Odlingens och lagringens inverkan på utsädes grobarhet
At seed-growing the aim is to produce a commodity with high germination capacity, good soundness and purity, and also slight admixture of seeds from other species. The capacity of germination and the vigour of the seeds may become impaired in consequence of mechanical damage, infection of diseases...
| Autor principal: | |
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| Formato: | Otro |
| Lenguaje: | sueco sueco |
| Publicado: |
2004
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| Materias: | |
| Acceso en línea: | https://stud.epsilon.slu.se/12923/ |
| _version_ | 1855572156088320000 |
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| author | Stenson, Carl-Henrik |
| author_browse | Stenson, Carl-Henrik |
| author_facet | Stenson, Carl-Henrik |
| author_sort | Stenson, Carl-Henrik |
| collection | Epsilon Archive for Student Projects |
| description | At seed-growing the aim is to produce a commodity with high germination capacity, good soundness
and purity, and also slight admixture of seeds from other species. The capacity of germination and the
vigour of the seeds may become impaired in consequence of mechanical damage, infection of diseases,
growth of mould, attacks of vermin, high drying temperature, secret germination, sprouting in the ears
etc. The germ belongs to the outer and most unprotected parts of the seed, and consequently this is
much exposed. Even quite sound seeds can instantaneously have low capability of germination. It can
be due to the fact that the seeds are in rest of germination, i.e. they absorb water without germinating,
or that they are unable to take up water (a condition called hard seeds). All plant species have a more or
less pronounced rest of germination. During damp harvest weather, seeds with optimal rest of
germination escape secret germination and sprouting in the ears, but later at germination test or sowing,
they are tended to germinate. At germination analysis, there are methods to break the rest of
germination, partly by chemical treatment but also by influence from the surroundings as for example
temperature regulation. Hard seeds occur in legumes for ley and in some other leguminous plants as for
instance lupin and field beans. The hardness may be short, but often it lasts in several years.
In order to attain a high capacity of germination in the finished product an even ripeness is required, for
which the conditions are best in even plant stands with optimal compactness. The mother seed should
be of good vigour, the conditions of germination proper, the growing of side-shoots reduced etc. At
seed breeding, threshing is ought to be performed during the later parts of the harvesting ripeness,
because the germination capacity is rising during the advancing of ripening, provided that no sprouting
in the ears is initiating. This doesn't concern peas, which are particularly crack-willing at low water
content. Regarding peas and oil plants the sensitivity to mechanical effects is continuously increasing
with lowering water content of the seeds. Generally grain however have a minimum of sensitivity at a
water content of 17-20 %. At lower water content, there is a risk of cracks or other defects in the germ
of the hard and dry seed. At higher water content the seed is so soft that it easily is split at rough
treatment for example in the thresher. Ley plants are more tended to shed seeds and have more
pronounced disposition towards sprouting in the ears than the contemporary assortment of cereals. As
for pasture grass, the risk of shedding seeds can be reduced by a sufficiently early windrowing or by a
well-balanced supplying of nitrogen.
The velocity of circumference of the threshing cylinder is determining the emergence of damage on the
seeds, while the concave clearance to a greater extent regulates the threshing and wearing. High
number of revolutions on the cylinder easily cause cracks, which are impairing the germination
viability. These cracks can induce increased breathing, sensitivity to drying and disinfection and also
constitute an entrance-gate for pathogens. The pods of the oil plants are very easy to thresh and the
threshing shouldn't be harder than that the unripe seeds stay in their pods and are separated from the
seed goods. Clover seed demands comparatively hard threshing with concave cover plates, at the same
time as too high number of revolutions risk occasioning damage of germination on the superficial
germ. If the plants are quite dry and the weather is sunny the clover hulling is making easier. To grass
seed, which generally is easily threshing the cylinder-speed should be the lowest possible to avoid
damage of germination. At threshing of timothy, there is a risk that the seeds will be hulled. At
combine harvesting of peas, you must notice that the pegs of the reel easily can harm the inside of the
pods at incautiously handling. In general, at threshing and internal transport, the seeds are exposed to
the most mechanical strain. During the drying the sensitivity to mechanical damage of the goods have
increased.
6
In order to prevent increasing heat production and growth of mould with deteriorated germinating as a
consequence, a moist crop product requires an immediate after-treatment. The moister the seed is the
more sensitive to high drying temperature it is. At specific initial water content, it's the temperature in
the seed which is determining the reduction in capability of germination. The highest permitted
temperature in the drying-air is individual for different drying plants, but as a rule it is a little higher
than the critical temperature of the seed. Carefully performed drying and cooling reduce the risk of
attacks of the heat-depending noxious insects, which often search for the nutritious germ. At heavy
drying oil-seeds become more brittle and sensitive to mechanical influence during the later handling. In
opposite of peas, for oil-seed the drying itself doesn't seem to initiate emergence of cracks. Owing to
large volume, weak permeability of the shells and the great tendency to emergence of cracks, peas are a
kind of seed which is much difficult to dry. Drying with supplemental heating may be an advisable
method, considering the apparent risk of cracks. Peas can also be dried in hot air, but this high
temperature-drying must be done with especial carefulness. At drying, the risk of emergence of cracks
is enhanced with increasing water content, drying temperature and drying time. After harvest moist leyseed
demands to be prompt blown through with large air quantities. When the water content have gone
down below 20 % the final drying with slightly heated air can begin. Drying to level of solid storing
must be finished before growth of mould is initiated, for which reason the humidity of the drying air
isn't allowed to be too high, the drying temperature not too low and the height of storage must be
limited. Furthermore the air quantity must be large, whereas the air speed and the distance between the
side canals should be restricted. |
| format | Otro |
| id | RepoSLU12923 |
| institution | Swedish University of Agricultural Sciences |
| language | Swedish swe |
| publishDate | 2004 |
| publishDateSort | 2004 |
| record_format | eprints |
| spelling | RepoSLU129232018-10-09T10:59:22Z https://stud.epsilon.slu.se/12923/ Odlingens och lagringens inverkan på utsädes grobarhet Stenson, Carl-Henrik Handling, transport, storage and protection of agricultural products At seed-growing the aim is to produce a commodity with high germination capacity, good soundness and purity, and also slight admixture of seeds from other species. The capacity of germination and the vigour of the seeds may become impaired in consequence of mechanical damage, infection of diseases, growth of mould, attacks of vermin, high drying temperature, secret germination, sprouting in the ears etc. The germ belongs to the outer and most unprotected parts of the seed, and consequently this is much exposed. Even quite sound seeds can instantaneously have low capability of germination. It can be due to the fact that the seeds are in rest of germination, i.e. they absorb water without germinating, or that they are unable to take up water (a condition called hard seeds). All plant species have a more or less pronounced rest of germination. During damp harvest weather, seeds with optimal rest of germination escape secret germination and sprouting in the ears, but later at germination test or sowing, they are tended to germinate. At germination analysis, there are methods to break the rest of germination, partly by chemical treatment but also by influence from the surroundings as for example temperature regulation. Hard seeds occur in legumes for ley and in some other leguminous plants as for instance lupin and field beans. The hardness may be short, but often it lasts in several years. In order to attain a high capacity of germination in the finished product an even ripeness is required, for which the conditions are best in even plant stands with optimal compactness. The mother seed should be of good vigour, the conditions of germination proper, the growing of side-shoots reduced etc. At seed breeding, threshing is ought to be performed during the later parts of the harvesting ripeness, because the germination capacity is rising during the advancing of ripening, provided that no sprouting in the ears is initiating. This doesn't concern peas, which are particularly crack-willing at low water content. Regarding peas and oil plants the sensitivity to mechanical effects is continuously increasing with lowering water content of the seeds. Generally grain however have a minimum of sensitivity at a water content of 17-20 %. At lower water content, there is a risk of cracks or other defects in the germ of the hard and dry seed. At higher water content the seed is so soft that it easily is split at rough treatment for example in the thresher. Ley plants are more tended to shed seeds and have more pronounced disposition towards sprouting in the ears than the contemporary assortment of cereals. As for pasture grass, the risk of shedding seeds can be reduced by a sufficiently early windrowing or by a well-balanced supplying of nitrogen. The velocity of circumference of the threshing cylinder is determining the emergence of damage on the seeds, while the concave clearance to a greater extent regulates the threshing and wearing. High number of revolutions on the cylinder easily cause cracks, which are impairing the germination viability. These cracks can induce increased breathing, sensitivity to drying and disinfection and also constitute an entrance-gate for pathogens. The pods of the oil plants are very easy to thresh and the threshing shouldn't be harder than that the unripe seeds stay in their pods and are separated from the seed goods. Clover seed demands comparatively hard threshing with concave cover plates, at the same time as too high number of revolutions risk occasioning damage of germination on the superficial germ. If the plants are quite dry and the weather is sunny the clover hulling is making easier. To grass seed, which generally is easily threshing the cylinder-speed should be the lowest possible to avoid damage of germination. At threshing of timothy, there is a risk that the seeds will be hulled. At combine harvesting of peas, you must notice that the pegs of the reel easily can harm the inside of the pods at incautiously handling. In general, at threshing and internal transport, the seeds are exposed to the most mechanical strain. During the drying the sensitivity to mechanical damage of the goods have increased. 6 In order to prevent increasing heat production and growth of mould with deteriorated germinating as a consequence, a moist crop product requires an immediate after-treatment. The moister the seed is the more sensitive to high drying temperature it is. At specific initial water content, it's the temperature in the seed which is determining the reduction in capability of germination. The highest permitted temperature in the drying-air is individual for different drying plants, but as a rule it is a little higher than the critical temperature of the seed. Carefully performed drying and cooling reduce the risk of attacks of the heat-depending noxious insects, which often search for the nutritious germ. At heavy drying oil-seeds become more brittle and sensitive to mechanical influence during the later handling. In opposite of peas, for oil-seed the drying itself doesn't seem to initiate emergence of cracks. Owing to large volume, weak permeability of the shells and the great tendency to emergence of cracks, peas are a kind of seed which is much difficult to dry. Drying with supplemental heating may be an advisable method, considering the apparent risk of cracks. Peas can also be dried in hot air, but this high temperature-drying must be done with especial carefulness. At drying, the risk of emergence of cracks is enhanced with increasing water content, drying temperature and drying time. After harvest moist leyseed demands to be prompt blown through with large air quantities. When the water content have gone down below 20 % the final drying with slightly heated air can begin. Drying to level of solid storing must be finished before growth of mould is initiated, for which reason the humidity of the drying air isn't allowed to be too high, the drying temperature not too low and the height of storage must be limited. Furthermore the air quantity must be large, whereas the air speed and the distance between the side canals should be restricted. Frönas grobarhet och vitalitet kan försämras till följd av mekanisk skada, sjukdomsangrepp, mögelangrepp, skadedjursangrepp, hög torktemperatur, fältgroning, lönnmältning mm. Grodden tillhör fröets yttersta delar, varför denna är mycket utsatt. Även helt friska frön kan momentant uppvisa låg grobarhet. Det kan bero på att fröna befinnes i groningsvila, d.v.s. de upptar vatten utan att gro, eller att de är oförmögna att absorbera vatten (ett tillstånd benämnt hårda frön). Alla arter har en mer eller mindre utpräglad groningsvila. Frön med optimal groningsvila undgår fältgroning och lönnmältning under fuktigt skördeväder, men är benägna att gro senare vid grobarhetsundersökning eller sådd. Vid grobarhetsanalys finns metoder att bryta groningsvilan, dels genom kemisk behandling men också genom yttre miljöpåverkan som t.ex. temperaturreglering. Hårda frön förekommer hos vallbaljväxter och vissa trindsädesslag som t.ex. lupin och åkerböna. Hårdheten kan vara kortvarig men varar ofta i flera år. För att uppnå en hög grobarhet i slutprodukten fordras en jämn mognad, för vilken förutsättningarna är bäst i jämna bestånd med optimal täthet. Moderutsädet skall vara av god vitalitet, groningsbetingelserna goda, bestockningen begränsad etc. Vid utsädesodling bör tröskning eftersträvas under skördemognadens senare delar, eftersom grobarheten stiger under mognaden förutsatt att ingen fältgroning initieras. Detta gäller inte ärter, som är särskilt sprickbenägna vid låg vattenhalt. För ärter och oljeväxtfrön tilltar frönas känslighet för mekanisk påverkan kontinuerligt med sänkt vattenhalt. Spannmål har däremot i regel ett minimum i känslighet i vattenhaltsområdet 17-20 %. Vid lägre vattenhalter riskeras sprickor eller andra skador på groddanlagen på de hårda och torra kärnorna. För högre vattenhalter är kärnan så mjuk att den lätt spräcks vid omild behandling i t.ex. tröskverk. Vallväxterna är mer drösningsbenägna och har större tendens till fältgroning än det moderna spannmålssortimentet. Drösningsrisken i gräsfrövall kan minskas genom tillräckligt tidig strängläggning eller genom riktigt avvägd kvävetillförsel. Cylinderns periferihastighet är avgörande för uppkomsten av skador på kärnorna/fröna medan slagskoavståndet i större utsträckning styr urtröskningen. Högt cylindervarvtal förorsakar lätt grobarhetsnedsättande sprickor. Dessa kan föranleda förhöjd andning, känslighet för torkning och betning samt utgöra inkörsport för patogener. Oljeväxternas skidor är mycket lättröskade och tröskningen bör inte vara hårdare än att omogna frön stannar kvar i skidorna och avskiljes från frövaran. Klöverfrö fordrar relativt hård urtröskning med agnavskiljarplåtar i slagskon, samtidigt som alltför högt cylindervarv riskerar att bringa grobarhetsskador på de ytliga groddanlagen. Om beståndet är riktigt torrt och vädret soligt underlättas urnötningen. Till gräsfrö som i regel är lätt urtröskat bör cylinderhastigheten vara lägsta möjliga för att undvika grobarhetsskador. I timotej riskeras avskalning vid hård urtröskning. Vid skörd av ärter måste man beakta att haspelns pinnar lätt kan skada baljornas innanmäte vid ovarsamt handhavande. I allmänhet utsättes frön och kärnor för störst mekanisk påkänning vid urtröskning och interna transporter. Under nedtorkningen har varans känslighet för mekaniska skador stigit. En fuktig skördevara kräver omgående efterbehandling för att förhindra tilltagande värmebildning och mögeltillväxt med sänkt grobarhet som följd. Ju fuktigare spannmålen/frövaran är desto känsligare är den för hög torktemperatur. Det är temperaturen i kärnan/frömassan som är avgörande för grobarhetsnedsättningen vid specifik inläggningsvattenhalt. Högsta tillåtna torkluftstemperatur är individuell för olika torksystem men är som regel något högre än kritiska temperaturen i kärnan eller frömassan. Omsorgsfull nedtorkning och nedkylning minskar risken för angrepp av de värmeberoende skadeinsekterna som gärna hemsöker den näringsrika grodden. Vid kraftig nedtorkning av oljeväxtfrö blir fröet skörare och känsligare för mekanisk påverkan under senare hantering. I motsats till ärter synes inte själva torkningen initiera sprickbildning hos oljeväxtfrö. Ärter är ett svårtorkat fröslag beroende på hög känslighet för sprickbildning, stor volym och dålig genomsläpplighet i skalen. Kalluftstorkning med tillsatsvärme kan vara en tillrådlig metod med tanke på ärters uttalade benägenhet för sprickbildning. Ärter kan även varmlufttorkas men denna process måste ske med stor varsamhet. Risken för sprickbildning vid torkning tilltar med ökande vattenhalt, torktemperatur och torktid. Fuktigt vallfrö fordrar efter inläggning omgående genomblåsning av stora luftmängder. När fröets vattenhalt krupit under 20 % kan sluttorkningen med tillsatsvärme påbörjas. Nedtorkningen till lagringsstabil nivå måste vara fullbordad innan mögelbildning initieras, varför torkluftens fuktighet inte får vara för hög, torktemperaturen inte för låg och lagringshöjden måste vara begränsad. Vidare skall luftmängden vara stor medan lufthastigheten och avståndet mellan sidokanalerna bör begränsas. 2004-12-14 Other NonPeerReviewed application/pdf sv https://stud.epsilon.slu.se/12923/1/stenson_c_171120.pdf Stenson, Carl-Henrik, 2004. Odlingens och lagringens inverkan på utsädes grobarhet. UNSPECIFIED, Alnarp. Alnarp: (LTJ, LTV) > Dept. of Crop Science <https://stud.epsilon.slu.se/view/divisions/ANSTI=3A655.html> urn:nbn:se:slu:epsilon-s-8950 swe |
| spellingShingle | Handling, transport, storage and protection of agricultural products Stenson, Carl-Henrik Odlingens och lagringens inverkan på utsädes grobarhet |
| title | Odlingens och lagringens inverkan på utsädes grobarhet |
| title_full | Odlingens och lagringens inverkan på utsädes grobarhet |
| title_fullStr | Odlingens och lagringens inverkan på utsädes grobarhet |
| title_full_unstemmed | Odlingens och lagringens inverkan på utsädes grobarhet |
| title_short | Odlingens och lagringens inverkan på utsädes grobarhet |
| title_sort | odlingens och lagringens inverkan på utsädes grobarhet |
| topic | Handling, transport, storage and protection of agricultural products |
| url | https://stud.epsilon.slu.se/12923/ https://stud.epsilon.slu.se/12923/ |