Growth, physiology and yield of durum wheat (Triticum durum) treated with sewage sludge under water stress conditions

In arid and semi-arid areas, low soil fertility and water deficit considerably limit crop production. The use of sewage sludge as an organic amendment could contribute to the improvement of soil fertility and hence the agronomic production. The study aims to highlight the behaviour of durum wheat to the application of sewage sludge associated with water stress. The assessment focused on morphophysiological parameters of the wheat plant and yield. Under greenhouse conditions, the variety Mohamed Ben Bachir was treated by four water stress levels (100 %, 80 %, 50 % and 30 %). Each stress level comprised five fertilizer treatments: 20, 50 and 100 t/ha of dry sludge, 35 kg/ha of urea, and a control with no fertilization. Results revealed a significant loss in water content and chlorophyll a in leaves. Water stress negatively affected the development of wheat plants by reducing significantly seed yield, leaf area and biomass produced. Plant’s responses to water stress manifested by an accumulation of proline and a decrease in total phosphorus. However, the increasing doses of sewage sludge limited the effect of water stress. Our findings showed an increase in the amount of chlorophyll pigments, leaf area, total phosphorus, biomass and yield. In addition, excessive accumulation of proline (1.11 ± 1.03 μg/g DM) was recorded as a result of the high concentration of sludge (100 t/ha DM). The application of sewage sludge is beneficial for the wheat crop, but the high accumulation of proline in plants treated with high dose of sludge suggests to properly consider this fact. The application of sludge should be used with caution in soils where water is limited. Because the combined effect of these two factors could result in a fatal osmotic stress to crop development

Validation de la mesure de réfractivité avec un radar en bande C équipé d'un émetteur à magnétron

La caractérisation du champ d'humidité à fine échelle spatio-temporelle est importante pour améliorer la compréhension des mécanismes impliqués lors de la formation de la convection, ainsi que la qualité de la prévision de ces phénomènes à travers leur assimilation par un modèle numérique de prévision. Le présent travail a été effectué en utilisant des données du réseau opérationnel ARAMIS des radars de précipitations de Météo France, et au sein des équipes radar de Météo France. Une nouvelle formulation de la mesure de la réfractivité par un radar à magnétron a été proposée, qui montre que la variation de phase d'un signal provenant d'une cible fixe dépend de trois termes. A l'issue d'une série de campagnes expérimentales, au cours desquelles de nombreux problèmes de mesure ont pu être identifiés et corrigés, les trois termes de la formulation théorique ont pu être validés par une comparaison avec des mesures au sol de réfractivité atmosphérique. Les travaux permettent de conclure que la mesure de réfractivité est aussi performante avec un radar à magnétron qu'avec un radar à klystron à condition d'appliquer les nécessaires corrections. Cependant les mesures de réfractivité, qui sont basées sur la phase du signal, peuvent facilement devenir ambiguës. Afin d'évaluer l'impact de ce problème sur la précision de la mesure de phase des études ont été effectuées qui permettent de mieux caractériser le problème.The small scale caracterization of moisture field is a key for a better understanding of the convection formation mechanism, and for the quality of the prediction of these phenomena through assimilation by a numerical model. The present work has been done in the operational French radar team, and uses data from the French operational radar network. A new formulation of the refractivity measurements for magnetron radar is proposed. It shows that the phase variation of a signal reflected by a fixed distant target depends on three terms. After a serie of experimental campaigns, a lot of measurement problems have been identified and corrected. Finally good data has been obtained and the three terms of the theoretical formulation have been validated by comparison with ground in-situ measurements of atmospheric refractivity. We can conclude that refractivity measurements can be done with magnetron radar as well as with klystron radar. However the measurement, based on a signal phase, can easily become ambiguous. A few studies have been done to characterize it and to evaluate its importance on the measurement accuracy

Constantine of Tomorrow: Towards a shared vision

At the dawn of 21st century, Algeria has undergone major upheavals in its political, economic and social structures. The emergence of real vehicles of change give only one choice, that is to integrate into the global system, considered to be a milestone in any development and which was favored by the Algerian economic context in the early 2000s. These years were also marked by the country's commitment to sustainable development, introducing various laws and new planning instruments to reinforce the challenge of the living conditions for the inhabitants. It seems that a real "participation policy" was born in Algeria at minor scales including cities, but whose impact and evaluation remains in place! The aim of this study is to highlight the participation of inhabitants, their roles, capacities and the obstacles encountered in creating positive changes in their urban spaces lived. An assessment study of some pilot projects for rehabilitation and urban improvement is considered, which involved five ZHUN (New Urban Housing Zone), developed with the participation of inhabitants in Algiers, Tizi-Ouzou, Bechar and Oran. The experience of urban improvement at Daksi district in Constantine is also treated. Our objective is to better understand the participation of the inhabitants, between theoretical discourses and concrete actions. What changes will there be for the Algerian city of tomorrow?

Numerical study and design of a dew point evaporative cooler for buildings

Refreshing air remains a crucial problem in warm climates where electricity consumption for air conditioning has become excessive and irrational for several years, notably in Algeria. Research in this field is increasingly oriented towards new techniques that can reduce costs and environmental impacts. Among these techniques, the evaporative dew point cooling technology is the most promising as it can cool outdoor air to temperatures below its wet bulb temperature. The aim of this work is to model and design a dew point cooler for french and algerian climates. This model is used to study the effect of the cooler parameters such as its length, water temperature and working air ratio on its cooling effectiveness and supply temperature

Comparative effectiveness of exogenous organic amendments on soil fertility, growth, photosynthesis and heavy metal accumulation in cereal crops

With soil fertility loss reached a critical state in arid and semi-arid regions, farmers are constrained to use mineral fertilizers, which are costly, non-eco-friendly and less effective in improving soil fertility than organic fertilizers such as dewatered sewage sludge (SS) and poultry manure (PM). In this regard, the current study aimed to highlight through experiments the positive effect of SS and PM applications on soil fertility and durum wheat growth. It targeted to demonstrate the safe and wise use of organic fertilization while assessing heavy metals in both soil and plant. The experiment was carried out in two batches of thirty-two pots, one for each treatment (SS and PM), in addition to the control with no fertilization. SS and PM were applied separately in three doses (D1 = 50 g, D2 = 100 g, and D3 = 200 g DM fertilizer/pot). The applications of both SS and PM induced a significant increase in plant-available phosphorus, organic matter, nitrates, moisture and electrical conductivity in soil, where these improvements were higher in PM compared to SS treatment. A significant accumulation of proline associated with an increase in biomass that were both proportional with fertilizer dose levels. Our findings revealed a loss in relative water content and leaf area of the plant. Correlations showed several significant relationships between soil parameters studied. The dose D2 of each fertilizer was the most efficient to improving both soil properties and plant components. Plant zinc concentration increased significantly with increase in soil zinc in PM amendments, however it decreased in SS. These relationships were not significant in copper for the two fertilizers. Both SS and PM improved soil fertility and plant growth compared to the control, thus this practice is a promising solution to tackle soil fertility loss and low production in drylands

Peptides contraints à motif sulfahydantoïne (synthèse, structure et réactivité)

MONTPELLIER-BU Sciences (341722106) / SudocSudocFranceF