Little is known about C-N-P stoichiometries and content in teak(Tectona grandis)plantations in South China,which are mostly sited on hilly areas with lateritic soil,and the effect of slope position on the accumulation...Little is known about C-N-P stoichiometries and content in teak(Tectona grandis)plantations in South China,which are mostly sited on hilly areas with lateritic soil,and the effect of slope position on the accumulation of these elements in trees and rhizosphere soils.Here we analyzed the C,N,P content and stoichiometry in leaves,fine roots and rhizosphere soils of trees on the upper and lower slopes of a 12-year-old teak plantation.The Kraft classification system of tree status was used to sample dominant,subdominant and mean trees at each slope position.The results showed that the C,N and P contents in leaves were higher than in fine roots and rhizosphere soils.The lowest C/N,C/P and N/P ratios were found in rhizosphere soils,and the C/N and C/P ratios in fine roots were higher than in leaves.Nutrient accumulation in leaves,fine roots and rhizosphere soils were significantly influenced by slope position and tree class with their interaction mainly showing a greater effect on rhizosphere soils.Leaf C content and C/N ratio,fine root C and P contents,and C/N and C/P ratios all increased distinctly with declining slope position.The contents of organic matter(SOM),ammonium(NH4+-N),nitrate-nitrogen(NO3--N)and available potassium(AK)in rhizosphere soils were mainly enriched on upper slopes,but exchange calcium(ECa),available phosphorus(AP),and pH were relatively lower.Variations in the C,N and P stoichiometries in trees were mainly attributed to the differences in rhizosphere soil properties.N and P contents showed significant positive linear relationships between leaf and rhizosphere soil,and C content negative linear correlation among leaves,fine roots and rhizosphere soils.Chemical properties of rhizosphere soils,particularly C/N and NH4+-N,had significant effects on the leaf nutrients in trees on the upper slope.Correspondingly,rhizosphere soil properties mainly influenced fine root nutrients on the lower slope,and soil AK was the major influencing factor.Overall,these results offer new insights for the sustainability and management of teak plantations in hilly areas.展开更多
Moistube irrigation was driven by the gradient of water potential inside and outside the pipe wall,which has the advantages of continuous irrigation during the crop growth period.However,the response mechanism of soil...Moistube irrigation was driven by the gradient of water potential inside and outside the pipe wall,which has the advantages of continuous irrigation during the crop growth period.However,the response mechanism of soil nutrients and enzyme activities of greenhouse tomatoes under the integration of water and fertilizer by moistube irrigation is still unclear.In order to explore the changes in soil nutrients and enzyme activities of greenhouse tomatoes regulated by irrigation and fertilization in moistube irrigation greenhouse,a completely randomized experimental design was conducted to explore the effects of different irrigation amounts(I,controlling the work-ing pressure head of moistube to achieve different irrigation amount gradients,capillary working pressure was 1(I1),2(I2),3(I3)m)and fertilization amounts(F,single fertilization amount was 100(F1),200(F2),300(F3)kg/hm2)on soil nutrients,enzyme activities and yield of greenhouse tomato.It was found that with the increase of I,the total organic carbon content(TOC),soilβ-glucosidase(BG),leucine amino peptidase(LAP),N-acetylglucosaminidase(NAG),and alkaline phosphatase(AP)activities enzyme of greenhouse tomato soil increasedfirst and then decreased.When the I increased from I1 to I3,the soil total nitrogen(TN)decreased by 5.07%and 4.91%,respectively,and the soil total phosphorus(TP)by 4.37%and 4.22%,respectively.With the increase of fertilizer amounts,the TOC of tomato soil increasedfirst and then decreased,the activities of BG,LAP,NAG and AP in soil increasedfirst and then decreased,and the contents of TN and TP in soil decreased by 4.79%and 4.68%,12.32%and 10.47%,respectively.The yield of tomatoes treated with I2 was significantly higher than that of I1 and I3 by about 13.99%and 1.29%,respectively.The tomato yield of F2 treatment was significantly higher than that of F1 and F3 treatments by about 22.57%and 1.72%,respectively.Based on the analysis of stoichiometry,it was found that soil carbon was more scarcity than nitrogen in greenhouse tomatoes under the integration of water and fertilizer by moistube irrigation.Soil carbon,nitrogen,phosphorus,enzyme activity and their respective stoichiometry showed a quadratic curve relationship with yield.Therefore,I2F2 treat-ment of greenhouse tomatoes can not only reduce soil carbon and nitrogen limitations but also improve soil enzyme activity and achieve multiple goals of increasing greenhouse tomato yield,and saving water and fertilizer.This conclusion contributes to a more reasonable irrigation and fertilization of tomatoes in moistube irrigation greenhouse and soil nutrient management of facility agriculture through empirical proofs.展开更多
基金funded by the National Key Research and Development Program(grant number 2017YFD0601100)。
文摘Little is known about C-N-P stoichiometries and content in teak(Tectona grandis)plantations in South China,which are mostly sited on hilly areas with lateritic soil,and the effect of slope position on the accumulation of these elements in trees and rhizosphere soils.Here we analyzed the C,N,P content and stoichiometry in leaves,fine roots and rhizosphere soils of trees on the upper and lower slopes of a 12-year-old teak plantation.The Kraft classification system of tree status was used to sample dominant,subdominant and mean trees at each slope position.The results showed that the C,N and P contents in leaves were higher than in fine roots and rhizosphere soils.The lowest C/N,C/P and N/P ratios were found in rhizosphere soils,and the C/N and C/P ratios in fine roots were higher than in leaves.Nutrient accumulation in leaves,fine roots and rhizosphere soils were significantly influenced by slope position and tree class with their interaction mainly showing a greater effect on rhizosphere soils.Leaf C content and C/N ratio,fine root C and P contents,and C/N and C/P ratios all increased distinctly with declining slope position.The contents of organic matter(SOM),ammonium(NH4+-N),nitrate-nitrogen(NO3--N)and available potassium(AK)in rhizosphere soils were mainly enriched on upper slopes,but exchange calcium(ECa),available phosphorus(AP),and pH were relatively lower.Variations in the C,N and P stoichiometries in trees were mainly attributed to the differences in rhizosphere soil properties.N and P contents showed significant positive linear relationships between leaf and rhizosphere soil,and C content negative linear correlation among leaves,fine roots and rhizosphere soils.Chemical properties of rhizosphere soils,particularly C/N and NH4+-N,had significant effects on the leaf nutrients in trees on the upper slope.Correspondingly,rhizosphere soil properties mainly influenced fine root nutrients on the lower slope,and soil AK was the major influencing factor.Overall,these results offer new insights for the sustainability and management of teak plantations in hilly areas.
基金The research is funded by the Natural Science Foundation of China(No.41807041)the Science and Technology Research Project of Henan Province(No.242102111101)Social Science Foundation of Shaanxi Province(2023SJ03).
文摘Moistube irrigation was driven by the gradient of water potential inside and outside the pipe wall,which has the advantages of continuous irrigation during the crop growth period.However,the response mechanism of soil nutrients and enzyme activities of greenhouse tomatoes under the integration of water and fertilizer by moistube irrigation is still unclear.In order to explore the changes in soil nutrients and enzyme activities of greenhouse tomatoes regulated by irrigation and fertilization in moistube irrigation greenhouse,a completely randomized experimental design was conducted to explore the effects of different irrigation amounts(I,controlling the work-ing pressure head of moistube to achieve different irrigation amount gradients,capillary working pressure was 1(I1),2(I2),3(I3)m)and fertilization amounts(F,single fertilization amount was 100(F1),200(F2),300(F3)kg/hm2)on soil nutrients,enzyme activities and yield of greenhouse tomato.It was found that with the increase of I,the total organic carbon content(TOC),soilβ-glucosidase(BG),leucine amino peptidase(LAP),N-acetylglucosaminidase(NAG),and alkaline phosphatase(AP)activities enzyme of greenhouse tomato soil increasedfirst and then decreased.When the I increased from I1 to I3,the soil total nitrogen(TN)decreased by 5.07%and 4.91%,respectively,and the soil total phosphorus(TP)by 4.37%and 4.22%,respectively.With the increase of fertilizer amounts,the TOC of tomato soil increasedfirst and then decreased,the activities of BG,LAP,NAG and AP in soil increasedfirst and then decreased,and the contents of TN and TP in soil decreased by 4.79%and 4.68%,12.32%and 10.47%,respectively.The yield of tomatoes treated with I2 was significantly higher than that of I1 and I3 by about 13.99%and 1.29%,respectively.The tomato yield of F2 treatment was significantly higher than that of F1 and F3 treatments by about 22.57%and 1.72%,respectively.Based on the analysis of stoichiometry,it was found that soil carbon was more scarcity than nitrogen in greenhouse tomatoes under the integration of water and fertilizer by moistube irrigation.Soil carbon,nitrogen,phosphorus,enzyme activity and their respective stoichiometry showed a quadratic curve relationship with yield.Therefore,I2F2 treat-ment of greenhouse tomatoes can not only reduce soil carbon and nitrogen limitations but also improve soil enzyme activity and achieve multiple goals of increasing greenhouse tomato yield,and saving water and fertilizer.This conclusion contributes to a more reasonable irrigation and fertilization of tomatoes in moistube irrigation greenhouse and soil nutrient management of facility agriculture through empirical proofs.
