2000 * XI * 1

https://agrt.emu.ee/pdf/contents/2000_1_sisukord.pdf

On plant growing experiments in Estonia and Northern Livonia in the 19^th century and the first two decades of the 20^th century.

Prerequisites and conditions for improvements in plant growing. Agrarian reforms provided the basis for further economic development. Introduction of new crops (potato, clover, alfalfa) as well as the demand for flax and animal products enhanced agricultural production and facilitated to experimental work carried out in the field of plant growing. The Livonian Public Benefit and Economic Society and the agricultural societies established by the farmers played an important role in this development.

https://agrt.emu.ee/pdf/2000_1_annuk.pdf

https://agrt.emu.ee/pdf/2000_1_karelson.pdf

https://agrt.emu.ee/pdf/2000_1_lillak1.pdf

Natural and artificial afforestation of abandoned agricultural lands. The management of abandoned agricultural lands is an actual problem in Estonian society since 1992. Some hundred thousand hectares of farm lands will be covered step by step with shrubs and young trees. The process is still not regulated by the state. At the same time specialists of silviculture have enough practical experiences from the last half century: which tree species are suitable for afforestation and how to tend the natural regeneration of trees at previous fields. Broad-leaved tree species have many ecological advantages, but for better biodiversity of future stands also coniferous are recommended for planting. The main investment (finan-cial support from state and from EU) during next decade must be used for tending of young stands, specially for regulating the composition of tree species and stand density of naturally regenerated previous fields.

Key words: afforestation, abandoned agricultural lands, broad-leaved species.

https://agrt.emu.ee/pdf/2000_1_tullus.pdf

The nutritive value and digestibility of feeds prepared of local cereals. Five trials were carried out during the investigation. In the first experiment in vitro digestibility of whole crop barley, oat, cereal-legume mixture with peas and maize silage was studied. In the second experiment in vitro digestibility of oat and barley straw and the digestibility of ammo-nia-treated oat straw were studied on young cattle. In the 3^rd trial the effect of oat grain silage preserved with Ensimax on intake and productivity were investigated. In the 4^th trial on rams, digestibility of barley grain silage, prepared with AIV 2000 was determined. In the 5^th trial dry matter digestibility of oat and barley grain silage and oat and barley meal was determined in vitro.

On the basis of the results of the trials the following conclusions can be drawn:

1. The digestibility of whole crop silage is low (maize silage excepted). Dry matter in vitro digestibility of whole crop barley, oats and cereal-legume mixture (with pea) silage was 58.9%; 49.1% and 55.2%, respectively. Dry matter digestibility of maize silage was 72.2% only.
2. Digestibility of ammonia-treated oat straw was higher than that of untreated oat straw.
3. Dry matter digestibility and in vitro organic matter digestibility of oat straw was higher than these of barley straw.
4. Intake of crushed oat grain silage was good. That silage can substitute compound feedingstuffs in the case sunflower oil meal and minerals are added.
5. Oat grain silage increased milk production, mainly due to the increase in fat and pro-tein content.
6. 6. Increasing the proportion of barley grain silage in the ration favoured the digestibility of the ration.
7. Dry matter digestibility of barley grain silage was 76.5% and that of organic matter was 78.0%. Digestibility of barley grain silage crude protein was 77.8%.
8. When feed digestibility is determined by in vitro methods, the coefficient of digestibil-ity tends to be higher than that gained by in vivo digestion experiments.

https://agrt.emu.ee/pdf/2000_1_kaldmae.pdf

On the aggregation of the automorphic and semihydromorphic soils of Estonian nonarable lands. The Aorg horizon (epipedon) of the automorphic and semihydromorphic soils studied contains up to 32% organic matter (1.72 Corg). Their content of clay (<0.01 mm) ranges from 6…70%. The correlation of the basic structural characteristics of the epipedon with its organic matter and clay contents can be expressed by the following equations:

A_ma = 91.7 + 0.23fs – 0.96hu; R = 0.66

A_v > 0.1 = 32.3 + 0.93fs + 0.61hu; R = 0.62

A_v >0.25 = 47.4 + 1.00fs + 0.28hu; R = 71

K_dis = –0.27 + 0.07fs; r = 0.71

K_agr = 11,5 + 0.22hu + 0.61fs; R = 0.85

where A_v > 0.1 – % of water-stable macroaggregates with a diameter over 0.1 mm;

A_v >0.25 – % of water-stable macroaggregates with a diameter over 0.25 mm;

K_dis – the Beiver-Roades coefficient of microaggregate dispersion;

K_agr – degree of aggregation after Beiver and Roades;

hu – 1.72 Corg (%);

fs – granulometric fraction < 0.01 mm, %.

For all soils the water stability of microaggregates is the lower the deeper down we get from the Aorg horizon. The rest of the characteristics change mainly alongside the granu-lometric composition of the soils. Another important factor is the change of the content of non-silicate iron. In the eluvial horizon (A₂ or E) aggregation decreases as the clay and non-silicate iron are washed out, whereas in the illuvial horizon aggregation, on the contrary, increases. In the B-horizon of sod-calcareous soils aggregation may even surpass that of the A₁-horizon. In the gleyed and gley horizons the aggregation of soils decreases. As for the aggregation of the Gox-horizon it depends on its content of hydrogenically accumulated non-silicate iron.

https://agrt.emu.ee/pdf/2000_1_kask.pdf

Degradation of alfalfa sward. The degradation of alfalfa (Medicago sp. L.) sward through assessing the crown and root development and health, stand density (number of plants per square meter), alfalfa yielding ability, and weed infestations, and interactions with plant aging, cutting intensity (2…4 cuts per season), date of the final cut (August 28–October 2), and variety characteristics (14 different cv. were used) has been studied since 1995 at Eerika EAU Grassland Experimental Station. The investigation based on two field experiments established on loamy Podzoluvisol soil with content of organic matter in 0…20 cm soil layer 2.80…3.20%, available potassium and phosphorus content – 74.3…86.9 and 45.4…50.1 mg/kg, respectively, and pHKCl – 6.2…6.4. The changing in quality of alfalfa sward in direction of degradation started at the end of the first wintering when extensive furrows in the roots of alfalfa caused by the larvae’s of clover root curculio (Sitona sp.) were possible to observed. These lesions opened a way for infection of pathogens causing root rot and which is progressed year after year. At the same time, depending mostly on the cutting frequency, the number of plants per area unit started consistently decrease. Mortality of alfalfa plants occurred not only during the overwintering period but also during the vegeta-tion period. In the first years of development, compensated by increasing of single plant size, the deterioration of stand density was not resulted by decreasing in yielding ability of alfalfa sward. However, DM-yield started sharply to decrease when the number of plants per square meters to the spring of productive year fall down below 160. Thinning of alfalfa stand and decreasing its productivity allowed the invasion of nonseeded weed species into the sward, which was especially intensive in using 4-cut harvesting system.

https://agrt.emu.ee/pdf/2000_1_lillak2.pdf

Quality of fresh semen collected from Estonian Holstein A.I. bulls. From February to December 1998 twenty nine dairy A.I. Holstein bulls were used to study the effects of age, breed and season on sperm concentration, the incidence of morphological abnormalities, sperm motility and intactness of plasma membrane in fresh semen. The highest percentage value of sperm abnormalities was recorded for bulls imported from Germany (12.8%), however if compared to the corresponding values for the bulls imported from the Netherlands (10.6%) or raised in Estonia (9.8%), these differences were nonsignificant (P>0.1). The incidence of sperm abnormalities was not significantly affected by age of the bulls and the season of semen collection. The tendency was recorded for higher incidence of sperm abnormalities during summer season (13.8%).

The intactness of sperm plasma membrane assessed by HOS-test was affected by country of origin and age of the bull, and season of semen collection. Differences in sperm motility were caused by country of origin and age of the bull. The season effect was not detected.

These results indicated that bull age, breed and season of semen collection can influence sperm characteristics and must be considered in evaluation of bulls for breeding and planning semen collection.

https://agrt.emu.ee/pdf/2000_1_padrik.pdf

Organic acid, ascorbic acid and sugar content of arctic bramble depending on variety and its cultivation place. Organic acids (expressed as citric acid), ascorbic acid and sugars of frozen arctic bramble (Rubus arcticus L.) berries were analysed in the winters of 1996, 1997 and 1998. The followings cultivars and clones ‘Pima’ (the control cultivar), ‘Mespi’, ‘Marika’, ‘Muuruska’, ‘Elpee’, 039, ‘Astra’ (R. arcticus × R. stellatus), ‘Aura’ (R. arcticus × R. stellatus) were analysed. The Estonian natural arctic bramble under the name Kaansoo was included. The berries from three different growing places (Tartu, Vasula, Kambja) were analysed in the experiment. Two experiments were located on production fields, and the growing method with plastic mulch was used there. In Tartu the experimental field lay in the experimental garden of Department of Horticulture of the Estonian Agricultural University. Growing without plastic mulch was used there.

The fruit quality characteristics (aroma, fruit colour and colour of 2% juice) were determined in 1997 and 1998. The organic acid content of arctic bramble and its hybrid berries, expressed as citric acid, was 0.19…0.29% (average of three years). The organic acid content was highest in the arctic bramble hybrid varieties ‘Astra’ and ‘Aura’. The average ascorbic acid content in berries was 19.0…25.2 m%. The content of sugars was 4.9…5.8%. The varieties ‘Astra’ and ‘Aura’ had lowest sugar content.

The berries of Estonian natural arctic bramble clone are not essentially different from well-known arctic bramble cultivars in Finland.

Key words: wild berry, arctic bramble, I, chemical composition, organic acid, sugars, ascorbic acid, aroma

https://agrt.emu.ee/pdf/2000_1_starast.pdf