The effect of riparian restoration on channel complexity and soil nutrients

2017 ◽  
Vol 68 (11) ◽  
pp. 2041 ◽  
Author(s):  
J. Patrick Laceby ◽  
Nina E. Saxton ◽  
Kate Smolders ◽  
Justine Kemp ◽  
Stephen J. Faggotter ◽  
...  

Restoration of riparian vegetation may reduce nutrient and sediment contamination of waterways while potentially enhancing stream channel complexity. Accordingly, the present study used a paired-site approach to investigate the effects of mature regrowth riparian vegetation on river channel morphology and soil nutrients (i.e. nitrogen and phosphorus), comparing four sites of degraded (pasture) and reforested reaches. A revised rapid assessment of riparian condition (RARC) was used to validate the site pairings. Riparian soil nutrient and elemental geochemistry were compared between paired sites, along with two parameters of channel width complexity and two for channel slope complexity. The RARC analysis confirmed the validity of the paired site design. The elemental geochemistry results indicated that underlying geology may affect the paired site analyses. Reaches with mature regrowth vegetation had greater channel width complexity but no difference in their riverbed slope complexity. In addition, degraded reaches had higher soil nutrient (i.e. nitrogen and phosphorus) concentrations, potentially indicative of the greater nutrient retention of pasture grass sites compared with mature regrowth forested reaches with less ground cover. Overall, the present study indicates that restoring mature regrowth riparian vegetation may increase river channel width complexity, although it may require canopy management to optimise the nutrient retention potential necessary to maximise the effect of riparian restoration strategies on freshwater environments.

Botany ◽  
2013 ◽  
Vol 91 (2) ◽  
pp. 82-90 ◽  
Author(s):  
David R. Johnson ◽  
Laura Gough

Greater soil nutrients are thought to increase graminoid tolerance to herbivory (within-season regrowth following herbivore damage) by enabling new growth in response to defoliation, but these responses vary among graminoid species. We studied how two arctic graminoids, Eriophorum vaginatum (L.) in moist acidic tussock (MAT) tundra and Hierochloe alpina (Roem. & Schult.) in dry heath (DH) tundra, tolerate both experimental and natural herbivory when fertilized with nitrogen and phosphorus. Fertilization reduced the tolerance and recovery (regrowth in subsequent years) of defoliated Eriophorum relative to plants growing without fertilization. In contrast, fertilized Hierochloe plants regrew well following defoliation. These opposing results may be due to differential abilities of these two species to access other resources in MAT and DH when fertilized. Herbivory may be affecting access to light of Eriophorum in the more productive, closed canopy MAT, in spite of its ability to grow bigger when fertilized. Hierochloe may not face such a limitation in the more open DH community. Alternatively, the different responses between these two species could be caused by environmental differences between the two communities. Regardless, our results suggest that although high tolerance is thought to be a functional characteristic of graminoids, tolerance to herbivory varies within and between species with soil nutrient availability and thus caution must be exercised in predicting responses to herbivory within this plant growth form.


2021 ◽  
pp. 969-976
Author(s):  
Lirong He ◽  
Yuhu Luo

The soil nutrient characteristics under three vegetation types of arbor ( I ), shrub ( II ) and herb ( III ) were studied by mathematical statistics method combined with field investigation and indoor detection analysis. The change characteristics of soil nutrients under different land use patterns were discussed. The results showed that the average contents of soil organic matter, total nitrogen, available phosphorus and available potassium were 21.30 and 0.65 g/kg, 3.67 and 67.61 mg/kg, respectively. Compared with grassland, woodland has better effect on fertilizer conservation in the Loess Plateau. In the process of soil nutrient improvement, the nutrient indexes such as organic matter, total nitrogen, available phosphorus and available potassium increased synchronously, and the soil alkaline environment that was not conducive to plant growth was also gradually improved. In the correlation between soil nutrients, available phosphorus and available potassium have good relative independence. In the future, organic fertilizer should be applied in this area, and nitrogen and phosphorus fertilizers should be supplemented to improve soil organic matter, nitrogen and phosphorus content, and to ensure soil nutrient balance by optimizing fertilization methods. In addition, in the case of uneven distribution of soil nutrients in the soil profile, it is recommended to take appropriate soil ploughing and reasonable human management measures to improve soil nutrient status, achieve high-quality sustainable development of soil, and promote the positive succession of vegetation communities. Bangladesh J. Bot. 50(3): 969-976, 2021 (September) Special


2021 ◽  
Vol 5 (2) ◽  
pp. 99-103
Author(s):  
Dhruba Baral ◽  
Anup Paudel ◽  
Himal Acharya ◽  
Madhav Prasad Neupane

This study was conducted to assess the fertility status of different altitude of apple orchard and their effect upon soil nutrients and to study the relationship between different altitude and their availability. Seven different orchards located in 2800, 2700 2600, 2500, 2400, 2300 and 2200 at Apple Zone, Raskot, Kalikot were selected as treatments. They were replicated three times in Randomized Complete Block Design. Composite soil samples were collected in each study site from 0-3 ft soil depth in ‘W’ pattern from each plot. Analyses of soil samples were done in regional soil testing laboratory, Surkhet for chemical properties. There was a significant effect (p<0.05) of altitude on soil macronutrients except available potassium level. Maximum amounts of soil organic matter, acidic and soil rich in nitrogen and phosphorus were found in 2800 masl whereas more basic soil , poor soil organic matter and soil poor in nitrogen and phosphorus were found in 2200 masl. Result showed that in altitude of 2200 masl has poor soil nutrients compared to apple orchards in higher altitude. Kalikot is the top producer of apple in Nepal. This assessment will helps apple growers for adopting better nutrient management plan in their orchards according to the altitude in the district. Further, it is recommended to conduct soil nutrient assessments for all other apple growing regions in the country.


2015 ◽  
Vol 12 (5) ◽  
pp. 4057-4106 ◽  
Author(s):  
Q. Zhu ◽  
W. J. Riley ◽  
J. Tang ◽  
C. D. Koven

Abstract. Soil is a complex system where biotic (e.g., plant roots, micro-organisms) and abiotic (e.g., mineral surfaces) consumers compete for resources necessary for life (e.g., nitrogen, phosphorus). This competition is ecologically significant, since it regulates the dynamics of soil nutrients and controls aboveground plant productivity. Here we develop, calibrate, and test a nutrient competition model that accounts for multiple soil nutrients interacting with multiple biotic and abiotic consumers. As applied here for tropical forests, the Nutrient COMpetition model (N-COM) includes three primary soil nutrients (NH4+, NO3−, and POx (representing the sum of PO43−, HPO42−, and H2PO4−)) and five potential competitors (plant roots, decomposing microbes, nitrifiers, denitrifiers, and mineral surfaces). The competition is formulated with a quasi-steady-state chemical equilibrium approximation to account for substrate (multiple substrates share one consumer) and consumer (multiple consumers compete for one substrate) effects. N-COM successfully reproduced observed soil heterotrophic respiration, N2O emissions, free phosphorus, sorbed phosphorus, and free NH4+ at a tropical forest site (Tapajos). The overall model posterior uncertainty was moderately well constrained. Our sensitivity analysis revealed that soil nutrient competition was primarily regulated by consumer-substrate affinity rather than environmental factors such as soil temperature or soil moisture. Our results imply that the competitiveness (from most to least competitive) followed this order: (1) for NH4+, nitrifiers ~ decomposing microbes > plant roots, (2) for NO3−, denitrifiers ~ decomposing microbes > plant roots, (3) for POx, mineral surfaces > decomposing microbes ~ plant roots. Although smaller, plant relative competitiveness is of the same order of magnitude as microbes. We then applied the N-COM model to analyze field nitrogen and phosphorus perturbation experiments in two tropical forest sites (in Hawaii and Puerto Rico) not used in model development or calibration. Under soil inorganic nitrogen and phosphorus elevated conditions, the model accurately replicated the experimentally observed competition among different nutrient consumers. Although we used as many observations as we could obtain, more nutrient addition experiments in tropical systems would greatly benefit model testing and calibration. In summary, the N-COM model provides an ecologically consistent representation of nutrient competition appropriate for land BGC models integrated in Earth System Models.


2016 ◽  
Vol 13 (1) ◽  
pp. 341-363 ◽  
Author(s):  
Q. Zhu ◽  
W. J. Riley ◽  
J. Tang ◽  
C. D. Koven

Abstract. Soil is a complex system where biotic (e.g., plant roots, micro-organisms) and abiotic (e.g., mineral surfaces) consumers compete for resources necessary for life (e.g., nitrogen, phosphorus). This competition is ecologically significant, since it regulates the dynamics of soil nutrients and controls aboveground plant productivity. Here we develop, calibrate and test a nutrient competition model that accounts for multiple soil nutrients interacting with multiple biotic and abiotic consumers. As applied here for tropical forests, the Nutrient COMpetition model (N-COM) includes three primary soil nutrients (NH4+, NO3− and POx; representing the sum of PO43−, HPO42− and H2PO4−) and five potential competitors (plant roots, decomposing microbes, nitrifiers, denitrifiers and mineral surfaces). The competition is formulated with a quasi-steady-state chemical equilibrium approximation to account for substrate (multiple substrates share one consumer) and consumer (multiple consumers compete for one substrate) effects. N-COM successfully reproduced observed soil heterotrophic respiration, N2O emissions, free phosphorus, sorbed phosphorus and NH4+ pools at a tropical forest site (Tapajos). The overall model uncertainty was moderately well constrained. Our sensitivity analysis revealed that soil nutrient competition was primarily regulated by consumer–substrate affinity rather than environmental factors such as soil temperature or soil moisture. Our results also imply that under strong nutrient limitation, relative competitiveness depends strongly on the competitor functional traits (affinity and nutrient carrier enzyme abundance). We then applied the N-COM model to analyze field nitrogen and phosphorus perturbation experiments in two tropical forest sites (in Hawaii and Puerto Rico) not used in model development or calibration. Under soil inorganic nitrogen and phosphorus elevated conditions, the model accurately replicated the experimentally observed competition among nutrient consumers. Although we used as many observations as we could obtain, more nutrient addition experiments in tropical systems would greatly benefit model testing and calibration. In summary, the N-COM model provides an ecologically consistent representation of nutrient competition appropriate for land BGC models integrated in Earth System Models.


2021 ◽  
Vol 13 (7) ◽  
pp. 3957
Author(s):  
Yingying Xing ◽  
Ning Wang ◽  
Xiaoli Niu ◽  
Wenting Jiang ◽  
Xiukang Wang

Soil nutrients are essential nutrients provided by soil for plant growth. Most researchers focus on the coupling effect of nutrients with potato yield and quality. There are few studies on the evaluation of soil nutrients in potato fields. The purpose of this study is to investigate the soil nutrients of potato farmland and the soil vertical nutrient distributions, and then to provide a theoretical and experimental basis for the fertilizer management practices for potatoes in Loess Plateau. Eight physical and chemical soil indexes were selected in the study area, and 810 farmland soil samples from the potato agriculture product areas were analyzed in Northern Shaanxi. The paper established the minimum data set (MDS) for the quality diagnosis of the cultivated layer for farmland by principal component analysis (PCA), respectively, and furthermore, analyzed the soil nutrient characteristics of the cultivated layer adopted soil quality index (SQI). The results showed that the MDS on soil quality diagnosis of the cultivated layer for farmland soil included such indicators as the soil organic matter content, soil available potassium content, and soil available phosphorus content. The comprehensive index value of the soil quality was between 0.064 and 0.302. The SPSS average clustering process used to classify SQI was divided into three grades: class I (36.2%) was defined as suitable soil fertility (SQI < 0.122), class II (55.6%) was defined as moderate soil fertility (0.122 < SQI < 0.18), and class III (8.2%) was defined as poor soil fertility (SQI > 0.186). The comprehensive quality of the potato farmland soils was generally low. The proportion of soil nutrients in the SQI composition ranged from large to small as the soil available potassium content = soil available phosphorus content > soil organic matter content, which became the limiting factor of the soil organic matter content in this area. This study revolves around the 0 to 60 cm soil layer; the soil fertility decreased gradually with the soil depth, and had significant differences between the respective soil layers. In order to improve the soil nutrient accumulation and potato yield in potato farmland in northern Shaanxi, it is suggested to increase the fertilization depth (20 to 40 cm) and further study the ratio of nitrogen, phosphorus, and potassium fertilizer.


2013 ◽  
Vol 389 ◽  
pp. 67-72
Author(s):  
Heng Jia Zhang ◽  
Jun Hui Li

An experiment was conducted to explore the integrated evaluation on soil nutrients in spring maize field subjected to limited irrigation (LI) in oasis region. The soil organic matter (SOM), soil total and available nitrogen (STN and SAN) and phosphorus (STP and SAP), and soil available potassium (SAK) in 0~40 cm increment at harvest of maize subjected to LI were selected as the evaluation factors to calculate the weighing coefficient of each soil nutrient and the IEI for soil nutrients using the membership function in fuzzy mathematics. At maize harvest, differences were not significant (p>0.05) in SOM, STN, STP, SAP, and SAK within 0~40 cm increment among treatments and CK, but significant difference (p<0.05) was found in SAN, with the maximum SAN maintained in MI5, which was respectively 187.3%, 96.8%, and 41.2% higher over MI2 valued the minimum, MI1, and CK. The IEI was improved by 12.4% to 22.3% in all the other treatments and CK compared to the minimum marked in MI4, with the maximum valued in MI3 treatments. Therefore, after one year experiment, the optimized irrigation management was maintained in MI3 treatment due to its maximum IEI in all the LI regimes.


1974 ◽  
Vol 4 (4) ◽  
pp. 530-535 ◽  
Author(s):  
Edwin H. White

This paper reports the effects of whole-tree harvesting of eight cottonwood stands on the soil nutrient pool. The data indicate possible site degradation by depletion of soil reserves of N, P, and K but not Ca and Mg on a range of alluvial site conditions in Alabama. Foresters must establish the rate of nutrient removal in intensive tree cropping systems for a variety of species and sites and develop prescriptions to minimize the impact.


2021 ◽  
Author(s):  
Mengjiao Sun ◽  
Enqing Hou ◽  
Jiasen Wu ◽  
Jianqin Huang ◽  
Xingzhao Huang

Abstract Background: Soil nutrients play critical roles in regulating and improving the sustainable development of economic forests. Consequently, an elucidation of the spatial patterns and drivers of soil nutrients in these forests is fundamental to their management. For this study, we collected 314 composite soils at a 0-30 cm depth from a typical hickory plantation in Lin 'an, Zhejiang Province, China. We determined the concentrations of macronutrients (i.e., soil organic carbon, hydrolyzed nitrogen, available phosphorus, and available potassium) and micronutrients (i.e., iron, manganese, zinc, and copper.) of the soils. We employed random forest analysis to quantify the relative importance of soil-forming factors to predict the soil nutrient concentrations, which could then be extrapolated to the entire hickory region. Results: Random forest models explained 61%–88% of the variations in soil nutrient concentrations. The mean annual temperature and mean annual precipitation were the most important predictor of soil macronutrient and micronutrient concentrations. Moreover, parent material was another key predictor of soil available phosphorus and micronutrient concentrations. Mapping results demonstrated the importance of climate in controlling the spatial distribution of soil nutrient concentrations at finer scales, as well as the effect of parent material, topography, stand structure, and management measures of hickory plantations. Conclusions: Our study highlights the biotic factors, abiotic factors, and management factors control over soil macronutrient and micronutrient concentrations, which have significant implications for the sustainability of soil nutrients in forest plantations.


2018 ◽  
Vol 40 ◽  
pp. 05044
Author(s):  
Andrés Vargas-Luna ◽  
Alessandra Crosato ◽  
Protogene Byishimo ◽  
Wim Uijttewaal

Alluvial rivers are shaped by sequences of water flows excavating their channels. Observations show that besides the magnitude, also the frequency and duration of streamflow oscillations might be important for the river channel formation. In addition, the river morphology appears influenced also by both size and degree of uniformity of the sediment. Nevertheless, many morphodynamic studies still represent the flow regime with a single value of the discharge, often corresponding to the bankfull condition, and the sediment with its median grain size. This work investigates the effects of streamflow variability and sediment characteristics on channel width formation, analysing the evolution of experimental streams with different sediments and discharge hydrographs. Results show that the formative condition of the channel width is not the geometric bankfull flow but a rather frequent peak flow. Remarkably different channel configurations arise from different sediment characteristics in the laboratory, where sediment non-uniformity produces more stable banks.


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