The native reserves of phosphorus (P) in Finnish soils are sizeable but poorly available to plants. The P status has been generally poor, but large rates of P applied since the 1940s have substantially enhanced the supply of P from the soil. As a means of optimising P fertilisation of crops grown in the improved soils and promoting agro-environmental sustainability of agriculture, long-term field experiments were established in 1977-1981 on various soil types around Finland, between the latitudes of 60 and 65 N. The experimental sites (8 Cambisols, 9 Regosols, 6 Histosols, 1 Podsol) were moderately acidic (pH w 5.6, range 4.6-6.6) and contained 1.6-31.2% organic C, and (mineral soils) 3-74% clay. The concentration of total P was 1.22 (0.66-1.87) g kg -1 , and the inorganic fraction separated with fluoride and hydroxide extractions (Al,Fe-P) was 8.2% (4.5-12.4%) of oxalate extractable Al+Fe (P saturation index). In mineral topsoil the pool of Al,Fe-P was 850 kg ha -1 , which is 300 kg ha -1 larger than was obtained in the early 1960s and 600 kg ha -1 larger than found in virgin soils. The soil test P value was 13.1 (3.7-60) mg dm -3 by the acid ammonium acetate method, 11.5 (1.6-42) mg dm -3 by a water extraction method (1:60 v/v) and 61 (23-131) mg kg -1 with a modified Olsen method. The intensity factor of soil P status has remained at a relatively low level in a major part of the cultivated area.;

The dry matter yields and forage quality of seven grassland plant species and mixed stands which included three cutting regimes (pasture 4-5 cuts, silage 2-3 cuts, hay and aftermath) were studied at two locations in northern Finland, Ruukki (64°40’N) and Rovaniemi (66° 35’N). Increased cutting frequency lowered the total dry matter yields of all plant species. Production of timothy (Phleum pratense L.) and smooth brome grass (Bromus inermis L.) swards was significantly reduced by taking four or five cuts instead of one or two cuts. Meadow fescue (Festuca pratensis Huds.) and meadow grass (Poa pratensis L.) showed only a minor interaction with harvesting regimes and were less affected by the cutting frequency. The increased cutting frequency raised the crude protein content, this causing the highest protein yields despite the smaller dry matter yields. The inclusion of red clover in seed mixtures had a favourable effect on the crude protein content of grass swards. Stands of sown plants decreased and the proportion of weeds in yields increased with time, reflecting the suitability of plant species to various cutting regimes. Meadow fescue and meadow grass with rapid regrowth had a positive effect on sward density and also caused less invasion of weeds when the cutting frequency was increased.

Fertilising with phosphorus (P) ensures continuous supply of an essential growth factor as necessary for productive and sustainable agriculture. The amounts of P required to attain and maintain an adequate P status in the soil were investigated in field experiments at 22 sites in Finland on soils containing large amounts of residual fertiliser P. The effects of five rates (0, 15, 30, 45 and 60 kg ha -1 ) of annual P application were measured in the soil by chemical methods after 9 to 15 experimental years, and the changes in soil test P values (STP) were compared with P balances. Stratification of P in ley soil by broadcast application of fertilisers was assessed at four sites. The mean changes of STP in the whole topsoil caused by P fertilisation expressed as per cent of the balance difference were 3.5% (0.0159 mg dm -3 )/(kg ha -1 ) in the acid ammonium acetate test (P Ac ), 4.7% (0.0214 mg dm -3 )/(kg ha -1 ) in water extraction (P w ) and 9.7% (0.058 mg kg -1 )/(kg ha -1 ) in sodium bicarbonate extraction (modified Olsen P). Initially high P Ac values tended to slowly decrease at zero P balance, while low values

The study was conducted to investigate the effect and benefit of applying plant growth regulators (PGR) to two easily lodging barley cultivars, Arra and Kilta, which were commonly used for fodder production all over Finland. Field trials were conducted at six experimental sites in different parts of the country. Of the PGRs tested, ethephon and mepiquat/ethephon were the most effective in shortening the culm and preventing lodging. However, neither could prevent the lodge adequately in all growing circumstances. When applied at flag-leaf stage (FS 10) they increased yield under conditions favourable for lodging. They also raised the volume weight of barley, which was important for the final price of the yield. The most important factors determining future lodging of barley were an effective temperature sum of over +5°C and precipitation during the period from sowing to the beginning of tillering (FS 2). About 64-68% of the lodging risk of the cultivars studied could be predicted from weather conditions during early development of the crop. Local growing conditions and the presence of lodge had a marked impact on the results obtained with PGRs. In the case of moderate lodging the compound used determined whether a profit or loss was made on the crop. In the case of heavy lodging, compounds containing ethephon contributed to an economic return. Their application at flag-leaf stage gave a profit of FIM 70 - 390 ha-1. Since the profitability of PGR treatments depended on lodging, treatments are recommended for fodder barley only when lodging is expected. The lodging risk can be predicted within certain limits at the tillering stage of barley.