Effect of water stress on growth, water consumption and yield of silage maize under flood irrigation in semi-arid clilmate of Tadla (Morocco)

The field study of crops response to water stress is important to reduce agricultural water use in areas where the water resources are limited. This study was carried out during two growing periods of 2009 and 2010 in order to study the effect of water stress on crops growth, water consumption and dry matter yield of silage maize supplied with flood irrigation under the semiarid climate of Tadla in Morocco. Four to five irrigation treatments were applied at the rates of 100, 80, 60, 40 and 20% of ETc of maize. Soil water status, crop growth, leaf area index and above-ground biomass were measured. Results showed that growth dynamic of maize passes by three distinct phases: exponential phase, linear phase and a final phase. The irrigation deficit accelerates the senescence of the sheets and reduces the leaf area index. The maximum values of this parameter reached at flowering under the full irrigation treatment (100%ETc) are 5.1 and 4.8 in 2009 and 2010 respectively. Dry matter yields varied from 5.3 t/ha under T4 (40%ETc) to 16.4 t/ha under T1 (100% ETc) in 2009 whereas in 2010, it oscillated between 3.9 t/ha under T5 (20%ETc) to 12.5 t/ha under T1 (100%ETc). The actual evapotranspiration under T1 (100%ETc) was 478 mm and 463 mm in 2009 and 2010 respectively. According to the averaged values of two years, linear relationships have been evaluated between dry matter yield and water consumption ETa. Yield response factor (ky) for the silage maize for all growth season was 1.12

Effect of water stress on growth, water consumption and yield of silage maize under flood irrigation in a semi-arid climate of Tadla (Morocco)

The field study of crop response to water stress is important to maximize yield and improve agricultural water use efficiency in areas where water resources are limited. This study was carried out during two growing periods in 2009 and 2010 in order to study the effect of water stress on crop growth, water consumption and dry matter yield of silage maize (Zea mays L.) supplied with flood irrigation under the semi-arid climate of Tadla in Morocco. Four to five irrigation treatments were applied at the rates of 100, 80, 60, 40 and 20% crop evapotranspiration (ETc) of maize. Soil water status, crop growth, leaf area index and above-ground biomass were measured. Results showed that irrigation deficit affected plant height growth, accelerated the senescence of the leaves and reduced the leaf area index. The maximum values of this parameter reached at flowering under the full irrigation treatment (100% ETc) were 5.1 and 4.8 in 2009 and 2010, respectively. Dry matter yields varied from 5.3 t·ha-1 under T4 (40% ETc) to 16.4 t·ha-1 under T1 (100% ETc) in 2009, whereas in 2010, it oscillated between 3.9 t·ha-1 under T5 (20% ETc) to 12.5 t·ha-1 under T1 (100% ETc). The establishment of the water budget by growth phase showed that the water use efficiency was higher during the linear phase of growth. Water use efficiency calculated at harvest varied between 2.99 kg·m-3 under T1 to 1.84 kg·m-3 under T5. The actual evapotranspiration under T1 (100% ETc) was 478 mm and 463 mm in 2009 and 2010, respectively. Using the averaged values of the two years, linear relationships were evaluated between dry matter yield and water consumption ETa. The yield response factor (Ky) for the silage maize for both growth seasons was 1.12. Under the Tadla semi-arid climate, it is proposed that silage maize should be irrigated as a priority before other crops with a Ky lower than 1.12. It is also recommended that, under limited water supplies, irrigation be applied during the linear phase of growth of this crop

Effect of water stress on growth, yield and water use efficiency of berseem (Trifolium alexandrium) in Tadla

The study of crop response to water deficit is important in areas where water resources are limited. This study was carried out over the period 2008-2011 in order to study the effect of water deficit on the productivity of berseem in the Tadla region. Four water regimes (100%, 80%, 60% and 40% ETc) were compared under both flood and drip irrigation techniques. Observations were made on the soil, biomass at each cut and root system. The results showed that the average annual maximum yield obtained was 16.2 t/ha. Reductions in yields by applying 60% of water inputs are 40% and 42% in 2009/10 and 2010/11, respectively. The contribution of cycles without irrigation to annual biomass yield varies from 35% under 100% ETc to 52% under 40% ETc. Water use efficiency of berseem over the over the entire crop period is 3.37 kg/m3. The maximum average yield obtained under drip irrigation was 15.7 t/ha. It was obtained with a water supply of 411 mm which allowed a saving of 57% of water supply versus flood irrigation technique

Modelling of berseem (Trifolium Alexandrinum) growth and biomass yield under different levels of water stress in Tadla, Morocco

This work compares the performance of PILOTE, an operative crop model developed by IRSTA Montpellier France, with that of well established model, CropSyst, in simulating berseem (Trifolium Alexandrinum L.) growth under different water regimes in the semi-arid climate of Tadla (Morocco). Both based on Beer’s law via the intercepted potential active radiation (IPAR) regarding dry matter accumulation, the models differ in the level of complexity describing crop development, biomass growth, root water uptake principle and consequently, in the number of input parameters. The models were calibrated on an unstressed irrigation treatment in 2009/10, and were validated on other stressed and unstressed treatments in 2009/10 and 2010/11. Although PILOTE required fewer input parameters and data than CropSyst, it performed similarly better when simulating both biomass and soil water balance. The use of different numbers of parameters and crop growth modules by the tested models did not influence substantially the simulation results. Therefore, for management purposes and in conditions of limited input information, the use of simpler models should be encouraged