The ideal reducing reagent in testing available nitrogen of soil by Conway Methodis Devard‘s alloy.The optimum ratio of soil:Devard’s alloy:1.0N NaOH solution is 5.0g:0.2g:5ml.When reaction goes on at 30℃ for 4 hou...The ideal reducing reagent in testing available nitrogen of soil by Conway Methodis Devard‘s alloy.The optimum ratio of soil:Devard’s alloy:1.0N NaOH solution is 5.0g:0.2g:5ml.When reaction goes on at 30℃ for 4 hours,the rate of soil NO<sub>3</sub>-N reduction is about 90%,and the recovery rate of soil NH<sub>4</sub>-N is about 95%.Some organic nitrogen can be measured at thesame time.This method is defined as the Modified Conway Method and the soil N-min is r=0.982（n=10）.In predicting soil nitrogen supplying power,the Modified Conway Method takesonly 1/6 of time needed by Conway Method.The Modified Conway Method can also be used forthe measure of soil N-min.展开更多
Long term tillage in mollisol of Northeast China has led to an inhomogeneous distribution of soil organic matter content.Biochar,a carbon material,changes the soil carbon pool and physical-chemical characteristics aft...Long term tillage in mollisol of Northeast China has led to an inhomogeneous distribution of soil organic matter content.Biochar,a carbon material,changes the soil carbon pool and physical-chemical characteristics after adding to the soil.However,the mechanism remains unclear for the relation between the soil organic matter level and biochar amount.So,the soil physical and chemical properties and soybean growth in a two-year pot experiment were detected at three levels of soil organic matter and three biochar additions(0,1%and 10%).The difference was found in two biochar application rates.The 1%biochar addition had no positive effect on the soil chemical properties based the two-year experiment.However,10%biochar application significantly increased the soil water content(8.0%-39.7%),the total porosity(9.7%-21.3%),pH(0.26-0.84 unit),organic matter content(89.0%-261.2%),and the available potassium content(29.0%-109.1%).The biomass of soybean increased by 19.4%-78.1%after biochar addition,yet,the soil bulk density reduced at the range of 12.6%-26.0%by 10%biochar addition.Only the 100-grain weight was correlated to the interaction of biochar and the native soil organic matter.All the indicators showed that the interaction between biochar and soil organic matter level was weak in mollisol.The effects of biochar on the physical-chemical properties relied on its amount.When biochar is applied to the soil,the amount of biochar should be considered rather than the native soil organic matter level.展开更多
【目的】探寻不同生境下石灰岩山地优势种淡竹Phyllostachys glauca Mc Clure蔸根和鞭根根际与非根际土壤的养分供应特征与根际效应差异,为喀斯特生境植物的养分管理利用提供理论依据。【方法】根据石灰岩山地裸岩率的不同划分了连续土(...【目的】探寻不同生境下石灰岩山地优势种淡竹Phyllostachys glauca Mc Clure蔸根和鞭根根际与非根际土壤的养分供应特征与根际效应差异,为喀斯特生境植物的养分管理利用提供理论依据。【方法】根据石灰岩山地裸岩率的不同划分了连续土(CS)、半连续土(SCS)、零星土(SS)3种生境,对3种生境淡竹林设置样地调查,进行淡竹不同类型根系土壤取样,测定其养分含量及根际效应,分析不同生境下淡竹根系土壤养分含量及根际效应的变化。【结果】1)随着裸岩率的升高,淡竹根际与非根际土壤铵态氮、硝态氮以及有效磷含量整体呈上升趋势。其中,以SS生境淡竹蔸根非根际土的铵态氮和硝态氮最高,分别为(28.10±1.70)、(2.81±0.35)mg/kg;有效磷则以SCS生境鞭根的非根际土含量最高,为(5.97±0.23)mg/kg,不同生境类型土壤铵态氮含量差异显著(P<0.05)。2)淡竹铵态氮根际效应随裸岩率的升高呈现由正效应转变为负效应的趋势,分布范围为-6.56%~44.57%。硝态氮根际效应在3种生境中变化趋势与铵态氮相同,分布范围为-35.22%~1.33%。3)蔸根和鞭根土壤有效磷含量及根际效应没有显著差异。【结论】石灰岩山地淡竹蔸根和鞭根的根际效应无显著差异,但从不同生境淡竹根系铵态氮和硝态氮的根际效应来看,淡竹具有喜铵厌硝的特点。展开更多
文摘The ideal reducing reagent in testing available nitrogen of soil by Conway Methodis Devard‘s alloy.The optimum ratio of soil:Devard’s alloy:1.0N NaOH solution is 5.0g:0.2g:5ml.When reaction goes on at 30℃ for 4 hours,the rate of soil NO<sub>3</sub>-N reduction is about 90%,and the recovery rate of soil NH<sub>4</sub>-N is about 95%.Some organic nitrogen can be measured at thesame time.This method is defined as the Modified Conway Method and the soil N-min is r=0.982（n=10）.In predicting soil nitrogen supplying power,the Modified Conway Method takesonly 1/6 of time needed by Conway Method.The Modified Conway Method can also be used forthe measure of soil N-min.
基金Supported by the National Natural Science Fund(41301316,32172072)the Project of Nature Scientific Foundation of Heilongjiang Province(LH2021C025)Open Project of Key Laboratory for Germplasm Innovation and Physiological Ecology of Food Crops in Cold Regions of the Ministry of Education(CXSTOP2021008)。
文摘Long term tillage in mollisol of Northeast China has led to an inhomogeneous distribution of soil organic matter content.Biochar,a carbon material,changes the soil carbon pool and physical-chemical characteristics after adding to the soil.However,the mechanism remains unclear for the relation between the soil organic matter level and biochar amount.So,the soil physical and chemical properties and soybean growth in a two-year pot experiment were detected at three levels of soil organic matter and three biochar additions(0,1%and 10%).The difference was found in two biochar application rates.The 1%biochar addition had no positive effect on the soil chemical properties based the two-year experiment.However,10%biochar application significantly increased the soil water content(8.0%-39.7%),the total porosity(9.7%-21.3%),pH(0.26-0.84 unit),organic matter content(89.0%-261.2%),and the available potassium content(29.0%-109.1%).The biomass of soybean increased by 19.4%-78.1%after biochar addition,yet,the soil bulk density reduced at the range of 12.6%-26.0%by 10%biochar addition.Only the 100-grain weight was correlated to the interaction of biochar and the native soil organic matter.All the indicators showed that the interaction between biochar and soil organic matter level was weak in mollisol.The effects of biochar on the physical-chemical properties relied on its amount.When biochar is applied to the soil,the amount of biochar should be considered rather than the native soil organic matter level.
文摘【目的】探寻不同生境下石灰岩山地优势种淡竹Phyllostachys glauca Mc Clure蔸根和鞭根根际与非根际土壤的养分供应特征与根际效应差异,为喀斯特生境植物的养分管理利用提供理论依据。【方法】根据石灰岩山地裸岩率的不同划分了连续土(CS)、半连续土(SCS)、零星土(SS)3种生境,对3种生境淡竹林设置样地调查,进行淡竹不同类型根系土壤取样,测定其养分含量及根际效应,分析不同生境下淡竹根系土壤养分含量及根际效应的变化。【结果】1)随着裸岩率的升高,淡竹根际与非根际土壤铵态氮、硝态氮以及有效磷含量整体呈上升趋势。其中,以SS生境淡竹蔸根非根际土的铵态氮和硝态氮最高,分别为(28.10±1.70)、(2.81±0.35)mg/kg;有效磷则以SCS生境鞭根的非根际土含量最高,为(5.97±0.23)mg/kg,不同生境类型土壤铵态氮含量差异显著(P<0.05)。2)淡竹铵态氮根际效应随裸岩率的升高呈现由正效应转变为负效应的趋势,分布范围为-6.56%~44.57%。硝态氮根际效应在3种生境中变化趋势与铵态氮相同,分布范围为-35.22%~1.33%。3)蔸根和鞭根土壤有效磷含量及根际效应没有显著差异。【结论】石灰岩山地淡竹蔸根和鞭根的根际效应无显著差异,但从不同生境淡竹根系铵态氮和硝态氮的根际效应来看,淡竹具有喜铵厌硝的特点。
