Cultivar, sowing date and plant density studies of fibre hemp (Cannabis sativa L.) in Tasmania

2000 ◽  
Vol 40 (7) ◽  
pp. 975 ◽  
Author(s):  
S. N. Lisson ◽  
N. J. Mendham

This paper reports on a 3-year agronomic study into fibre hemp (Cannabis sativa L.) conducted in Tasmania, Australia. The performance of selected hemp cultivars, and the responses to sowing date and plant density were investigated as part of a broad feasibility study to assess the potential of fibre hemp and flax (Linum usitatissimum L.) as sources of fibre for the Australian newsprint industry. Trials were conducted at separate sites in north-west and south-east Tasmania. Nine cultivars from the Ukraine, Hungary and France were examined in 2 separate trials. The Hungarian cultivars, Kompolti and Unico B, and the French cultivar Futura 77 had the highest single plot dry stem yields (up to 1500 g/m 2 ) and bark proportions (up to 40%). All the cultivars flowered toward the end of January, suggesting that the growing season in Tasmania could accommodate much later flowering and potentially higher yielding genotypes. Levels of the psychoactive agent, delta-9-tetrahydrocannabinol were consistently below the legal maximum of 0.35% (dry weight basis). Three sowing date trials were conducted across 2 seasons incorporating dates between mid September and mid November and a single autumn planting at the end of May. Interactions with cultivar and planting density were also considered. Stem and bark yield declined with delays in sowing after early–mid October in response to a decline in calendar days and thermal time from sowing to flowering. The response was most pronounced in sowings of Kompolti, which flowered within a short period and differed more substantially in durations to flowering. Earlier sowings were limited by premature flowering in response to shorter daylengths and by poor drainage at one of the 2 trial sites. The success of early sowings in Tasmania would appear to depend on finding cultivars less sensitive tophotoperiod, and cultivation on well drained sites. A further trial was conducted to investigate the influence of plant density on hemp yields. Treatments included densities from 50 to 300 plants/m 2 . Plant density declined with crop growth across all treatments and was most pronounced for populations of 200 and 300 plants/m 2 . Final harvest stem yield responded in a parabolic manner to plant density, with maximum yields at about 110 plants/m 2 . Differences in the percentage of the long, high quality bark fibre at final harvest were generally small and not significant. However, regression analysis of the response of bark percentage suggested a linear decline with increasing initial density.

2000 ◽  
Vol 40 (8) ◽  
pp. 1101 ◽  
Author(s):  
S. N. Lisson ◽  
N. J. Mendham

This paper reports on field agronomy studies into flax (Linum usitatissimum L.) conducted in Tasmania, Australia from 1994 to 1997. These studies investigated the performance of selected cultivars, and responses to sowing date, plant density and irrigation. The work formed part of a feasibility study assessing the potential of fibre hemp (Cannabis sativa L.) and flax as sources of fibre for the Australian newsprint industry. Two cultivar evaluation trials were conducted at the University of Tasmania Farm, Cambridge, in Tasmania’s south-east. One of these included 7 European and Australian flax cultivars, and the other, 4 mucilage linseed cultivars. The European flax cultivars yielded significantly more stem and bark fibre than the Australian flax cultivars. Of the former group, Ariane (841 g/m 2 ) and Marina (883 g/m 2 ) performed the best in terms of stem yield production, while Viking had comparable bark yields to these 2 cultivars. With the exception of cv. Kreola (543 g/m 2 ), which produced comparable stem yields to the Australian flax cultivars, the linseed cultivars were short and produced relatively low stem yields. Interestingly, seed yields (149–194 g/m 2 ) were not superior to those for the flax cultivars (156–218 g/m 2 ). While offering little dual-purpose seed/fibre potential, they may supply a future niche market for seed production. Three other trials were conducted to investigate the response of flax to seeding rate and sowing date, and the interactions between seeding rate, sowing date and irrigation availability. Autumn sowings of flax gave higher yields of both stem and seed compared with winter and spring sowings. Reasonable stem and seed yields were achieved from dryland cropping of flax. However, good results from such rainfed crops in Tasmania will depend on autumn sowing and good rainfall during winter and spring seasons. There were clear yield benefits from irrigation between early November and January, when the amount and distribution of rainfall was poor. The selection of an optimum seeding rate will depend on the sowing date and involve a compromise between maximising yield and minimising potential losses from lodging. The decreased occurrence of lodging with winter and spring sowings in this study, suggests that later sowings can accommodate higher seeding rates.


2003 ◽  
Vol 51 (1) ◽  
pp. 25-35 ◽  
Author(s):  
A. Y. Allam ◽  
G. R. El-Nagar ◽  
A. H. Galal

This investigation was carried out at the Experimental Farm of Assiut University during the summers of 2000 and 2001 to study the responses of two sunflower hybrids (Vidoc and Euroflora) to planting dates (May 1st, June 1st and July 1st) and planting densities (55,533, 83,300 and 166,600 plants/ha). The results indicated that the two varieties differed highly significantly in all studied traits except oil yield/ha. The highest seed yield (3.64 t/ha) was obtained with the variety Vidoc. In addition, the results revealed that the planting date exerted a highly significant influence on all vegetative growth traits along with yield and its components. Increasing plant density increased the seed and oil yield/ha. By contrast, the stem diameter, head diameter, 100-seed weight and seed yield/plant decreased with increasing plant density. The interaction between varieties and plant density had a highly significant effect on head diameter. The greatest head diameter (20.06 cm) was recorded for the variety Vidoc planted at lower density. Concerning the interaction between planting density and planting date, the highest seed yield (4.47 t/ha) was obtained from dense plants at the early sowing date, and the highest oil % (45.32) at the late planting date and the lowest plant density. The second order interaction exerted a highly significant influence on stem and head diameter in addition to seed yield/plant, where the highest value (78.13 g/plant) was obtained with the variety Vidoc planted on May 1st at the lowest plant density.


2019 ◽  
Vol 65 (No. 8) ◽  
pp. 377-386 ◽  
Author(s):  
Bogdan Kulig ◽  
Edward Gacek ◽  
Roman Wojciechowski ◽  
Andrzej Oleksy ◽  
Marek Kołodziejczyk ◽  
...  

The study aimed at comparing the yield of dry biomass and energy efficiency of 22 willow cultivars depending on the harvesting frequency and variable plant density. The field experiment was established in 2010. The willow cultivars were planted in two densities; 13 300 and 32 500 plants per ha. Among the compared cultivars in the second year (2013) of full production, high yield of dry matter was obtained from cvs. Tordis (33.1 t/ha/year), Inger (30.4 t/ha/year) and Klara (29.0 t/ha/year). After six years of cultivation, the highest aboveground dry matter was given by cvs. Tora (27.4 t/ha/year) and Tordis (27.0 t/ha/year). The gross calorific value of willow biomass ranged from 15.2–20.1 GJ/t dry weight. Greater energy efficiency (329.3 GJ/ha/year) occurred in willow cultivars collected in a two-year cycle than in the one-year cycle (286.4 GJ/ha/year). In the two-year cycle collected in the third year after planting, energy efficiency was greater (379.5 GJ/ha/year) than in the two-year cycle harvested in the sixth year after planting (279.15 GJ/ha/year). The initial slower growth of biomass does not determine plant yielding.


1989 ◽  
Vol 112 (3) ◽  
pp. 359-375 ◽  
Author(s):  
A. E. Abuzeid ◽  
S. J. Wilcockson

SummaryIn field experiments in 1983–85 in Northumberland, UK, early sowings achieved a leaf area index (LAI) of 3·5, capable of intercepting 90–95% total incident solar radiation, earlier than late sowings. As there was a close relationship between total dry weight, bud dry weight and amount of intercepted solar radiation, early sowings invariably outyielded later ones. The efficiency of energy conversion of radiation was 1·28, 2·05 and 2·11 g/MJ for total dry weight and 0·97, 0·83 and 0·67 g/MJ for bud dry weight in 1983, 1984 and 1985, respectively. Harvest index ranged from ca. 25% in 1985 to 40% in 1984.Increasing plant density from 2·22 to 6·66 plants/m2 advanced and increased maximum LAI and total and bud dry weight per m2 but had an adverse effect on distribution of dry matter. Maximum total dry weights were achieved at or slightly after maximum LAI. The onset of rapid bud growth coincided with maximum total standing dry weight and was advanced by early sowing but largely unaffected by plant density.Early-sown crops produced more buds than late-sown ones because of a longer growing season. Plant density had a large effect on the number of buds per m2, which was almost directly proportional as the number of buds per plant was not severely affected. However, individual bud size was restricted as a result of competition for assimilates. Approximately 80% of buds finally recorded had been produced before significant bud growth had occurred.Total bud fresh yields averaged over all sowing dates reached 17 t/ha in 1983 and 31 t/ha in 1984. The lower yield in 1983 was the result of late sowing caused by unfavourable weather. Early sowings significantly outyielded late ones because of earlier onset of rapid bud growth which gave a longer growing period. The effect of plant density on total sprout yield was less pronounced than that of sowing date but effects on yield per plant were large.Yields of buds in the freezing grade (20–30 mm) increased rapidly between late September and early to mid-November in both 1983 and 1984 and reached 7·5 and 8·8 t/ha, respectively. The difference between freezing-grade yields in the two years (1·3 t/ha) was much less than the difference between total yields (14 t/ha). Late sowing in 1983 restricted bud growth resulting in a higher proportion in the freezing grade. Plant density had a greater effect on freezing-grade yield than on total yield. Low planting densities gave high yields of small buds at early harvests but denser planting gave higher yields at later harvests. Generally, increases in bud fresh weight over the harvest period were greater than those in bud dry weight because of water uptake. The average dry matter content of buds declined by 2–5 % from October to January.The experiments confirmed that manipulation of sowing date and planting density is an effective way of spreading harvest date throughout the season in order to achieve an orderly sequence of crops for the fresh market and for processing.


1974 ◽  
Vol 25 (5) ◽  
pp. 697 ◽  
Author(s):  
N Thurling

Variation in sowing date was found to have a marked effect on the seed yield and different morphological and growth characteristics of spring cultivars of the oilseed rape species Brassica campestris and Brassica napus. The two species differed appreciably, however, in their responses to successive delays in sowing date. In B. napus, there was a significant and continuous decline in seed yield with later sowings. This decline in seed yield was associated primarily with a reduction in the total dry weight of the plant at the final harvest which, in turn, was most closely correlated with the duration of the vegetative phase of growth. The total dry weight of the plant and the seed yield were greatest in the first sowing where flowering was substantially later than in either of the later sowings. Since earlier-flowering cultivars of B. napus would be better adapted to Western Australian conditions, where there is a rapid decline in soil moisture reserves during the spring, significant improvements in seed yield could depend largely on increasing the rate of pre-anthesis growth. In this experiment, however, no significant variation in the relative rate of growth prior to flowering was observed because of the marked negative association between net assimilation rate and leaf area ratio. Further studies of the variation in growth amongst a far wider range of genotypes will, nevertheless, be necessary to properly assess the feasibility of increasing relative growth rates by selection. The seed yield of B. campestris was substantially greater in the second sowing than in either the first or third sowings. Although seed yield was significantly correlated with both total dry weight of the plant at final harvest and the harvest index, the latter appeared to be the most important determinant of seed yield in this species. By contrast with B. napus, most of the dry weight of the plant at the final harvest was accumulated during the post-anthesis phase of growth. Accordingly, the character leaf area duration between anthesis and final harvest was found to be the most significant determinant of the total dry weight of the plant in B. campestris. The leaf weight ratio of the plant at anthesis also contributed significantly to total dry weight at the final harvest; this indicates that the pattern of dry matter distribution in the plant during the vegetative phase could prove a useful criterion for selecting potentially high-yielding strains of this species.


2016 ◽  
Vol 29 (4) ◽  
pp. 976-983 ◽  
Author(s):  
NALÍGIA GOMES DE MIRANDA E SILVA ◽  
MÉRCIA VIRGINIA FERREIRA DOS SANTOS ◽  
JOSÉ CARLOS BATISTA DUBEUX JÚNIOR ◽  
MÁRCIO VIEIRA DA CUNHA ◽  
MÁRIO DE ANDRADE LIRA ◽  
...  

ABSTRACT Cactus is crucial for the livestock of semi-arid regions in Brazil. This plant has shown the high productivity of forage, which is influenced by several management factors. This study aimed to evaluate the effect of organic fertilization doses (20, 40 and 80 t/ ha of bovine manure/ha/two years) and planting densities (20, 40, 80 and 160 thousand plants/ha) on the productivity of cactus pear Clone IPA-20 (Opuntia ficus-indica Mill). At the Experimental Station of Caruaru at the Agronomic Institute of Pernambuco, IPA has conducted the experiment. The experimental design was randomized blocks, with split plot arrangements. Higher shoot productivity was observed with increased population density and the application of manure at 80 t ha-1 two years-1 with values of 61, 90, 117 and 139 t DM ha-1 two years-1 at densities of 20, 40, 80 and 160,000 plants ha-1. The planting density influenced the productivity of cladode-plant and root dry weight, showing exponential responses, with higher cladode-plant and roots weight by area observed with increased plant density. The efficiency of organic fertilization decreased with the increase in manure doses. For increase cactus productivity, 40 t of bovine manure ha-1 two years-1 for plantations with 160,000 plants/ha is recommended.


2012 ◽  
Vol 40 (1) ◽  
pp. 183
Author(s):  
Hamid MADANI ◽  
Christos DORDAS ◽  
Ahad MADANI ◽  
Mohammad-Ali MOTASHAREI ◽  
Shima FARRI

Chicory is considered one of the alternatives crops that can be used in crop rotation and contains many phytochemicals that can be used in medicine. In addition, lengthening the growing season by early sowing may increase root chicory yield potential, and thus increase its competitiveness with traditional crops. The objectives of the present study were to determine whether early sowing date risks can be decreased by higher sowing density and also to study the effect of sowing date and sowing density on dry matter accumulation and partitioning of chicory. Growing season did not affect any of the characteristics that were studied. Also plant density affected the flowers biomass, root biomass per plant and the respective yield together with the plant height and essence yield and total yield. The sowing date affected the leaf, flower and stem biomass on a plant basis. However, the interaction between plant density and sowing date affected the total biomass per plant, the flower biomass per plant, the root biomass per plant, the flower yield, the root yield and the essence yield. These results indicate that for higher production it is important to determine the right plant density and sowing date which can affect growth, dry matter accumulation and essence yield.


Weed Science ◽  
1987 ◽  
Vol 35 (4) ◽  
pp. 490-495 ◽  
Author(s):  
Najib Malik ◽  
William H. Vanden Born

Seeds of false cleavers (Galium spurium L.) grown in mid-May germinated 12 to 14 days after planting in central Alberta. The plants flowered from early July to late August and developed fruits from mid-July to early September. Plants from the late-June sowing date developed fruits until early October unless early fall frost killed the plants. Plants from seeds sown after mid-July remained in a vegetative state until late September and did not flower. Seedlings that emerged in August and September survived a mild prairie winter and resumed growth the following spring. Under greenhouse conditions, plant height ranged from 77 to 113 cm and the number of branches at first node ranged from 6 to 14, as plant density decreased from 16 to 1 plant/pot. Shoot dry weight decreased by 50% as plant population doubled, 46 days after emergence. The number of seeds produced/plant decreased from 3500 to 175 as plant density increased from 1 to 16 plants/pot. In growth chamber studies, plant growth was greatest at 20 compared to 16 or 24C.


2019 ◽  
Vol 64 (1) ◽  
pp. 37-51
Author(s):  
Babak Jasemi ◽  
Ghobad Shabani ◽  
Mohammad Chaichi ◽  
Shahab Khoshkhoi ◽  
Negin Norozi

To study the effect of plant density and different nutritional systems (chemical, biological, and integrated) on the quantitative and qualitative performance of Thymus daenensis L. in Mahidasht Agricultural Training Center, Kermanshah/Iran, in 2017, an experiment was conducted in a split-plot design based on a randomized complete block with four replications. The first variable involved two planting distances in the row of 15 and 30 cm (the main factor), and the subsidiary factor comprised four different nutritional systems including control (no-fertilizer), chemical (100 kg superphosphate, 100 kg potassium sulfate, 150 kg urea per ha), biological (8 tons of cattle manure/ha), and integrated (50% cattle manure + 50% chemical) fertilizers. The results showed that the integrated fertilizer treatment produced the highest shoot dry weight (789.1 kg/ha), essential oil content (3.35%) and root length (15.97 cm). The integrated fertilizer treatment along with the 30-cm planting density resulted in the highest essential oil content of 3.35%. The results of this project have suggested that the integrated fertilizer and the 30-cm planting interval is the optimal treatment in thymus production due to the higher chemical fertilizer efficiency and better crop quality.


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