SD3) in all years, because of the high daily maximum temperature (Tmax) and wide diurnal temperature (Td) from silking to blister (R1–R2) of early-sown dates. The weight of maximum grain-filling rate (Wmax) of SD3 decreased compare with SD4 by the narrow Td from blister to physiological maturity (R2–R6) in all years (−5, −12, and −33 mg kernel−1 in 2014, 2015, and 2017, respectively). ii) In 2017, the pollination failure rates of early-sown dates were 8.4~14.5%, which was caused by the high Tmax and Td of R1–R2. The apical kernel abortion rates were 28.6 (SD2) and 38.7% (SD3), which were affected by Tmax and Td during R2–R6. iii) Compared with late-sown dates, the wide Td of early-sown dates in R1–R2 was caused by higher Tmax, but the narrow Td in R2-R6 was caused by higher Tmin. Our results indicate that high-yielding maize can be obtained by postponing the sowing date with a PTt of 480~750 °C, which can prevent the negative effects of the high Tmax of R1–R2 and high Tmin of R2–R6 on kernel number and weight formation. Moreover, these above-mentioned traits should be considered for heat tolerance breeding to further increase the maize yield.

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