Tubulering

This report contains the results of a series of field trials carried out on two sites, Ulfhäll and Fiholmsby in Södermanland, during the period 1998-2000. The aim of the trials was to evaluate the effects of mole drainage as a complement to tile drainage in combination with liming and variation in sowing date. The trial layout induded the following treatments and sowing dates: A = Control B = Mole drainage C = Piped mole drainage 1 = Conventional seedbed preparation with normal sowing date 2 = Conventional seedbed preparation with early sowing 3 = Sowing without harrowing and as early as possible a = Control b = Liming In the mole drainage treatments, the distance between drains was 3.0 m and the drains were installed at 0.5 m depth. Treatment b was limed with quicklime (CaO) 6 tons/ha. The plots were ploughed and levelled out in the autumn. Sowing treatments 1 and 2 were harrowed before sowing, while sowing treatment 3 was direct-drilled as early as possible. Yield and quality determinations, seedbed inspections, groundwater level and infiltration measurements and soil physical investigations in the laboratory were carried out for all plots. The soil at the Ulfhäll and Fiholmsby sites is a heavy to very heavy clay, and the soil at both sites contains some gyttja. At Ulfhäll, the hydraulic conductivity was very low in the topsoil and high in the subsoil, while at Fiholmsby, the conductivity was high throughout the profile to 80 cm depth. At both sites, the conductivity in the central topsoil of the limed plots increased to twice that in the control treatment. The yield results varied due to extreme variations in weather during the three-year experimental period. 1998 was an extremely wet year, while 1999 the precipitation was normal during the growing season. In 2000, there was a dry spring followed by a cool and rainy summer. The mild, wet winter and spring of 1997-1998 meant that the groundwater level in the soil was very high. The mole drains were water-filled for a time, causing some of them to collapse on both sites. The yield results from the trials showed that there were small and non-significant yield differences between treatments except for the first sowing without spring tillage treatment. In that treatment, the yield of grain was on average 10% lower for a total of 5 harvest years. A pea crop showed yield increases of 8 and 5 % for sowing treatments 2 and 3 respectively. The effect of mole drainage was better on Fiholmsby than Ulfhäll. There was an average yield increase of 6% for mole drainage on the Fiholmsby site. Liming produced grain yield increases of 2 and 5% on Ulfhäll and Fiholmsby respectively, while it decreased pea yields overall by 8%. The results of the investigation showed that mole drainage are not suitable on soils where the groundwater in the soil profile can rise to a high level. The mole drains can collapse and one must do the mole drainage over again. One way to avoid the mole drains to collapse are to put drain-pipe inside them. The results of different sowing dates showed that the early sowing date with conventional seedbed preparation increased the yield of grain while the extra early sowing date decreased the yield

Växtnäringsstyrning i potatis

During 1991-1993 an investigation concerning application of optimal amounts of nutrients to potatoes was carried out. The trials were situated at two locations, Hedemora in Dalarna at latitude 60° N and Halmstad in Halland at latitude 56° N. The research plan included 3 table potato varieties, Bintje, Matilda and Ukama, and 5 different ways to apply the nutrients. l. Broadcasting before planting. 2. Placing all nutrients in connection with planting. 3. Placing 1/2 of the nutrients at planting and placing 1/2 at the last hilling. 4. Placing half of NPK at planting + K to full rate + spraying 2 times with 1/4 N + 1/4 P. 5. Placing half the amount of NPK at planting + PK to full rate + spraying 2 times with 1/4 N. The result shows that placing at planting of the whole nutrient rate gave, on average, 9 percent higher yield than broadcasting before planting. Placing of 1/2 the rate at planting and 1/2 the rate at the last hilling gave, on average, 3 percent higher yield than broadcasting. Spraying with nitrogen and phosphorus gave lower yields than broad-casting. The dry matter content showed small differences between different treatments and were not statistically significant. The difference in cooking quality between different treat-ments was not statistically significant but a slight increase in sogginess in comparison with other treatments was observed when the nutrients had been placed. The highest contents of nitrogen and phosphorus were found in treatments where the fertilizers had been placed. The contents of potassium did not seem to be affected by different treatments. The contents of calcium, magnesium and sulphur were highest in tubers from the broadcast treatment. The method of analyzing nitrate in potato leaves in the field with "Nitrachek" showed very good correlation with methods in laboratory. This rapid method may therefore be of good help in following the nitrate content in the potato leaves during growth

Reglerad dränering

About 45% of the anthropogenic nitrogen loads from Sweden reaching the seas come from arable land. Within the work of the national environmental quality objective "No eutrophication", the Swedish government determined an environmental goal of reducing the nitrogen loads from arable land to the seas south of the sea of Åland by at least 50% compared with the level year 1985 level (to 38500 ton N year⁻¹). This goal should be reached by year 2020. The present programme contains legislation, extension service, economical management, research and development work and monitoring. Research and development work included in the programme are both aiming to promote technical development mainly in the domain of management of manure and growing catch crops. Despite the progress in reducing amount of available N for leaching, the variability in N loads between years remains, mainly due to the great variability in annual runoff. Controlled drainage has the potential to moderate this variability in annual runoff and to a certain degree control the timing of the outflow and even further reduce the amount of available N for leaching. Field experiments conducted in the South of Sweden between 1996 and 2001, show that controlled drainage has a great potential to regulate unnecessary drainage outflow from cropland and subsequently reduce nutrients leaching. However, the applicability of the technique in large scale in Sweden has not yet been evaluated which is the task of this project. The aim of the project was to assess the potential of arable land in the coastal areas of Southern Sweden suitable for controlled drainage. Some topographical and agro hydrological site conditions need to be present to en sure feasible and practical management of a controlled drainage system. The following six conditions indicate if a site is suitable for controlled drainage or not: the site needs to have drainage demand under natural conditions, level topography (slope 2%. Soil maps at a scale of 1:50000, 1:100000 and 1:1 000000 were used to classify the soil texture after assumed hydraulic conductivity into three classes; high, medium and low hydraulic conductivity. The depth of observations was 0.5 m. In order to identify land use, maps at a scale of 1:50 000 were used. After the data had been reclassified with the geographic information system software Arc info 8.2, the information was merged. The land identified as cultivated land was then further divided into five classes, classes l to 4 and other cultivated land, with decreasing suitability for controlled drainage. More than 720000 ha of cultivated land were included in the study of which 21 % was classified as highly suitable, 13% suitable regarding topography and hydraulic conductivity and 6% with some suitability. Since not all the land require drainage the total number of 289 000 ha with suitability will after more detailed investigations be reduced. Additional data will be brought into the evaluation, such as existing information on the drainage situation of the land. Furthermore, validation of the result will be performed by field survey in small catchments

Erfarenheter av bevattningsmaskiner i praktisk drift

1974 års erfarenheter av bevattningsmaskiner har gett oss en uppfattning om hur de fungerar under svenska förhållanden. Eftersom maskinerna är relativt nya har de haft en del barnsjukdomar. I många fall har dessa åtgärdats på 1975 års modell. Det synes dock återstå on del att förbättra för att öka driftssäkerheten. Trots de brister som visat sig, har ägarna i stort sett varit nöjda med sina maskiner. De flesta fel och missöden har varit relativt små och hade inte behövt inträffa. Om försäljningsfirman haft tillräcklig erfarenhet att delge köparen. Då skador på mark och gröda, som man tidigare befara, har varit obetydliga. Det är endast på slamningsbenägna jordarter, som man haft en del problem med skorpbildning vid bevattning före uppkomst. I övrigt tycks den höga bevattningsintensiteten inte ha inverkat menligt på mark och gröda