Protocols and Guidelines for Field-scale Measurement of Soil Salinity Distribution with ECa-Directed Soil Sampling

<p>The EU Water Framework Directive (WFD) aims to target prevalent poor water quality status. Of the various contributing sources agriculture is particularly important due to the high loading rates of sediment and nutrient losses associated with fertilisation, sowing, and cropping regimes. Understanding soil nutrient status and the potential pathways for nutrient loss either through point or diffuse sources is an important step to improve water quality from an agricultural perspective. Research has demonstrated extensive in-field variability in soil nutrient status. A sampling regime that explores this variability at a sub-field scale is necessary. Traditional soil sampling consists of taking 20-30 cores per field in a W-shaped formation to produce a single bulked core, however, it generally fails to locate nutrient hotspots at finer resolutions. Inappropriate generalised fertilisation and management recommendations can be made in which nutrient hotspots or deficient zones are overlooked. Gridded soil sampling can reveal the full degree of in-field variability in nutrient status to inform more precise and site-specific nutrient applications. High soil phosphorus levels and the concept of legacy nutrient accumulation due to long-term over-application of phosphorus fertiliser in addition to animal slurry is a problem across the island of Ireland.</p><p>This research aims to locate and quantify the presence of soil nutrient hotspots at several field-scale locations in the cross-border Blackwater catchment in Northern Ireland / Republic of Ireland. Based on 35 m sampling grids, the nutrient content at unsampled locations in each field was determined using GIS interpolation techniques. Particular attention was paid to phosphorus, given its role in eutrophication. Gridded soil sampling enables the identification of nutrient hotspots within fields and when combined with an analysis of their location in relation to in-field landscape characteristics and knowledge of current management regimes, the risk of nutrient or sediment loss potential may be defined. This research concluded that traditional W soil sampling of producing one average value per field is not appropriate to uncover the degree of spatial variability in nutrient status and is inappropriate for catchment management of agricultural systems for controlling nutrient losses. Soil sampling at multiple locations per field is deemed to be cost-prohibitive for many farmers. However, sub-field scale soil sampling and appropriate geostatistical interpolation techniques can reveal the degree of variability and suggest an appropriate resolution for field-scale nutrient management that may be necessary to achieve measurable improvements in water quality.</p>

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Field-scale distribution and heterogeneity of soil salinity in the mulched-drip-irrigation cotton field

Archives of Agronomy and Soil Science ◽

10.1080/03650340.2018.1562273 ◽

2018 ◽

Vol 65 (9) ◽

pp. 1248-1261 ◽

Cited By ~ 3

Author(s):

Xuguang Xing ◽

Wei Du ◽

Xiaoyi Ma

Keyword(s):

Soil Salinity ◽

Drip Irrigation ◽

Cotton Field ◽

Field Scale ◽

Mulched Drip Irrigation

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Field-Scale Characterization of Spatio-Temporal Variability of Soil Salinity in Three Dimensions

Remote Sensing ◽

10.3390/rs12244043 ◽

2020 ◽

Vol 12 (24) ◽

pp. 4043

Author(s):

Hongyi Li ◽

Xinlu Liu ◽

Bifeng Hu ◽

Asim Biswas ◽

Qingsong Jiang ◽

...

Keyword(s):

Electrical Conductivity ◽

Soil Salinity ◽

Three Dimensions ◽

Soil Core ◽

Arid Areas ◽

Field Scale ◽

Natural Factors ◽

Secondary Salinity ◽

Spatio Temporal ◽

Semi Arid

Information on spatial, temporal, and depth variability of soil salinity at field and landscape scales is important for a variety of agronomic and environment concerns including irrigation in arid and semi-arid areas. However, challenges remain in characterizing and monitoring soil secondary salinity as it can largely be impacted by managements including irrigation and mulching in addition to natural factors. The objective of this study is to evaluate apparent electrical conductivity (ECa)-directed soil sampling as a basis for monitoring management-induced spatio-temporal change in soil salinity in three dimensions. A field experiment was conducted on an 18-ha saline-sodic field from Alar’s Agricultural Science and Technology Park, China between March, and November 2018. Soil ECa was measured using an electromagnetic induction (EMI) sensor for four times over the growing season and soil core samples were collected from 18 locations (each time) selected using EMI survey data as a-priori information. A multi-variate regression-based predictive relationship between ECa and laboratory-measured electrical conductivity (ECe) was used to predict EC with confidence (R2 between 0.82 and 0.99). A three-dimensional inverse distance weighing (3D-IDW) interpolation clearly showed a strong variability in space and time and with depths within the study field which were mainly attributed to the human management factors including irrigation, mulching, and uncovering of soils and natural factors including air temperature, evaporation, and groundwater level. This study lays a foundation of characterizing secondary salinity at a field scale for precision and sustainable management of agricultural lands in arid and semi-arid areas.

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Soil salinity distribution and its relationship with soil particle size in the lower reaches of Heihe River, Northwestern China

Environmental Earth Sciences ◽

10.1007/s12665-016-5603-8 ◽

2016 ◽

Vol 75 (9) ◽

Cited By ~ 10

Author(s):

Yu Zhao ◽

Qi Feng ◽

Huaide Yang

Keyword(s):

Particle Size ◽

Soil Salinity ◽

Soil Particle ◽

Northwestern China ◽

Heihe River ◽

Salinity Distribution ◽

Soil Particle Size

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Soil salinity and its distribution determined by soil sampling and electromagnetic techniques

Soil Use and Management ◽

10.1079/sum2002178 ◽

2003 ◽

Vol 19 (2) ◽

pp. 119-126 ◽

Cited By ~ 38

Author(s):

J. Herrero ◽

A.A. Ba ◽

R. Aragüés

Keyword(s):

Soil Salinity ◽

Soil Sampling

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A Heritage Agronomic Study as a Database for Monitoring the Soil Salinity of an Irrigated District in NE Spain

Agronomy ◽

10.3390/agronomy12010126 ◽

2022 ◽

Vol 12 (1) ◽

pp. 126

Author(s):

Juan Herrero ◽

Carmen Castañeda ◽

Rosa Gómez-Báguena

Keyword(s):

Soil Salinity ◽

State Of The Art ◽

Soil Sampling ◽

Irrigation District ◽

Sustainable Land Management ◽

Irrigation Methods ◽

Irrigated Area ◽

Sampling Campaign ◽

Salinity Data ◽

Study Sites

This article presents and reviews the soil salinity data provided by a rescued vintage agronomic report on an irrigated area of 35,875 ha located in the center of the Ebro River basin, in the NE of mainland Spain. These data come from a soil sampling campaign conducted from May to the first half of July 1975 for the purpose of delineating saline and non-saline soils. The agronomic report was produced in response to demands from farmers to combat soil salinity, and represents the state of the art in those years for salinity studies. Our paper presents the scrubbed soil salinity data for this year, checking their consistency and locating the study sites. The main finding is the unearthing of this heritage report and the discussion of its soil salinity data. We show that the report supplies an assessment and a baseline for further soil salinity tracking by conducting new measurements either by direct soil sampling or by nondestructive techniques, providing an estimate of soil salinity at different locations. This task is feasible, as shown in our previously published articles involving nearby areas. A comparison of the salt amount in the soil over the years would provide a means to evaluate irrigation methods for sustainable land management. This comparison can be conducted simultaneously with analysis of other agricultural features described in the report for the irrigation district in 1975.

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