An agronomic test to manage phosphorus environmental risk from pastures with good grazing management

Soil Research ◽  
2014 ◽  
Vol 52 (3) ◽  
pp. 293 ◽  
Author(s):  
M. R. Hart ◽  
P. S. Cornish

Management of phosphorus (P) environmental risk has been hampered by the lack of widely applicable threshold values for the soil properties that determine concentrations of P in runoff. This paper simplified the task of developing threshold values by restricting land-use to pastures and by using a single methodology based on simulated rainfall across 38 field sites (76 plots) that included a range of land-use intensities, and soils that varied widely in lithology and soil properties. An ‘adjusted’ soil-test P was determined from the measured Colwell-P minus the threshold P for agronomic response, which was estimated from P-buffering index (PBI). Concentrations of total P (TP) in runoff rose exponentially with rising ‘adjusted’ soil-test P, although only with pastures with high groundcover (r2 = 0.87), or if plots were protected from erosion with a cover of shade-cloth (r2 = 0.70). Concentrations of TP in runoff were low (<0.5 mg L–1) where adjusted Colwell-P was less than zero, which on this scale is the threshold for agronomic response. Similar results were found for dissolved reactive P (DRP) in runoff, although for plots with soil P below the agronomic threshold, the concentrations of DRP were lower than for TP. We conclude that Colwell-P and soil PBI together provide a widely applicable test for environmental P risk from pastures with good ground cover. The same threshold values may be used for both agronomic and environmental purposes.

2013 ◽  
Vol 93 (3) ◽  
pp. 343-358 ◽  
Author(s):  
J. J. Miller ◽  
T. W. Curtis ◽  
E. Bremer ◽  
D. S. Chanasyk ◽  
W. D. Willms

Miller, J. J., Curtis, T. W., Bremer, E., Chanasyk, D. S. and Willms, W. D. 2013. Evaluation of selected soil properties for indicating cattle activity at off-stream watering and river access sites in southern Alberta. Can. J. Soil Sci. 93: 343–358. Off-stream watering troughs may reduce surface water pollution by shifting nutrient distribution from natural watering sites along the river to around artificial water troughs some distance from the river. The objective of our study was to evaluate the suitability of nine soil properties for assessing the impacts of cattle activity adjacent to eight watering sites. Nine surface (0–5 cm) soil properties were evaluated along four 100-m transects at the five off-stream water troughs and three river access sites along the Lower Little Bow River in southern Alberta over 4 yr (2007–2010). The properties included P (total P, soil test P or STP), N (total N, NO3-N, NH4-N), total C, total C:total N ratio (TC:TN), chloride (Cl), and soil bulk density. Soil test P was significantly (P≤0.05) enriched at 65% of site-year comparisons, followed by total C (63%), NO3-N (55%), total P and TC:TN (50%). This suggested that these soil properties were relatively good indicators of cattle activity at the majority (>50%) of watering sites. Chloride was a valid indicator only in non-saline areas (100% of four non-saline sites). Total C and TC:TN ratios were not valid indicators in the calcareous soils at all sites because of possible confounding influence of inorganic C. Overall, we recommend Cl as an indicator of cattle activity at watering sites not affected by soil salinity and high natural Cl levels, and STP as the best overall indicator of cattle activity at off-stream watering sites and river access sites. Certain soil properties were also influenced by distance from watering site, stocking rate, precipitation, and age of water trough.


2003 ◽  
Vol 83 (4) ◽  
pp. 443-449 ◽  
Author(s):  
R. H. McKenzie ◽  
E. Bremer

Soil tests for available P may not be accurate because they do not measure the appropriate P fraction in soil. A sequential extraction technique (modified Hedley method) was used to determine if soil test P methods were accurately assessing available pools and if predictions of fertilizer response could be improved by the inclusion of other soil P fractions. A total of 145 soils were analyzed from field P fertilizer experiments conducted across Alberta from 1991 to 1993. Inorganic P (Pi) removed by extraction with an anion-exchange resin (resin P) was highly correlated with the Olsen and Kelowna-type soil test P methods and had a similar relationship with P fertilizer response. No appreciable improvement in the fit of available P with P fertilizer response was achieved by including any of the less available P fractions in the regression of P fertilizer response with available P. Little Pi was extractable in alkaline solutions (bicarbonate and NaOH), particularly in soils from the Brown and Dark Brown soil zones. Alkaline fractions were the most closely related to resin P, but the relationship depended on soil zone. Inorganic P extractable in dilute HCl was most strongly correlated with soil pH, reflecting accumulation in calcareous soils, while Pi extractable in concentrated acids (HCl and H2SO4) was most strongly correlated with clay concentration. A positive but weak relationship as observed between these fractions and resin P. Complete fractionation of soil P confirmed that soil test P methods were assessing exchangeable, plant-available P. Key words: Hedley phosphorus fractionation, resin, Olsen, Kelowna


2017 ◽  
Vol 10 (5) ◽  
pp. 1435
Author(s):  
Viviane Capoane ◽  
Tales Tiecher ◽  
Danilo Rheinheimer dos Santos

Este trabalho investigou os efeitos da topografia e das práticas de uso e manejo do solo na variabilidade de alguns atributos do solo ao longo de três topossequências localizadas no planalto do Rio Grande do Sul. As topossequências (Tps) estão inseridas em uma bacia hidrográfica situada no município de Júlio de Castilhos. Na Tp1 foram definidos quatro pontos de amostragem e na Tp2 e Tp3, cinco pontos. Em cada perfil foram coletadas amostras em 5 camadas de solo (0‒5, 5‒10, 10‒20, 20‒40 e 40‒60 cm). Em laboratório foram determinados os atributos: densidade, argila, pH em água, carbono (C) orgânico total, fósforo (P) total, P orgânico total, P disponível, óxidos de ferro (Fe) e alumínio (Al) cristalinos e amorfos. Os resultados encontrados mostram que o movimento de sedimentos em superfície e através do perfil do solo é controlado pela posição, forma e declividade da encosta e, pelas atividades antrópicas como o uso e manejo do solo e aplicação de fertilizantes. Considerando as classes de uso da terra, os maiores teores de C e P (total, orgânico e disponível) foram obtidos na área úmida, seguido da lavoura e campo nativo. Considerando a posição na encosta os teores de C e P foram maiores na baixada seguido da base da encosta, topo e meia encosta. A condição hidromórfica ao longo das topossequências desempenhou um papel importante na disponibilidade de P, acúmulo C orgânico total e solubilização dos óxidos de Fe e Al. A B ST R A C TThis work investigated the effects of topography and land use and soil management practices on the variability of some soil properties along three toposequences located in the Rio Grande do Sul plateau, Southern Brazil. The toposequences (Tps) evaluated are from a watershed located in the municipality of Júlio de Castilhos. Soil samples were taken in four points in Tp1 and in five points in Tp2 and Tp3. In each point samples were taken at five depths (0‒5, 5‒10, 10‒20, 20‒40, and 40‒60 cm). The soil properties evaluated were soil density, clay, pH in water, total organic carbon (C), total phosphorus (P), total organic P, available P, and amorphous and crystalline iron (Fe) and aluminum (Al) oxides. Results show that the transport of sediments on the surface and through the soil profile is controlled by topographic position, landform, slope, and also by the anthropic activities such as the use and management of the soil and the application of fertilizers. Considering the classes of land use, the highest levels of C and P (total, organic and available) were obtained in the wetlands, followed by the crop fields and natural grasslands. Considering the topographic position, the contents of C and P were higher in the floodplain followed by the base of the slope, top and middle slope. Hydromorphic conditions along the toposequences played an important role in P availability, total organic C accumulation and solubilization of Fe and Al oxides.keywords: Land use, topographic position, soil profile, soil properties. 


Soil Research ◽  
1994 ◽  
Vol 32 (3) ◽  
pp. 503 ◽  
Author(s):  
MDA Bolland ◽  
IR Wilson ◽  
DG Allen

Twenty-three virgin Western Australian soils of different buffer capacities (BC) for phosphorus (P) were collected. The effects of BC on the relationships between Colwell soil test P and the level of P applied, yield and soil test P, and yield and the level of P applied were studied. Wheat (Triticum aestivum cv. Reeves), grown for 27 days in a glasshouse, was used. Two methods of measuring P sorption of soils, P buffer capacity (PBC) and P retention index (PRI), were used. The PBC is determined from a multi-point sorption curve. The PRI is a new, diagnostic, one-point, sorption method now widely used for commercial soil P testing in Western Australia. Both PBC and PRI produced similar results. The relationship between soil test P and the level of P applied was adequately described by a linear equation. When the slope coefficient of the linear equations was related to PBC or PRI, there was no relationship. The other two relationships were adequately described by a Mitscherlich equation. When the curvature coefficient of the Mitscherlich equation was related to PBC or PRI, the trend was for the value of the coefficient to decrease with increasing PBC or PRI. Consequently, as the capacity of the soil to sorb P increased the trend was for larger soil test P or higher levels of P application to produce the same yield.


Soil Research ◽  
2010 ◽  
Vol 48 (8) ◽  
pp. 682 ◽  
Author(s):  
M. D. A. Bolland ◽  
W. K. Russell

Soil testing was conducted during 1999–2009 to determine lime and fertiliser phosphorus (P), potassium (K), and sulfur (S) requirements of intensively grazed, rain-fed, ryegrass dairy pastures in 48 paddocks on sand to sandy loam soils in the Mediterranean-type climate of south-western Australia. The study demonstrated that tissue testing was required in conjunction with soil testing to confirm decisions based on soil testing, and to assess management decisions for elements not covered by soil testing. Soil testing for pH was reliable for indicating paddocks requiring lime to ameliorate soil acidity, and to monitor progress of liming. Soil P testing proved reliable for indicating when P fertiliser applications were required, with no P being required when soil-test P was above the critical value for that soil, and when no P was applied, tissue testing indicated that P remained adequate for ryegrass production. Soil testing could not be used to determine paddocks requiring fertiliser K and S, because both elements can leach below the root-zone, with rainfall determining the extent of leaching and magnitude of the decrease in pasture production resulting from deficiency, which cannot be predicted. The solution is to apply fertiliser K and S each year, and use tissue testing to improve fertiliser K and S management. Research has shown that, for dairy and other grazing industries in the region, laboratories need measure and report every year soil pH and soil-test P only, together with measuring every 3–5 years the P-buffering index (estimating P sorption of soil), organic carbon content, and electrical conductivity.


2006 ◽  
Vol 53 (2) ◽  
pp. 303-310 ◽  
Author(s):  
E. van Bochove ◽  
G. Thériault ◽  
F. Dechmi ◽  
A.N. Rousseau ◽  
R. Quilbé ◽  
...  

The indicator of risk of water contamination by phosphorus (IROWC_P) is designed to estimate where the risk of water P contamination by agriculture is high, and how this risk is changing over time based on the five-year period of data Census frequency. Firstly developed for the province of Quebec (2000), this paper presents an improved version of IROWC_P (intended to be released in 2008), which will be extended to all watersheds and Soil Landscape of Canada (SLC) polygons (scale 1:1, 000, 000) with more than 5% of agriculture. There are three objectives: (i) create a soil phosphorus saturation database for dominant and subdominant soil series of SLC polygons – the soil P saturation values are estimated by the ratio of soil test P to soil P sorption capacity; (ii) calculate an annual P balance considering crop residue P, manure P, and inorganic fertilizer P – agricultural and manure management practices will also be considered; and (iii) develop a transport-hydrology component including P transport estimation by runoff mechanisms (water balance factor, topographic index) and soil erosion, and the area connectivity to water (artificial drainage, soil macropores, and surface water bodies).


2018 ◽  
Vol 102 (4) ◽  
pp. 11-13
Author(s):  
Florencia Sucunza ◽  
Flavio Gutiérrez Boem ◽  
Fernando García ◽  
Miguel Boxler ◽  
Gerardo Rubio

Data from long-term crop rotation study sites were combined to evaluate the effect of long-term application (and omission) of P fertilizers. The impact of maintaining either a negative or positive P balances on soil test P at five distinct sites was described by single response functions despite a range of differences in soil properties.


2012 ◽  
Vol 92 (3) ◽  
pp. 537-542 ◽  
Author(s):  
Chunyu Song ◽  
Xingyi Zhang ◽  
Xiaobing Liu ◽  
Yuan Chen

Song, C., Zhang, X., Liu, X. and Chen, Y. 2012. Effect of soil temperature and moisture on soil test P with different extractants. Can. J. Soil Sci. 92: 537–542. Temperature and moisture are important factors affecting adsorption, transformation and the availability of soil phosphorus (P) to plants. The different temperatures and moisture contents at which soil is sampled might affect the results of soil test P (STP). In order to evaluate the effect of the temperature and moisture, as well as the fertilization level, on the results of soil test P, an incubation study involving three soil temperatures (5, 10, and 20°C), and three soil moisture contents (50, 70, 90% of field water-holding capacity) was conducted with Chinese Mollisols collected from four fertilization treatments in a long-term experiment in northeast China. Four soil P test methods, Mehlich 3, Morgan, Olsen and Bray 1 were used to determine STP after a 42-d incubation. The effect of temperature and moisture on STP varied among soil P tests. Averaged across the four fertilization treatments, the temperature had significant impact on STP, while the responses varied among soil P test methods. Mehlich 3, Morgan and Bray 1 STP decreased and Olsen STP increased with increase in temperature. Effect of soil moisture was only significant for Mehlich 3 P and Olsen P. Soil temperature had greater impact on STP than soil moisture content. The responses of the Olsen method to temperature differed from the other three methods tested. The interaction between soil temperature and soil moisture on soil test P was only significant for Mehlich 3 P. Fertilization level does not affect the STP in as a clear pattern as the temperature and moisture varied for all four methods. Consistent soil sampling conditions, especially the soil temperature, appear to be the first step to achieve a reliable STP for any soil P test.


HortScience ◽  
2008 ◽  
Vol 43 (7) ◽  
pp. 2162-2166 ◽  
Author(s):  
Thomas A. Obreza ◽  
Robert E. Rouse ◽  
Kelly T. Morgan

No calibrated phosphorus (P) soil test exists to guide Florida citrus fertilization. Applying P fertilizer to citrus when it is not needed is wasteful and may cause undesirable P enrichment of adjacent surface water. The objective of this study was to establish guidelines for P management in developing Florida grapefruit (Citrus paradisi Macf.) and orange (Citrus sinensis L. Osb.) orchards by determining the effect of P fertilizer rate on soil test P and subsequently calibrating a P soil test for citrus yield and fresh fruit quality. Two orchards were planted on sandy soil with 3 mg·kg−1 (very low) Mehlich 1 soil test P. In Years 1 through 3, P fertilization increased soil test P up to 102 mg·kg−1 (very high). In Years 4 through 7, canopy volume, yield, and fruit quality did not respond to available soil P as indexed by soil testing. As tree size and fruit production increased, leaf P was below optimum where soil test P was below 13 mg·kg−1 (grapefruit) or 31 mg·kg−1 (oranges). Total P in the native soil at planting was ≈42 mg·kg−1, which was apparently available enough to support maximum tree growth, fruit yield, and fruit quality for the first 7 years after planting. Trees were highly efficient in taking up P from a soil considered very low in available P. Citrus producers can likely refrain from applying P fertilizer to young trees on Florida sandy soils if soil test P is very high or high and probably medium as well.


Author(s):  
Sviatoslav Baluk ◽  
Liudmyla Vorotyntseva

The directions of the transformation of the properties of chernozems under the influence of agricultural use and irrigation are shown. For balanced and sustainable land use is required anthropogenic load on the soil based on the definition of acceptable environmental risk of degradation, taking into account the soil stability to anthropogenic pressure. Keywords: soil properties, soil, humus, irrigation, soil stability, black soil.


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