Lake eutrophication （LE） has become an increasingly severe environmental problem recently. However, there has been no nutrient standard established for LE control in many developing countries such as China. This stu...Lake eutrophication （LE） has become an increasingly severe environmental problem recently. However, there has been no nutrient standard established for LE control in many developing countries such as China. This study proposes a structural equation model to assist in the establishment of a lake nutrient standard for drinking water sources in Yunnan-Guizhou Plateau Ecoregion （Yungui Ecoregion）, China. The modeling results indicate that the most predictive indicator for designated use-attainment is total phosphorus （TP） （total effect =-0.43）, and chlorophyll a （Chl-a） is recommended as the second important indicator （total effect =-0.41）. The model is further used for estimating the probability of use-attainment associated with lake water as a drinking water source and various levels of candidate criteria （based on the reference conditions and the current environmental quality standards for surface water）. It is found that these candidate criteria cannot satisfy the designated 100% use-attainment. To achieve the short-term target （85% attainment of the designated use）, TP and Chl-a values ought to be less than 0.02 mg/L and 1.4 μg/L, respectively. When used as a long-term target （90% or greater attainment of the designated use）, the TP and Chl-a values are suggested to be less than 0.018 mg/L and 1 μg/L, respectively.展开更多
针对新疆棉花生产中缺乏先进高效的推荐施肥方法和不合理施肥带来的肥料利用率低的现状,本研究以1996—2019年新疆主要植棉区21个植棉县的414个棉花田间肥料试验为基础,建立养分管理大数据库。采用QUEFTS模型模拟棉花最佳养分需求量,并...针对新疆棉花生产中缺乏先进高效的推荐施肥方法和不合理施肥带来的肥料利用率低的现状,本研究以1996—2019年新疆主要植棉区21个植棉县的414个棉花田间肥料试验为基础,建立养分管理大数据库。采用QUEFTS模型模拟棉花最佳养分需求量,并分析土壤基础养分供应、肥料的农学效率与产量反应之间的相关关系,在此基础上构建施肥模型,并开发了适用于新疆棉花生产的养分专家系统。为验证该系统的应用效果,于2017—2021年在新疆主要棉花种植区开展田间验证试验。试验共设6个施肥处理,分别为棉花养分专家系统推荐施肥(NE),基于NE推荐施肥基础上的不施氮肥、不施磷肥和不施钾肥,农民习惯施肥(FP)和当地的优化推荐施肥(ST),调查了棉花产量、肥料利用效率和经济效益。QUEFTS模型模拟棉花养分吸收结果表明,每生产1 t籽棉地上部所需氮、磷和钾养分分别为27.7、6.2和29.3 kg。施用氮、磷和钾肥的平均产量反应分别为1624、1096和804 kg hm^(–2),平均相对产量分别为0.7、0.8和0.8,平均农学效率分别为6.8、8.5和16.7 kg kg^(–1)。田间验证结果显示,与FP处理相比,NE处理分别减施氮、磷、钾肥40.7%、60.1%和10.7%;与ST处理相比,NE处理分别减施氮、磷肥30.3%和38.0%,增施钾肥10.8%。与FP和ST相比,NE处理的棉花产量分别增加了365 kg hm^(–2)和92 kg hm^(–2),经济效益分别增加了4302元hm^(–2)和1094元hm^(–2),氮、磷和钾肥回收率分别提高了18.8和11.8、14.2和11.5、13.4和6.0个百分点,氮和磷肥农学效率分别增加了3.5 kg kg^(–1)和2.2 kg kg^(–1)、7.2 kg kg^(–1)和4.4 kg kg^(–1),钾肥农学效率分别减少了1.6 kg kg^(–1)和0.6 kg kg^(–1)。综上所述,基于产量反应和农学效率构建的智能化新疆棉花养分专家系统,能够为每块地提供个性化的施肥方案。连续多点的田间试验结果充分证明,该方法优化了肥料用量与养分配比,提高了棉花产量和肥料利用率,增加了经济效益,是适用于新疆棉花生产的推荐施肥新方法。展开更多
基金supported by the Mega-projects of Science Research for Water Environment Improvement (No. 2009ZX07106-001-005-01)the National Nature Science Foundation of China (No. 71103166)
文摘Lake eutrophication （LE） has become an increasingly severe environmental problem recently. However, there has been no nutrient standard established for LE control in many developing countries such as China. This study proposes a structural equation model to assist in the establishment of a lake nutrient standard for drinking water sources in Yunnan-Guizhou Plateau Ecoregion （Yungui Ecoregion）, China. The modeling results indicate that the most predictive indicator for designated use-attainment is total phosphorus （TP） （total effect =-0.43）, and chlorophyll a （Chl-a） is recommended as the second important indicator （total effect =-0.41）. The model is further used for estimating the probability of use-attainment associated with lake water as a drinking water source and various levels of candidate criteria （based on the reference conditions and the current environmental quality standards for surface water）. It is found that these candidate criteria cannot satisfy the designated 100% use-attainment. To achieve the short-term target （85% attainment of the designated use）, TP and Chl-a values ought to be less than 0.02 mg/L and 1.4 μg/L, respectively. When used as a long-term target （90% or greater attainment of the designated use）, the TP and Chl-a values are suggested to be less than 0.018 mg/L and 1 μg/L, respectively.
文摘针对新疆棉花生产中缺乏先进高效的推荐施肥方法和不合理施肥带来的肥料利用率低的现状,本研究以1996—2019年新疆主要植棉区21个植棉县的414个棉花田间肥料试验为基础,建立养分管理大数据库。采用QUEFTS模型模拟棉花最佳养分需求量,并分析土壤基础养分供应、肥料的农学效率与产量反应之间的相关关系,在此基础上构建施肥模型,并开发了适用于新疆棉花生产的养分专家系统。为验证该系统的应用效果,于2017—2021年在新疆主要棉花种植区开展田间验证试验。试验共设6个施肥处理,分别为棉花养分专家系统推荐施肥(NE),基于NE推荐施肥基础上的不施氮肥、不施磷肥和不施钾肥,农民习惯施肥(FP)和当地的优化推荐施肥(ST),调查了棉花产量、肥料利用效率和经济效益。QUEFTS模型模拟棉花养分吸收结果表明,每生产1 t籽棉地上部所需氮、磷和钾养分分别为27.7、6.2和29.3 kg。施用氮、磷和钾肥的平均产量反应分别为1624、1096和804 kg hm^(–2),平均相对产量分别为0.7、0.8和0.8,平均农学效率分别为6.8、8.5和16.7 kg kg^(–1)。田间验证结果显示,与FP处理相比,NE处理分别减施氮、磷、钾肥40.7%、60.1%和10.7%;与ST处理相比,NE处理分别减施氮、磷肥30.3%和38.0%,增施钾肥10.8%。与FP和ST相比,NE处理的棉花产量分别增加了365 kg hm^(–2)和92 kg hm^(–2),经济效益分别增加了4302元hm^(–2)和1094元hm^(–2),氮、磷和钾肥回收率分别提高了18.8和11.8、14.2和11.5、13.4和6.0个百分点,氮和磷肥农学效率分别增加了3.5 kg kg^(–1)和2.2 kg kg^(–1)、7.2 kg kg^(–1)和4.4 kg kg^(–1),钾肥农学效率分别减少了1.6 kg kg^(–1)和0.6 kg kg^(–1)。综上所述,基于产量反应和农学效率构建的智能化新疆棉花养分专家系统,能够为每块地提供个性化的施肥方案。连续多点的田间试验结果充分证明,该方法优化了肥料用量与养分配比,提高了棉花产量和肥料利用率,增加了经济效益,是适用于新疆棉花生产的推荐施肥新方法。
