Håkan Rosenqvist

Economics of using municipal wastewater irrigation of willow coppice crops

Abstract Until now, treatment of municipal wastewater in Sweden has mainly consisted of removal of phosphorus and easily biodegradable organic substances. Most of the nitrogen has been released in the water phase to the recipients. The recently introduced legal requirements to remove also nitrogen have encouraged the recirculation approach, meaning that, before chemical phosphorus precipitation, municipal wastewater can be used as an adequate nutrient resource for biomass production. The general aim of this paper is to illustrate a realistic way of handling and utilising this resource in a recirculation system, applying a combination of waste water treatment and biomass production. The economic calculations (based on nitrogen, which is a topical problem at the treatment plants) show that the costs for a conventional technical system for removal of nitrogen and phosphorus in wastewater (70–180 SEK (kgN) −1 ) (1 USD = 6.70 SEK) can allow a good margin for investment, operation and management of an irrigation system for wastewater treatment in willow cultivation. The calculations show that treatment costs in willow cultivations vary depending on type of system and size. Nitrogen application rate also has a major impact on costs.

Willow growers in Sweden

Abstract The number of willow plantations on Swedish farmland increased considerably between 1991 and 1996. The main driving forces behind this development were: (1) The introduction in 1991 of a new agricultural policy in Sweden which, through deregulation, created lower grain prices and simultaneously introduced compensation for set-aside land as well as subsidies for willow plantations on surplus arable land; (2) higher taxes on fossil fuels; and (3) the existence of a biofuel market in Sweden based on forest fuels. This paper presents a statistical study of willow growers in southern and central–eastern Sweden. Data about willow growers and a stratified random sample of non willow growers were acquired from the 1995 Farm Register compiled by Statistics Sweden. Willow growers are described according to geographical distribution, willow parcel sizes, farm sizes, and farm types. Comparisons are also made with the population of farmers who are not growing willow. A high concentration of willow growers is recorded for central Sweden around Lake Malaren. Willow growers are more often in the age span 50–65 years, and as compared to non-willow growers, have larger farms. They are less often focused on animal and milk production, and more often on cereal and food crop production, when compared with other farmers. Implications of the Swedish experience for policy making in the fields of energy and agriculture are discussed.

Farm-related factors influencing the adoption of short-rotation willow coppice production among Swedish farmers.

The area of short-rotation willow coppice energy plantations on Swedish farmland increased quickly in the early 1990s because of subsidies for energy crop production, an increased CO2 tax on fossil fuel and an already existing biofuel market in the country. In this study farm-related determinants for the adoption of short-rotation willow coppice production among Swedish farmers are identified and estimated. A Tobit model is applied to cross-sectional data on Swedish farmers in 1995. The results show that the decision to plant willow and the areas planted depend positively on arable land area, forest land area, the area of other land types, leasing out of arable land and tractor ownership. Negative factors are pasture area, tenancy and animal production. Differences in willow growing between ownership types, age groups and geographical regions are also important. The policy implications of the results are discussed.

CALCULATION METHOD AND ECONOMY IN SALIX PRODUCTION

ABSTRACT A cost estimation model has been developed to compare the profitability of annual versus perennial crops. The method consists of modified total step calculation, which takes account of time-dependence. The difference between the applied method and a traditional total step calculation is the way money flow is considered. Both methods are able to handle different planning situations. A traditional total step calculation is a modified calculation of variable costs and calculation of prime costs. The modified total step calculation can also be used for profitability calculations of different agricultural techniques and even other products, which have different cash flows from year to year. The time aspect in the modified total step calculation is taken into consideration by a factor for each single element, which is multiplied by the cash-flow for different payments and disbursements. The factor is based on the sum of the present value factors for incoming and outgoing transactions during the total life-span of the crop, multiplied with the annuity factor of the interest rate estimate and the number of years which the life-span of the crop measure. By applying sensitivity analysis for Salix, it is possible, with the help of the model, to show the economic importance on the individual farm enterprise, of different rates of growth, life-spans of the cultivation, energy prices etc. A general requirement is that the proceeds from Salix production must match the yield of grain production. The calculation model for profitability analysis of SRC and other crops, is easy to use for extension personnel and others. The results show the profitability of Salix production from the farmers’ point of view.

Study on Biological and Economic Considerations in the Control of Potato Late Blight and Potato Tuber Blight

An economic analysis was made of old results from 1993-1996 (22 field trials) and new results from 2010-2013 (12 field trials) obtained in field trials with different doses of fungicides to control potato late blight (PLB) and potato tuber blight (PTB) caused by Phytophthora infestans. The objective was to determine the economically optimal dose for effective control. In 1993-1996, the economic net return was highest for long intervals of about two weeks between treatments and a dose of 60% of the recommended level. The difference between the experimental treatment with the highest net return and the untreated control was 1587 € per hectare (ha-1) in susceptible cultivars, but only 531 € ha-1 in moderately resistant cultivars. In addition, the mean difference in net return between all treated susceptible and all treated moderately resistant cultivars was 874 € ha-1. In the half of the field trials with the lowest maximum attack of PLB, the difference between the experimental treatment with the highest economic income and untreated control was 547 € ha-1, while it was 1571 € ha-1 in the half of the trials with the highest maximum attack. The results for 2010-2013, which were all based on a short treatment interval of about one week between treatments, showed that in table potato the economic net return was highest at 100% and 75% of the recommended dose, whereas in starch potato cultivars it was highest at 50% and 25% of the recommended dose. The net financial result was calculated for 13 different scenarios. As expected, potato price and potato crop yield and quality were of the greatest importance. The price of fungicides affected net profits by between 167 and 656 € ha-1 depending on treatment intervals and dose. These results challenge the way in which late blight is controlled in conventional potato farming today, especially in starch potatoes. We therefore propose investment in future years be based on the dose-range response in cultivars with differing host resistance to both PLB and PTB, and on forecasting and warning with respect to PLB- and PTB-control in different potato cultivars. We believe that such investment could be very valuable in optimizing the use of fungicides in potato cultivation.