Arbuscular mycorrhizae and soil/plant water relations

2004 ◽  
Vol 84 (4) ◽  
pp. 373-381 ◽  
Author(s):  
Robert M. Augé
Keyword(s):  
Soil Moisture ◽  
Stomatal Conductance ◽  
Water Relations ◽  
Arbuscular Mycorrhizae ◽  
Glomus Intraradices ◽  
Sandy Loam ◽  
Characteristic Curve ◽  
Mycorrhizal Symbiosis ◽  
Plant Colonization ◽  
Moisture Characteristic

The water relations of arbuscular mycorrhizal (AM) plants have been compared often. However, virtually nothing is known about the comparative water relations of AM and nonAM soils or about the relative influence of AM colonization of soil vs. AM colonization of plants on host water balance. In this review, I summarize findings that support the assertion that colonization of soil may play as important a role as colonization of roots regarding how AM symbiosis affects the water relations of host plants. We observed a slight but significant AM effect on the soil moisture characteristic curve of a Sequatchie fine sandy loam following 7 mo of mycorrhization by Glomus intraradices/Vigna unguiculata. In a separate study, few AM effects on either the wet or dry hysteretic curves were discernible after 12 mo of mycorrhization by G. intraradices or Gigaspora margarita on roots of Phaseolus vulgaris. Using myc- bean mutants, we determined that about half of the considerable promotion of stomatal conductance by G. intraradices and Gi. margarita was attributable to soil colonization and about half to plant colonization. A path analysis modeling approach revealed that soil hyphal colonization had larger direct and total effects on dehydration tolerance of bean than did root hyphal colonization or several other soil or plant variables. Key words: Mycorrhizal symbiosis, soil moisture characteristic, stomatal conductance, water relations

Partitioning mycorrhizal influence on water relations of Phaseolus vulgaris into soil and plant components

2004 ◽  
Vol 82 (4) ◽  
pp. 503-514 ◽  
Author(s):  
Robert M Augé ◽  
David M Sylvia ◽  
Soon Park ◽  
Brian R Buttery ◽  
Arnold M Saxton ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Water Relations ◽  
Drought Resistance ◽  
Mycorrhizal Fungi ◽  
Glomus Intraradices ◽  
Characteristic Curve ◽  
Arbuscular Mycorrhizal ◽  
Mycorrhizal Symbiosis ◽  
Gigaspora Margarita ◽  
Soil Water Retention

There is growing appreciation of arbuscular mycorrhizal effects on soil properties and their potential consequences on plant behavior. We examined the possibility that mycorrhizal soil may directly influence plant water relations. Using wild-type and noncolonizing bean mutants planted into soils previously produced using mycorrhizal or nonmycorrhizal sorghum plants, we partitioned mycorrhizal influence on stomatal conductance and drought resistance into soil and root components, testing whether effects of mycorrhizal fungi occurred mostly via mycorrhization of roots, mycorrhization of soil, or both. The mutation itself had no effect on any water relations parameter. Colonization by Gigaspora margarita Gerdemann & Trappe and Glomus intraradices Schenck & Smith had appreciable effects on leaf water potential at the lethal point and on osmotic adjustment, relative to nonmycorrhizal plants of comparable size. Mycorrhizal effects on drought resistance were attributable to an effect on the plant itself rather than to an effect of mycorrhizal soil. Mycorrhizal effects on stomatal conductance were attributable to mycorrhization of both roots and soil, as well as to mycorrhization of roots alone. Surprisingly, merely growing in a mycorrhizal soil resulted in promotion of stomatal conductance of nonmycorrhizal plants in both amply watered and droughted plants. Mycorrhizal effects on droughted plants did not appear to be related to altered soil water retention properties, as Gigaspora margarita and Glomus intraradices altered the soil's moisture characteristic curve only slightly.Key words: arbuscular mycorrhizal symbiosis, bean, drought, Gigaspora margarita, Glomus intraradices, stomatal conductance.

COMPARISON OF METHODS FOR DETERMINING SATURATED HYDRAULIC CONDUCTIVITY AND DRAINABLE POROSITY OF TWO SOUTHERN ALBERTA SOILS

1986 ◽  
Vol 66 (2) ◽  
pp. 249-259 ◽  
Author(s):  
G. D. BUCKLAND ◽  
D. B. HARKER ◽  
T. G. SOMMERFELDT
Keyword(s):  
Soil Moisture ◽  
Hydraulic Conductivity ◽  
Characteristic Curve ◽  
Subsurface Drainage ◽  
Saturated Hydraulic Conductivity ◽  
Drainage Design ◽  
Moisture Characteristic ◽  
Constant Head ◽  
Subsurface Drains ◽  
Drainable Porosity

Saturated hydraulic conductivity (Ks) and drainable porosity (f) determined by different methods and for different depths were compared with those determined from the performance of drainage systems installed at two locations. These comparisons were made to determine which methods are suitable for use in subsurface drainage design. Auger hole and constant-head well permeameter Ks were 140 and 110%, respectively, of Ks determined from subsurface drains. Agreement of horizontal or vertical Ks, from in situ falling-head permeameters; to other methods was satisfactory providing sample numbers were large. Ks by Tempe cells was only 3–10% of drain Ks and in one instance was significantly lower than Ks determined by all other methods. At one site a profile-averaged value of f determined from the soil moisture characteristic curve (0–5 kPa) of semidisturbed cores agreed with that determined from drainage trials. At the other site, a satisfactory value of f was found only when the zone in which the water table fluctuated was considered. Results indicate that Ks determined by the auger hole and constant-head well permeameter methods, and f determined from the soil moisture characteristic curve of semidisturbed cores, are sufficiently reliable and practical for subsurface drainage design. Key words: Subsurface drainage, hydraulic conductivity, drainable porosity

scholarly journals Evaluation of commercial inorganic and organic fertilizer effects on arbuscular mycorrhizae formed by Glomus intraradices

2004 ◽  
Vol 14 (2) ◽  
pp. 196-202 ◽  
Author(s):  
R.G. Linderman ◽  
E.A. Davis
Keyword(s):  
Root Growth ◽  
Arbuscular Mycorrhizae ◽  
Glomus Intraradices ◽  
Sandy Loam ◽  
Organic Fertilizer ◽  
Am Fungi ◽  
Organic Fertilizers ◽  
Main Element ◽  
Growth Responses ◽  
And Function

Formation and function of arbuscular mycorrhizae (AM) are affected by levels of fertility in soil or fertilizers applied to soilless container mixes. For AM fungi, phosphorus (P) is the main element influencing colonization of host plant roots. The question addressed in this study was whether inorganic or organic fertilizers were more compatible with the formation and function of AM. Several controlled-release inorganic (CRI) fertilizers were compared with several organic (OR) fertilizers at different rates (½× to 4× the recommended rate) to determine (1) threshold levels of tolerance by the AM fungus Glomus intraradices in relation to root colonization, and (2) growth responses of `Guardsman' bunching onion (Allium cepa) and `Orange Cupido' miniature rose (Rosa spp.) plants grown in a soilless potting mix or sandy loam soil. AM colonization in soil was greatly decreased or totally inhibited by CRI fertilizers with high P content at the 2× rate or greater, whereas colonization was decreased but never eliminated by low-P OR fertilizers at the 3× rate or greater. Shoot growth of onions was similar with or without AM inoculation when fertilized with CRI, but in general was only enhanced by OR fertilizers if inoculated with AM fungi, compared to the noninoculated controls. Shoot and root growth of onions were significantly increased by AM inoculation when OR fertilizers were used at the 1× rate. In contrast, root growth was not increased by the combination of CRI fertilizers and AM fungal inoculation. Inoculation of miniature roses grown in sandy loam amended with 25% peat and perlite and fertilized with all the CRI or OR fertilizers resulted in high AM colonization, but without much AM-induced growth increase except where OR fertilizers or CRI fertilizers with low P were used. In a soilless potting mix, growth of miniature roses was less with OR fertilizers at the rates used than CRI fertilizers, but mycorrhiza formation was greater in the former unless P was low in the latter. These results indicate that release of nutrients from organic fertilizers, as a result of microbial activity, favors AM establishment and function more than most inorganic fertilizers unless P levels of the latter are low.

The Estimation of Soil Moisture Characteristic Curve and Model Parameters in a Steep Hillslope

2017 ◽  
Vol 17 (6) ◽  
pp. 175-184 ◽  
Author(s):  
Minji Cho ◽  
◽  
Yongseok Gwak ◽  
Sanghyun Kim ◽  
◽  
...  
Keyword(s):  
Soil Moisture ◽  
Characteristic Curve ◽  
Model Parameters ◽  
Moisture Characteristic

scholarly journals A scaling approach, predicting the continuous form of soil moisture characteristics curve, from soil particle size distribution and bulk density data

2013 ◽  
Vol 10 (11) ◽  
pp. 14305-14329 ◽  
Author(s):  
F. Meskini-Vishkaee ◽  
M. H. Mohammadi ◽  
M. Vanclooster
Keyword(s):  
Particle Size ◽  
Soil Moisture ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Characteristic Curve ◽  
Soil Samples ◽  
Continuous Form ◽  
Packing Parameter ◽  
Physically Based ◽  
Moisture Characteristic

Abstract. A substantial number of models, predicting the Soil Moisture Characteristic Curve (SMC) from Particle Size Distribution (PSD) data, underestimate the dry range of the SMC especially in soils with high clay and organic matter contents. In this study, we applied a continuous form of the PSD model to predict the SMC and subsequently, we developed a physically based scaling approach to reduce the model's bias at the dry range of the SMC. The soil particles packing parameter, obtained from the porosity was considered as a characteristic length. The model was tested by using eighty-two soil samples, selected from the UNSODA database. The result showed that the scaling approach properly estimate the SMC for all soil samples. In comparison to the formerly used physically based SMC model, the proposed approach improved the model estimations by an average of 30% for all soil samples. However, the advantage of this new approach was larger for the fine and medium textured soils than that for the coarse textured soil. In view that in this approach there is no further need for empirical parameters, we conclude that this approach could become applicable for estimating SMC at the larger field scale.

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