Feeding costs could be reduced by use of alternative energy and protein sources. Leguminous trees remain green through the dry season, serving as a crude protein bank besides improving soil fertility through nitrogen ...Feeding costs could be reduced by use of alternative energy and protein sources. Leguminous trees remain green through the dry season, serving as a crude protein bank besides improving soil fertility through nitrogen fixation, nutrients recycling and stabilising soil on terraces. Some Kenyan farmers intercrop bananas with forages to cope with the perennial feed shortages. A simulation model assumed a family of six （husband, wife and four children） owning one cow producing 15 kg milk per day, living on 0.4 ha of land. Bananas grown on 0.36 ha in alleys of alternating rows ofLeucaena diversifolia and Calliandra calothyrses, intercropped with Guinea grass （Panicum maximum） and Desmodium uncinatum. Napier （Pennisetum purpureum） was planted in the alleys as a pure stand on 0.08 ha. Model analysis showed the household had adequate energy and protein all the year and was financially secured, with income exceeding routine expenditure. There were positive balances for nitrogen and phosphorus, but potassium application was required. A replica of the model was then tested.展开更多
为了确定通用性园艺作物发育期和采收期模拟模型的最优模拟路径,该研究获取了9 a 58茬分期播种试验观测数据,分别以黄瓜(‘津优35’和‘津盛206’)、番茄(‘瑞粉882’和‘普罗旺斯’)、芹菜(‘尤文图斯’)、菠菜(‘大叶’)、香芹(‘四季...为了确定通用性园艺作物发育期和采收期模拟模型的最优模拟路径,该研究获取了9 a 58茬分期播种试验观测数据,分别以黄瓜(‘津优35’和‘津盛206’)、番茄(‘瑞粉882’和‘普罗旺斯’)、芹菜(‘尤文图斯’)、菠菜(‘大叶’)、香芹(‘四季’)、郁金香(‘粉色印象’、‘白日梦’、‘艾斯米’和‘夜皇后’)、茶叶(‘龙井’)为供试材料,依据作物生长发育与关键气象因子(辐射和温度)的关系,基于4类建模方法(温差法、积温法、生理发育时间法和辐热积法)构建了园艺作物发育期和采收期模拟模型,确定了模型关键参数,并以4种方式(平均值、最值均值、中值和逐步回归)集成模拟结果,最终确定模型最优模拟路径。结果表明:1)不同时间尺度发育期和采收期模拟模型的均方根误差(root mean square error,RMSE)为4.85~17.01 d,归一化均方根误差(normalized root mean square error,NRMSE)为10.65%~16.31%;不同作物发育期和采收期模拟模型的RMSE为0.50~17.08 d,NRMSE为4.33%~20.24%,郁金香发育期模拟模型最优,黄瓜采收期模拟模型最优;不同模拟方法发育期和采收期模拟模型的RMSE为0.08~24.37 d,NRMSE为0.18%~54.81%。2)通过比较不同模拟方法的模拟精度,得出逐时优于逐日时间尺度,集成方法优于单一方法模拟,正弦优于线性温度响应模式,叶温优于气温温度形式,温度响应模拟需要考虑下限和上限温度。3)最优模拟路径为先选择逐时尺度、考虑生物学下限和上限温度的正弦温度响应模式和叶温温度形式构建模型,再选择集成法优化发育期(中值集成)和采收期(逐步回归集成)模型。研究结果为指导园艺作物智慧生产管理和高效利用农业资源方面提供理论基础和技术支撑。展开更多
文摘Feeding costs could be reduced by use of alternative energy and protein sources. Leguminous trees remain green through the dry season, serving as a crude protein bank besides improving soil fertility through nitrogen fixation, nutrients recycling and stabilising soil on terraces. Some Kenyan farmers intercrop bananas with forages to cope with the perennial feed shortages. A simulation model assumed a family of six （husband, wife and four children） owning one cow producing 15 kg milk per day, living on 0.4 ha of land. Bananas grown on 0.36 ha in alleys of alternating rows ofLeucaena diversifolia and Calliandra calothyrses, intercropped with Guinea grass （Panicum maximum） and Desmodium uncinatum. Napier （Pennisetum purpureum） was planted in the alleys as a pure stand on 0.08 ha. Model analysis showed the household had adequate energy and protein all the year and was financially secured, with income exceeding routine expenditure. There were positive balances for nitrogen and phosphorus, but potassium application was required. A replica of the model was then tested.
文摘为了确定通用性园艺作物发育期和采收期模拟模型的最优模拟路径,该研究获取了9 a 58茬分期播种试验观测数据,分别以黄瓜(‘津优35’和‘津盛206’)、番茄(‘瑞粉882’和‘普罗旺斯’)、芹菜(‘尤文图斯’)、菠菜(‘大叶’)、香芹(‘四季’)、郁金香(‘粉色印象’、‘白日梦’、‘艾斯米’和‘夜皇后’)、茶叶(‘龙井’)为供试材料,依据作物生长发育与关键气象因子(辐射和温度)的关系,基于4类建模方法(温差法、积温法、生理发育时间法和辐热积法)构建了园艺作物发育期和采收期模拟模型,确定了模型关键参数,并以4种方式(平均值、最值均值、中值和逐步回归)集成模拟结果,最终确定模型最优模拟路径。结果表明:1)不同时间尺度发育期和采收期模拟模型的均方根误差(root mean square error,RMSE)为4.85~17.01 d,归一化均方根误差(normalized root mean square error,NRMSE)为10.65%~16.31%;不同作物发育期和采收期模拟模型的RMSE为0.50~17.08 d,NRMSE为4.33%~20.24%,郁金香发育期模拟模型最优,黄瓜采收期模拟模型最优;不同模拟方法发育期和采收期模拟模型的RMSE为0.08~24.37 d,NRMSE为0.18%~54.81%。2)通过比较不同模拟方法的模拟精度,得出逐时优于逐日时间尺度,集成方法优于单一方法模拟,正弦优于线性温度响应模式,叶温优于气温温度形式,温度响应模拟需要考虑下限和上限温度。3)最优模拟路径为先选择逐时尺度、考虑生物学下限和上限温度的正弦温度响应模式和叶温温度形式构建模型,再选择集成法优化发育期(中值集成)和采收期(逐步回归集成)模型。研究结果为指导园艺作物智慧生产管理和高效利用农业资源方面提供理论基础和技术支撑。
