Towards Comparative and Aggregate Vulnerability: An Analysis of Welfare Distributions in Rural Provinces in Thailand and Vietnam

Several measures of vulnerability to poverty have been suggested in the literature. In practise, only little is known about the robustness of vulnerability comparisons based on these often quite specific measures. The theory of stochastic orders can be applied to shed some light on such issues. In the DFG research project "Impact of Shocks on the Vulnerability to Poverty: Consequences for Development of Emerging Southeast Asian Economies" (DFG FOR 756), an extensive panel survey was carried out in six rural provinces of Thailand and Vietnam in 2007. We establish cumulative distribution functions for income and consumption at the provincial level and search for stochastic dominance relations between these distributions. Our comparisons allow for initial, but quite robust conclusions on welfare and provide benchmarks for assessing the vulnerability to poverty in the research regions. --welfare distribution,stochastic ordering,vulnerability

The spatial distribution and interregional dynamics of vegetable production in Thailand

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Alleviation of nematode-mediated apple replant disease by pre-cultivation of tagetes

Apple replant disease (ARD) is a severe problem in orchards and tree nurseries caused by yet unknown soil biota that accumulate over replanting cycles. This study tested the contribution of nematodes to ARD, and cultivation of Tagetes as a control option. In a pot experiment, Tagetes patula or Tagetes tenuifolia were grown in ARD soil, incorporated or removed. Nematodes extracted from untreated ARD soil and washed on 20-µm sieves induced ARD symptoms when inoculated to apple plantlets growing in a sterile substrate. In contrast, nematodes from Tagetes treated ARD soil did not reduce root growth compared to uninoculated plants, irrespective of Tagetes species and incorporation. In plots of five apple tree nurseries or orchards, either Tagetes or grass was grown on ARD soil. Nematodes extracted from the grass plots and inoculated to apple plantlets significantly reduced plant growth compared to nematodes from Tagetes plots for all five farms. Apple rootstocks showed overall a significantly higher increase in shoot base diameter when grown on Tagetes-treated plots compared to grass plots, while this effect differed among farms. Plant-parasitic nematodes were too low in abundance to explain plant damage. In conclusion, Tagetes alleviated ARD by changing the nematode community in soil. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

Comparing costs for different conservation strategies of garlic (Allium sativum L.) germplasm in genebanks

The maintenance of plant genetic resources in living plant collections (genebanks) causes costs due to employment of staff, usage of buildings, equipment and consumables. Since this is especially challenging in vegetatively propagated material, studies were performed for the case of garlic, which is one of the major vegetatively maintained crops in the genebank of IPK Gatersleben. Data were recorded to compare various scenarios of the main strategies field maintenance and cryopreservation. A spreadsheet tool was developed to be used for cost assessment and for drawing conclusions concerning the most effective way of maintenance. Field culture is cheaper in the short term, whereas after a break-even point cryopreservation becomes the more efficient storage method in the long term. This break-even point depends on the particular scenario, which is determined by various factors such as field and in vitro multiplication rates of various genotypes, presence of bulbils in a part of the genepool, the sample size of the accessions as well as the number of stored accessions in cryopreservation. The comparative discussion is exemplified for a 1-year field rotation versus cryopreservation using either in vitro plantlets or a combination of bulbils and unripe inflorescence bases as organ sources. For the more expensive use of in vitro plants cryopreservation becomes less costly than field culture only after 13 years, whereas this is the case already after 8-9 years when using a combination of bulbils in winter and inflorescence bases in summer

EFFICIENT FARMING OPTIONS FOR GERMAN APPLE GROWERS BASED ON STOCHASTIC DOMINANCE ANALYSIS

Apple production is afflicted with various risks. As it is a permanent crop, apple producers are less flexible to react upon undesirable events. As a result, for a sustainable economic performance, the determination of efficient farming options, as a combination of the production system and risk management instruments (RMI), is crucial. Our investigation focuses on this choice problem utilizing stochastic dominance criteria, which apply to a wide range of risk preferences. Based on data for 134 apple producers operating in the two main production areas in Germany, we compare and determine efficient production options for the most common regional varieties. Furthermore, appropriate RMIs are identified using stochastic dominance criteria. In this context we investigate internal RMI (frost irrigation and hail nets) as well as external risk protection tools (insurance options). In Germany only a single insurance concept against hail is available, whereas insurance against late frosts is not at the apple growers’ disposal. As frost insurance exists in neighboring countries, we analyze the effect of the latter based on a hypothetic hail-frost insurance policy. Simulated net present values of a one hectare level serve as decision criterion, for which the associated cumulative probability distributions are evaluated according to first and second degree stochastic dominance criteria. In addition, we use SERF (Stochastic Efficiency with Respect to a Function) as it evaluates farming options for defined ranges of relative risk aversion and thus has a higher discriminative power. The results indicate that Red Prince is the most efficient option in the north and subsidized hail insurance with frost irrigation is superior to frost irrigation as single RMI. In the south Braeburn should be chosen under rational aspects, but the tested insurance solutions are not as efficient as the common production practice under hail nets

Rationalizing apple growers’ decision making in Germany – a utility based whole farm programming approach

Commercial apple production is exposed to various sources of risks. This paper presents a normative utility-efficient programming (UEP) approach, calculating optimal farm plans for apple growers in two different regions of Germany. It takes weather-related quality and yield risks, as well as price risks into account. It is based on risk attitude and risk perception collected from a sample of 134 apple growers. After combining subjective estimates of the apple growers with relevant historical data, input data for the UEP-model were derived from Monte-Carlo simulations. The UEP-model determines optimal portfolios, consisting of combinations of apple varieties and risk management instruments. The results indicate that the degrees of risk aversion affect optimum farming strategies only to a minor extent. They also provide evidence that farmers would benefit from a combined frost-hail insurance, whereas the absence of frost irrigation systems may cause high yield-losses in the northern part of Germany

Experimentally-validated survey evidence on individual risk attitudes in rural Thailand

This study validates a survey-based measure of general risk attitude by an incentive compatible experiment among more than 900 participants in rural Thailand. The survey measure of self-assessed risk attitude provides a useful approximation of the experimentally derived risk attitude. This holds when we add various socio-demographic control variables to the survey-experiment-relation which are available from the representative household survey and which are related to risk attitude in plausible ways. The survey measure also predicts individual behavior towards risk in other cases; the survey measure even outperforms the experimental measure in this respect.field experiment, socio-economic survey, risk attitude