Assessment of uncertainty in soil test phosphorus using kriging techniques and sequential Gaussian simulation: implications for water quality management in southern Quebec

2013 ◽  
Vol 48 (4) ◽  
pp. 344-357 ◽  
Author(s):  
Alaba Boluwade ◽  
C. A. Madramootoo
Keyword(s):  
Best Management Practices ◽  
Management Practices ◽  
Water Quality Management ◽  
Sequential Gaussian Simulation ◽  
Soil Test ◽  
Conditional Probability Distribution ◽  
Land Use Pattern ◽  
Soil P ◽  
Soil Test Phosphorus ◽  
Gaussian Simulation

Missisquoi Bay, located in southern Quebec at the north-eastern extremity of Lake Champlain, is subject to eutrophication arising from excess nutrients, predominantly phosphorus (P), contributed by agricultural watersheds. Factors such as land use pattern, management practices, soil properties and geomorphology have an impact on soil P levels. Land patches under different management practices introduce a cyclic pattern, especially when fitting the variogram. Geostatistics procedures were used to model soil test phosphorus (STP) within the 11 km2 Castor Watershed in southern Quebec, Canada. An ordinary kriging (OK) method was used to estimate STP at unsampled points, but this had a smoothing effect, resulting in an underestimation of high values and overestimation of low values. Therefore, a more efficient technique was needed to draw predictions from the conditional probability distribution at the simulation grid nodes. A sequential Gaussian simulation (SGS) was adopted for this purpose, and used to create 50 equal probable realizations. Uncertainty was modelled using the E-type (mean) of the realizations, which ranged from 12.5 to 223 mg P kg–1 soil. The adequate spatial probability pattern for STP is a valuable criterion when seeking to delineate areas of high STP for site-specific best management practices (BMPs).

Soil test phosphorus and nitrate adjacent to artificial and natural cattle watering sites in southern Alberta

2010 ◽  
Vol 90 (2) ◽  
pp. 331-340 ◽  
Author(s):  
J J Miller ◽  
T W Curtis ◽  
E. Bremer ◽  
D S Chanasyk ◽  
W D Willms
Keyword(s):  
Best Management Practices ◽  
Management Practices ◽  
Surface Soil ◽  
Management Practice ◽  
Soil Test ◽  
Nutrient Distribution ◽  
Background Levels ◽  
Southern Alberta ◽  
Subsurface Soil ◽  
Soil Test Phosphorus

Off-stream watering troughs may reduce surface water pollution by keeping nutrients away from natural water bodies, but may increase nutrient contaminant of groundwater. The objective of this study was to determine to what extent off-stream watering troughs active for 2 to 7 yr caused enrichment and leaching of soil test P (STP) and KCl-extractable NO3-N. The study was conducted in the Lower Little Bow (LLB) River watershed of southern Alberta, Canada. Soil samples were obtained at three recently installed off-stream watering troughs, four active cattle watering sites adjacent to the LLB River, and at two sites along a fenced reach of the river with no cattle access. At each location, samples were obtained along four 100-m transects. Surface (0-5 cm) soil immediately adjacent to the LLB River was not enriched in STP or NO3-N, which was attributed to flushing of nutrients during periods of high flow. Surface soil at distances ≤ 5 m from the three water troughs was approximately three times higher in STP than surface soil obtained at distances ≥10 m and was seven times higher in NO3-N. Subsurface soil layers adjacent (3 m distance) to the three water troughs were not enriched in STP compared with background levels (100 m distance). The subsurface soil adjacent (3 m) to the longest active watering trough was enriched in NO3-N to the 60 cm depth compared with background levels (100 m). Greater nutrient enrichment at the off-stream watering troughs than at the cattle watering sites adjacent to the river suggested that this beneficial management practice (BMP) was effective in shifting nutrient distribution away from the river. Key words: Pasture, nutrient leaching, nitrate, best management practices

Agronomic and environmental soil test phosphorus in manured and non-manured Manitoba soils

2007 ◽  
Vol 87 (1) ◽  
pp. 73-83 ◽  
Author(s):  
D. Kimaragamage ◽  
O O Akinremi ◽  
D. Flaten ◽  
J. Heard
Keyword(s):  
Iron Oxide ◽  
Surface Soil ◽  
Single Equation ◽  
Soil Samples ◽  
Soil Test ◽  
Regression Equations ◽  
Soil P ◽  
Soil Test Phosphorus ◽  
Bray 1 ◽  
Water Extractable

Quantitative relationships between soil test phosphorus (STP) methods are needed to guide P management especially in manured soils with high P. Our objectives were: (i) to compare amounts of P extracted by different methods; (ii) to develop and verify regression equations to convert results among methods; and (iii) to establish environmental P thresholds for different methods, in manured and non-manured soils of Manitoba. We analyzed 214 surface soil samples (0–15 cm), of which 51 had previous manure application. Agronomic STP methods were Olsen (O-P), Mehlich-3 (M3-P), Kelowna-1 (original; K1-P), Kelowna-2 (modified; K2-P), Kelowna-3 (modified; K3-P), Bray-1 (B1-P) and Miller and Axley (MA-P), while environmental STP methods were water extractable (W-P), Ca Cl2 extractable (Ca-P) and iron oxide impregnated filter paper (FeO-P) methods. The different methods extracted different amounts of P, but were linearly correlated. For an O-P range of 0–30 mg kg-1, relationships between O-P and other STP were similar for manured and nonmanured soils, but the relationships diverged at higher O-P levels, indicating that one STP cannot be reliably converted to another using a single equation for manured and non-manured soils at environmentally critical P levels (0–100 mg kg-1 O-P). Suggested environmental soil P threshold ranges, in mg P kg-1, were 88–118 for O-P, 138–184 for K1-P, 108–143 for K2-P, 103–137 for K3-P, 96–128 for B1-P, 84–111 for MA-P, 15–20 for W-P, 5–8 for Ca-P and 85–111 for FeO-P. Key words: Phosphorus, soil test phosphorus, manured soils, non-manured soils, environmental threshold

Indicator of risk of water contamination by phosphorus from Canadian agricultural land

2006 ◽  
Vol 53 (2) ◽  
pp. 303-310 ◽  
Author(s):  
E. van Bochove ◽  
G. Thériault ◽  
F. Dechmi ◽  
A.N. Rousseau ◽  
R. Quilbé ◽  
...  
Keyword(s):  
Water Contamination ◽  
Crop Residue ◽  
Management Practices ◽  
Agricultural Land ◽  
Soil Phosphorus ◽  
Soil Test ◽  
Soil P ◽  
Soil Test P ◽  
P Balance ◽  
Balance Factor

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).

scholarly journals Phosphorus Sources and Management in Organic Production Systems

2007 ◽  
Vol 17 (4) ◽  
pp. 442-454 ◽  
Author(s):  
Nathan O. Nelson ◽  
Rhonda R. Janke
Keyword(s):  
Best Management Practices ◽  
Phosphate Rock ◽  
Management Practices ◽  
Production Systems ◽  
Organic Production ◽  
P Availability ◽  
Soil P ◽  
Best Management ◽  
P Loss ◽  
P Sources

Organically produced fruit and vegetables are among the fastest growing agricultural markets. With greater demand for organically grown produce, more farmers are considering organic production options. Furthermore, there is an increasing interest in maintaining optimal production in an organic system, which involves appropriate nutrient management. The objectives of this review were to summarize the current state of our knowledge concerning effects of organic production systems on phosphorus (P) availability, describe P availability in common organically accepted P sources, and review best management practices that can reduce environmental risks associated with P management in organic systems. Organic production systems seek to improve soil organic matter and biological diversity, which may impact P cycling and P uptake by crops. Increases in organic matter will be accompanied by an increase in the organic P pool. Furthermore, management of cover crops and potentially enhanced arbuscular mycorrhizal fungi colonization from organic production practices can increase the availability of soil P pool (both organic and inorganic) by stimulating microbial activity and release of root exudates. This can help compensate for low soil P, but will not supersede the need to replace P removed by the harvested crop. Phosphorus fertilization in organic production systems entails balancing the P inputs with crop removal through selection and management of both nitrogen (N) and P inputs. Organic production systems that rely on manure or composts for meeting crop N demand will likely have a P surplus; therefore, P deficiencies will not be an issue. Systems using other N sources may have a P deficit, therefore requiring P supplementation for optimal plant growth. In such situations, maintenance P applications equal to crop removal should be made based on soil test recommendations. Primary organically approved P sources are phosphate rock (PR), manure, and compost. Phosphate rock is most effective at supplying P in soils with low pH (less than 5.5) and low calcium concentrations. Phosphate rock applications made to soils with pH greater than 5.5 may not be effective because of reduced PR solubility. Manure- and compost-based P has high plant availability, ranging from 70% to 100% available. Use of manures and composts requires extra considerations to reduce the risk of P loss from P sources to surface waters. Best management practices (BMPs) for reducing source P losses are incorporation of the manures or composts and timing applications to correspond to periods of low runoff risk based on climatic conditions. Organic production systems that use manures and composts as their primary N source should focus on minimizing P buildup in the soils and use of management practices that reduce the risks of P loss to surface waters. Evaluation of P loss risk with a P index will assist in identification of soil and management factors likely to contribute to high P loss as well as BMPs that can decrease P loss risks. BMPs should focus on controlling both particulate and dissolved P losses.

Evaluation of AnnAGNPS in cold and temperate regions

2006 ◽  
Vol 53 (2) ◽  
pp. 263-270 ◽  
Author(s):  
S. Das ◽  
R.P. Rudra ◽  
P.K. Goel ◽  
B. Gharabaghi ◽  
N. Gupta
Keyword(s):  
Best Management Practices ◽  
Sediment Yield ◽  
Management Practices ◽  
Water Quality Management ◽  
Point Sources ◽  
Runoff Generation ◽  
Southern Ontario ◽  
Best Management ◽  
Sediment Component ◽  
Selection Of

Identification of the pollution sources and understanding the processes related to runoff generation and pollution transportation is effective for the water quality management and selection of the Best Management Practices. The ANNualized AGricultural Non-Point Source (AnnAGNPS) model was applied to a watershed in Southern Ontario to evaluate the hydrology and sediment component from the non-point sources. The model was run for two years (1998 to 1999); one year's data was used to calibrate and the second year's data was used for validation purposes. The model has under predicted runoff amount and over predicted the sediment yield. However, the simulated runoff and sediment yield compared fairly well with the observed data indicating that the model had an acceptable performance in simulation of runoff and sediment. The study is still in progress to assess its performance for estimation of TMDL and improvements needed for the model to use under Ontario conditions.

Phosphorus accumulation and leaching in two irrigated soils with incremental rates of cattle manure

2010 ◽  
Vol 90 (2) ◽  
pp. 355-362 ◽  
Author(s):  
B M Olson ◽  
E. Bremer ◽  
R H McKenzie ◽  
D R Bennett
Keyword(s):  
Bos Taurus ◽  
Irrigation Management ◽  
Calcareous Soils ◽  
Soil Test ◽  
Soil P ◽  
P Loss ◽  
Phosphorus Accumulation ◽  
Soil Test P ◽  
Soil Test Phosphorus ◽  
P Leaching

The risk of P leaching increases on land that receives manure at rates sufficient to meet crop N requirements, but calcareous subsoils may minimize P loss due to P adsorption. An 8-yr field experiment was conducted to determine the effects of different rates of manure on the accumulation and leaching of soil P in a coarse-textured (CT) soil and a medium-textured (MT) soil under typical irrigation management in southern Alberta. Treatments included a non-manured control and four rates of cattle (Bos taurus) manure (20, 40, 60, and 120 Mg ha-1 yr-1, wet-weight basis). In manured treatments, P addition ranged from about 80 to 450 kg P ha-1 yr-1, while P removal by annual cereal silage crops ranged from 15 to 22 kg P ha-1 yr-1. High soil test P (STP) concentrations occurred to a depth of 0.6 m at the CT site and 0.3 m at the MT site. Increase in STP concentration to 0.6 m was equivalent to 43% of net P input, and increase in total soil P was equivalent to 78% of net P input. Non-recovery of net P input suggests that P loss by leaching occurred at these sites and that leaching was more prevalent at the CT site. These calcareous soils have considerable potential to hold surplus P, but may still allow P leaching.Key words: Manure, phosphorus dynamics, soil test phosphorus, phosphorus leaching, soil texture

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