Influence of soil water content on the supply of phosphate to plants

Soil Research ◽  
1986 ◽  
Vol 24 (3) ◽  
pp. 435 ◽  
Author(s):  
MCH Mouat ◽  
P Nes
Keyword(s):  
Water Treatment ◽  
P Uptake ◽  
The Other ◽  
Water Volume ◽  
Phosphate Adsorption ◽  
Lolium Perenne L ◽  
Water Treatments ◽  
Water Holding ◽  
P Supply ◽  
High Phosphate

Ryegrass (Lolium perenne L.) was grown in a pot trial in soil of high phosphate adsorption capacity at 10 levels of P-supply and at two water regimes, one regularly adjusted to the water-holding capacity of the pots corresponding to a water potential of -2 to -3 kPa, and the other at 20% less water volume corresponding to - 20 kPa. P uptake was lower in the lower water treatment at all P-supply levels, even when the P-supply was severely limiting P uptake. This reduction in P uptake at all P levels was equivalent to the reduction in water volume between the two water treatments, and is apparently a result of a lower supply of solution phosphate in the lower water treatment in the highly buffered soil.

scholarly journals Management options to recover perennial ryegrass populations and productivity in run-out pastures

2021 ◽  
Vol 17 ◽  
Author(s):  
Wendy Griffiths ◽  
Mike Dodd ◽  
Barbara Kuhn-Sherlock ◽  
David Chapman
Keyword(s):  
Lolium Perenne ◽  
Perennial Ryegrass ◽  
Insect Pest ◽  
The Other ◽  
Grazing Management ◽  
Management Options ◽  
Lolium Perenne L ◽  
Management Interventions ◽  
Summer Pasture ◽  
Water Holding

In parts of the upper North Island, farmers frequently report perennial ryegrass (Lolium perenne L.) pastures failing within 3 or 4 years post-sowing. This appears to be related to interactions between several factors: climatic (drier, hotter summers), biotic (insect pest), soil (texture, water-holding capacity) and grazing management factors that vary spatially and temporally. The efficacy of three management interventions for recovering ryegrass populations and production in runout pasture was assessed in an experiment initiated in 2018/19 in central Waikato. Treatments were a long-spring rotation (LSR), a longer grazing deferral during late spring and summer (pasture deferral, PD) and under-sowing with perennial ryegrass (US), each applied to pastures of four ryegrass cultivars. In the year after the treatments were implemented, the yield of ryegrass in PD was 2.4 t DM/ha greater than for the control (7-year-old pasture), and ryegrass tiller populations initially doubled but later declined. Yields in US and LSR were intermediate but not significantly different from the control. Ground score changes responded more positively to PD compared with the other treatments. Relative to the baseline prior to initiation of the study, tiller populations increased for PD and US but declined for control and LSR. There were no interactions between management treatment and cultivar for any of the variables measured. Pasture deferral shows promise as an intervention for recovering failing ryegrass pastures through natural reseeding. However, the longevity of the benefits observed here has yet to be determined.

A treatability index for reservoir water

1998 ◽  
Vol 37 (2) ◽  
pp. 27-33 ◽  
Author(s):  
C. T. Ta ◽  
C. A. Woodward
Keyword(s):  
Water Treatment ◽  
Filtration Rate ◽  
Water Area ◽  
Reservoir Water ◽  
Algal Concentration ◽  
Run Lengths ◽  
Water Treatments

A Treatability Index is developed to allow comparison of different reservoir waters according to their effects on a water treatments works. For the water treatment works which employs rapid gravity filters, the index is the product of the algal concentration, the clarification coefficients of algae and the filtration rate. The index is applied to reservoir waters within Thames Water area. Algae observed in reservoirs are grouped according to their shapes. Among these groups, twenty frequently observed species were selected and their clarification coefficients were measured. The treatability index was then evaluated for different waters and at different times of the year. The results were correlated to the filter run lengths and the development of headloss across the filters.

Sex-specifically responsive strategies to phosphorus availability combined with different soil nitrogen forms in dioecious Populus cathayana

2021 ◽  
Author(s):  
Xiucheng Liu ◽  
Yuting Wang ◽  
Shuangri Liu ◽  
Miao Liu
Keyword(s):  
Root Length ◽  
Root Length Density ◽  
Specific Root Length ◽  
P Uptake ◽  
Root Tip ◽  
P Availability ◽  
P Deficiency ◽  
Populus Cathayana ◽  
Leaf P ◽  
P Supply

Abstract Aims Phosphorus (P) availability and efficiency are especially important for plant growth and productivity. However, the sex-specific P acquisition and utilization strategies of dioecious plant species under different N forms are not clear. Methods This study investigated the responsive mechanisms of dioecious Populus cathayana females and males based on P uptake and allocation to soil P supply under N deficiency, nitrate (NO3 −) and ammonium (NH4 +) supply. Important Findings Females had a greater biomass, root length density (RLD), specific root length (SRL) and shoot P concentration than males under normal P availability with two N supplies. NH4 + supply led to higher total root length, RLD and SRL but lower root tip number than NO3 − supply under normal P supply. Under P deficiency, males showed a smaller root system but greater photosynthetic P availability and higher leaf P remobilization, exhibiting a better capacity to adaptation to P-deficiency than females. Under P deficiency, NO3 − supply increased leaf photosynthesis and PUE but reduced RLD and SRL in females while males had higher leaf P redistribution and photosynthetic PUE than NH4 + supply. Females had a better potentiality to cope with P deficiency under NO3 − supply than NH4 + supply; the contrary was true for males. These results suggest that females may devote to increase in P uptake and shoot P allocation under normal P availability, especially under NO3 − supply, while males adopt more efficient resource use and P remobilization to maximum their tolerance to P-deficiency.

scholarly journals Genetic loci regulating cadmium content in rice grains

Euphytica ◽  
2021 ◽  
Vol 217 (3) ◽  
Author(s):  
Gareth J. Norton ◽  
Anthony Travis ◽  
Panthita Ruang-areerate ◽  
Graeme W. Nicol ◽  
Ayotunde A. Adeosun ◽  
...  
Keyword(s):  
Water Treatment ◽  
Water Regime ◽  
Field Experiments ◽  
Cadmium Concentration ◽  
Chromosome 9 ◽  
Chromosome 7 ◽  
Cadmium Content ◽  
Rice Grains ◽  
Water Treatments ◽  
Grain Cadmium

AbstractIt has been estimated that up to 90% of human exposure to cadmium is through food, and that cadmium within rice grains can be a major contributor to that dietary source. In this study genome wide association mapping was conducted on the Bengal and Assam Aus Panel (BAAP) of rice to identify quantitative trait loci and candidate genes for lowering grain cadmium. Field experiments were conducted over two years under two different irrigation systems: continually flooded and alternate wetting and drying (AWD). There was significant effects of water treatment, genotype, and genotype by water treatment interaction. Importantly, AWD increased grain cadmium, on average, by 49.6% and 108.8% in year 1 and 2 respectively. There was between 4.6 and 28 fold variation in cadmium concentration. A total of 58 QTLs were detected but no loci are clearly specific to one water regime despite approximately 20% of variation attributable to genotype by water regime interaction. A number of QTLs were consistent across most water treatments and years. These included QTLs on chromosome 7 (7.23–7.61, 8.93–9.04, and 29.12–29.14 Mbp), chromosome 5 (8.66–8.72 Mbp), and chromosome 9 (11.46–11.64 Mbp). Further analysis of the loci on chromosome 7 (8.93–9.04 Mbp), identified the candidate gene OsNRAMP1, where cultivars with a deletion upstream of the gene had higher concentrations of cadmium compared to the cultivars that did not have the deletion. The distribution of alleles within the BAAP suggest this QTL is easily detected in this population because it is composed of aus cultivars. Local genome cluster analysis suggest high Cd alleles are uncommon, but should be avoided in breeding.

scholarly journals Forces Necessary to Initiate Dispersal for Three Tumbleweeds

2008 ◽  
Vol 1 (1) ◽  
pp. 59-65 ◽  
Author(s):  
Dirk V. Baker ◽  
K. George Beck ◽  
Bogusz J. Bienkiewicz ◽  
Louis B. Bjostad
Keyword(s):  
Water Treatment ◽  
Conversion Factor ◽  
Common Garden ◽  
High Water ◽  
Western United States ◽  
Field Collection ◽  
Stem Strength ◽  
Wind Velocities ◽  
Diffuse Knapweed ◽  
Water Treatments

AbstractAlthough diffuse knapweed, kochia, and Russian thistle are important tumbleweeds of the western United States, environmental factors contributing to their dispersal are not well understood. Bolting rosettes of these species were transplanted to pots and reared in a common garden to determine the affect of postsenescence water on stem strength. There were no differences in stem strength among three water treatments for Russian thistle. Kochia, under moderate water treatment, required more than twice the force to break compared to plants under the zero and high water treatments. In contrast, diffuse knapweed plants under zero water treatment required four to six times greater force to break compared to plants under the moderate and high water treatments. There was a strong difference in diffuse knapweed stem strength between field collection sites that corresponded to observed differences in proportion of plants tumbling. A wind tunnel was used to develop a conversion factor between force and wind velocity. Wind velocities necessary to break diffuse knapweed stems ranged from 16 to 37 m/s (36 to 77 mph).

scholarly journals A Comparative Study of Growth and Nutrition in Barley and Rye As Affected by Low-Water Treatment

1955 ◽  
Vol 8 (4) ◽  
pp. 435 ◽  
Author(s):  
RF Williams ◽  
RE Shapter
Keyword(s):  
Water Stress ◽  
Water Treatment ◽  
Comparative Study ◽  
Plant Parts ◽  
Stage Of Development ◽  
Growth And Nutrition ◽  
Water Treatments

A comparative study of growth and nutrition in barley and rye was made with two water treatments. The low-water treatment was of an intermittent character and harvests were made after each of the five periods of water stress. Yield reductions due to low-water treatment were highly significant at all five harvests and for both species. The severity of the effects on various plant parts was conditioned by the stage of development of those parts.

Equipment and Technology Research of Ballast Water Treatments

2014 ◽  
Vol 998-999 ◽  
pp. 414-417
Author(s):  
Jun Wang
Keyword(s):  
Water Treatment ◽  
Chemical Treatment ◽  
Ballast Water ◽  
Comprehensive Treatment ◽  
Technology Research ◽  
Advantages And Disadvantages ◽  
Marine Environmental Protection ◽  
Ballast Water Treatment ◽  
Water Treatments ◽  
Marine Environmental

Biological invasions caused by Ballast water is always one of the diffcult problems of marine environmental protection, and the technology of ballast water treatment is an effective way to solve biological invasion. This article introduce many equipments of ballast water treatment, introduce physical ballast water treatment, chemical treatment and comprehensive treatment, then describes the advantages and disadvantages of these metheods.

scholarly journals The Phosphate Inhibition Paradigm: Host and Fungal Genotypes Determine Arbuscular Mycorrhizal Fungal Colonization and Responsiveness to Inoculation in Cassava With Increasing Phosphorus Supply

2021 ◽  
Vol 12 ◽  
Author(s):  
Ricardo Alexander Peña Venegas ◽  
Soon-Jae Lee ◽  
Moses Thuita ◽  
Deusdedit Peter Mlay ◽  
Cargele Masso ◽  
...  
Keyword(s):  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizal ◽  
Field Trials ◽  
P Uptake ◽  
Fungal Colonization ◽  
P Availability ◽  
Terrestrial Plants ◽  
Soil Microbial ◽  
Arbuscular Mycorrhizal Fungal ◽  
P Supply

A vast majority of terrestrial plants are dependent on arbuscular mycorrhizal fungi (AMF) for their nutrient acquisition. AMF act as an extension of the root system helping phosphate uptake. In agriculture, harnessing the symbiosis can potentially increase plant growth. Application of the AMF Rhizophagus irregularis has been demonstrated to increase the yields of various crops. However, there is a paradigm that AMF colonization of roots, as well as the plant benefits afforded by inoculation with AMF, decreases with increasing phosphorus (P) supply in the soil. The paradigm suggests that when fertilized with sufficient P, inoculation of crops would not be beneficial. However, the majority of experiments demonstrating the paradigm were conducted in sterile conditions without a background AMF or soil microbial community. Interestingly, intraspecific variation in R. irregularis can greatly alter the yield of cassava even at a full application of the recommended P dose. Cassava is a globally important crop, feeding 800 million people worldwide, and a crop that is highly dependent on AMF for P uptake. In this study, field trials were conducted at three locations in Kenya and Tanzania using different AMF and cassava varieties under different P fertilization levels to test if the paradigm occurs in tropical field conditions. We found that AMF colonization and inoculation responsiveness of cassava does not always decrease with an increased P supply as expected by the paradigm. The obtained results demonstrate that maximizing the inoculation responsiveness of cassava is not necessarily only in conditions of low P availability, but that this is dependent on cassava and fungal genotypes. Thus, the modeling of plant symbiosis with AMF under different P levels in nature should be considered with caution.

scholarly journals Breaking Dormancy in Red Raspberry with Hot Water Treatment and its Effects on Cold Hardiness

2006 ◽  
Vol 131 (2) ◽  
pp. 209-213 ◽  
Author(s):  
Pauliina Palonen ◽  
Leena Lindén
Keyword(s):  
Water Treatment ◽  
Cold Hardiness ◽  
Treatment Temperature ◽  
Rubus Idaeus ◽  
Hot Water ◽  
Bud Dormancy ◽  
Hot Water Treatment ◽  
Red Raspberry ◽  
Breaking Dormancy ◽  
Water Treatments

`Maurin Makea', `Muskoka', ` Ottawa', and `Preussen' red raspberry (Rubus idaeus L.) canes were collected from the field and subjected to different hot water treatments (20, 35, 40, 45, and 50 °C) to determine if endodormancy could be removed by a near lethal stress. Estimation of days for 50% budbreak (DD50) was found useful for describing the state of bud dormancy in the samples. Bud dormancy was broken in `Ottawa' by immersing the canes in 45 °C water for 2 hours, in `Maurin Makea' by treating the canes in 40 °C water, and in `Preussen' by both 40 and 45 °C treatments. The influence of this treatment on dormancy and cold hardiness at different times of the winter was further examined using `Ottawa' raspberry. The treatment removed bud dormancy most effectively in October, when the samples were in deepest dormancy. A slight effect was observed in November, but no effect in January. During ecodormancy in February the treatment delayed budbreak. Hot water treatment reduced cold hardiness of `Ottawa' canes by 8 to 15 °C, and that of buds by 9 to 13 °C during both endo- and ecodormancy. Based on the capacity of buds and canes to reacclimate, recovery from the stress treatment was possible at temperatures ≥4 °C. Loss of cold hardiness was caused by high treatment temperature itself and was not related to breaking of dormancy in samples. This finding suggests that dormancy and cold hardiness are physiologically unconnected in raspberry.

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