EPIC-PHASE: a model to explore irrigation strategies

bstract The erosion productivity impact calculator phase (EPIC-PHASE) model has been used to simulate, using 1972 to 1994 climatic date, two irrigation strategies with a non-limited water supply: (1) a standard strategy based on simple decision rules advisable for moderately deep soils of the Lauragais region (France) and in the Alentejo region (Portugal); and (2) a model strategy based on the daily development of soil water depletion and daily water stress intensity predicted by the model. At Lauragais, the results show that for the same level of yield it would have been possible with the model to save 73 mm on average, equivalent of two irrigations per year, compared to the standard strategy. These savings are due to an increased soil water contribution during the cycle and to an earlier end of the irrigation supply. At Alentejo, the results show that for the same level of yield as obtained with the standard strategy, it would have been possible with EPIC-PHASE model to save 100 mm of water on average, equivalent of two irrigations per year due to an increased use of soil water during the cycle. Although the results are from simulations it is proved that the standard strategy is inadequate. Regarding the environmental impact, the model management allows for an increase in the level of water depletion at harvest, delaying the risk of percolation and nitrogen losses during the refill period. The EPIC-PHASE model proved to be a tool capable of defining an irrigation schedule better adapted to the Mediterranean region

Impacts of extreme weather on wheat and maize in France: evaluating regional crop simulations against observed data

Extreme weather conditions can strongly affect agricultural production, with negative impacts that can at times be detected at regional scales. In France, crop yields were greatly influenced by drought and heat stress in 2003 and by extremely wet conditions in 2007. Reported regional maize and wheat yields where historically low in 2003; in 2007 wheat yields were lower and maize yields higher than long-term averages. An analysis with a spatial version (10x10 km) of th EPIC crop model was tested with regards to regional crop yield anomalies of wheat and maize resulting from extreme weather events in France in 2003 and 2007, by comparing simulated results against reported regional crops statistics, as well as using remotely sensed soil moisture data. Causal relations between soil moisture and crop yields were specifically analyzed. Remotely sensed (AMSR-E) JJA soil moisture correlated significantly with reported regional crop yield for 2002-2007. The spatial correlation between JJA soil moisture and wheat yield anomalies was positive in dry 2003 and negative in wet 2007. Biweekly soil moisture data correlated positively with wheat yield anomalies from the first half of June until the second half of July in 2003. In 2007, the relation was negative the first half of June until the second half of August. EPIC reproduced observed soil dynamics well, and it reproduced the negative wheat and maize yield anomalies of the 2003 heat wave and drought, as well as the positive maize yield anomalies in wet 2007. However, it did not reproduce the negative wheat yield anomalies due to excessive rains and wetness in 2007. Results indicated that EPIC, in line with other crop models widely used at regional level in climate change studies, is capable of capturing the negative impacts of droughts on crop yields, while it fails to reproduce negative impacts of heavy rain and excessively wet conditions on wheat yield, due to poor representations of critical factors affecting plant growth and management. Given that extreme weather events are expected to increase in frequency and perhaps severity in coming decades, improved model representation of crop damage due to extreme events is warranted in order to better quantify future climate change impacts and inform appropriate adaptation responses

Sequence-dependent effects of ZD1839 (‘Iressa’) in combination with cytotoxic treatment in human head and neck cancer

Elevated levels of epidermal growth factor receptor in head and neck cancer have been extensively reported, and are correlated with poor prognosis. The combination of cisplatin and 5-fluorouracil is a standard treatment regimen for head and neck cancer, with radiation representing another therapeutic option. Six head and neck cancer cell lines were used to study the cytotoxic effects of combining ZD1839 (‘Iressa’), a new selective epidermal growth factor receptor tyrosine kinase inhibitor, and radiation. Two of the cell lines were also used to study the combination of ZD1839 and cisplatin/5-fluorouracil. Cytotoxic effects were assessed by the MTT test. The results indicated that ZD1839 applied before radiation gave the best effects (P=0.002); an effect that was strongest in those p53-mutated cell lines that express the highest epidermal growth factor receptor levels. The effects of ZD1839 with cisplatin and/or 5-fluorouracil were sequence dependent (P<0.003), with the best results achieved when ZD1839 was applied first. For the triple combinations, ZD1839 applied before cisplatin and 5-fluorouracil resulted in a slight synergistic effect (P=0.03), although the effect was greater when ZD1839 was applied both before and during cytotoxic drug exposure. In conclusion, ZD1839 applied before radiation and before and/or during cisplatin/5-fluorouracil may improve the efficacy of treatment for head and neck cancer

Polymorphisms of glutathione S-transferases (GST) and thymidylate synthase (TS) – novel predictors for response and survival in gastric cancer patients

To evaluate the predictive value of a panel of gene polymorphisms involved in metabolism of 5-FU and cisplatin on clinical outcome in advanced gastric cancer patients. A total of 52 patients were enrolled in this study. DNA was extracted from paraffin-embedded tumour specimen. Genotypes were determined using PCR-RFLP. Median survival time was 6.0 months (95% CI 3.9;8.1). Overall response rate was 26%. Patients possessing the glutathione S-transferase P1-105 Valine/Valine (GSTP1-105VV) genotype showed a response rate of 67% compared to 21% in patients harbouring at least one GSTP1-105 Isoleucine (GSTP1-105I) allele (P=0.038). GSTP1-105VV patients demonstrated a significant superior median survival time of 15.0 months (95% CI 7.8;22.0) compared to 6.0 months (95% CI 5.1;7.0) in patients with at least one GSTP1-105I allele (P=0.037). Patients possessing a favourable thymidylate synthase (TS) genotype (2R/2R, 2R/3RC, 3RC/3RC) experienced a superior survival time of 10.2 months (95% CI 5.1;15.3) compared to 6.0 months (95% CI 5.0;7.0) in patients with unfavourable TS genotypes (P=0.099). Patients harbouring the GSTP1-105II genotype and one of the unfavourable TS genotypes showed an inferior median survival time of 6.0 months (95% CI 3.9;8.1) compared to 11 months (95% CI 6,23;15,77) in patients with either GSTP1-105VV or a favourable TS genotype (P=0.044). Testing for TS and GSTP1 polymorphisms may allow identification of gastric cancer patients who will benefit from 5-FU/cisplatin chemotherapy, sparing others the side effects of this chemotherapy

Adaptation des ressources en eau aux principales cultures regionales

INRA Centre de Toulouse, Station d'AgronomieNational audienc

Use of EPIC model to study cropping systems. II-Improved simulation of the water use, growth and harvest index in corn.

International audienc

Mais, tournesol, soja, sorgho : quatre cultures d'ete irriguees dans le sud-ouest de la France.

National audienc

Facteurs technico-economiques de la valorisation de l'irrigation : le cas des grandes cultures d'ete dans le sud-ouest de la France.

Diplôme : Dr. d'Universit

Manuel d'utilisation du modèle EWQTPR (EPIC-phase temps réel) (version 2.13)

*INRA, Centre de Toulouse, Station d'Agronomie Diffusion du document : INRA, Centre de Toulouse, Station d'AgronomieNational audienc

Influence de l'accroissement du prix des engrais sur les couts de production et les marges brutes de quelques cultures d'ete : mais, soja, tournesol,sorgho.

National audienc