Evaluation of a phenological model for strategic decisions for hemp (Cannabis Sativa L.) biomass production across European sites (original) (raw)
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Fibre hemp can be grown under a wide range of agro-ecological conditions, but it requires special attention for several physiological features and crop management. A management strategy in order to reduce inputs and thus achieve acceptable yield could be achieved optimizing sowing time. With this respect, the effects of sowing date on hemp biology and yield was studied, using two monoecious and two dioecious genotypes. Field experiments were carried out in two subsequent years (2003-2004) in South of Italy, using drip irrigation system. Sowing time, in the two year period, ranged between March 10th and July 22nd. Optimal sowing time was observed between the end of April and the first three weeks of May; in that range, the dioecious Fibranova yielded the most in terms of aboveground biomass and stem dry yield, followed by Tiborszallasi, while the two monoecious showed the lowest yield. On the contrary, before and after that period, the shorter day length caused an early floral induction that strongly reduced stem and fibre elongation, and thus aboveground dry biomass and consequently stem yields. Based on this study a simulation model focusing on flowering prediction in Mediterranean environment was developed.
Modelling post-emergent hemp phenology (Cannabis sativa L.): Theory and evaluation
European Journal of Agronomy, 2008
Temperature and photoperiod can be used to simulate post-emergent hemp (Cannabis sativa L.) phenology. With reference to hemp in Italy, our main objective was to model field crops grown under a range of temperature and day length regimes. Dates of emergence and 50% of flowering were collected at Cadriano (Bologna) from serially sown field experiments (1996)(1997)(1998)(1999)(2003)(2004)(2005) on five cultivars: Carmagnola (late maturity), Felina 34 (medium maturity), Fibranova (late maturity), Futura (medium-late maturity), and Tiborszallasi (medium-late maturity). The database of phenological records was segregated into calibration and validation subsets. A phenology model was developed which utilises the beta function for response to hourly air temperature, and a switch-off function for response to day length. The life cycle of hemp from emergence to 50% of flowering was defined in terms of physiological development days (chronological days at the optimum photoperiod and temperature) and considered in three phases: juvenile phase (BVP), photo-sensitive phase (PIP), flower development phase (FDP). Critical temperatures (T b , base; T o , optimum, T c , ceiling), which did not vary widely across phases and cultivars, were estimated as common values: T b = 1.9 • C for BVP and 11.3 • C for the other phases, T o = 26.4 • C and T c = 40.0 • C for all phases. Other parameters, i.e. day length of half-maximum development rate at PIP, and physiological development days for FDP, were also estimated as common values for all cultivars. Different genotypes were mainly characterised for the sensitivity to photoperiod (shape parameter n) and BVP length. With n ∼ 50, Felina 34 and Futura are regarded as low sensitive cultivars. Tiborszallasi was estimated as the highest sensitive cultivar (n close to 70), whereas Carmagnola and Fibranova showed an intermediate sensitivity (n ∼ 62). Felina 34 also differentiated for its relatively short BVP length at optimum conditions, i.e. ∼13 days; duration of about 20 days was the estimate for the other cultivars.
Industrial Hemp Varieties Productivity Potential in the Latvian Climatic Conditions
ENVIRONMENT. TECHNOLOGIES. RESOURCES. Proceedings of the International Scientific and Practical Conference
Varieties grown for fibre-only will be established, managed and harvested differently than varieties grown for seeds or dual-purpose. The aim was analysed yield productivity and length of vegetation period dependency of the two types of hemp variety and identified perspective hemp variety for highest yield under different meteorological conditions in Latvia. Varieties/line from diverse European and Latvian origin (seed hemp varieties/ line 'Adzelvieši', 'Pūriņi', KA-2-2011, 'Finola', 'Henola' and fibre hemp varieties 'USO 31', 'Futura 75', 'Austa') were sown in randomized field experiments in Latvia. Biomass, stem, seed yield, fibre contents and vegetation period length were assessed across tree growing seasons from 2020 to 2022. Results show that hemp, seeds and fibre varieties/line, performed well giving high yield productivity between variety. Agrometeorological conditions for hemp growth and yield were favourable in 2022. I...
Agronomy of fibre hemp (Cannabis sativa L.) in Europe
Industrial Crops and Products, 2000
Fibre hemp may yield up to 25 t above ground dry matter per hectare (20 t stem dry matter ha − 1 ) which may contain as much as 12 t ha − 1 cellulose, depending on environmental conditions and agronomy. Its performance is affected by the onset of flowering and seed development. Effects of cultivar and management on yield and quality were tested at three contrasting sites in Italy, the Netherlands and the UK in three years, making use of standardised protocols for experimental design and research methodology. Highest yields (up to 22.5 t dry matter ha − 1 ) were obtained in Italy when later cultivars were used. Attainable yields proved slightly lower in the Netherlands and much lower in the UK. The quality of the cellulose was relatively stable over the growing season, but lignification may proceed rapidly some time after flowering. Crop development was very rapid and crops maintained green leaf area for a long time, thus radiation interception was considerable. The radiation use efficiency changed during development. It was lower after flowering (about 1.0 g MJ − 1 PAR) than before (about 2.2 g MJ − 1 PAR). Growing earlier cultivars to obtain some seed set advanced the reduction in radiation use efficiency. Nitrogen proved to affect yield only slightly. A relatively small amount of fertiliser will be adequate to cover the crop's needs. Plant density declined during growth in a site-specific manner when it was high initially. Very low plant densities may not show this self-thinning but reduced yield and (especially) quality. Final plant densities were proven to depend more on initial plant stands than expected from literature. This was true at all three contrasting sites and in the different years. Nitrogen and plant density hardly interacted within one site. Results suggest that hemp can yield large quantities of useful cellulose when ecologically adapted cultivars are sown in proper plant densities. The cultivation is environmentally friendly with little harmful accumulation or emission of chemical inputs. More research on ideotyping is required and breeding efforts should be broadened.
Journal of Industrial Hemp, 2004
Hemp seed yields of the variety Fedora-19 in an on-farm scientific field experiment on small plots and in an on-farm evaluation in 11 hemp fields under practical organic growing conditions in Lower Austria were compared to give a realistic view of the variability of yields. Dry matter seed yields from the on-farm field experiment ranged from 127 to 143 g m Ϫ2 . Under practical growing conditions, yields ranged from 34 to 151 g m Ϫ2 in the sample plots. The reported hemp seed yield after combine harvesting, drying, and cleaning was between 324 kg ha Ϫ1 and 717 kg ha Ϫ1 . The results of the experiment show that harvesting by hand considerably influences yields. Yields of the manual harvest in sample plots indicate a high correlation with yields harvested by the combine harvester (R 2 = 0.91). The commercial yield is 71% of the yields recorded in sample plots in the fields. Our data questions the transfer of results and conclusions drawn from the data of scientific field experiments that employ manual harvest to that of practical circumstances, and support the notion of on-farm research.
LIFE SCIENCE AND SUSTAINABLE DEVELOPMENT
Hemp is a multi-purpose crop, being used mainly for the production of stems and fiber, seed, but also for food and medicine. In the western part of the country and not only, dioecious hemp finds favorable conditions for cultivation. One of the research centers in Romania, with a rich tradition in hemp breeding and cultivation is at S.C.D.A. Lovrin. Hemp is a plant with special requirements for temperature, humidity and fertilization. The optimum temperature at which the highest seed and stem productions are obtained is 20-22⁰C together with a good supply of pressing nutrients. During the analyzed period, 2016-2018 the climatic conditions had an atypical evolution, considerably influencing the harvest. The aim of the paper is to evaluate the production of a number of ten varieties, Romanian and foreign, from the S.C.D.A. Lovrin. Climatic conditions had a significant influence on production, the minimum production being recorded in 2017 (240 kg / ha - average experience) and the maxim...
Population density of industrial hemp (Cannabis sativa L.) in the field influences crop growth habit, fibre yield and quality. Therefore, optimization of plant population density is required to control growth and secure fibre yield and quality. Initial hand-thinned plant populations of 100, 200, 300 and 400 plants m-2 were established in a replicated field trial. Density of planting significantly influenced weed suppression and a number of phenological characters, and yield of industrial hemp. Weed suppression increased with increasing plant population. An increase from 100 to 200 plants m-2 markedly reduced weed weight from 23.2 to 6.5 g m-2. Further reductions in weed weights were observed at 300 plants m-2 (2.6 g m-2) and 400 plants m-2 (1.5 g m-2). Weekly height data showed that the high-density plantings resulted in shorter plants at harvest due to a more rapid decline in growth rate than for the low density planting (100 plants m-2). Stem thickness was inversely related to plant population density as low density produced thicker stems compared to that of high density planting. Leaf chlorophyll content and root mass m-2 were not significantly affected by differences in planting density. Raw fibre yields were greatest at 300 plants m-2, which was significantly higher in comparison to 100 plants m-2 (128.4 vs 102.8 g dry weight m-2). Yields were very poor overall with a maximum of 1.28 t ha-1 of raw bast compared to European yields of 2–3 t ha-1. Low yields were attributed to the unsuitable short photoperiods that caused early flowering and therefore shorter stem length in the current variety under trial. New varieties or crop management practices that delay flowering are necessary for regions of short day duration to produce economically viable fibre yields for the industry in subtropical Queensland, Australia. Keywords: Industrial hemp, planting density, fibre yield, new crop
Agronomy
Farmers’ interest in renewable raw materials such as hemp (Cannabis sativa L.) fibres has recently increased, but hemp productivity is strongly affected by genotype and environment conditions. A 3-year field experiment was conducted under Mediterranean environment in northern Greece to evaluate the productivity (regarding fibres and seeds) of six monoecious hemp varieties. The vars. Futura 75 and Bialobrzeskie provided the greatest (p < 0.01) fibre productivity (4.57 and 4.27 t ha−1, respectively), which were 77.1% and 65.5%, respectively, greater than that of the least productive var. Fedora 17. However, the vars. Santhica 27, Tygra and Bialobrzeskie provided the highest (p < 0.05) seed yield (2.7, 2.9 and 2.6 t ha−1, respectively), which were 28.6%, 38.1% and 23.8%, respectively, greater than that of the least productive var. Futura 75. Hemp fibre yield was strongly positively correlated with total biomass (R2 = 0.8612) and stem biomass yield (R2 = 0.9742), while it was inve...
A B S T R A C T Together, the Netherlands and Belgium are the largest indoor cannabis producing countries in Europe. In both countries, legal prosecution procedure of convicted illicit cannabis growers usually includes recovery of the profits gained. However, it is not easy to make a reliable estimation of the latter profits, due to the wide range of factors that determine indoor cannabis yields and eventual selling prices. In the Netherlands, since 2005, a reference model is used that assumes a constant yield (g) per plant for a given indoor cannabis plant density. Later, in 2011, a new model was developed in Belgium for yield estimation of Belgian indoor cannabis plantations that assumes a constant yield per m 2 of growth surface, provided that a number of growth conditions are met. Indoor cannabis plantations in the Netherlands and Belgium share similar technical characteristics. As a result, for indoor cannabis plantations in both countries, both aforementioned yield estimation models should yield similar yield estimations. By means of a real-case study from the Netherlands, we show that the reliability of both models is hampered by a number of flaws and unmet preconditions. The Dutch model is based on a regression equation that makes use of ill-defined plant development stages, assumes a linear plant growth, does not discriminate between different plantation size categories and does not include other important yield determining factors (such as fertilization). The Belgian model addresses some of the latter shortcomings, but its applicability is constrained by a number of preconditions including plantation size between 50 and 1000 plants; cultivation in individual pots with peat soil; 600 W (electrical power) assimilation lamps; constant temperature between 20 C and 30 C; adequate fertilizer application and plants unaffected by pests and diseases. Judiciary in both the Netherlands and Belgium require robust indoor cannabis yield models for adequate legal prosecution of illicit indoor cannabis growth operations. To that aim, the current models should be optimized whereas the validity of their application should be examined case by case.
Response of hemp to plant population and nitrogen fertilisation
BACKGROUND. Hemp (Cannabis sativa L.) used to be a traditional industrial crop in many regions of Europe and of the World. After many years of aban-don the crisis of agriculture and the need for natur-al raw materials cast a renewed interest over this crop. In the frame of the EU project "HEMP", field experiments were carried out to evaluate the effect of agronomic factors over yield and fibre quality. METHODS. The effects of plant density (from 30 to 250 plants m -2) and available nitrogen (100, 160, and 220 kg ha -1) on fibre hemp were studied at Cadriano (BO) over three years 1996 -1998. These two factors were studied on different genotypes, sowing and har-vest times. Significant results for major crop para-meters are reported. RESULTS. Results confirmed that optimal production is obtained with a plant density of 90-100 plants m -2 . The weight of a single plant decreased exponential-ly as plant density increased. The same trend was ob-served in different years and with...