Photosynthetic production is a major determinant of final yield in crop plants. A simulation model was developed for canopy photosynthesis and dry matter accumulation in oilseed rape (Brassica napus L.) based on the e...Photosynthetic production is a major determinant of final yield in crop plants. A simulation model was developed for canopy photosynthesis and dry matter accumulation in oilseed rape (Brassica napus L.) based on the ecophysiological processes and using a three-layer radiation balance scheme for calculating the radiation interception and absorption by the layers of flowers, pods, and leaves within the canopy. Gaussian integration method was used to calculate photosynthesis of the pod and leaf layers, and the daily total canopy photosynthesis was determined by the sum of photosynthesis from the two layers of green organs. The effects of physiological age, temperature, nitrogen, and water deficit on maximum photosynthetic rate were quantified. Maintenance and growth respiration were estimated to determine net photosynthetic production. Partition index of the shoot in relation to physiological development time was used to calculate shoot dry matter from plant biomass and shoot biomass loss because of freezing was quantified by temperature effectiveness. Testing of the model for dynamic dry matter accumulation through field experiments of different genotypes, sowing dates, and nitrogen levels showed good fit between the observed and simulated data, with an average root mean square error of 10.9% for shoot dry matter. Thus, the present model appears to be reliable for the prediction of photosynthetic production in oilseed rape.展开更多
氮肥的过量施用和低效利用,造成资源浪费和环境污染,不利于农业的可持续发展。为了减少氮肥的投入量,发挥氮肥的增产效益,本研究对玉米-大豆套作模式的施氮量和施肥距离进行优化调整。通过两年田间试验,探讨了减氮36%(RN36%)、减...氮肥的过量施用和低效利用,造成资源浪费和环境污染,不利于农业的可持续发展。为了减少氮肥的投入量,发挥氮肥的增产效益,本研究对玉米-大豆套作模式的施氮量和施肥距离进行优化调整。通过两年田间试验,探讨了减氮36%(RN36%)、减氮18%(RN18%)和习惯施氮(CN)3种施氮水平和距离窄行玉米0 cm (D1)、15 cm (D2)、30 cm (D3)、45 cm (D4)4种施肥距离对作物产量和玉米花后干物质积累与转运、籽粒灌浆特征的影响。结果表明,与习惯施氮相比,减氮18%处理的玉米花后干物质转移量、转移率及对籽粒的贡献率分别提高了22.65%、18.75%和15.90%,籽粒平均灌浆速率和最大灌浆速率提高了9.79%和10.76%;玉米、大豆产量及系统周年产量提高了4.95%、7.07%和5.35%;各施肥距离间,以距离窄行玉米15-30 cm的施肥效果最佳。减氮18%时, D2处理下玉米的平均灌浆速率、最大灌浆速率、穗粒数及百粒重比玉米常规穴施(D1)处理分别提高了10.32%、10.92%、9.08%和4.75%;玉米、大豆产量和系统总产最高。玉米-大豆套作体系下,减氮18%和距离窄行玉米15-30 cm施肥有利于增加玉米花后干物质的积累,促进干物质向籽粒中转运,增大灌浆速率,增加百粒重和穗粒数,提高玉米产量和大豆产量,以实现系统周年作物增产。展开更多
基金Project supported by the National High Technology Research and Development Program (863 Program) of China(No. 2006AA10A303)the Post-Doctoral Program of Jiangsu Province, China (No. 0602027C)
文摘Photosynthetic production is a major determinant of final yield in crop plants. A simulation model was developed for canopy photosynthesis and dry matter accumulation in oilseed rape (Brassica napus L.) based on the ecophysiological processes and using a three-layer radiation balance scheme for calculating the radiation interception and absorption by the layers of flowers, pods, and leaves within the canopy. Gaussian integration method was used to calculate photosynthesis of the pod and leaf layers, and the daily total canopy photosynthesis was determined by the sum of photosynthesis from the two layers of green organs. The effects of physiological age, temperature, nitrogen, and water deficit on maximum photosynthetic rate were quantified. Maintenance and growth respiration were estimated to determine net photosynthetic production. Partition index of the shoot in relation to physiological development time was used to calculate shoot dry matter from plant biomass and shoot biomass loss because of freezing was quantified by temperature effectiveness. Testing of the model for dynamic dry matter accumulation through field experiments of different genotypes, sowing dates, and nitrogen levels showed good fit between the observed and simulated data, with an average root mean square error of 10.9% for shoot dry matter. Thus, the present model appears to be reliable for the prediction of photosynthetic production in oilseed rape.
文摘氮肥的过量施用和低效利用,造成资源浪费和环境污染,不利于农业的可持续发展。为了减少氮肥的投入量,发挥氮肥的增产效益,本研究对玉米-大豆套作模式的施氮量和施肥距离进行优化调整。通过两年田间试验,探讨了减氮36%(RN36%)、减氮18%(RN18%)和习惯施氮(CN)3种施氮水平和距离窄行玉米0 cm (D1)、15 cm (D2)、30 cm (D3)、45 cm (D4)4种施肥距离对作物产量和玉米花后干物质积累与转运、籽粒灌浆特征的影响。结果表明,与习惯施氮相比,减氮18%处理的玉米花后干物质转移量、转移率及对籽粒的贡献率分别提高了22.65%、18.75%和15.90%,籽粒平均灌浆速率和最大灌浆速率提高了9.79%和10.76%;玉米、大豆产量及系统周年产量提高了4.95%、7.07%和5.35%;各施肥距离间,以距离窄行玉米15-30 cm的施肥效果最佳。减氮18%时, D2处理下玉米的平均灌浆速率、最大灌浆速率、穗粒数及百粒重比玉米常规穴施(D1)处理分别提高了10.32%、10.92%、9.08%和4.75%;玉米、大豆产量和系统总产最高。玉米-大豆套作体系下,减氮18%和距离窄行玉米15-30 cm施肥有利于增加玉米花后干物质的积累,促进干物质向籽粒中转运,增大灌浆速率,增加百粒重和穗粒数,提高玉米产量和大豆产量,以实现系统周年作物增产。