Vegetable production in South East Asia often is in rotation with flooded rice. The puddling of the soil with flooded rice production may result in unfavourable soil conditions for the subsequent production of dry lan...Vegetable production in South East Asia often is in rotation with flooded rice. The puddling of the soil with flooded rice production may result in unfavourable soil conditions for the subsequent production of dry land crops. To establish whether permanent vegetable production results in favourable soil conditions for vegetables, the effects of five different permanent vegetable production systems and a system of vegetable production in rotation with flooded rice on soil properties after flooded rice were studied in a 2-year field experiment. Bulk density at 0.05–0.10 m depth layer decreased with permanent vegetable production and vegetable production in rotation with flooded rice. The decrease in bulk density was influenced by the application of organic manure and rice husks, and especially by the number of crops cultivated, suggesting that frequency of soil tillage had a major effect on bulk density. Ploughing with buffalo traction after flooded rice, in combination with construction of raised beds, could reduce or totally eliminate negative effects of puddling on soil structure. Bulk density at 0.15–0.20 m soil depth was not influenced. Soil acidity decreased significantly in all systems. Soil organic carbon increased in all systems, but significant increase was only found in two permanent vegetable production systems. Available phosphorus(P) significantly increased in two permanent vegetable production systems, with a positively correlation to the amount of P applied. The significant decrease in bulk density and increase in p H(H2O), after only 2 years, showed that soil conditions after flooded rice could be improved in a short time under intensive vegetable production.展开更多
Drought tolerance is governed by constitutive and acquired traits.Combining them has relevance for sustaining crop productivity under drought.Mild levels of stress induce specific mechanisms that protect metabolism wh...Drought tolerance is governed by constitutive and acquired traits.Combining them has relevance for sustaining crop productivity under drought.Mild levels of stress induce specific mechanisms that protect metabolism when stress becomes severe.Here,we report a comparative assessment of“acquired drought tolerance(ADT)”traits in two rice cultivars,IR64(drought susceptible)and Apo(tolerant),and a drought-tolerant wheat cultivar,Weebill.Young seedlings were exposed to progressive concentrations of methyl viologen(MV),a stress inducer,before transferring to a severe concentration.“Induced”seedlings showed higher tolerance and recovery growth than seedlings exposed directly to severe stress.A novel phenomic platform with an automated irrigation system was used for precisely imposing soil moisture stress to capture ADT traits during the vegetative stage.Gradual progression of drought was achieved through a software-controlled automated irrigation facility.This facility allowed the maintenance of the same level of soil moisture irrespective of differences in transpiration,and hence,this platform provided the most appropriate method to assess ADT traits.Total biomass decreased more in IR64 than in Apo.The wheat cultivar showed lower levels of damage and higher recovery growth even compared to Apo.Expression of ROS-scavenging enzymes and drought-responsive genes was significantly higher in Apo than in IR64,but differences were only marginal between Apo and Weebill.The wheat cultivar showed significantly higher stomatal conductance,carbon gain,and biomass than the rice cultivars,under drought.These differences in ADT traits between cultivars as well as between species can be utilised for improving drought tolerance in crop plants.展开更多
基金carried out in the framework of the‘Perm Veg’project(2007-2013)part of the strategic research program KB1"Global Food Security:Scarcity and Transition"which was funded by the Dutch Ministry of Economic Affairs,and carried out by Wageningen University and Research Centre
文摘Vegetable production in South East Asia often is in rotation with flooded rice. The puddling of the soil with flooded rice production may result in unfavourable soil conditions for the subsequent production of dry land crops. To establish whether permanent vegetable production results in favourable soil conditions for vegetables, the effects of five different permanent vegetable production systems and a system of vegetable production in rotation with flooded rice on soil properties after flooded rice were studied in a 2-year field experiment. Bulk density at 0.05–0.10 m depth layer decreased with permanent vegetable production and vegetable production in rotation with flooded rice. The decrease in bulk density was influenced by the application of organic manure and rice husks, and especially by the number of crops cultivated, suggesting that frequency of soil tillage had a major effect on bulk density. Ploughing with buffalo traction after flooded rice, in combination with construction of raised beds, could reduce or totally eliminate negative effects of puddling on soil structure. Bulk density at 0.15–0.20 m soil depth was not influenced. Soil acidity decreased significantly in all systems. Soil organic carbon increased in all systems, but significant increase was only found in two permanent vegetable production systems. Available phosphorus(P) significantly increased in two permanent vegetable production systems, with a positively correlation to the amount of P applied. The significant decrease in bulk density and increase in p H(H2O), after only 2 years, showed that soil conditions after flooded rice could be improved in a short time under intensive vegetable production.
文摘Drought tolerance is governed by constitutive and acquired traits.Combining them has relevance for sustaining crop productivity under drought.Mild levels of stress induce specific mechanisms that protect metabolism when stress becomes severe.Here,we report a comparative assessment of“acquired drought tolerance(ADT)”traits in two rice cultivars,IR64(drought susceptible)and Apo(tolerant),and a drought-tolerant wheat cultivar,Weebill.Young seedlings were exposed to progressive concentrations of methyl viologen(MV),a stress inducer,before transferring to a severe concentration.“Induced”seedlings showed higher tolerance and recovery growth than seedlings exposed directly to severe stress.A novel phenomic platform with an automated irrigation system was used for precisely imposing soil moisture stress to capture ADT traits during the vegetative stage.Gradual progression of drought was achieved through a software-controlled automated irrigation facility.This facility allowed the maintenance of the same level of soil moisture irrespective of differences in transpiration,and hence,this platform provided the most appropriate method to assess ADT traits.Total biomass decreased more in IR64 than in Apo.The wheat cultivar showed lower levels of damage and higher recovery growth even compared to Apo.Expression of ROS-scavenging enzymes and drought-responsive genes was significantly higher in Apo than in IR64,but differences were only marginal between Apo and Weebill.The wheat cultivar showed significantly higher stomatal conductance,carbon gain,and biomass than the rice cultivars,under drought.These differences in ADT traits between cultivars as well as between species can be utilised for improving drought tolerance in crop plants.
