Reduced tillage was compared with traditional ploughing in terms of erosion and phosphorus (P) and nitrogen (N) losses in an experimental field in southern Finland. One part of the field has been ploughed (treatment PF) and the other part harrowed (treatment NPF) every autumn since 1986. Flow volume and water quality data was collected separately from surface runoff and subsurface drainage waters during 1991-1995 (surface runoff volume since 1993). Erosion was higher in PF (on average 234 kg ha-1yr-1 in drainage flow and 479 kg ha-1 yr-1 in surface runoff) than in NPF (158 kg ha-1yr-1 in drainage flow and 160 kg ha-1yr-1 in surface runoff). Total N loss in drainage flow was also higher in PF (7.2 kg ha-1yr-1) than in NPF (4.6 kg ha-1yr-1). Total P losses did not differ much

At Suitia, Southern Finland, weed populations in different crop rotations at conventional and organic cropping systems were investigated in 1982—1988. The number of weeds and the dry matter yields of weeds were greater in organic cropping (on average 324 weeds/m2 and 425 kg DM/ha) compared to conventional cropping (94 weeds/m2 and 61 kg DM/ha). There were least weeds in the conventionally cultivated ley. The first year, clover ley in organic cropping prevented the growth of weeds as well as the grass ley in conventional cropping. Overwintering damages in organically cultivated leys increased the amounts of weeds in the following ley years. Organically cultivated winter wheat reduced the amount and weight of weeds almost as well as conventionally cultivated winter wheat although its biomass was three-fourths of the conventionally cultivated winter wheat. The biomass of organically cultivated barley later on in the rotations was only one-fifth of the conventionally cultivated barley and had five times more weeds. In conventional cropping, the number of weeds in almost all weed species was decreased or stayed at the same level during the experiment. In organic cropping, the number of most weeds in weed species increased from the level for 1982. Most increased Stellaria media, Fallopio convolvulus, Lamium sp and Chenopodium album.

SU MMARYRecent studies of precision cereal farming systems have documented large within-field and annual variation in grain yield and quality. The principal aim of the present study was to evaluate the degree of within-and between-field variation in biomass, yield, yield component structure and quality traits, such as grain protein of two-row barley (Hordeum vulgare L.), using crop samples collected from field patches of varying yield potential. Plant samples were collected from the fields of commercial farmers located in southern Finland in 2000 and 2001. Selection of low, intermediate and high yielding patches for crop sampling was based on aerial infrared colour images taken twice during the growing season. When stands were mature, plant samples from an area of 0 . 5 m 2 were uprooted for yield component and quality analysis. Nitrogen accumulation prior to heading was strongly associated with biomass accumulation, indicating differences in growth potential of the different field patches. The principal yield determining trait in two-row barley was grain number/m 2 , whereas single grain weight (SGW) had a lesser effect on grain yield. The degree of variation in the quality parameters, namely protein and SGW, was not associated with grain yield. This suggests that within-field variation in yield potential does not determine heterogeneity of the grain yield in terms of grain weight or grain protein content.

In Finland, there seems to be a substantial amount of unutilized production capacity in grassland cultivation that can, and should, be better used in the future. Ley farming is generally based on three-year leys, harvested two or three times per year for silage. Timothy and meadow fescue are the two most common species used in forage grass production in Finland. Nitrogen (N) is the most important nutrient in yield formation of grasses. Dry matter (DM) yield responses of perennial cool-season grasses to fertilizer N generally range from 20 to 25 kg DM ha -1 year -1 kg -1 N (Hopkins, 2000), with greater incremental responses at lower N rates, that is curvilinear relationship between N rates and DM production. High N rates late in the growing season have promoted vegetative growth instead of hardening processes, which has led to increased overwintering damages in cold regions and, consequently, enhanced the curvilinearity of the relationship (Huokuna Abstract Finnish N fertilizer application regulations for forage grasses are based on field experiments mainly conducted in the 1960-1970s with cultivars and management practices typical of the time. In order to update the yield response function of N, to make it better suited to current grassland farming, field experiments were conducted at two sites in 2015-2017 with two cultivars of timothy (Phleum pratense L.) and one of meadow fescue (Festuca pratensis Huds.). Dry matter (DM) yield, nutritive value and N balance were evaluated, with N application levels 0, 150, 200, 250, 300, 350, 400 and 450 kg N ha −1 year −1 . The grasses were harvested three times per season. The dataindicate that the DM yield response was significantly stronger, and N was used more efficiently for DM production than earlier without compromising the nutritive value, especially during the first two years. The third harvest produced on average 23% of the annual yield, utilizing N efficiently. N application rates below 350 kg N ha −1 year −1 did not cause substantial overwintering losses or lodging. The data indicate that with changing climate and improved cultivars and management practices, there is a need to modify the rates and timing of N application. The results suggest that N application levels could be increased by at least 50 kg N ha −1 year −1 from the current maximum accepted rate (250 kg N ha −1 year −1 ) without too high NO 3 or CP concentrations in feed, or too high N balance that indicates increasing risk of N leaching.

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