Comparison of Conventional,Integrated and Organic Potato Production in Field Experiments in Finland

Abstract

In 1987, a potato research project called “Minimized use of chemical inputs in potato production” was started in all five Scandinavian countries. In this paper, the results of one field trial series carried out at the Potato Research Institute, Lammi, Finland, during the years 1987–90 are reported. The main plots in a split-plot designed trial series consisted of three cropping systems: conventional, integrated and organic. The subplots included three cultivars differing especially in their late blight (Phythophtora infestans, (Mont.) de Bary) resistance: Bintje, Record and Matilda.

Canopy measurements showed differences that can be attributed to different nitrogen supply in decreasing order from conventional to integrated to organic system. The trial sites were very heavily infested with potato scab, resulting in a very low percentage of I-class yield in susceptible cultivars Bintje and Matilda. Late blight was a serious problem in organically grown Bintje, as expected.

Total yields in the integrated and organic systems were 10% and 36% lower, respectively, than in the conventional system. There was an interaction between cropping system and cultivar in favour of Bintje and the conventional system and Record in the organic system. The percentage of I-class yield was lowest in the conventional system. Some of the quality characteristics were slightly improved in the integrated and/or organic systems. Storage losses, caused mainly by tuber blight, were high in organically grown potatoes.

There were no large differences in production costs between the cropping systems. The main determinants of the unit production cost of potatoes were total yield and yield of I-class potatoes. The average unit costs were 1.76 FIM kg^?1 in the conventional, 1.68 FIM kg^?1 in the integrated and 2.36 FIM kg^?1 in the organic system. Record showed the lowest unit production costs in all systems ?1.33, 1.37 and 1.80 FIM kg^?1, respectively.     

Optimizing the joint production of timber and bilberries

Berries and mushrooms are increasingly appreciated products of Finnish forests. Therefore, there is a need to integrate them in silvicultural planning. Bilberry (Vaccinium myrtillus L.) is an economically important wild berry that is widely collected for household consumption and sale in North Karelia, Finland. In this study, bilberry yield models developed recently were included in a stand growth simulator and the joint production of timber and bilberry was optimized by maximizing soil expectation value (SEV) with 3% discounting rate, assuming that 75% of the bilberry yield is harvested. The effect of bilberry production on the optimal stand management increased with increasing bilberry price. With high bilberry prices (4–8 € kg⁻¹) it was optimal to manage the mixed stand of Scots pine, Norway spruce and birch, and the pure stand of Norway spruce so as to promote bilberry production. In the Scots pine stand, where bilberry yields are higher, bilberry production affected optimal stand management already with a price of 2 € kg⁻¹. Compared to timber production, joint production led to longer rotation lengths, higher thinning intensities, more frequent thinnings, and higher share of Scots pine in the mixed stand. The contribution of bilberries to the total SEV increased with increasing bilberry price and discounting rate. In the mixed stand and pine stand the SEV of bilberry production, calculated with 3% discounting rate, exceeded the SEV of timber production when bilberry price was 4 € kg⁻¹.With 4% discounting rate this happened already with bilberry price of 2 € kg⁻¹. It was concluded that forest management which promotes bilberry yields is the most profitable in pine stands where the potential bilberry yields are high.     

Correlation of Whole Blood Concentrations of Acetoacetate, β-Hydroxybutyrate,Glucose and Milk Yield in Dairy Cows as Studied Under Field Conditions

The whole blood concentrations of acetoacetate (AA concn), β-hydroxybutyrate (BHB concn) and glucose (gluc concn) of 662 Ayrshire and Friesian dairy cows were measured and their milk yield during the indoor-housing period was recorded. Simple correlations among these parameters were evaluated. The correlation between the AA concn and the BHB concn (r = 0.869) was statistically highly significant (P < 0.001), as were the correlations of the logarithmic value of the AA concn with the gluc concn (r = —0.471) and with the milk yield (r = 0.259), and the correlation between the BHB concn and the glue concn (r = —0.288). The milk yield was found also to be associated with the BHB concn and the glue concn (P< 0.001). The associations between each pair of blood parameters were highly significant, too (P < 0.001). The AA concn was taken to be at least as good an indicator of the energy status of dairy cows as the BHB concn and the gluc concn. The AA concn is not diet-derived like the BHB concn and not as stress-sensitive as the blood concentration of free fatty acids and its diurnal variation is not as wide as the BHB concn and the gluc concn in subclinically ketotic cows. Thus the AA concn may be used as a proxy of the energy status and the ketotic stage of dairy cows under field conditions.Key words: acetoacetate, ß-hydroxy butyrate, glucose, energy status, dairy cattle     

The Stability and Automatic Determination of Ketone Bodies in Blood Samples Taken in Field Conditions

An automated, spectro-photometric determination of blood acetoacetate and β-hydroxybutyrate was developed with a Gilford 3500 autoanalyzer. The stability of ketone bodies was studied in different conditions. An immediate precipitation with 0.6 M perchloric acid and cooling the sample effectively prevent the loss of acetoacetate from samples during transport to the laboratory (at 4°C a 6 % loss of acetoacetate was noted during 24 h). Freezing the sample makes it practically stable (less than 2 % loss of acetoacetate per week during a study lasting 2 months). At room temperature (20°C) the sample’s acetoacetate was instable and disappeared with a rate of 6 % per h. β-hydroxybutyrate was stable in precipitated samples. Because the precipitation also retains the sample’s glucose, 3 main parameters for the indication of ketosis could be analyzed automatically from the same sample with a total capacity of 40 samples in 2½ h.     

Public Wildlife Management on Private Lands: Reciprocity,Population Status,and Stakeholders’ Normative Beliefs

Wildlife agencies balance the effectiveness of management with public acceptability. Past research has demonstrated stakeholders’ normative beliefs regarding management are influenced by the severity of the human-wildlife interaction, and the harshness of human response. Such beliefs may be more complex when public and private interests intertwine. In Montana, concerns about Brucellosis spreading from wild elk to domestic livestock prompted agencies to consider new management actions on private lands. We investigated how normative beliefs within stakeholder groups related to reciprocity between landowners and the public, and elk population status, using a linear mixed-effects analysis of mail survey responses. Proposed actions were considerably more acceptable in scenarios where landowners reciprocated with public hunting access, and where elk populations were abundant. Acceptability of lethal actions varied substantially across scenarios, indicating a need for a nuanced understanding of how stakeholders perceive different wildlife control measures, especially in private land contexts.