M.M. van den Berg

Water uptake in crop growth models for land use systems analysis. I. A review of approaches and their pedigrees

Abstract Descriptions of crop water uptake/transpiration are of widely varying complexity and employ considerably different approaches. This paper examines simple approaches that could be used in crop growth simulation models for application in land use systems analysis. Many apparently conceptual differences stem from different interpretations of averaged or generalised data, and the dogmatic use of pragmatic ad hoc choices. Proliferation of terms has perhaps contributed more to mystification than to clarification of the problems involved. Simplified theoretical descriptions based on physical laws have their merits, e.g. for educational purposes or for practical assessments if they are properly tested throughout their range of application. However, they can only be applied in practice using “default parameters” and/or “surrogate” input data. In this way, models that are intended to explain may degenerate and there is no reason why they would be more appropriate than empirical approaches. For empirical approaches, it is concluded that using, e.g. “soil water depletion fraction” or “soil water potential” to indicate the limit of readily available soil water is an arbitrary choice. Most water uptake models were originally designed and tested for irrigated crops with a closed canopy. Adaptations to different conditions rely heavily on intuitive interpretations. Models suited to rain fed conditions must be able to handle situations where wet and dry parts of the soil occur side by side and an “average soil water status” seems meaningless. Field experiments to test alternative approaches are scarce. Therefore, many uncertainties persist, that call for further research. Land use systems studies should attempt to quantify these uncertainties by numerical analyses as a routine activity.

Farmers' welfare, food production and the environment: a model-based assessment of the effects of new technologies in the northern Philippines.

Policy objectives of attaining food self-sufficiency and improving the well-being of subsistence farmers while protecting the environment have stimulated the development of many improved agricultural production technologies. With a choice of technologies, farm household decisions are governed not only by productivity and profitability considerations but also by factors such as available resources and their quality, family consumption preferences and attitudes towards risks, and prevailing policies. It is therefore necessary to analyse the adoption of such technologies from a whole-farm perspective. In this paper, a farm household model is used to assess possible technology adoption behaviour of farmers in Ilocos Norte Province, Philippines. Four alternative technologies were evaluated: hybrid rice production (HYR), balanced fertilization strategy (BFS), site-specific nutrient management (SSNM) and integrated pest management (IPM). Possible impacts of price policies and infrastructure improvements on technology adoption were assessed. The results show that all four alternative technologies considered are attractive to farmers, although simulations show differential adoption rates for poor, average and better-off households. IPM and HYR appear the most attractive amongst all technologies considered. In all technology simulations, relative profitability and risks, labour and capital requirements and availabilities are decisive factors in the adoption of alternative technologies. Adoption of alternative technologies would result in higher discretionary income, higher rice production and lower biocide use and nitrogen loss. Amongst policy simulations considered, availability of low-cost credit shows the largest improvements in farmer welfare for poor and average households, but its effect on simulated adoption of alternative technologies was variable. We argue that the methodology and results presented can contribute to ex ante assessments of policies targeted at stimulating technology adoption by farmers.

Variability of apparently homogeneous soilscapes in São Paulo state, Brazil: I. spatial analysis

Abordou-se, quantitativamente, a variabilidade espacial de solos fortemente intemperizados sob cana-de-acucar e rotacao soja/trigo de 33 glebas em duas regioes do estado de Sao Paulo, Brasil: Araras (15 glebas com cana-de-acucar) e Assis (11 glebas com cana-de-acucar e sete glebas com rotacao soja/trigo). Os metodos estatisticos empregados foram analise da variância por amostragem aninhada (para 11 glebas), analise de semivariância e analise de variância dentro das glebas e entre elas. Foram analisados niveis espaciais entre 50 m e varios km. Os resultados foram discutidos em relacao a um estudo nas redondezas de Passo Fundo (RS) publicado anteriormente. Foram encontrados padroes de variacao similares para teor de argila, teor de C-orgânico e capacidade de troca cationica. As glebas estudadas mostram-se bastante homogeneas em relacao a estas caracteristicas relativamente estaveis. A variabilidade espacial de outras caracteristicas (P-resina, pH, saturacao por bases e por aluminio e tambem cor dos solos) variou entre regioes e, ou, uso/manejo das terras. O manejo dos solos com cana-de-acucar provocou, aparentemente, modificacoes ate camadas mais profundas em relacao a rotacao soja/trigo. Camadas superficiais dos solos sob soja/trigo apresentaram, aparentemente, pouca variacao como resultado do manejo muito intensivo. Em todos os casos estudados, a maior parte da variacao dentro das glebas ocorreu a pequenas distâncias (< 50 m). Esperava-se, portanto, obter pouca informacao adicional pela intensificacao da amostragem de 1/km2 para 1/50 m2. Para muitas finalidades, os solos estudados podem ser mapeados com a mesma densidade de observacoes, porem a variacao nao explicada pode nao ser a mesma em todas as areas. A coleta de amostras compostas possivelmente ajudaria revelar padroes espaciais entre 50 e 1.000 m.

CREB expression in the brains of two closely related parasitic wasp species that differ in long-term memory formation

The cAMP/PKA signalling pathway and transcription factor cAMP response element‐binding protein (CREB) play key roles in long‐term memory (LTM) formation. We used two closely related parasitic wasp species, Cotesia glomerata and Cotesia rubecula, which were previously shown to be different in LTM formation, and sequenced at least nine different CREB transcripts in both wasp species. The splicing patterns, functional domains and amino acid sequences were similar to those found in the CREB genes of other organisms. The predicted amino acid sequences of the CREB isoforms were identical in both wasp species. Using real‐time quantitative PCR we found that two low abundant CREB transcripts are differentially expressed in the two wasps, whereas the expression levels of high abundant transcripts are similar.

Perceptions of Dutch health care professionals on weight gain during chemotherapy in women with breast cancer

PurposeDutch Health care professionals (HCPs) provide little information concerning health risks associated with weight gain during chemotherapy for breast cancer. Women with breast cancer have specified the need for more information on nutrition and physical activity to deal with weight gain. The aims of this study were to assess the perceptions of Dutch HCPs on weight gain during chemotherapy and in addition evaluate whether and what kind of information on dietary intake and physical activity HCPs provide to prevent/treat weight gain during (neo)adjuvant chemotherapy.MethodsA qualitative study was conducted using semi-structured interviews with 34 HCPs involved in breast cancer care: general practitioners, oncologists, specialized nurses, and dieticians.ResultsTo date, little information about nutrition, physical activity, and weight gain is given during chemotherapy because it is not part of most HCPs’ training, it is not included in the guidelines and it is not the best time to bring up information in the opinion of HCPs. Weight gain was perceived as just a matter of a few kilos and not an important health issue during treatment. All HCPs felt it is better that women themselves addressed their weight gain after chemotherapy.ConclusionMore knowledge about health risks associated with chemotherapy-induced weight gain and how to combat these issues needs to be made readily available to the HCPs and should become part of their training. Existing patient guidelines should include information on how to prevent and/or reduce weight gain through self-management of nutrition intake and physical activity during and post chemotherapy.

Cash-based versus water-based payment for environmental services in the uplands of northern Vietnam: potential farmers participation using farm modeling

The forested areas of northern Vietnam, mostly located in mountainous areas, have important watershed regulating functions. However, current land-use changes pose a threat to the continuing provision of environmental services. This chapter investigates two alternative payment for environmental services (PES) programs tailored to reestablish natural or productive forests in the uplands of northern Vietnam: “Payments for Forest” (PFF) and “Terraces for Forest” (TFF). Both programs involve setting aside sloping land for reforestation but they differ in the type and amount of compensation offered. PFF offers annual payments per area of retired land. TFF offers to convert a certain amount of the current sloping land into a terraced area, combined with annual payments per area of retired land. The main objective of the chapter is to compare the two types of programs in terms of potential participation (what type of farmers will likely participate?), and what impact it would have on their revenues. Using mathematical programming, we developed a set of farm models corresponding to typical farms of a mountainous district of northern Vietnam. We simulated the level of participation of different types of farms for the two types of PES programs. For each specific PES, we analyzed participation, measured by the area of land converted into forest land and its impacts on land use and household revenues. Results show that, given the assumptions of the models, increasing access to irrigated terraces as a way to compensate for land conversion to forest increases the participation of the poorest farmers. Therefore, our research suggests that PES schemes, when fine-tuned to a Southeast Asian context, may not only be used as a way to restore ecosystem services but also as a way to alleviate poverty.

1960 The perceptions of women with breast cancer during treatment with chemotherapy on changes in weight; a mixed methods approach

Background: Weight gain and undesirable changes in body composition in women receiving chemotherapy (CT) for early stage breast cancer is a common, but poorly understood phenomenon. This sarcopenic obesity consists of an increase in fat mass and a decrease in lean body mass, which is associated with disease recurrence, an increased risk of cardiovascular disease and diabetes, lower quality of life, and a lower overall survival. The purpose of this study was to explore in-depth the perceptions of women with breast cancer on determinants of changes in body composition and muscle strength as dietary intake, physical activity and quality of life and their possible interventions on these potential changes. Interpreted against the individual measurements made during the treatment trajectory such as changes in weight, fat mass, lean body mass. Methods: As part of a greater mixed methods study, a longitudinal qualitative multiple case study was conducted. Newly diagnosed women with breast cancer were recruited and purposively selected (n = 18) from several hospitals in the Netherlands before the start of their treatment with CT. Semi structured face-to face interviews were conducted during the treatment trajectory at three time points: before start of CT, (T1), halfway (T2) and after CT (T3). Interviews (n = 54) were audiotaped and transcribed verbatim. A thematic content analysis approach was used to explore womens perceptions, such as changes in weight and taste and to interpret these qualitative findings against the individual quantitative data such as changes in weight, fat mass, lean body mass (DEXA scans), BMI, muscle strength and results of the Hospital Anxiety and Depression Scale (HADS). Results: All women, mean age 51 yr (26-65 yr) experienced known side effects from CT such as hair loss, nausea, sore mouth, mucositis. Fourteen out of 18 women gained weight between 2 and 7 kg; three women lost some weight (3-7 kg), whereas one woman lost 14 kg. All women said to be less physically active and complained about fatigue. They all experienced undesirable changes regarding taste, smell and food preferences sometimes leading to loss of appetite. Others experienced more appetite despite changes in food preferences or changes in taste and smell. Depending on their illness perception women differed in how they acted upon these changes. Some women monitored the impact of therapy reactively, other women tried to respond proactively and often creatively to all changes that happens to them. Results of the interviews were supplementary and explanatory to the weight and BMI changes and the results of the HADS. Conclusion: Suffering from weight changes, being less physically active, monitoring changes differently are important elements to take into account for the development of interventions to prevent weight gain in women with breast cancer during CT.