Artur Granstedt

Studies of the Flow, Supply and Losses of Nitrogen and Other Plant Nutrients in Conventional and Ecological Agricultural Systems in Sweden

ABSTRACT Studies were made of plant nutrients, especially the flow, supply and losses of nitrogen in different agricultural and community systems in Sweden at the farm, regional and national levels. Nitrogen losses from the agricultural systems exceeded 100 kg/ha/year in southern Swedish regions. Losses exceeded 200 kg/ha/year in association with animal husbandry. Nitrogen can be conserved by maximizing the recycling of crop nitrogen within the agroecosystem and between the agricultural and the community systems. This requires that the level of animal production on a given farm must be adjusted on the basis of the farms crop—and feed-production capacities which in turn are determined partly by the climatic and soil conditions. Such an adjustment on mixed farm, regional and national levels, would contribute to minimize nitrogen and other plant nutrient losses to the environment. This would also decrease the costs to the environment associated with artificial fertilizers.

Case Studies on the Flow and Supply of Nitrogen in Alternative Farming in Sweden. I. Skilleby-Farm 1981–1987

ABSTRACT Case studies examining nitrogen supply dynamics were carried out on two biodynamic farms in Sormland (for a 7 year rotation period on one farm and 3 years on the other) and on one biodynamic farm in Skane (for 3 years) in Sweden. Each of the farm locations had a different set of climatic and soil conditions. Two conventional farms, one with and one without livestock, served as controls in each of the two areas. In this paper results from the biodynamic farm in Sormland are presented. Changes in soil mineral nitrogen, nitrogen uptake by the crop and productivity were studied in relation to previous crops, crop rotations, and nitrogen fixation. A nitrogen balance and flow of nitrogen in the farm ecosystem is presented. For a farm to meet its nitrogen needs without resorting to the use of artificial fertilizers requires that nitrogen be effectively recycled within the farm with only small losses; that enough nitrogen-fixing crops be cultivated (legumes on a third of the area in the circulation); and...

Ecological Recycling Agriculture to Reduce Nutrient Pollution to the Baltic Sea

ABSTRACT HELCOM (Helsinki Commission) has adopted a programme with a vision of a healthy Baltic Sea Environment, with diverse biological components functioning in balance, resulting in good environmental status and supporting a wide range of sustainable human economic activities. HELCOM assessments presented in the Stakeholder Conference plan of 2007 clearly show that problems with eutrophication exist in most of the sub-basins of the Baltic and that good environmental status has not been achieved. Agriculture is responsible for a large share of the leaching of nutrients to watercourses, including groundwater lakes and finally the sea. The analysis of data presented in this paper concludes that specialized agriculture with its separation of crop and animal production results in a high load of nitrogen and phosphorus to the Baltic Sea. This agricultural specialization took place throughout the Scandinavian countries after World War II and has resulted in farms with a high density of animals and great surpluses of plant nutrients concentrated to certain regions. Examples from Sweden are presented in this paper. This trend of increasing products per animal and per hectare on fewer farms and a higher surplus of nutrients on each of them is continuing in Sweden and is likely to spread to new EU member countries within the Baltic Sea drainage area with the probable consequence of increasing nutrient loads. Ecological Recycling Agriculture (ERA) is defined as an agriculture system based on local and renewable resources that integrate animal and crop production on each farm or farms in close proximity. As a result a large part of the nutrient uptake in the fodder is effectively recycled. This in effect means that each farm strives to be self-sufficient in fodder production, which in turn limits animal density and ensures a more even distribution of animals geographically. This study of 12 Swedish farms confirms earlier results that agriculture based on these principles of ecological recycling can lead to a decrease in the potential emission of reactive nitrogen by half as well as a significant reduction in the accumulation and loss of reactive phosphorus. Application of these agricultural principles throughout the Baltic region in all EU countries would result in the halving of reactive nitrogen losses and minimizing losses of reactive phosphorus. In this way the goals, set by the states of the region, could be met and the process leading to the worst-case scenario of greatly increased nutrient loads to the Baltic Sea could be stopped.

Effects of different organic fertilization practices and mineral fertilization on potato quality

ABSTRACT The short-term effects of different fertilization practices were the target of the three year series of experiments. The effects of organic fertilizers and a mineral fertilizer were investigated on selected quality characteristics of potato (Solanum tuberosum cv. Matilda). Chemical composition, new contemporary quality parameters, ‘change of electrical conductivity’ and ‘darkening of potato extract’, and a parameter of environmental quality were analysed to discover the qualitative effects of increasing rates of fertilizers (fresh and composted farmyard manure, aerated slurry and mineral fertilization). In contrast to farmyard manure, the high application rate of the mineral fertilizer raised the concentration of nitrogenous compounds (nitrate and free amino acids) in potato. The slurry fertilization caused a similar but smaller reaction. The potato dry matter content differed more strongly than starch between the organic and the mineral fertilizer and between the application rates. The minerally-fertilized potatoes showed a lower dry matter content than the organically-fertilized. Thus, the dry matter and starch yield showed no significant difference between the mineral and organic treatments, even though the fresh matter yield was higher with the mineral fertilization. The ‘change of electrical conductivity of potato extract’ was highest with the mineral fertilization and the difference between organic fertilizers widened with increasing fertilization levels. The concentrations of mineral compounds and vitamin C, and the ‘darkening of potato extract’, due to a strong variation between replications, showed only a few statistically significant differences between the treatments.

The potential for Swedish farms to eliminate the use of artificial fertilizers

This paper discusses data on plant-nutrient conservation in Sweden between 1950 and 1980 and on plant-nutrient balances in conventional and alternative farming. The amounts of plant nutrients supplied in the form of artificial fertilizer in Sweden increased severalfold between 1950 and 1980. The amounts of N and P applied were four times higher than those recovered in agricultural products. This difference not only represents a loss to farmers but also a burden on the environment. This problem is a consequence of the increased separation of crop management from animal husbandry in Sweden. The flow of plant nutrients through the agroecosystem can be represented as follows: Artificial Fertilizers- > Crop Production-> Animal Husbandry- > Losses (air, water, or immobilization). This paper suggests that all farms in Sweden can operate effectively without relying on applications of highly soluble plant nutrients. By recirculating plant nutrients in manure and cultivating nitrogen-fixing species, the need for artificial fertilizers can be eliminated while minimizing nutrient losses and their associated adverse effects on the environment. Successful alternative farms provide practical examples of how a farming system can eliminate its dependence on applications of highly soluble plant nutrients by stressing effective nutrient economy and biological activity. The strategies they use include: matching animal management practices to the farms own production of feed, thereby reducing net removal of plant nutrients per unit area (in Sweden 0.6–0.8 animal units per ha); minimizing nutrient losses through careful manure management and by using cover crops; and supplying N by nitrogen-fixing ley species, and P and K by soil weathering and by applying supplementary soil improvement materials.

Correlations between Polyacetylene Concentrations in Carrot (Daucus carota L.) and Various Soil Parameters

This study assessed the concentrations of three falcarinol-type polyacetylenes (falcarinol, falcarindiol, falcarindiol-3-acetate) in carrots and the correlations between these and different soil traits. A total of 144 carrot samples, from three different harvests taken a single season, were analysed in terms of their polyacetylene concentrations and root development. On one of the harvesting occasions, 48 soil samples were also taken and analysed. The chemical composition of the soil was found to influence the concentrations of falcarinol-type polyacetylenes in carrots. When the total soil potassium level was 200 mg/100 g soil, the concentration of falcarindiol (FaDOH) in the carrot samples was 630 μg/g DW, but when carrots were grown in soil with a total potassium level of 300 mg/100 g soil, the FaDOH concentration in the carrots fell to 445 μg/g DW. Carrots grown in soils generally low in available phosphorus exhibited higher levels of falcarindiol if the soil was also low in available magnesium and calcium. The concentrations of polyacetylenes in carrots were positively correlated with total soil phosphorus level, but negatively correlated with total soil potassium level. Of the three polyacetylenes analysed, FaDOH concentrations were influenced most by changes in soil chemical composition.

Influences of Biodynamic and Conventional Farming Systems on Quality of Potato (Solanum Tuberosum L.) Crops: Results from Multivariate Analyses of Two Long-Term Field Trials in Sweden

The aim of this paper was to present results from two long term field experiments comparing potato samples from conventional farming systems with samples from biodynamic farming systems. The principal component analyses (PCA), consistently exhibited differences between potato samples from the two farming systems. According to the PCA, potato samples treated with inorganic fertilizers exhibited a variation positively related to amounts of crude protein, yield, cooking or tissue discoloration and extract decomposition. Potato samples treated according to biodynamic principles, with composted cow manure, were more positively related to traits such as Quality- and EAA-indices, dry matter content, taste quality, relative proportion of pure protein and biocrystallization value. Distinctions between years, crop rotation and cultivars used were sometimes more significant than differences between manuring systems. Grown after barley the potato crop exhibited better quality traits compared to when grown after ley in both the conventional and the biodynamic farming system.

Sustainable Food System – Targeting Production Methods, Distribution or Food Basket Content?

Agriculture is the single most important contributor to the eutrophication of the Baltic Sea. Itis responsible for 59% of the anthropogenic nitrogen and 56% of the phosphorous emissions(HELCOM, 200 ...