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This study investigated the influence of supplemental irrigation (SI) on yearly variation in potato yield and associated economics in a humid climate. On-farm trials were conducted in four to five fields annually in Prince Edward Island, Canada from 2019 to 2022. The research involved four different treatments: rainfed production as the control group, irrigation following conventional practices, irrigation guided by soil moisture monitoring, and irrigation guided by soil moisture monitoring coupled with a 20% reduction in fertilizer input. While six commonly-grown russet potato cultivars were used, local standard cultural practices were followed at all sites. In 2019 SI significantly increased marketable yields (MY), which was primarily attributed to a drought period that extended from July to early August. Similarly, in 2020 SI led to a substantial rise in MY due to growing season rainfall being significantly lower than the optimal water demand for the potato plant. Conversely, in 2021 and 2022, when rainfall was relatively sufficient and evenly distributed, farmers either refrained from irrigating or employed minimal irrigation rates, resulting in negligible MY responses. Tuber yield increase as a result of SI varied with rainfall and thus fluctuated yearly. Cross-year comparisons revealed that SI can effectively mitigate annual fluctuations in tuber yield. A cost–benefit analysis indicated that employing SI to minimize yearly variation in tuber yield can be either profitable or unprofitable in the long term, and is contingent on the costs linked to irrigation equipment, the water supply system, operational aspects, field scale, and rainfall distribution. These findings hold significance for guiding decisions in water management for potato production in humid environments. [ABSTRACT FROM AUTHOR]

Linkages between the micro‐scale of soil water and landscape scale of hydrological data could be improved with the analysis of soil factors in preferential flow rates. This rearrangement of the terminology on soil pore size from published literature focused on the relationship between aggregate and pore size. In the range of pore size relevant to water flow (>0.005 mm), a 2:1 ratio of aggregate to pore diameter approximated the mean of proposed pore size categories. Major functional change points in soil pore size were identified where water becomes mobile in soil (0.005 mm), where preferential flow among aggregate surfaces begins (0.3 mm), and where water flows without soil interaction (bypass flow ∼1.0 mm). A number of published equations supported the application of soil pore size in permeability estimation for modeling hydraulic conductivity. Common understanding of soil pore terminology would support water flow estimation from soil to landscape scales. Core Ideas: Preferential flow refers to water flowing faster through soil void space than through the soil matrix.Soil pore diameter of ∼0.3 mm is associated with the initiation of preferential flow in modeling.Soil cracks and biopores >1 mm could be classified as bypass flow following pipe flow theory.Soil pore size can be estimated from aggregate diameter ratio or from mean pore size ranges.Soil pore size, specific surface area, or void ratio can be used to estimate permeability in K equations. [ABSTRACT FROM AUTHOR]

Average potato yield in Prince Edward Island, Canada, has been stagnant since 2006. Two field studies were conducted on Charlottetown fine sandy loam soil to address this concern. In the first experiment, two alternative crop rotations, grain corn (Zea mays L.)–sorghum sudan grass (Sorghum × drummondii)–potato (C–SS–P) and soybean (Glycine max (L.) Merr.)–mustard (Brassica juncea (L.) Czern.)–potato (Soy–M–P), were compared to a conventional barley (Hordeum jubatum L.) (under seeded with red clover)–red clover (Trifolium pratense L.)–potato (Solanum tuberosum L.) (B–RedCl–P) rotation. This experiment was conducted for two 3‐year cycles comparing the effects of potato rotation, nitrogen fertilizer, and supplemental irrigation. The second experiment evaluated the inclusion of winter cover crops in a 3‐year potato crop rotation. The profitability of potatoes in each rotation was assessed using a stochastic budget of yields and fertilizer and crop prices. The effects of supplemental irrigation were not significant; however, nitrogen fertilization increased potato yields by 48%. Potato yields and net revenues in C–SS–P increased by 10.5% and 32.6% and in Soy–M–P by 6.7% and 20.5%, respectively, compared to potato in B–RedCl–P rotation. The use of winter rape cover increased potato yields by 18.6% compared to a system without winter covers, although some of these increases could be due to the use of sudan grass instead of red clover in B–RedCl–P rotation. It is recommended that potato producers implement the alternative rotation with additional fertilization and winter cover crops to increase yields and profits. Core Ideas: Alternate rotations increased potato yields by 8.6% compared to the standard rotation.Potatoes with corn and sorghum increased profit by 32% compared to the standard rotation.N fertilizers raised potato yields by 48% but supplemental irrigation was insignificant.Winter cover cropping increased potato yields by 18.6% compared to no winter cover. [ABSTRACT FROM AUTHOR]

The export of anthropogenic nitrate to coastal waters, which depends on the interplay between many factors such as land use and meteorological forcing, is a rising concern in many regions of the world. The present study investigates the effect of precipitation event magnitude on baseflow and associated groundwater‐driven nitrate export in Prince Edward Island, Canada. Twenty‐year time‐series of precipitation, stream flow, and groundwater levels across the island were analysed to establish a three‐way relationship between precipitation, groundwater level rise, and baseflow increase along a hydrological response pathway in this island setting. The analysis was performed by extracting hydrological responses for groundwater level and baseflow for a selected subset of relatively isolated precipitation events. The results reveal a non‐linear relationship between precipitation event magnitude and baseflow change that is also observed for precipitation events associated with hurricanes and post tropical storms. A time‐series of streamflow nitrate concentrations during Hurricane Dorian's passage (September 2019) was used to evaluate the relevance of these findings for nitrate export. The data show that baseflow increases after a heavy precipitation event have limited impact on streamflow concentrations, but result in substantial and sustained increase of nitrate export (calculated by multiplying concentration by flow). These observations are consistent with a recharge‐induced water table rise leading to increased hydraulic gradients that drive discharge of shallow nitrate‐containing groundwater. Due to the similarity of the processes governing groundwater flow to the sea and to streams, the results can be used to gain insights into the impacts of precipitation event magnitude on direct groundwater discharge to coastal waters. On Prince Edward Island, this applies to at least the 13% of the island's surface area that is closer to the ocean than to any stream and likely feeds submarine groundwater discharge pathways. [ABSTRACT FROM AUTHOR]

Willow (Salix viminalis spp.) shrubs are being planted along riverbanks, on erodible and marginal farmland. Wood chips made from the woody biomass could improve the properties of light-textured soils with low organic matter content in potato-based systems. Willow chips were applied at 0, 20, 40, and 60mgha?1 (fresh weight) as a soil amendment. Soil health parameters were evaluated after 12months, followed by C and N contents in whole soil, particulate, and mineral-associated organic matter fractions after 18months. Willow chip application increased soil aggregation, respiration, C and N contents in whole soil, and plant-available K. On plante l'osier blanc (Salix viminalis spp.) le long des berges ainsi que sur les terres agricoles sujettes à l'érosion ou peu rentables. Des copeaux de bois tirés de la biomasse ligneuse pourraient améliorer les propriétés des sols à texture légère pauvres en matière organique, comme ceux servant à la culture de la pomme de terre. Les auteurs ont appliqué un amendement correspondant à 0, 20, 40 ou 60 Mg (poids frais) de copeaux d'osier par hectare. Douze mois plus tard, ils ont évalué la vitalité du sol puis, au bout de dix-huit mois, la teneur en C et en N du sol complet ainsi que les fractions de matière organique associées aux particules et aux minéraux. Les copeaux d'osier améliorent l'agrégation et la respiration du sol, la concentration de C et de N dans le sol complet, de même que le K assimilable par les plantes. [Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

Copyright of American Journal of Potato Research is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of American Journal of Potato Research is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Leachable nutrients such as sulfur (S) and magnesium (Mg) may become limiting under temperate regions with sandy soils. This long-term georeferenced study assessed changes in Mehlich-3-extractable S and Mg in the province of Prince Edward Island (PEI), Canada. The Island was sampled over 3 years (one cycle, over 500 sampling points) from 1998 to 2015 for a total of six cycles. Regression kriging was used as a method of interpolation. Sulfur in the high category (>25 mg kg−1) dominated during the first two cycles (69%–98% of the total area) and then decreased below 1% of the total area during the last two cycles. The area in the low to medium category (7–18.50 mg kg−1) represented less than 1% of the total area in the first three cycles and increased to 84% in the last cycle. Magnesium distribution was dominated by soils within the low to medium range (36–116 mg kg−1), representing 74% to 97% of the total area from cycle 1 to cycle 6, respectively. Areas within the Mg range of 116 to 196 mg kg−1 changed from 24% of the total area in cycle 1 to 3% of the total area by the end of cycle 6. The S and Mg contents were positively correlated to soil organic carbon and negatively correlated to phosphorus. In a temperate climate and sandy loam soils, S and Mg decline over time under intensive cultivation, and the soil supply alone may not meet the crop S and Mg requirements. Abbreviations: Al: aluminum; C: carbon; CEC: cation-exchange capacity; CV: coefficient of variation; DEM: digital elevation model; Fe: iron; GIS: geographic information system; GPS: Global Positioning System; K: potassium; Mg: magnesium (extracted by Mehlich-3 solution); N: nitrogen; OK: ordinary kriging; P: phosphorus; PEI: Prince Edward Island; RK: regression kriging; RMSE: root mean square error; S: sulfur (extracted by Mehlich-3 solution); SOC: soil organic carbon; SOM: Soil Organic Matter. [ABSTRACT FROM AUTHOR]

Core Ideas: Fall plowing created more post–fall‐plowing nitrate leaching than spring plowing.Fall or spring plowing did not influence post–potato‐harvest nitrate leaching and potato yield.Increasing fertilizer N input to potato crops increased post–potato‐harvest nitrate leaching.Increasing fertilizer N input to potato crops suppressed potato yield. Excessive nitrate leaching from potato (Solanum tuberosum L.) production has been linked to groundwater nitrate contamination and eutrophication in receiving surface water. This study was conducted to assess the effects on nitrate leaching and potato yield of delaying red clover (Trifolium pratense L.) plowing from late fall to spring in a barley (Hordeum vulgare L.)–red clover–potato rotation and varying additions of fertilizer N to potato crops in Prince Edward Island, Canada, between 2014 and 2017. The experiment used a split‐plot arrangement in a completely randomized design with three replications. A stainless steel lysimeter was installed in each plot to collect soil water to test nitrate concentrations in leachate. Nitrate leaching occurred primarily between late fall, after the potato harvest, and in spring. Delaying forage plowing from late fall to spring reduced post–fall‐plowing nitrate leaching but had no influence on either post–potato‐harvest nitrate leaching or potato yield. Increasing fertilizer N input to the potato crops was shown to not only increase the risk of excessive nitrate leaching but also to suppress potato yield. Higher levels of soil N supplies from the mineralization of the plowed‐down red clover and soil organic matter to the potato crops in combination with a shorter than ideal growth period for the long‐season Russet Burbank potato appear to create overfertilizing situations, resulting in excessive post–potato‐harvest nitrate leaching and suppressed yields. Adequately accounting for soil N supplies is critical for enhancing potato productivity while minimizing nitrate leaching. [ABSTRACT FROM AUTHOR]

Copyright of American Journal of Potato Research is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Strategies to improve sustainability are important in intensively managed potato (Solanum tuberosum L.) systems. This study has assessed rotation systems and N sources to mitigate potato yield and soil organic matter decline in Prince Edward Island (PEI), Canada. Three‐year potato rotation systems were initiated in 2006: continuous potato (CP); potato–barley (Hordeum vulgare L.) underseeded with red clover (Trifolium pratense L.)–red clover (PBR); and potato–barley–sorghum sudan grass ([Sorghum bicolor L.) used as green manure])/winter rape (Brassica napus subsp. rapifera) (PBSW); and potato–barley–canola ([Brassica napus susbsp. napus] used as green manure)/winter rape (PBCW). Three different N sources (mineral N fertilizer, liquid hog manure, and lobster flake) were applied in a split‐plot fashion during the potato phase. Potatoes were grown in 2006, 2009, 2012, and again in 2013 to evaluate residual effects. In 2012, total N or total C in the whole soil, in particulate organic matter or in the slurry fractions were not affected by N sources or rotation systems. The PBSW and PBCW rotations generated significantly higher potato yields in 2009 and 2013, whereas the CP rotation produced significantly lower potato yields in 2 of 4 yr. The addition of lobster flake suppressed yield compared with other N sources in 3 of 4 yr. The PBR rotation, which is common in PEI can increase nitrate losses over winter. Alternatively, the PBSW and PBCW rotations may represent a good substitute to the PBR rotation as they can increase potato yield while minimizing nitrate losses. [ABSTRACT FROM AUTHOR]

High levels of nitrate leaching losses from potato rotation systems have caused concerns for both drinking water quality and aquatic ecosystem protection in Prince Edward Island ( PEI). Paired-field experiments were carried out in commercial fields to evaluate the potential of delayed plowing forages within potato rotation from fall to spring on reducing nitrate leaching at two separate sites in PEI during 2010 and 2013. Monitoring showed that fall plowing resulted in elevated tile-drain nitrate concentrations compared to spring plowing, probably mainly due to crop residue mineralization during fall which was hastened by earlier herbicidal termination of forage (i.e., herbicidal killing) at Site 1. A similar trend was also observed regarding nitrate concentrations of shallow groundwater at Site 2 during the forage phase. The practice of delaying the plowing of forages and/or associated earlier herbicidal termination of forage until spring reduces forage-phase nitrate leaching loss by 20 to 61%, and should therefore be encouraged for nitrate mitigation. The study also demonstrated that only a small fraction (9.6 to 22%) of the fall plow-down forages decayed during the forage phase and a large portion was retained in the soil into the next season. Growers should consider accounting for some of the carried-over N for the subsequent crops regardless implementing fall or spring plowing. [ABSTRACT FROM AUTHOR]

Understanding agricultural contamination in bedrock aquifers is challenging due to complexity of fracture networks and limitations in data acquisition imposed by instrumentation and drilling costs. Engineered assemblages known as multilevel monitoring systems ( MLSs) maximize data from each borehole by providing numerous, depth-discrete monitoring intervals for profiles of hydraulic head and hydrochemistry. This article describes a hybrid MLS that uses key components of the Waterloo MLS, with extra piezometers of sufficient diameter to accommodate removable transducers for continuous pressure monitoring, attached to the outside using custom clamps. Monitoring intervals are created with sand packs separated by bentonite seals, either via backfilling from surface or tremie placement. The hybrid MLS is best suited for use in rotary drilled boreholes 12 to 15 cm diameter, smaller holes have insufficient space for the MLS and added piezometer(s) while larger holes have excessive backfill material and purge requirements. Variations were installed to 60 m depth in sandstone in Prince Edward Island, and to 150 m in dolostone in southwestern Ontario. Transducers in the external piezometers provided temporal head data under ambient and stressed conditions in key intervals, and manual measurements in all ports provided detailed vertical hydraulic snapshots. Combined with hydrochemistry profiles from groundwater sampling, the hybrid MLS provided detailed composite datasets for interpreting flow and transport in these bedrock aquifers. The hybrid MLS offers promise as a versatile low-cost option for groundwater studies in agricultural areas providing improved insights on groundwater flow systems and vertical distribution of nitrate and other contaminants, allowing more informed management decisions. [ABSTRACT FROM AUTHOR]

Potato production is critical to economy of Prince Edward Island ( PEI), but has been linked to increasing groundwater nitrate contamination and anoxic events in estuaries. Given that PEI is entirely groundwater-dependent for potable water, this has resulted in considerable pressure to find solutions to protect water quality. However, our understanding of the controls on nitrate loading to groundwater, and the consequent potential to mitigate nitrate loading through beneficial management practices ( BMPs), is limited. In PEI, flow and nitrate transport in the vadose zone are controlled by the matrix porosity of the till and sandstone, while flow and transport in the saturated zone are controlled by a conductive fracture network with limited storage capacity. Diffusion of nitrate stored in the matrix may introduce a significant time lag between reduced nitrate loading from implementation of BMPs and measureable improvement in groundwater quality. BMPs with potential to mitigate nitrate loading to groundwater through improved nitrogen fertilizer practices in producing potato crops have been identified, but implementation of these practices alone is not sufficient to control nitrate loading due to the economic context of potato production. Additional BMPs for improved potato cropping systems have also been identified; however, reducing the intensity of agricultural production, including the proportion of land in potato production, at the watershed level may be required to meet the drinking water guideline for nitrate in PEI. Given the important role of market forces in determining profitability of crop production, it becomes challenging to modify crop production practices to meet an environmental goal without some additional external incentive or public pressure. [ABSTRACT FROM AUTHOR]

LEACHN was employed to simulate nitrate leaching from a representative potato production system in Prince Edward Island (PEI), Canada and enhance the understanding of impacts of potato ( Solanum tuberosum L.) production on groundwater quality. The model's performance on predicting drainage was examined against water table measurements through coupled LEACHN and MODFLOW modeling. LEACHN was calibrated and verified to data from tile-drain leaching experiments of potato grown in rotation with barley ( Hordeum vulgare L.) and red clover ( Trifolium pratense L.) during 1999-2008. Long-term simulations using the calibrated model were performed to evaluate the effects of climate and N fertilization for the potato crop on nitrate leaching. The modeling suggests LEACHN can be an effective tool for predicting nitrate leaching from similar cropping systems in PEI. Both measurements and simulations showed nitrate leaching primarily occurred during the non-growing season when crop uptake diminishes, and nitrate from mineralization and residual fertilizer coexists with excessive moisture from rainfall and snowmelt infiltration. Annual average nitrate leaching following potato, barley and red clover phases was predicted to be 81, 54 and 35 kg N ha, respectively, and the corresponding leached concentrations were 15.7, 10.1 and 7.3 mg N l. Increased N input for potato alone increased nitrate leaching not only during potato phase but also during the rotation crop phases. To reduce the risk of nitrate leaching, practices should be developed to minimize nitrate accumulation in soil both during and outside of the growing season and in both the potato and the rotation crop phases. [ABSTRACT FROM AUTHOR]

The Bayesian inverse approach proposed by Woodbury and Ulrych (2000) is extended to estimate the transmissivity fields of highly heterogeneous aquifers for steady state ground water flow. Boundary conditions are Dirichlet and Neumann type, and sink and source terms are included. A first-order approximation of Taylor's series for the exponential terms introduced by sinks and sources or the Neumann condition in the governing equation is adopted. Such a treatment leads to a linear finite element formulation between hydraulic head and the logarithm of the transmissivity--denoted as ln(T)--perturbations. An updating procedure similar to that of Woodbury and Ulrych (2000) can be performed. This new algorithm is examined against a generic example. It is found that the linearized solution approximates the true solution with an R² coefficient = 0.96 for an In(T) variance of 9 for the test case. The addition of hydraulic head data is shown to improve the In(T) estimates, in comparison to simply interpolating the sparse In(T) data alone. The new Bayesian code is also employed to calibrate a high-resolution finite difference MODFLOW model of the Edwards Aquifer in southwest Texas. The posterior In(T) field from this application yields better head fit when compared to the prior In(T) field determined from upscaling and cokriging. We believe that traditional MODFLOW grids could be imported into the new Bayes code fairly seamlessly and thereby enhance existing calibration of many aquifers. [ABSTRACT FROM AUTHOR]