Viljelytoimenpiteiden ja kasvutekijöiden vaikutus apila-heinänurmen kasvurytmiin ja sadonmuodostukseen

The effect of the first cutting date and cutting frequency on the clover-grass stand growth and development and on the relationships between plant species were studied at the University of Helsinki in 1974—76. The second study objective was the relationships between several growth factors and the yield components of the stand. The third study area comprised the energy value changes and the photosynthetic activity of the stand during different phases of the growing season. The most rapid growth and development occurred within the temperature range of 400—500° C (∑ > 0° C). The late first cutting date increased yields most in the 2 and 3-cutting systems and least in the 4-cutting system, due to two summer cuts during the dry period of the season. Due to the regrowth ability of the species and lack of water in midsummer leading easily to dormancy there was a negative correlation between the first and the second cut and a positive correlation between the following successive cuts. The most important variables in the regression model describing DM production in the first, second, third and fourth cut were temperature sum in degree days, precipitation during the week before the previous cut, amount of precipitation between cuts and the physiological activity of the stand, respectively. The energy value of spring and autumn DM yield was higher than that of midsummer. The average photosynthetic efficiency was 0.95 % in 1974 and 0.47 % in 1975. The DM content of the yield in spring decreased until the temperature sum of 420° C (∑ > 0° C) and then increased linearly. The DM content, protein content, digestibility of DM and protein yield in the total yields were mostly influenced by the first cut if made when the slope showed either decreasing or increasing values of DM content. Otherwise a late first cutting date or low cutting frequency lowered the quality of the forage. In the mixture the spring growth of timothy ceased by the end of June and was replaced by red-clover. The regrowth of timothy ceased by the middle of July and was replaced by meadow fescue. The growth of red clover was the most uniform throughout the entire growing season.Helsingin yliopiston koetilalla Viikissä tutkittiin 1974—76 ensimmäisen niiton ajankohdan ja niittokertojen lukumäärän vaikutusta apila-heinänurmenkasvuun ja kehitykseen sekä kasvilajien välisiin määrällisiin ja laadullisiin suhteisiin. Toisena tutkimuskohteena olivat kasvutekijäin ja satokomponenttien väliset suhteet eri kasvuvaiheissa. Kolmantena selvityksen kohteena olivat seosnurmen kuiva-aineen energia-arvon muutokset ja fotosynteettinen tehokkuus kasvukauden eri ajankohtina. Sekanurmen kasvu oli tehokkainta lämpötilasumma-alueella 400—500°C (∑> 0° C). Tärkeimmät kuiva-ainesadon muodostumista kuvaavat muuttujat regressiomallissa olivat lämpötilasumma ensimmäisessä niitossa, viikon aikana ennen edellistä niittoa saatu sade toisessa niitossa, niittojen välinen sadesumma kolmannessa niitossa ja edellisen niiton kasvuston kasvupotentiaali neljännessä niitossa. Ensimmäisen ja toisen niiton satojen välillä vallitsi negatiivinen korrelaatio. Erilaiset korrelaatiot olivat indikaattoreita siitä, että ensimmäisen niiton ajankohtaa myöhästyttämällä saatu sadonlisä johtaa sadon alenemiseen toisessa niitossa, mutta korkea satotaso loppukesän niitoissa edellyttää aktiivista sadonmuodostumista aina edellisessä niitossa. Kokonaissadoissa ensimmäisen niiton ajankohdan myöhästyttäminen lisäsi eniten satoa 2- ja 3-niittosysteemeissä ja vähiten 4-niittosysteemissä, jossa kaksi keskimmäistä niittoa saattaa sattua kasvukauden kuivalle jaksolle. Alkukesällä kuukauden sateeton ajanjakso aiheutti kasvustolle niin syvän dormanssin, että oli mahdollista saada vain yksi sato. Kevään ja syksyn kuiva-ainesadon energia-arvo oli suurempi kuin keskikesällä. Keskimääräinen yhteyttämistehokkuus oli v. 1974 0.95 % ja v. 1975 0.47 % laskettuna pinta-alalle tulleesta kokonaissäteilystä ja 2,26 % ja 1.11 % näkyvän valon alueella. Suotuisana kasvukautena niittotiheydellä ei ollut vaikutusta yhteyttämistehokkuuteen. Kasvuston ka-pitoisuus aleni kevätkasvussa lämpötilasumman 420° C saakka ja kasvoi tämän jälkeen lineaarisesti. 4-niittosysteemin kokonaissadoissa kuiva-ainepitosuuden, raakavalkuaispitoisuuden ja valkuaissadon muodostumiseen sekä kuiva-aineen sulavuuteen vaikutti voimakkaimmin se, tehtiinkö ensimmäinen niitto kevään kuiva-ainepitoisuuden ollessa vielä laskeva tai sen ollessa nouseva. Muutoin niiton myöhästyttäminen tai niittokertojen vähentäminen huononsi rehun laatua. Sekanurmessa timotein kevätkasvu pysähtyi kesäkuun loppuun mennessä, jolloin sen syrjäytti puna-apila. Toisessa niitossa timotein kasvu pysähtyi heinäkuun puoliväliin mennessä, jolloin sen syrjäytti nurminata. Tuottavuus syksyä kohden aleni ensin timoteilla, sitten puna-apilalla ja viimeksi nurminadalla. Proteiinipitoisuudet eri niittotiheyksillä olivat sekaruohossa timoteilla ja nurminadalla hyvin lähellä toisiaan ja n. 2 %-yksikköä alemmat kuin puna-apilalla. Timotein ja puna-apilan kuiva-aineen sellulaasisulavuudet olivat koko kasvukauden lähes yhteneväiset ja n. 5 %-yksikköä alemmat kuin nurminadalla. Yhden kasvukauden jälkivaikutuksena merkitsi 4-niittosysteemin 13 %-yksikköä 2-niittoa heikompi talvehtiminen (visuaalisena havaintona) 21 %-yksikköä alhaisempaa satotasoa. Vuoden 1975 vedenpuute osoitti, että epäedulliset kasvuolot tasaavat viljelyteknillisiä jälkivaikutuksia, mutta samalla alentavat kasvuston yleistä kasvukuntoa

Tuloksia apilan virallisista siemenviljelyn lajikekokeista vuosilta 1978-84

vokMyynti MTT:n kirjasto. Yksikön huom.: Kirjasto Aj-

Puna-apilalajikkeiden siemenmuodostus

vokMyynti MTT:n kirjasto. Yksikön huom.: Kirjasto Aj-

Kotoisten karkearehujen kannattavuudesta maamme keskisatotasolla ja intensiteettiä nostamalla

vokkirjasto Aj-

Growth factors and management technique used in relation to the developmental rhythm and yield formation pattern of a clover-grass stand

The effect of the first cutting date and cutting frequency on the clover-grass stand growth and development and on the relationships between plant species were studied at the University of Helsinki in 1974—76. The second study objective was the relationships between several growth factors and the yield components of the stand. The third study area comprised the energy value changes and the photosynthetic activity of the stand during different phases of the growing season. The most rapid growth and development occurred within the temperature range of 400—500° C (∑ > 0° C). The late first cutting date increased yields most in the 2 and 3-cutting systems and least in the 4-cutting system, due to two summer cuts during the dry period of the season. Due to the regrowth ability of the species and lack of water in midsummer leading easily to dormancy there was a negative correlation between the first and the second cut and a positive correlation between the following successive cuts. The most important variables in the regression model describing DM production in the first, second, third and fourth cut were temperature sum in degree days, precipitation during the week before the previous cut, amount of precipitation between cuts and the physiological activity of the stand, respectively. The energy value of spring and autumn DM yield was higher than that of midsummer. The average photosynthetic efficiency was 0.95 % in 1974 and 0.47 % in 1975. The DM content of the yield in spring decreased until the temperature sum of 420° C (∑ > 0° C) and then increased linearly. The DM content, protein content, digestibility of DM and protein yield in the total yields were mostly influenced by the first cut if made when the slope showed either decreasing or increasing values of DM content. Otherwise a late first cutting date or low cutting frequency lowered the quality of the forage. In the mixture the spring growth of timothy ceased by the end of June and was replaced by red-clover. The regrowth of timothy ceased by the middle of July and was replaced by meadow fescue. The growth of red clover was the most uniform throughout the entire growing season

Development and productivity of timothy (Phleum pratense L.)

The research series on the growth and development of timothy was comprised of a comparison between the three most important timothy varieties in Finland, Tammisto, Nokka and Tarmo in different parts in Finland. The second part of the investigation involved the greenhouse study of the development of the same three varieties together with the northern type Norwegian variety Engmo and southern type Swedish line Sv. 0873. The development and growth of the three Finnish timothy varieties had similar dry matter and protein production capabilities. The Tammisto variety exhibited rather demanding requirements for growth factors and had regression coefficients greater than one for both dry matter and protein production. The Nokka variety can be classified as a general variety on the basis of its dry matter production, and a well thriving variety with a low level of growth factors on the basis of its raw protein production. The Nokka regression coefficients were approximately one and less than one for dry matter and protein production respectively. The Tarmo variety in regard to energy and protein production is considered a modest variety which had the lowest regression coefficient of the three varieties. Tarmo variety and Svalöv line Sv. 0873 had exceptionally slow primary development. In later growing stages, however, these same two varieties developed faster than the others. The regrowth capabilities of the Sv. 0873 line and the Engmo variety were weaker than those of the Finnish varieties. The Engmo variety, suited for northern conditions, had the largest root production whereas Sv. 0873, bred for southern conditions, had the weakest. The Engmo variety’s large root production promoted fast LAI development. Seeding depth had significance only in the first cutting. The size of the regrowth yield was primarily influenced by the size of the previous cutting. The yields of consecutive cuttings were negatively correlated

Tärkeimpien kasvutekijöiden ja käytetyn viljelytekniikan suhteet nurmen kasvurytmiin ja sadonmuodostukseen

The relationships of the growth rhythm and yield formation pattern of a clover-grass stand and a pure grass stand to the growth factors and management techniques were studied at Viikki in 1973—78. The objectives concerning management were the first cutting date and cutting frequency of a clover-grass stand and the number of cuttings, N-fertilization and seeding rate of a pure fescue stand. The most important growth factors in spring dry matter production were temperature sum (∑ > 0° C), solar radiation sum and N-fertilization. In summer growth the most important variables in the regression model were factors relating to precipitation. In the fall DM growth the most determining factors were the growth activity in the previous cut, N-fertilization and the amount of light. The spring growth was characterized by the distinct changes among all components of the yield studied. The shape of all spring growth models was strongly sigmoidal. As the growing season progressed DM yield or quality characteristics of the yield as a function of time or temperature sum in degree days approached the quadratic or linear relationships. The energy value of a clover-grass stand varied between the range of 4.274— 4.633 kcal gr-1. The photosynthetic efficiency of the stand among different cutting systems in 1974—75 was between 0.31—1.12 % determined from the total radiation per unit area. Deficiency of water was the most important factor causing variation in assimilation efficiency. Cutting frequency was the most important factor influencing the yield distribution of the season, the relationships among plant species and the formation of the total yields. Less important management factor was the first cutting date. N fertilization increased DM yields significantly in all cutting systems. The increase in use of nitrogen from 130 to 260 kg N ha-1 raised the protein content of the yield by 4.2 % units and the protein yield by 485 kg ha-1. The maximum DM yields in the seeding year and during the following three production years were obtained with seeding rates of 60, 30, 15 and 7.5 kg ha-1 respectively. The quality of the yield was very little influenced by growing density

Cellulase digestion technique compared with the in vitro digestibility of forages

A red clover-grass mixture and a couch grass (E. repens) pure stand were studied at eighteen different stages of maturity in Viikki. The analytical techniques were a cellulase digestion method and a two stage in vitro digestion technique. A high correlation (r = .99*** for both types of stand and residual standard deviations (RSD) of 0.9 and 1.3 respectively) was found between cellulase DM digestibility and in vitro DM digestibility. The difference between cellulase and in vitro DM digestibility increased as the plants advanced in maturity, because the effect of enzyme decreased, as the plants were more matured. The relationship between cellulase DM digestibility and plant protein content was very close, (r = .99***for the clover-grass mixture and couch grass and RSD’s of 0.6 and 0.5 respectively). At the early stages of maturity when the plant protein content and in vitro DM digestibility were high, the cellulase technique digested more efficiently the clover-grass mixture than the couch grass. The cellulase method was rapid, reproduciple and well suited to the evaluation of the plant material studied

Seeding year alfalfa population development as influenced by weed competition and density of establishment

The research in intraspecific competition within an alfalfa stand and interspecific competition between alfalfa and weeds was begun on the Michigan State University farm in East Lansing in 1972. Alfalfa seeding densities of 50, 400 and 800 seeds/m2 were used to determine intraspecific competition. Interspecific competition between alfalfa and weeds occurred mainly in noncontrolled alfalfa stands at various levels of seeding densities. Plant competition was evaluated with importance values and with relative crowding coefficients. Both measurements were found to be suitable for this kind of study. Importance values primarily indicated the quantity relationships of different species. Relative crowding coefficients mainly characterized the competitive ability of a species in a mixed stand. The importance of alfalfa exceeded the importance of weeds in noncontrolled and herbicide controlled stands at the seeding rates of 14 and 7 kg/ha respectively. Relative crowding coefficients show the competitive ability of alfalfa with regard to weeds. In the case of intraspecific competition there was no change in the crowding coefficient of alfalfa in respect of weeds when the seeding rate of alfalfa was increased beyond 9 kg/ha. The crowding coefficient of weeds presented equal values under all treatments thereby indicating the variability and plasticity of weeds. The maximum yield level was obtained in all treatments with the alfalfa seeding rate of 9 kg/ha. The total biomass production per unit area was equal in the noncontrolled system at all seeding densities and in the herbicide controlled system at seeding rates of 9 kg/ha or more

Growth factors and management technique in relation to the developmental rhythm yield formation pattern of a seeding year lucerne stand

The investigation of seeding year Lucerne stand development and yield formation pattern was carried out at the University of Helsinki in Viikki in 1973—74. The management techniques studied were the number of cuttings and the density of stand establishment. The variety used was Danish Isis-Daenfeldt. The maximum DM yield was obtained from a seeding rate of 20 kg/ha. The maximum DM yield produced under the favourable growing conditions in 1973 was 5. 7 tons/ha and under the less favourable conditions in 1974 3.3 tons/ha. No more than two cuts in the year of seeding are recommended. The radiation used by lucerne was 0.3—0.5 %of the total radiation reaching the surface. A 10% decrease in radiation in 1974 resulted in a 50 % decrease in photosynthetic activity mainly due to differences in temperature and overabundant precipitation. The optimum LAI was obtained from seedingrates ≥5 kg/ha. From seeding to emergence a temperature sum of 120 °C is needed and from seeding to flowering a sum of 800°C. From cutting to the next flowering a sum of 600— 700°C is needed. Three cuts provided forage 6.3 % units more digestible than two cuts. Root carbohydrate levels suggest that the last cut should not be made later than mid-August