2001 * XII * 1

https://agrt.emu.ee/pdf/contents/2001_1_sisukord.pdf

Complex experiment in apple orchard: fertilizing in store (before the planting) and during the growing seasons. In 1985-1999, an experiment was carried out at the Polli Horticultural Institute on the fertile soddy-podzolic soil. It was turned out that fertilizing with PK-fertilizers and manure in growing seasons gave only a Iittle advantage. But one third of yield efficiency was obtained in pre-planting fertilizing in store (mineral pli fertilizers and ianure) together with nitogen fertilizing every year. The equivalent effect was obtained if manure, (100 t per ha) plus mineral fertilizers P₂O₅ 200 kg/ha, K₂O 200 kg/ha were used in pre-planting fertiLizing (in the depth of 30-50 cm.) or P₂O₅ 700 kg/ha and K₂O 700 kg/ha (without manure) in preplanting 'fertilizing plus nitogen every year were used. The quality of fruit: size and chemical composition didn't depend upon dffirent fertilizing methods.

https://agrt.emu.ee/pdf/2001_1_haak1.pdf

On apple rootstock evaluations in orchard experiments in Estonia. Orchard experiments were establishedin two places: at the Rõhu (State)Experimental Farm in 1983 and at the Polli Horticultural Institute in 1985. Soil in both orchards was soddy, podzolic, medium-texture clay loam. Both experitnents were completed in 1999. Three cultivcrrs: 'Talvenauding',''Tellissaare' and 'sidrunkollane Taliõun' were propagated on 9 rootstocks of Estonian origin (bred at the Polli Horticultural Institute), 2 rootstocks of England origin, 3 rootstocks of Russiano rigin (from Michurinsk), and one from Sweden (Alnarp). The set of rootstocks at Rõhu was less numerous; 4 from Estonia, 2 from Russia, 1from England and 1 from Sweden. Seedlings of cultivar 'Antonovka' were used as the base of comparison. Most of the rootstocks were strong-growing. Only E 20 from Polli, M 11 and MM 106 from East Malling (England) and 54-l18 from Michurinsk were medium-strong. The yield per tree was the biggest on strong-growig rootstocks A 2, E 53 and E 56. The trees on medium-strong rootstocks had a smaller yield. However, trees on MM 106 and 54-118 had greater yield, if calculated to the 1 m³ crown volume.

https://agrt.emu.ee/pdf/2001_1_haak2.pdf

On increasing ω-3 fatty acid content in poultry products. During the last decade dietologists all over the world have focused their studies on ω-3 fatty acids that are known for their ability of inhibiting platelet aggregation and thus reducing the risk of atherosclerosis and heart attacks. Moreover, in many cases their positive effect on the share of different cholesterol fractions in blood plasma has been observed. Favourable results have been obtained in the studies of the effect of ω-3 fatty acids on the diets for pregnant women and premature children. Therefore the possibilities of enriching regular foodstuffs with ω-3 fatty acids are being worldwide. To prevent high cardiovascular mortality in Estonia, an investigation into the possibilities of enriching chicken and quail eggs as well as broiler and quail meat with ω-3 fatty acids was initiated at the Institute of Animal Science of the Estonian Agricultural University in 1997. The experiments of enriching the chicken eggs and hen broiler meat were carried out on the poultry farms of the Sakala Poultry Breeding Co-operative and Tamsalu TERKO, the enrichment trials of quail eggs and meat on the quail farm of Järveotsa farmstead. The experiments on quail egg consumption were conducted in the Department of Cardiology of the Tartu University Clinic. The results, based on ten research works, indicated that linseed oil, rapeseed oil and linseed cake in chicken and quail diets enabled a 6- to 8-fold increase in the ω-3 fatty acid content of egg yolk and meat fat. The nutrition experiments conducted with young healthy mail volunteers, confirmed that consumption of ω-3fatty acid enriched quail eggs reduced the platelet aggregation, thus decreasing the risk of heart attacks as well.

https://agrt.emu.ee/pdf/2001_1_hammal.pdf

On the contents of moving magnesium and the ratio of potassium and magnesium in field soils of Estonia. Due to the source rocks, Estonian soils are very heterogeneous by their contents of chemical elements. The methodologies used to identify fertilisation needs influence the objectivity of the results of contents of acquired nutritional elements and their ratio.

The research compared the moving magnesium contents identified b), ammonium lactate (AL) methodology and by IN KCl- 0,025N CaCl2-extraction. The results show that the magnesium contents in soils identified by the IN KCI and 0,025N CaCl2 extraction (Schachtschabel methodology) differ to a relatively small extent. Whereas the difference between the latter two and AL methodology is great (Figure 1). The difference is greater in case of soils that have high contents of calcium and specifically so in case Schachtschabel methodology is being used (Figure 2). In case of soils rich in calcium, some soils identified bv the AL methodology are rich in magnesium but poor as identified by 0,025N CaCl2 extraction methodology and there is no plausible relation between the results of research. The plausible linear connection between magnesium contents between magnesium contents identified by two methodologies appears in soils that contain moving calcium up to 2500 mg/kg (Figure 3). Therefore, the contents of magnesium identified by the AL and Schachtschabel methodology are only partly comparable since none of the methodologies have been worked out for soils rich in calcium.

When identifying the ratio of antagonistic nutrients that plants need, it is necessary to consider the identification methodologies because of great differences between them. In identifying magnesium by the AL methodology, the ratio of magnesium and potassium in soils (potassium was identified by the double lactate methodology (DL) is 0,5...0,6:1, but when identified from IN KCI and 0,025N CaCl2 extraction, the ratio is 2: 1. Thus, due to the differences in identifying methodologies, it is not possible to compare the ratio of contents of magnesium and potassium in the case of other methodologies

https://agrt.emu.ee/pdf/2001_1_loide.pdf