Moist-Soil Plants as Ecohydrologic Indicators for Recovering the Flood Pulse in the Illinois River

The hydrologic regime of the Illinois River has been substantially altered by locks and dams, floodplain levees, water diversion, and development of the watershed over the past 100 years. The natural flood pulse, a fundamental rhythm to which the plants and animals of both the river and its floodplain had adapted, has been disrupted. State, federal, and non‐governmental organizations are currently trying to naturalize the Illinois floodplain‐river system. Little, however, is known about how to recover those elements of the flood pulse essential to the native biota. In this study we propose moist‐soil plants, whose life history is dependent upon flood pulsing, as ecohydrologic indicators of the flood pulse. We explain how moist‐soil plants are supported by the natural flood pulse and present a conceptual framework that links the flooding regimes of the river and the reproductive success of the plants. Successful germination and full growth of moist‐soil plants can be a useful indicator for optimum naturalization of flood regimes. The framework also shows how the interdisciplinary linkages between hydrology, ecology, and spatial analysis assist in predicting, measuring, and comparing consequences of alternative naturalization scenarios. A new ecohydrologic parameter, lowest elevation for successful moist‐soil plant production, is presented.     

Effect of soil texture and its organic content on the efficacy of Trichoderma harzianum (MIAU 145 C) in controlling Meloidogyne javanica and stimulating the growth of kidney beans

The efficiency of Trichoderma harzianum (MIAU 145 C) in promoting kidney bean (cv. Goli) growth in different soil texture (sandy loam, loam and clay loam) and organic matter content (0.5 and 2% of leaf litter) was assessed in a factorial experiment in the absence of Meloidogyne javanica. In another factorial experiment, the effect of soil texture, soil organic content and control measure (no control, 10?ml of T. harzianum containing 10⁶ spore ml^?1 and 2?mg ai cadusafos kg^?1 soil) was determined on nematode-infected kidney bean’s growth, fungus controlling activity and M. javanica reproduction. Except for the shoot length, the fungus improved plant growth. Clay loam was not a proper soil type for the cultivation of kidney bean plants (even in the soil without nematode), but the plant grew better in sandy loam and loam soil. The presence of leaf litter in the soil enhanced plant growth, increased fungal efficiency and increased nematode reproduction. It seems that T. harzianum can activate the plant defence system in sandy loam soil. T. harzianum was more effective in sandy loam or loam soil containing 2% organic matter (leaf litter) and reduced the reproduction factor of the nematode in the tested soil textures equally to the chemical nematicide treatment.     

Development and use of a short-term nutrient-absorption technique for evaluating soil magnesium status

Summary A greenhouse investigation was undertaken to study and evaluate the use of a short-term nutrient-absorption technique for evaluating soil magnesium status. Barley (Hordeum vulgare), variety Arivat, was used as the test plant. The investigation included four experiments with the following objectives: (1) to determine the need for base applications of nitrogen and phosphorus in a soil-magnesium study using a short-term nutrient absorption technique; (2) to study the effect of base applications of N and P on Mg-uptake by plants under three time periods of root-soil contact; (3) to study the effect of increasing soil moisture from 75 to 100 per cent of the soil moisture equivalent on the plant uptake of Mg; and (4) to evaluate the short-term nutrient-absorption technique in determining the magnesium status in six different soils: Gila silt loam, Tours silty clay loam, Cajon clay loam, La Palma fine sandy loam, Yavapai sandy clay loam, and Casa Grande loam. Magnesium was applied in the form of MgSO₄ and Sul-PO-Mag.Plant growth, potassium, calcium, and magnesium uptake were increased by the base application of nitrogen and phosphorus using a 7-day period of root-soil contact.Plant growth was not affected by soil moisture level. Potassium and calcium concentrations in the plant were decreased with increasing soil moisture, but the total plant uptake of these nutrients was not affected. Total plant uptake and concentration of magnesium were increased by increasing soil moisture level.The results obtained in this study agree with previous observations that soil response to Mg does not depend upon the amount of exchangeable magnesium in the soil.Published as Arizona Agr. Expt. Station Technical Publication No.848.     

Nutrients and antinutrient constituents of Amaranthus caudatus L. Cultivated on different soils

This study investigated variations in the concentration of nutrients, antinutrients and mineral content of Amaranthus caudatus harvested from different soil types at various stages of maturity. Four out the five soils namely; sandy clay loam, silty clay loam, clayey loam and loam were experimentally formulated from primary particles of silt, clay and sand in line with the United State Department of Agriculture’s (USDA) soil triangle protocol. The unfractionated soil was used as the control. After harvesting at pre-flowering (61 days after planting), flowering (71 days after planting) and post-flowering (91 days after planting) stages, nutrient and antinutrient analyses were carried out following Association of Official Analytical Chemists (AOAC) and other referenced methods while the Inductively Coupled Plasma- Optical Emission Spectrometer was used to determine mineral compositions of the plant samples. The results of the study revealed that particle size and physicochemical properties of the soil influenced the number of minerals deposited in plant tissues. It was further observed that the nutritional properties of the plant change as plant ages. For an optimal yield of vitamins A and E, clayey loam proved to be the best soil particularly when A. caudatus is harvested before flowering but for vitamin C, sandy clayey loam yielded the highest output at the same stage. Similarly, clayey loam and loam soils yielded the highest proximate compositions at flowering and pre-flowering; however, mineral elements (micro and macro) were highest in control and loam soils.     

The effect of traces of beryllium on the growth of kale,grass, and mustard

Summary The effects of varying concentrations of beryllium on the growth of kale, grass and mustard in soil and in nutrient culture are reported. One to two ppm of dissolved Be was toxic in cultures and in acid soils but not in soils containing free calcium carbonate. A soluble beryllium salt significantly increased growth of crops in a calcareous soil but was persistently toxic for an acid sandy loam.     

Experimental manipulation of water levels in two French riverine grassland soils

In this experimental study, we simulated the effects of different river flooding regimes on soil nutrient availability, decomposition and plant production in floodplain grasslands. This was done to investigate the influences of soil water contents on nutrient cycling. Water levels were manipulated in mesocosms with intact soil turfs from two French floodplain grasslands. Three water levels were established: a `wet' (water level at the soil surface), an `intermediate' (water level at –20 cm) and a `dry' treatment (water level at –120 cm). With increasing soil moisture, soil pH became more neutral, while redox-potential and oxygen concentration decreased. The `dry' treatment showed much lower values for process rates in soil and vegetation than the `intermediate' and `wet' treatments. Regressions showed that soil C-evolution and N-mineralization were positively related to soil moisture content. Not all mineralized N was available for plant uptake in the wet treatment, as a considerable part was denitrified here. Denitrification was especially high as soil water contents increased to levels above field capacity, where redox-potentials sharply dropped. Further, soil P availability was higher under wet conditions. In the `dry' treatment, soil water content was close to the wilting point and plant production was low. In the `intermediate' treatment, plant production was most likely limited by nitrogen. The `wet' treatment did not result in a further increase in plant production. Dam construction and river bed degradation can result in lower river levels and summer drought on floodplains. This experimental study suggests that summer drought on floodplain soils reduces decomposition of soil organic matter, nutrient availability, denitrification, plant production and nutrient uptake. This can affect the capacity of floodplains to remove or retain nutrients from river water in a negative way.     

Growth,root colonization and nutrient status of Helianthemum sessiliflorum Desf. inoculated with a desert truffle Terfezia boudieri Chatin

This study aims to investigate the effects of inoculation using Terfezia boudieri Chatin ascospores (ectomycorrhizal fungus) on growth, root colonization and nutrient status of Helianthemum sessiliflorum Desf. seedlings grown in pots on two-soil types (gypseous and sandy loam). Mycorrhizal seedlings had significantly increased their height and leaf number compared to non-mycorrhizal ones. Regardless of mycorrhizal inoculation treatments, the plants growing on gypseous soil showed higher growth as compared to sandy loam one. It appears that inoculation with T. boudieri changed root morphology, increasing branching of first-order lateral roots of H. sessiliflorum seedlings. The highest root mycorrhizal colonization was recorded in inoculated seedlings on sandy loam soil (89%) when compared to gypseous one (52%). N, P and K concentrations in mycorrhizal seedlings were significantly improved by fungal inoculation. It can be concluded that inoculation of H. sessiliflorum with T. boudieri increased growth attributes and improved plant nutritional status.     

Otolith trace element and stable isotopic compositions differentiate fishes from the Middle Mississippi River, its tributaries, and floodplain lakes

Naturally occurring stable isotope and trace elemental markers in otoliths have emerged as powerful tools for determining natal origins and environmental history of fishes in a variety of marine and freshwater environments. However, few studies have examined the applicability of this technique in large river-floodplain ecosystems. This study evaluated otolith microchemistry and stable isotopic composition as tools for determining environmental history of fishes in the Middle Mississippi River, its tributaries, and floodplain lakes in Illinois and Missouri, USA. Fishes were collected from 14 sites and water samples obtained from 16 sites during summer and fall 2006 and spring 2007. Otolith and water samples were analyzed for stable oxygen isotopic composition (δ¹⁸O) and concentrations of a suite of trace elements; otoliths were also analyzed for carbon isotopic composition (δ¹³C). Tributaries, floodplain lakes, and the Mississippi and Lower Missouri Rivers possessed distinct isotopic and elemental signatures that were reflected in fish otoliths. Fish from tributaries on the Missouri and Illinois sides of the middle Mississippi River could also be distinguished from one another by their elemental and isotopic fingerprints. Linear discriminant function analysis of otolith chemical signatures indicated that fish could be classified back to their environment of capture (Mississippi River, floodplain lake, tributary on the Illinois or Missouri side of the Mississippi River, or lower Missouri River) with 71–100% accuracy. This study demonstrates the potential applicability of otolith microchemistry and stable isotope analyses to determine natal origins and describe environmental history of fishes in the Middle Mississippi River, its tributaries, and floodplain lakes. The ability to reconstruct environmental history of individual fish using naturally occurring isotopic markers in otoliths may also facilitate efforts to quantify nutrient and energy subsidies to the Mississippi River provided by fishes that emigrate from floodplain lakes or tributaries.     

Uptake of six heavy metals by oat as influenced by soil type and additions of cadmium,lead, zinc and copper

Summary The influence of heavy metal additions on availability and uptake of cadmium, lead, zinc, copper, manganese and iron by oat was studied. The experiments were carried out as pot experiments using sandy loam, sandy soil and organic soil. Selective extractants were used to remove metals held in different soil fractions.Lead and copper were preferently bound by organics and oxides, zinc by oxides and inorganics, and cadmium by inorganics and organics.Addition of cadmium to the soils resulted in higher cadmium concentrations in all plant parts but lower concentrations of lead, zinc, copper, manganese and iron, and the accumulation indexes of these metals were also lower when cadmium was added to the soil.Addition of cadmium plus lead, zinc and copper resulted in higher cadmium concentrations in leaves and straw of plants grown in sandy loam and sandy soil, but lower concentrations when plants were grown in organic soil as compared with the results when cadmium was added separately. The transfer of cadmium, lead, zinc and copper from soil to plant was greatest from sandy soil, and zinc and cadmium were more mobile in the plant than were lead and copper.Cadmium concentrations in leaves correlated significantly with CaCl₂ and CH₃COOH extractions in sandy loam and sandy soil and with CH₃COOH extractions in organic soil.Generally, the total metal uptake was lowest from organic soil.     

Response of Potamogeton crispus root characteristics to sediment heterogeneity

Plant growth, biomass allocation, root distribution and plant nutrient content were investigated in the submerged macrophyte Potamogeton crispus growing in heterogeneous sediments. Three experimental sediments heterogeneous in nutrient content and phosphorus release capacity were used: sandy loam with low nutrient content (A), clay with intermediate nutrient content (B), and clay with high nutrient content (C). Biomass accumulation was significantly affected by the sediment type, and was highest in clay C (1.23 mg per plant dry weight) but lowest in sandy loam (0.69 mg per plant dry weight). The root:shoot ratios in treatments A, B and C were 0.30, 0.14 and 0.09, respectively. P. crispus allocated more biomass to roots in sandy loam compared with the other sediments. The average root numbers in sediments A, B and C were 16, 19 and 20, respectively, and the total root lengths in sediments A, B and C were 238.84, 200.36 and 187.21 cm, respectively. Almost 90% of the root biomass was distributed in the 0–15 cm depth in sediments B and C, compared with 64.53% in sediment A. The rank order of plant nitrogen and phosphorus concentrations in the sediment types was C > B > A. These results indicate that both sediment structure and nutrient availability influence the growth and distribution of the root system of P. crispus.     

Influences of vegetation status on seedling survival of a river-endemic plant Aster kantoensis in the floodplain

To assess the vegetation status and substrate condition on seedling survival and flowery of an endangered plant species Aster kantoensis, I carried out an in situ seed-sowing experiment in the gravelly/sandy floodplain of the Kinu River, central Japan. The coverage of plant species, especially that of an alien species Eragrostis curvula, increased, and the subsequent reduction in the relative photosynthetically active photon flux density (PPFD) (%) after the large-scale flood in 1998 caused a decline in the percentage of seedling survival and flowery of A. kantoensis. Performances of A. kantoensis were compared under four types of seminatural conditions, i.e., combinations of existence or absence of E. curvula combined with gravelly or sandy substrates. The highest percentage of survival and flowery were observed on the gravelly substrate under the E. curvula,-free conditions, but values were low in areas invaded by E. curvula. Aggressive invasion of E. curvula was the principal cause of loss of safe sites for colonization of river-endemic plants.     

Flood events overrule fertiliser effects on biomass production and species richness in riverine grasslands

Question: Do severe winter flood events lift the nutrient limitation of biomass production in a river floodplain? How does this affect plant species richness? How long do the effects last? Location: Floodplain grassland on calcareous sandy loam near river Rhine in The Netherlands. Methods: Plots were fertilised with four treatments (control, N, P, N+P) for 21 years; plant species composition, vegetation biomass and tissue nutrient concentrations were determined every year between 1985 and 2005. Results: Fertilisation with N generally increased biomass production and reduced species richness, but these effects varied over time. During the first four years of the experiment, biomass production appeared to be co‐limited by N and P, while N fertilisation dramatically reduced plant species richness; these effects became weaker subsequently. Following two extreme winter floods in 1993–94 and 1994–95 and a drought in spring 1996, the effects of fertilisation disappeared between 1998 and 2001 and then appeared again. Flooding caused an overall reduction in species richness (from c. 24 to 15 species m^‐2) and an increase in biomass production, which were only partly reversed after ten years. Conclusions: Long time series are necessary to understand vegetation dynamics and nutrient limitation in river floodplains, since they are influenced by occasional flood and drought events, whose effects may persist for more than ten years. A future increase in flooding frequency might be detrimental to species richness in floodplain grasslands.     

Control of pea cyst-nematode, Heterodera goettingiana, by small amounts of aldicarb, Du Pont 1410, Ciba-Geigy 10576 or Dowco 275 applied to the soil at planting time

Aldicarb, or Du Pont 1410 (S-methyl-I-(dimethylcarbamoyl)-N-[(methyl-carbamoyl)oxy]thioformimidate), at 2.8–22.4 kg a.i./ha incorporated in the seed-bed before sowing greatly increased the yield of peas in a clay loam and two sandy clay soils infested with pea cyst-nematode, Heterodera goettingiana, and lessened or prevented increase in the number of nematodes. CibaGeigy 10576 (an organophosphorus compound) at 5.6–22.4 kg a.i./ha was similarly effective in a sandy clay soil. Dowco 275 (O, O-diethylO-(6-fluoro-2 pyridyl) phosphorothioate) at 5.6 or 11.2 kg a.i./ha also controlled the nematode well in the clay loam and in a sandy clay soil but although it greatly increased the yield of peas in the clay loam, it did not increase yield in the sandy clay.     

Soil types with different texture affects development of Rhizoctonia root rot of wheat seedlings

The effect of different soil textures, sandy (97.5% sand, 1.6% silt, 0.9% clay), loamy sand (77% sand, 11% silt, 12% clay) and a sandy clay loam (69% sand, 7% silt, 24% clay), on root rot of wheat caused by Rhizoctonia solani Kühn Anastomosis Group (AG) 8 was studied under glasshouse conditions. The reduction in root and shoot biomass following inoculation with AG-8 was greater in sand than in loamy sand or sandy clay loam. Dry root weight of wheat in the sand, loamy sand and sandy clay loam soils infested with AG-8 was 91%, 55% and 28% less than in control uninfested soils. There was greater moisture retention in the loamy sand and sandy clay loam soils as compared to the sand in the upper 10–20 cm. Root penetration resistance was greater in loamy sand and sandy clay loam than in sand. Root growth in the uninfested soil column was faster in the sand than in the loamy sand and sandy clay loam soils, the roots in the sandy soil being thinner than in the other two soils. Radial spread of the pathogen in these soils in seedling trays was twice as fast in the sand in comparison to the loamy sand which in turn was more than twice that in the sandy clay loam soil. There was no evidence that differences among soils in pathogenicity or soil spread of the pathogen was related to their nutrient status. This behaviour may be related to the severity of the disease in fields with sandy soils as compared to those with loam or clay soils. This revised version was published online in June 2006 with corrections to the Cover Date.     

A comparison of fine root distribution and water consumption of mature Caragana korshinkii Kom grown in two soils in a semiarid region, China

Water is a key limiting factor for vegetation restoration in the semi-arid areas of China. Caragana korshinkii Kom is a shrub that is widely planted in this region to control soil erosion and land desertification. The objective of this study was to investigate the fine root distribution of mature C. korshinkii and its water consumption, when grown in either silt loam or sandy soils, in order to understand differences between the water cycles of two such soils found in the transition zone between fertile loess hills and desert of the Northern Loess Plateau. Fine root distributions were measured using the trench-profile method. Soil water dynamics were monitored with a neutron probe during two growing seasons. The results showed that fine root area density (FRAD) declined with increasing soil depth in both soils, with 70.7% and 96.6% of the total fine roots being concentrated in the upper 1-m layer of the silt loam and sandy soils, respectively. Water consumption by C. korshinkii in the silt loam was close to that in the sandy soil. Most water consumption in both soil types was from the upper 1-m layer. Little variation in plant available water (PAW) occurred in the 3–6 m soil layer during the whole study period. However, in this layer, the PAW was significantly lower in the silt loam soil than in the sandy soil. Total actual evapotranspiration (ET_a) was slightly higher from the sandy soil plots than from those of the silt loam soil during both growing seasons. Our study indicated that mature C. korshinkii effectively uses about the same amount of water from either the silt loam or sandy soils, but that more soil water at depth was extracted from silt loam soil than from sandy soil.     

Nutrient limitation of plant growth on the floodplain of the Narran River, Australia: growth experiments and a pilot soil survey

Water resource development has altered the hydrological regime on the Lower Balonne River in Queensland, Australia. Concerns have been raised about possible impacts to floodplain plant communities, which support a pastoral industry and a range of native fauna. Water and nutrients commonly limit plant growth in south central Queensland, where the climate is semi-arid and the soils are infertile. Floodplain plant productivity is boosted by inundation with water, but the role of flooding in nutrient provision is not known. Growth experiments and a pilot soil survey were conducted to help determine if soil nutrient deficiencies exist and if regular flooding is required to maintain floodplain soil fertility. Soils were sampled from areas representing three flood frequency classes: high, moderate, and low. Chemical extractions were performed as a surrogate for `bioavailable' nutrients. Soil nitrogen (N) but not phosphorus (P) limited the growth of seedlings of wheat (Triticum aestivum L. Gardia) based on responses to nutrient additions: plants supplied with N had greater shoot length and total biomass than plants without N. Clear evidence of an effect of flood frequency on fertility was not revealed. Neither soil P, soil N, nor plant growth varied significantly with flood frequency. However, this analysis had low statistical power. There were trends for greater biomass of seedlings grown on moderately flooded soils and thinner roots for seedlings grown on frequently flooded soils, but neither of these growth responses was clearly linked to nutrient limitation. Nevertheless, the possibility that flooding provides a nutrient subsidy to plants cannot be ruled out because of a number of factors, including the statistical power of this analysis and the possibility that short-term nutrient subsidies occur with floods.     

Studies of the cereal cyst-nematode, Heterodera avenae under continuous cereals, 1974–1978. I. Plant growth and nematode multiplication

Population changes of Heterodera avenae and crop growth in a sandy loam soil were studied from 1974 until 1978; the nematode decreased plant growth but failed in two of the years to multiply on susceptible hosts. Spring oats were the most heavily invaded cereal and produced the smallest shoots. Second-stage juveniles invaded cereal roots in decreasing numbers: spring oats > autumn oats > spring barley > spring wheat > autumn barley > autumn wheat. Numbers of females developing on the different cultivars were in a similar order. Most females developed on roots in 1976 despite poor crop growth in the severe drought. Numbers of H. avenae in soil treated with oxamyl (Vydate) at 8.8 kg/ha a. i. were less in all years except 1975. In the dry winter and spring of 1975/76 nematode multiplication was prevented in soil treated with oxamyl before drilling in the autumn. In all years large numbers of females were produced on the roots of all cultivars but in 1975 and 1978 nematode populations declined because few females survived to form cysts containing eggs and their fecundity was reduced. Numbers of cysts after harvest were not affected by formalin (38% formaldehyde) applied as a drench at 3000 litres/ha in 1977 but fecundity doubled in treated soil, and nematode multiplication increased from 3.8 × in untreated plots to 18.6 ×. When the plots were irrigated in 1978 numbers of cysts and fecundity increased in formalin treated soil resulting in an increase in multiplication from 0.3 × to 14.6 ×. Fungal parasites attacking H. avenae females and eggs are considered responsible for the poor multiplication of the nematode.     

Influence of soil factors,fertilizers and manures on pathogenicity ofRhizoctonia solani onVigna species

Rhizoctonia solani caused maximum mortality of mung bean seedlings at 20°C, and the disease incidence decreased with increase of temperature; 30° was optimum for mycelial growth of the fungusin vitro. The fungus grew best in nutrient broth of pH 5.5 but infected mung bean and pea seedlings more severely in neutral and alkaline river sand than in the sand adjusted to acidic reaction. The disease incidence was higher in adequately moist sandy loam and less in soil under moisture stress. Incidence of cowpea seedling rot was higher in heavy-textured loam and silt loam soils than in light-textured sandy- and loamy sand. Addition of montmorillonite and kaolinite in the sandy soil increased the disease incidence, but these clays reduced fungus growth in culture. More seedling rot occurred in the sandy soil fertilized with urea, potassium nitrate, monocalcium phosphate, or potassium dihydrogen phosphate while soil application of ammonium nitrate, potassium chloride, or potassium sulphate decreased the disease. In tests with combined soil application of N (as urea), P (as monocalcium phosphate) and K (as potassium chloride), disease incidence was more in all combinations having P. Among the six micronutrients tested, only boron reduced the disease incidence significantly both in presence and absence of NPK fertilizers. Farm-yard manure and biogas sludge aggravated seedling rot but their water extracts decreased it. Humic acid, extracted from farm-yard manure, increased the disease incidence but was inhibitory to fungus growth in culture. Green manure also resulted in more disease.     

Effect of soil atmosphere on bacterial populations and activity

Summary Bacteria were counted and the nitrogen mineralized was measured in a sandy loam, a clay loam, a clay soil and a humic clay by incubating the agar medium used for the countings and the soils (a) in petri dishes at 29°C in the atmosphere of the laboratory, (b) in petri dishes buried in a sandy loam and (c) in petri dishes buried in a sandy loam enriched with one per cent of lucerne meal. Most bacteria were found in treatment (a) and least in treatment (c). In some cases treatment (c) stimulated mineralization of nitrogen. However, the results obtained are still inconclusive. In the sandy loam, clay loam and clay soil fewer protein decomposers were found after 6 weeks with treatment (c) than with treatments (a) or (b). Compared with treatment (a) fewer starch decomposers were found in treatment (c) only in the clay loam and clay soil.     

The effect of formalin on potato cyst-nematode, Heterodera rostochiensis

Applying 5 ml of a 38% aqueous solution of formaldehyde to 1500 ml of sandy loam prevented potato cyst-nematode, Heterodera rostochiensis, from increasing on the roots of Arran Banner potatoes planted in the soil and increased the weight of tubers produced. A comparable dosage applied to plots of sandy loam and sandy clay in winter did not prevent the nematode from multiplying on Pentland Crown potatoes but increased tuber yields. Smaller amounts of formalin had less effect on tuber yields and drenching dilute formalin solutions onto the soil was no more effective than incorporating undiluted formalin into the soil by rotavation 15 cm deep.