Économies d'énergie dans la production de blé tendre (Triticum aestivum) dans les systèmes de terres arides

The objectives of this study were to determine the energy consumption in soft wheat production, and evaluate the possibility of energy savings. For this purpose, data were collected from 81 farms applying questionnaires via face-to-face interviews. Energy expenditures per hectare (MJ/ha) and specific energy consumption (MJ/kg grain produced) for four types of farms were studied. Results indicate that the total energy consumption varies from 9.7 to 11.1 GJ/ha. The share of fertilizers, seeds and diesel represents respectively 43.8%, 27.7% and 18.6%. Specific energy consumption is found to be 3.05 MJ/kg for small scale farms and 3.37 MJ/kg for large scale farms. According to these results and to farmer’s attitudes, a prediction equation for each type of farm was established to analyze the possibility of energy saving. 8.6% for small scale farms, 20.6 % for large scale farm of total energy consumption could be saved by reducing the seed rate and fuel consumption. The potential energy that can be saved represents 29.6% of the total fuel consumed in soft wheat production. Specific energy consumption could also be reduced by 19.6 to 22.9%. Adoption of the options outlined above would reduce GHG emissions from Morocco’s soft wheat farming by an estimated 119.1 kte CO2 a year.  Keywords: Soft wheat, Energy balance, Energy saving, GHG emissionLes objectifs de cette étude consistent à évaluer la consommation d’énergie directe et indirecte lors la production du blé tendre. Pour cela, une enquête a été menée auprès de 81 exploitations agricoles réparties en 4 catégories. Les résultats indiquent que la consommation d’énergie par hectare varie de 9,7 à 11,1 GJ. Les fertilisants, les semences et carburant représentent respectivement 43,8%, 27,7% et 18,6% de la consommation totale. Quant à la consommation spécifique, elle varie de 3,05 à 3,37 MJ/kg. En tenant compte de ces résultats et aux attitudes des agriculteurs, des équations de prédiction de la consommation d’énergie ont été établies. Les résultats montrent que la réduction de la dose de semis et de la consommation en carburant mènent à une économie d’énergie variant de 8,6 à 20,6 % .Ce potentiel représente l’équivalent de 29,6 % de la consommation du carburant dans la production du blé tendre au Maroc. La consommation spécifique pourrait également être réduite de 19,6 à 22,9% .L’adoption de ces pratiques réduira l’émission des gaz à effet de serre de 119,1 Kte CO2 par an. Mots-clés: Blé tendre, Énergie, Gaz à effet de serr

Natural ventilation and microclimatic performances of a large-scale banana greenhouse

International audienc

Energy savings in soft wheat (Triticum aestivum) production in dry land system

The objectives of this study were to determine the energy consumption in soft wheat production, and evaluate the possibility of energy savings. For this purpose, data were collected from 81 farms applying questionnaires via face-to-face interviews. Energy expenditures per hectare (MJ/ha) and specific energy consumption (MJ/kg grain produced) for four types of farms were studied. Results indicate that the total energy consumption varies from 9.7 to 11.1 GJ/ha. The share of fertilizers, seeds and diesel represents respectively 43.8%, 27.7% and 18.6%. Specific energy consumption is found to be 3.05 MJ/kg for small scale farms and 3.37 MJ/kg for large scale farms. According to these results and to farmer’s attitudes, a prediction equation for each type of farm was established to analyze the possibility of energy saving. 8.6% for small scale farms, 20.6 % for large scale farm of total energy consumption could be saved by reducing the seed rate and fuel consumption. The potential energy that can be saved represents 29.6% of the total fuel consumed in soft wheat production. Specific energy consumption could also be reduced by 19.6 to 22.9%. Adoption of the options outlined above would reduce GHG emissions from Morocco’s soft wheat farming by an estimated 119.1 kte CO2 a year

Phosphorus deficiency enhances water deficit impact on some morphological and physiological traits in four faba bean (Vicia faba L.) varieties

Moroccan soils, generally present low available phosphorus (P) levels which occur in almost all arid and semi-arid regions. Faba bean is one of the most significant crops in Morocco and is influenced by these constraints that affect its nutrient uptake and nitrogen fixation capacity and hence plants development. Therefore, we evaluated the response of four Vicia faba varieties - Aguadulce (Ag), Alfia (Al), Luz de Otono (LO) and Reina Mora (RM) -, grown under biological nitrogen fixation to water deficit and two phosphorus levels. The trial was conducted under greenhouse conditions and water stress was induced by keeping pots at 40% substrate field capacity (FC) versus 80% FC for the controls while phosphorus deficiency treatment consisted in the application of 25 mu mol P plant(-1) week(-1) versus 125 mu mol P plant(-1) week(-1) for sufficient P treatment. The results revealed a significant effect of water deficit and phosphorus deficiency either alone or combined on plants dry weights, leaf water parameters and nutrient concentrations. However sufficient phosphorus supply mitigated the adverse effects of water deficit on faba bean. We noticed significant differences between the studied varieties. Ag showed high performance concerning dry weights (1.25 g and 1.88 g plant(-1) respectively for shoot and root) and high concentration of nitrogen N (4.7%) and P (0.27 mg g(-1) DW) and was then qualified as the most tolerant variety to water deficit combined with P limitation. While RM was the least tolerant variety, as it showed the lowest dry weights (0.51 g and 1.4 g plant(-1) respectively for shoot and root) and concentration (2.74% and 0.19 mg g(-1) DW respectively for N and P). The tolerance was related to the ability to ensure efficient osmoregulation by glycine betaine accumulation, to keep leaf water balance and cell membrane stability that contribute together with adequate symbiotic nitrogen fixation to plant growth performance under combined stresses

Physiological, biochemical and morphological tolerance mechanisms of faba bean (Vicia fabaL.) to the combined stress of water deficit and phosphorus limitation

Water deficit and phosphorus (P) deficiency are among the most severe factors limiting agricultural productivity. In this study, two contrasting faba bean (Vicia faba L.) varieties for their response to water deficit were used to identify some agro-physiological and biochemical traits involved in the tolerance mechanisms to combined water deficit and P limitation. Plants were grown under greenhouse conditions in agronomic soil, under two P levels: 10.4 mg P kg(-1) (deficient) and 30.4 mg P kg(-1) (sufficient), and two watering regimes: 40% of soil field capacity (FC; water deficit) against 80% FC (control). We hypothesis that P fertilization improves the tolerance of faba bean plants and their symbiosis to water deficit. The results demonstrated that water deficit and P-deficiency treatments applied separately or combined reduced substantially plant biomass, leaf water parameters, and nitrate reductase activity. Similarly, nutrients concentrations were significantly reduced under P-deficiency, while sufficient P-conditions significantly increased their uptake under water deficit. The tolerance was positively correlated to the ability of plants to overcome the combined stressors by inducing phosphatase activity, accumulating glycine betaine and activation of antioxidant enzymes and also by maintaining cell membrane stability. The findings suggest that the combination of the two stresses alter more the plant metabolisms compared to individual stress, with Reina Mora being the most affected by the applied stressors. Likewise, P fertilization is a relevant approach to overcome some effects of water deficit