Effects Of Long-term Irrigation Research Articles

The effect of long-term wastewater irrigation on accumulation and transfer of heavy metals in Cupressus sempervirens leaves and adjacent soils

Wastewater reuse for agriculture is an important management strategy in areas with limited freshwater resources, yielding potential economic and environmental benefits. Here the effects of long-term irrigation with wastewater on the nutrient contents of green and senesced leaves of Cupressus sempervirens L. were assessed for three planted forests in Egypt. Stoichiometric ratios, transfer factors for nutrients from soil to plant and enrichment factors in contaminated soils were estimated and compared to a ground water irrigated control site. Under wastewater irrigation, C. sempervirens transferred most of the estimated nutrients, particularly heavy metals, from green to senesced leaves. This could be a self-protecting mechanism under continuous wastewater irrigation. The accumulation of four metals (Zn, Mn, Cu and Cd) with transfer factors>1 for wastewater-irrigated trees, indicated the ability for metal accumulation of C. sempervirens. Stoichiometric ratios decreased under wastewater irrigation compared to the control site and global trends, which suggests nutrient disorders in these plants. The values of enrichment factors in the wastewater-irrigated soils showed remarkable availability and distribution of metals. Decreased resorption of metals by senesced leaves of C. sempervirens will add considerable amount of these metals to the soils, which will likely have adverse affects on the desert ecosystem components.

Long-term effects of irrigation using water from the river receiving treated industrial wastewater on soil organic carbon fractions and enzyme activities

Reuse of wastewater for agricultural irrigation is one of the useful managements to alleviate the shortage of water resources in arid and semi-arid regions in China. Industrial wastewater from the city of Shijiazhuang is discharged into Wangyang River after treatment. The water is used downstream to irrigate agricultural soils. The objective of this study was to investigate how almost 20 years of irrigation with water from the Wangyang River affected soil characteristics, labile soil organic C and soil enzyme activities, and to compare the microbial response to the long-term irrigation in different locations alongside the river. The results showed that long-term irrigation with river water has resulted in accumulation of Hg, Cd, As, Pb, Cu, Cr, Zn and Mn in the downstream soils. In comparison with groundwater irrigated soils, long-term irrigation with river water significantly increased dissolved organic carbon (DOC), microbial biomass carbon (MBC) and permanganate oxidizable C (KMnO4-C) contents, and dehydrogenase, β-glucosidase, urease, alkaline phosphatase and arylsulphatase activities in the upstream and midstream soils (P<0.05), but not in the downstream soils. On the contrary, the enzyme activities in the downstream soils were significantly decreased after 20 years of river water irrigation (P<0.05). A significant negative correlation (P<0.01) was observed between enzyme activities and concentrations of heavy metals in the soils irrigated with river water, suggesting the inhibition of microbial activity caused by accumulated heavy metals, especially in the downstream soil. The effects of irrigation with water from the wastewater-receiving river on soil quality depends not only on the properties and components of irrigation water, but also on the soil characteristics such as soil type, nutrient conditions and concentrations of heavy metals.

Effects of long-term irrigation with treated wastewater on soil quality, soil-borne pathogens, and living organisms: case study of the vicinity of El Hajeb (Tunisia)

Medium (i.e. 15 years) and long-term (i.e. 20 years) impact of irrigation using secondary-treated municipal wastewater (TWW) was assessed on two agricultural soil samples, denoted by E and G, respectively, in the vicinity of El Hajeb region (Southern Tunisia). Soil pH, electrical conductivity particle size grading, potential risk of salinity, water holding capacity and chemical composition, as well as organic matter content, pathogenic microorganisms and heavy metal concentrations in the TWW-irrigated (E and G) and rainwater-irrigated (T) soils at various depths, were monitored and compared during a 5-year experiment. Our study showed that bacterial abundance is higher in sandy-clayey soil, which has an enhanced ability to retain moisture and nutrients. The high level of bacterial flora in TWW-irrigated soils was significantly (p < 0.05) correlated (r = ~0.5) with the high level of OM. Avoidance assays have been used to assess toxic effects generated by hazards in soils. The earthworms gradually avoided the soils from the surface (20 cm) to the depth (60 cm) of the G transect and then the E transect, preferring the T transect. The same behaviour was observed for springtails, but they seem to be less sensitive to the living conditions in transects G and E than the earthworms. The avoidance response test of Eisenia andrei was statistically correlated with soil layers at the sampling sites. However, the avoidance response test of Folsomia candida was positively correlated with silt-clay content (+0.744*) and was negatively correlated with sand content (-0.744*).

Long-term effects of irrigation with waste water on soil AM fungi diversity and microbial activities: the implications for agro-ecosystem resilience.

The effects of irrigation with treated urban wastewater (WW) on the arbuscular mycorrhizal fungi (AMF) diversity and soil microbial activities were assayed on a long-term basis in a semiarid orange-tree orchard. After 43 years, the soil irrigated with fresh water (FW) had higher AMF diversity than soils irrigated with WW. Microbial activities were significantly higher in the soils irrigated with WW than in those irrigated with FW. Therefore, as no negative effects were observed on crop vitality and productivity, it seems that the ecosystem resilience gave rise to the selection of AMF species better able to thrive in soils with higher microbial activity and, thus, to higher soil fertility.

Changes in Chemical Properties of Semiarid Soils under Long-Term Secondary Treated Wastewater Irrigation

Treated wastewater (TWW) is becoming a valuable resource for irrigation in semiarid regions, where freshwater is scarce; however, changes in soil chemical properties under TWW irrigation can have significant effects on agronomy, hydrology, and the environment. The effects of long-term irrigation with secondary TWW on chemical properties of two contrasting soils under semiarid Mediterranean conditions were determined in the present study. Experiments were conducted in two different grapefruit (Citrus paradise Macfad.) orchards, one with a noncalcareous sandy soil (a Typic Haploxeralf) and the other with a calcareous clayey soil (a Chromic Haploxerert). Two treatments were tested: (i) irrigation with fresh water and (ii) irrigation with domestic, secondary TTW. In both soils, a long-term irrigation (>7 yr) with TWW had insignificant effects on total organic matter content and concentrations of dissolved organic matter, Cu, Ni, and Zn in saturated paste extracts. In contrast, it increased salt accumulation in the upper ∼1-m layer in both soils; however, this salt was leached during each rainy season below 1.5 m. Sodium adsorption ratio was higher under TWW than under freshwater irrigation down to at least the 4.0- and 0.7-m depths in the sandy and clayey soils, respectively. The high clay and CaCO3 contents in the latter limited deeper movement of Na+ ions. The dominant N species in the soils under TWW irrigation was NO3− due to nitrification, and its concentration increased in the whole sampling depth in both soils. Olsen P and K+ accumulated in soil profiles above the 1.0-m depth. Boron concentration increased in the upper 1.75-m layer under TWW irrigation, where this concentration could be toxic to some crops.

Long term effect of irrigation with the treated sewage effluent on some soil properties of Al-Hassa Governorate, Saudi Arabia

A case study was undertaken to assess the long-term effect of sewage irrigation on some soil properties and heavy metals concentrations in the soils of the date palm at Al-Hassa Governorate, Saudi Arabia. Eighty-two surface soil samples were collected from the studying area. Half of it was collected from an area irrigated for more than 13 years with treated sewage effluent. Meanwhile the rest of soil samples were collected from an area irrigated with well water. Furthermore, samples from sewage effluents and well water used for irrigation were collected and analyzed mainly for their chemical composition and their metal contents. The obtained results pertaining irrigation water analysis indicated that sewage effluents were found to contain higher content of Pb, Zn, Cu, Co, Cr, As, Cd, Fe, Mn and Ni compared to well water. On the other hand data emphasized the role of sewage effluent irrigation on increasing heavy metals as well as organic matter contents in the soil samples when comparing with the respective values found in the soil irrigated with well water. The soil salinity ranged from 3.58 to 20.7 dS m −1 with an average of 7.9 dS m −1 due to irrigation with well water. While the respective soil salinity due to irrigation for long period with the treated sewage effluent ranged from 2.5 to 3.69 dS m −1 with an average of 2.8 dS m −1. There was an increase in organic matter content ranging from 17% to 30% in sewage-irrigated soil samples as compared to well water-irrigated ones. On an average, the soil pH dropped by 0.3 U as a result of sewage irrigation. Long term sewage irrigation resulted in significant build-up of total concentration of Zn (130%), Pb (55%), Fe (82%), Ni (84%), Mn (30%), Cu (40%), Cr (75%), Co (78%) and As (67%) in sewage-irrigated soil samples over adjacent well water-irrigated soil samples.

Effect of long-term irrigation with sewage effluent on the metal content of soils, Berlin, Germany

This study aimed to determine whether >110 years of sewage application has led to recognizable changes in the metal chemistry of soils from former sewage farms, Berlin, Germany. Background concentrations of soils and element enrichment factors were used for the evaluation of possible perturbations of natural element abundances in sewage farm soils. Calculations verify that precious metals (Ag, Au) as well as P, C(org), and heavy metals (Cd, Cu, Ni, Pb, Sn, and Zn) are invariably enriched in sewage farm topsoils (0-0.1 m depth) compared to local and regional background soils. Long-term irrigation of soils with municipal wastewater has caused significant heavy metal contamination as well as a pronounced enrichment in precious metals. Leaching of metals including Ag into underlying aquifers may impact on the quality of drinking water supplies.

Effects of long-term irrigation with treated wastewater. Part II: Role of organic carbon on Cu, Pb and Cr behaviour

Abstract The long-term impact of irrigation on a Mediterranean sandy soil irrigated with treated wastewater (TWW) since 1980 was evaluated. The main soil properties (CEC, pH, size distribution, exchangeable cations and chloride, hydraulic conductivity) as well as the organic matter and Cu, Cr and Pb speciation in an irrigated soil and a non-irrigated control soil at various soil depths were monitored and compared during a 2 year experiment. In this second part, we focused on Cu, Cr and Pb behaviour in relation with soil organic carbon (SOC). Soil samples were collected every 3 months during 2 years at the depths 0–20, 20–40 and 40–60 cm and were analysed for exchangeable and total metals, organic carbon content, metal sequential extraction and humic substances – Humic Acids (HA), Fulvic Acids (FA) and Non-Humified Fraction (NHF). Long-term irrigation with a domestic treated wastewater (TWW) may be considered safe with regard to trace metal accumulation in soil. Irrigation lowered the HA and NHF fractions of SOC and made the FA fraction more mobile. Cu bound preferentially to the SOC fraction, Cr was found mainly in the reducible fraction and Pb was bound to all fractions indiscriminately. Cu exhibited a high affinity for the HA fraction, while Pb and Cr had a high affinity for the FA fraction, which indicates a greater mobility of the organically-bound Pb and Cr than of the organically-bound Cu. Evaluation of the potential metal mobility has to take into account not only the usual speciation between labile, reducible and oxidisable fractions, but also the nature of the SOC responsible for the oxidisable fraction.

Effects of long-term irrigation with treated wastewater. Part I: Evolution of soil physico-chemical properties

Abstract The long-term impact of irrigation on a Mediterranean sandy soil irrigated with Treated wastewater (TWW) since 1980 was evaluated. The main soil properties (CEC, pH, size distribution, exchangeable cations and chloride, hydraulic conductivity) as well as the organic matter and Cu, Cr and Pb speciation in an irrigated soil and a non-irrigated control soil at various soil depths were monitored and compared during a 2 years experiment. In this first part, the evolution of the physico-chemical soil properties was described. The irrigation with TWW was beneficial with regard to water and nutrient supplying. All the exchangeable cations other than K + were higher in the irrigated soil than in the reference one. A part of the exchangeable cations was not fixed on the exchange complex but stored as labile salts or in concentrated soil solution. Despite the very sandy soil texture, both saturated and unsaturated hydraulic conductivity exhibited a significant diminution in the irrigated soil, but remained high enough to allow water percolation during rainy periods and subsequent leaching of accumulated salts, preventing soil salinization. In the irrigated soil, exchangeable sodium percentage (ESP) exhibited high values (20% on average) and the soil organic C was lower than in the reference. No significant effect was noticed on soil mineralogical composition due to irrigation.

Effects of long-term irrigation with brackish groundwater on soil microbial biomass in cotton field in arid oasis.

Effects of long-term irrigation with brackish groundwater on soil microbial biomass in cotton field in arid oasis.

Prediction of the environmental impact and sustainability of large-scale irrigation with gypsiferous mine-water on groundwater resources

Irrigation of agricultural crops is one of the most cost-effective options for the utilisation of gypsiferous mine wastewater. In addition, it creates the opportunity to produce crops during the dry season. Gypsum is a slightly soluble salt and concentrating the gypsiferous soil solution through crop evapotranspiration precipitates gypsum in the soil profile, removing it from the water system and reducing the potential for groundwater pollution. In previous research, it was found that crops can be commercially produced under irrigation with gypsiferous mine- water with no obvious impact on groundwater in the short term (3 years). It was, however, recommended that monitoring should continue to confirm findings over a longer period and for different conditions. A research project was therefore initiated in 2001 to determine the impact of irrigation with several gypsiferous water/soil combinations on crop performance, soil properties and groundwater quality. Field trials were carried out in South Africa on three mines: Kleinkopjé and New Vaal Collieries (Anglo Coal), and at Syferfontein (Sasol). Different crop and pasture species were grown on different soil types under centre-pivot irrigation with different mine-water qualities. Intensive monitoring systems were established in each irrigated field to determine the components of the soil-water and salt balance. Boreholes were also installed to monitor groundwater level and quality. Field water and salt balance data were used for calibration and validation of the mechanistic, generic crop, Soil-Water Balance (SWB) Model. The results of the field trials indicated that high crop and pasture yields can be obtained, provided site selection, land preparation, fertilisation and irrigation water management are appropriate. The results of the soil-water and salt balance studies indicated that considerable volumes of mine-water can be used and substantial amounts of salts can be removed from the water system through precipitation of gypsum in the soil profile. The groundwater impact was limited based on borehole measurements, indicating the presence of a zone of attenuation between the cropped soil profile and groundwater, but this should be monitored over a longer period. With appropriate management, water and salt runoff, and under specific conditions, drainage and salts leached can be intercepted, thereby minimising unwanted impacts on groundwater. Thirty-year scenario simulations were run with SWB and the generated salt loads from this model were used as input into a separate groundwater model in order to predict the likely long-term effects of irrigation with gypsiferous mine-water on groundwater. The results of these simulations showed that while salts reached the groundwater, there was a drop in concentration of the plume as it moved away from the irrigated area. This was due largely to dilution by infiltration from rainfall recharge and the dispersive characteristics of the aquifer. The simulations also showed the importance of matching the amount of drainage from an irrigated site with the transmissivity and storage properties of the aquifer below. These results suggest that large-scale irrigation with gypsiferous water could be viable if irrigated fields are carefully sited to prevent waterlogging and are well managed. A site-specific approach is essential. Water SA Vol 32(1)pp:21-28

Irrigation with treated wastewater under two different irrigation methods: Effects on hydraulic conductivity of a clay soil

Use of treated wastewater (TWW) for irrigation of semiarid and arid soils may lead to degradation of soil hydraulic properties, the magnitude of which may depend on the type of the irrigation system. Most studies evaluated the impact of irrigation with TWW on soil hydraulic conductivity (HC) using repacked samples, which do not necessarily represent soil field conditions. Our objectives were to (i) determine the effects of long term irrigation with TWW vs. fresh water (FW), and drip vs. microsprinkler method of irrigation on the saturated HC of intact and repacked soil samples, and (ii) establish possible relationship between saturated HC of intact and repacked soil samples, and aggregate stability. Samples (intact and disturbed) were taken from the upper soil layer (0–0.2 m) of FW- and TWW-irrigated by drippers and microsprinklers sections of an orchard, and adjacent TWW-irrigated cultivated and fallow fields of a clay soil. Saturated HC was determined by leaching with deionized water using a constant head device. Aggregate stability was determined on the disturbed samples using the high energy moisture characteristics method. Initial HC values were in the range of 0.025–0.25 mm h − 1 for the intact cores and 1.5–16 mm h − 1 in the repacked soil columns. In both types of measurement steady state HC was significantly lower than the initial HC. The effects of water quality and method of irrigation in determining the HC depended on the method of HC measurement; water quality had a greater impact when intact cores were used, while method of irrigation had a greater impact in the case of repacked soil columns. Irrigation water quality and method of irrigation did not have conclusive effects on aggregate stability. Significant relationships, between aggregate stability and steady state HC of the intact and repacked soil columns, were noted. Those suggested that aggregate stability determination could replace the more complicated and time consuming HC measurement in evaluating the impact of irrigation with TWW on soil HC.

The effect of long-term irrigation on the properties of leached chernozems in the forest-steppe of the southern Cis-Ural region

The effect of long-term irrigation (more than 30 years) on the properties of leached chernozem under vegetable crops has been studied. It is shown that the agrophysical, chemical, and physicochemical properties of the soil have worsened. The accumulation of salts is revealed.

The effect of long-term irrigation using wastewater on heavy metal contents of soils under vegetables in Harare, Zimbabwe

Abstract The magnitude of contamination, regulatory compliance and annual loadings of soils with copper (Cu), zinc (Zn), cadmium (Cd), nickel (Ni), chromium (Cr) and lead (Pb) were determined at three sites in Harare where wastewater was used to irrigate vegetable gardens for at least 10 years. Heavy metal total concentrations (mg kg−1) in sandy and sandy–clay soils of pH 5.1–8.1 from all sites ranged from 7.0 to 145 for Cu, 14 to 228 for Zn, 0.5 to 3.4 for Cd,

Effects of long-term irrigation with reclaimed water on soils of the Northern Adelaide Plains, South Australia

On a small scale, reclaimed water (RCW) use has been practised on the Northern Adelaide Plains (NAP) horticultural districts for more than 28 years. The RCW has had approximately 1.7 times the salinity and twice the sodium absorption ratio (SAR) of bore water commonly used for irrigation in the district. Recently, a large-scale reclamation scheme has been commissioned which could eventually supply approximately 30 GL of RCW to over 250 growers on the NAP. This study compared historical water quality and time of use data with physico-chemical properties of soil cores taken from sites where reclaimed (RCW-irrigated) or bore water had been used for irrigation, or sites that had not been irrigated (virgin). The aim was to determine if current farming practices irrigating with RCW could, now or in the future, lead to a decrease in yields through detrimental increases in soil salinity, sodicity, and boron (B) concentrations, and to determine if these changes were significantly different from bore-irrigated or virgin sites. Data suggested that changes in soil salinity and B concentration from RCW use would not decrease yields. However, changes in soil SAR had the potential to restrict drainage and consequently increase salinity; although a more functional critical SAR value for the NAP soils needs to be defined to assess this potential. These findings suggest that farming methods, in the 1967–95 period, did not address the physico-chemical changes associated with the use of more sodic RCW. Considering the future scale of RCW use, the SAR of the irrigation water may need to be decreased and/or appropriate farming methods developed and practised with the use of RCW to protect these soils for future horticultural activities. A low cost soil test, using a simple 1 : 5 soil : water extract was compared with accepted soil extracts (for assessing detrimental physico-chemical soil changes) and is proposed as a grower management tool to assist in monitoring the physico-chemical changes of the NAP soils.

Long term effects of irrigation with petrochemical industry wastewater

Abstract Split plot designed field trials were conducted during 1988–1995 to study the long term effects of petrochemical industry wastewater on six crops and agricultural soils. It was observed that wastewater irrigation resulted in increased seed yield of all the crops selected, viz. wheat, triticale, chickpea, lentil and pigeonpea, except summer moong which showed a decrease in seed yield. Soil receiving the wastewater showed no significant changes in pH, total organic carbon, electrical conductivity, cation exchange capacity, micro‐ and macro‐nutrients and SAR. Thus, it may be concluded that treated refinery wastewater met the irrigational quality requirements as its pysico‐chemical characteristics were within the permissible limits. The same could be said for the accumulation of heavy metals in the soil as well as in the grains making the latter safe for human consumption.

Long-term effect of irrigation with saline water on the development and productivity of jojoba clones

SummaryThree commercial clones of jojoba (Simmondsia chinensis) (64, Q-106 and 879–154) were planted in June 1991 at the Ramat Negev Experimental Station (Israel) and fertigated with water at three salinity levels, 1.2, 3.4 or 6.2 dS m−1. The effects of salinity over three and a half years on key metabolic activities, on plant growth and development, on flowering characteristics, and on yield were studied. Salinity barely inhibited the rate of net photosynthesis, although it did reduce stomatal conductivity by about 50%. Salinity also affected the water status of the plants by reducing water potential. Growth of the plants was not greatly affected by salinity. It was found that jojoba plants accumulate sodium and chloride ions in their leaves and use a strategy typical of many halophytes to cope with the salinity. The effect of salinity on flower development was also studied, since the vitality of flowers is a key factor in obtaining seeds. Salinity did not affect the timing of the breaking of flower bud ...

Long-term effects of irrigation and date-palm production on Torripsamments, Saudi Arabia

Specimens of soil profiles from four date-palm orchards under irrigation for periods ranging from 10 to 230 years, were compared with one another and with a profile from the nearly barren desert. Soil properties were recorded through field and laboratory observations. Distribution and mass of plant roots in each layer to a depth of 135 cm were also measured, as was the quality of the irrigation water used in each orchard. The data indicate changes in several characteristics of the soils after they were put under irrigation. Some differences were also observed among the profiles in the orchards in relation to their ages. Differences were found in the amounts and distribution of calcium carbonate, the levels of organic matter, the values of strength and bulk density, and possibly in the amounts and distribution of the clay fraction. Total amounts of carbonates are several times larger in profiles from the older orchards than in the one from the desert. Most of that difference is in carbonates of claysize. The largest amounts of carbonates occur in the same layers as where the greatest mass of plant roots is found. Levels of organic matter are two to three times as high in the profiles in the orchards as in that in the desert, with the biggest difference between the barren profile and that in the orchard of 10 years old. Amounts of the clay fraction are greater in the profiles under irrigation, with a tendency for the amounts to increase with time. Greater amounts of clay are attributed chiefly to precipitation of carbonates in that fraction. The profiles in the orchards developed increasing strengths and decreasing bulk densities over time. Differences among the profiles thus indicate not only that pathways of genesis have been altered under irrigation but that some effects become evident in a short space of time and are gradually enhanced over longer periods.

EFFECTS OF LONG-TERM IRRIGATION ON SOIL SALINITY AT SELECTED SITES IN SOUTHERN ALBERTA

The effects of long-term irrigation on soil salinity were studied at 13 selected sites within four major irrigation districts in southern Alberta. Of these sites, 10 have been under irrigation for over 60 yr and three for 25 yr. Soil textures ranged from sandy loam to clay. The total soluble salts in the soil profiles were either reduced or unchanged after long-term irrigation at all sites except one, which had an 11% increase but an EC of the saturation extract still less than 1 mS∙cm−1. The magnitude of reduction in soluble salts of the other soil profiles was related to the initial salt content and ranged from 0 to 82% of the original content. The SAR decreased in the subsoil at all sites. It is evident that long-term irrigation did not salinize the soils at these sites, which are considered to be representative of much of the irrigated land in this area.

Determining Impact of Irrigation on Ground Water

Agriclture in arid and subarid regions comprising some 22% of the world's arable land, depends on supplemental irrigation. Irrigation eventually may lead to salinity problems and has led to the theory that a civilization cannot long endure when dependent on irrigated agriculture. However, effective planning and management could delay or perhaps avert the ultimate destruction of the irrigated system. It may be too late for an effective action if the symptoms of salinization have already begun. A simple inexpensive modeling procedure is described here which may be used to determine the long term effects of irrigation and agricultural practices on the system. Pauma subbasin in Southern California is used to demonstrate the application of the model.