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1.
Due to increased population and urbanization, freshwater demand for domestic purposes has increased resulting in a smaller proportion for irrigation of crops. We carried out a 3‐year field experiment in the Indus Plains of Pakistan on salt‐affected soil (ECe 15·67–23·96 dS m−1, pHs 8·35–8·93, SAR 70–120, infiltration rate 0·72–0·78 cm h−1, ρ b 1·70–1·80 Mg m−3) having tile drainage in place. The 3‐year cropping sequence consisted of rice (Oryza sativa L.) and wheat (Triticum aestivum L.) crops in rotation. These crops were irrigated with groundwater having electrical conductivity (EC) 2·7 dS m−1, sodium adsorption ratio (SAR) 8·0 (mmol L−1)1/2 and residual sodium carbonate (RSC) 1·3 mmolc L−1. Treatments were: (1) irrigation with brackish water without amendment (control); (2) Sesbania (Sesbania aculeata) green manure each year before rice (SM); (3) applied gypsum at 100 per cent soil gypsum requirement (SGR) and (4) applied gypsum as in treatment 3 plus sesbania green manure each year (GSM). A decrease in soil salinity and sodicity and favourable infiltration rate and bulk density over pre‐experiment levels are recorded. GSM resulted in the largest decrease in soil salinity and sodicity. There was a positive relationship between crop yield and economic benefits and improvement in soil physical and chemical properties. On the basis of six crops, the greatest net benefit was obtained from GSM. Based on this long‐term study, combined use of gypsum at 100 per cent soil gypsum requirement along with sesbania each year is recommended for soil amelioration and crop production. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

2.
Chemical reclamation of sodic and saline-sodic soils has become cost-intensive. Cultivation of plants tolerant of salinity and sodicity may mobilize the CaCO3 present in saline-sodic soils instead of using a chemical approach. Four forage plant species, sesbania (Sesbania aculeata), kallar grass (Leptochloa fusca), millet rice (Echinochloa colona) and finger millet (Eleusine coracana), were planted in a calcareous saline-sodic field (ECe = 9·6–11·0 dS m−1, SAR = 59·4–72·4). Other treatments included gypsum (equivalent to 100 per cent of the gypsum requirement of the 15 cm soil layer) and a control (no gypsum or crop). The crops were grown for 5 months. The performance of the treatments in terms of soil amelioration was in the order: Sesbania aculeata ≅ gypsum > Leptochloa fusca > Echinochloa colona > Elusine coracana > control. Biomass production by the plant species was found to be directly proportional to their reclamation efficiency. Sesbania aculeata produced 32·3 Mg forage ha−1, followed by Leptochloa fusca (24·6 Mg ha−1), Echinochloa colona (22·6 Mg ha−1) and Eleusine coracana (5·4 Mg ha−1). Sesbania aculeata emerged as the most suitable biotic material for cultivation on salt-affected soils to produce good-quality forage, and to reduce soil salination and sodication processes.  相似文献   

3.
To understand the limitations of saline soil and determine best management practices, simple methods need to be developed to determine the salinity distribution in a soil profile and map this variation across the landscape. Using a field study in southwestern Australia, we describe a method to map this distribution in three dimensions using a DUALEM‐1 instrument and the EM4Soil inversion software. We identified suitable parameters to invert the apparent electrical conductivity (ECa – mS/m) data acquired with a DUALEM‐1, by comparing the estimates of true electrical conductivity (σ – mS/m) derived from electromagnetic conductivity images (EMCI) to values of soil electrical conductivity of a soil‐paste extract (ECe) which exhibited large ranges at 0–0.25 (32.4 dS/m), 0.25–0.50 (18.6 dS/m) and 0.50–0.75 m (17.6 dS/m). We developed EMCI using EM4Soil and the quasi‐3d (q‐3d), cumulative function (CF) forward modelling and S2 inversion algorithm with a damping factor (λ) of 0.07. Using a cross‐validation approach, where we removed one in 15 of the calibration locations and predicted ECe, the prediction was shown to have high accuracy (RMSE = 2.24 dS/m), small bias (ME = ?0.03 dS/m) and large Lin's concordance (0.94). The results were similar to those from linear regression models between ECa and ECe for each depth of interest but were slightly less accurate (2.26 dS/m). We conclude that the q‐3d inversion was more efficient and allowed for estimates of ECe to be made at any depth. The method can be applied elsewhere to map soil salinity in three dimensions.  相似文献   

4.
Abstract. Diagnosis of soil salinity and its spatial variability is required to establish control measures in irrigated agriculture. This article shows the usefulness of electromagnetic (EM) and soil sampling techniques to map salinity. We analysed the salinity of a 1‐ha plot of surface‐irrigated olive plantation in Aragon, NE Spain, by measuring the electrical conductivity of the saturation extract (ECe) of soil samples taken at 22 points, and by reading the Geonics EM38 sensor at 141 points in the horizontal (EMH) and vertical (EMV) dipole positions. EMH and EMV values had asymmetrical bimodal distributions, with most readings in the non‐saline range and a sharp transition to relatively high readings. Most salinity profiles were uniform (i.e. EMH=EMV), except in areas with high salinity and concurrent shallow water tables, where the profiles were inverted as shown by EMH > EMV, and by ECe being greater in shallow than in deeper layers. The regressions of ECe on EM readings predicted ECe with R2 > 84% for the 0–100 to 0–150 cm soil depths. We then produced salinity contour maps from the 141 ECe values estimated from the electromagnetic readings and the 22 measured values of ECe. Owing to the high soil sampling density, the maps were similar (i.e. mean surface‐weighted ECe values between 3.9 dS m?1 and 4.2 dS m?1), although the electromagnetically estimated ECe improved the mapping of details. Whereas soil sampling is preferred for analysing the vertical distribution of soil salinity, the electromagnetic sensor is ideal for mapping the lateral variability of soil salinity.  相似文献   

5.
In coastal China, there is an urgent need to increase land for agriculture. One solution is land reclamation from coastal tidelands, but soil salinization poses a problem. Thus, there is need to map saline areas and identify appropriate management strategies. One approach is the use of digital soil mapping. At the first stage, auxiliary data such as remotely sensed multispectral imagery can be used to identify areas of low agricultural productivity due to salinity. Similarly, proximal sensing instruments can provide data on the distribution of soil salinity. In this study, we first used multispectral QuickBird imagery (Bands 1–4) to provide information about crop growth and then EM38 data to indicate relative salt content using measurements of apparent soil electrical conductivity (ECa) in the horizontal (ECh) and vertical (ECv) modes of operation. Second, we used a fuzzy k‐means (FKM) algorithm to identify three salinity management zones using the normalized difference vegetation index (NDVI), ECh and ECv/ECh. The three identified classes were statistically different in terms of auxiliary and topsoil properties (e.g. soil organic matter) and more importantly in terms of the distribution of soil salinity (ECe) with depth. The resultant three classes were mapped to demonstrate that remote and proximally sensed auxiliary data can be used as surrogates for identifying soil salinity management zones.  相似文献   

6.
Electrical conductivity (EC) of soil-water extracts is commonly used to assess soil salinity. However, its conversion to the EC of saturated soil paste extracts (ECe), the standard measure of soil salinity, is currently required for practical applications. Although many regression models can be used to obtain ECe from the EC of soil-water extracts, the application of a site-specific model to different sites is not straightforward due to confounding soil factors such as soil texture. This study was conducted to develop a universal regression model to estimate a conversion factor (CF) for predicting ECe from EC of soil-water extracts at a 1:5 ratio (EC1:5), by employing a site-specific soil texture (i.e., sand content). A regression model, CF=8.910 5e0.010 6sand/1.298 4 (r2=0.97, P < 0.001), was developed based on the results of coastal saline soil surveys (n=173) and laboratory experiments using artificial saline soils with different textures (n=6, sand content=10%-65%) and salinity levels (n=7, salinity=1-24 dS m-1). Model performance was validated using an independent dataset and demonstrated that ECe prediction using the developed model is more suitable for highly saline soils than for low saline soils. The feasibility of the regression model should be tested at other sites. Other soil factors affecting EC conversion factor also need to be explored to revise and improve the model through further studies.  相似文献   

7.
Biological, chemical and bio‐chemical strategies have been tested in the past for reclamation of saline‐sodic and sodic soils. The efficiency of two crop rotations (rice‐wheat and Sesbania‐wheat) alone or in combination with either gypsum (CaSO4.2H2O) or sulfuric acid (H2SO4) was tested for ionic displacement from four saline‐sodic soils. Pure gypsum was applied at 50 per cent of soil gypsum requirement at the time of planting rice and Sesbania, whereas 95 per cent pure sulfuric acid was added at 50 per cent soil gypsum requirement as one‐third applications by mixing with the first three irrigations. The rice crop biomass decreased at a soil saturation extract electrical conductivity (ECe) of 8 dS m−1, whereas wheat and Sesbania were influenced at a sodium adsorption ratio (SAR) of ≥40. Gypsum treatment helped the crops flourish well at these ECe and SAR levels. The infiltrated volume of water dropped with decrease in ECe : SAR ratio of soils and increase in crop biomass production. Crops rotation treatments alone helped leach sodium (Na+) and other ions successfully at SAR ≤ 21 but were less effective at SAR ≥ 40 at which point plants growth was also curtailed. Gypsum and H2SO4 treatments significantly aided leaching of Na+ and other ions with water at SAR ≥ 40 under both the crop rotations. Hence, crops effectively reclaimed soil at low sodicity level, whereas at high SAR, chemical amendments are obligatory in order to reclaim soils. This study also suggests that the required dose of H2SO4 should be applied with pre‐planting irrigation for better yield of the first crop. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

8.
Saline–sodic and sodic soils are characterized by the occurrence of sodium (Na+) to levels that can adversely affect several soil properties and growth of most crops. As a potential substitute of cost‐intensive chemical amelioration, phytoremediation of such soils has emerged as an efficient and low‐cost strategy. This plant‐assisted amelioration involves cultivation of certain plant species that can withstand ambient soil salinity and sodicity levels. It relies on enhanced dissolution of native calcite within the root zone to provide adequate Ca2+ for the Na+ Ca2+ exchange at the cation exchange sites. There is a lack of information for the Na+ balance in terms of removal from saline–sodic soils through plant uptake and leaching during the phytoremediation process. We carried out a lysimeter experiment on a calcareous saline–sodic soil [pH of saturated soil paste (pHs) = 7.2, electrical conductivity of the saturated paste extract (ECe) = 4.9 dS m−1, sodium adsorption ratio (SAR) = 15.9, CaCO3 = 50 g kg−1]. There were three treatments: (1) control (without application of a chemical amendment or crop cultivation), (2) soil application of gypsum according to the gypsum requirement of the soil and (3) planting of alfalfa (Medicago sativa L.) as a phytoremediation crop. The efficiency of treatments for soluble salt and Na+ removal from the soil was in the order: gypsum ≈ alfalfa > control. In the phytoremediation treatment, the amount of Na+ removed from the soil through leaching was found to be the principal cause of reduction in salinity and sodicity. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

9.
Fertilization with nitrogen (N) or phosphorus (P) can improve plant growth in saline soils. This study was undertaken to determine wheat (Triticum aestivum L; cv Krichauff) response to the combined application of N and P fertilizers in the sandy loam under saline conditions. Salinity was induced using sodium (Na+) and calcium (Ca2+) salts to achieve four levels of electrical conductivity in the extract of the saturated soil paste (ECe), 2.2, 6.7, 9.2 and 11.8?dS?m?1, while maintaining a low sodium adsorption ratio (SAR; ≤1). Nitrogen was applied as Ca(NO3)2?·?4H2O at 50 (N50), 100 (N100) and 200 (N200)?mg?N?kg?1 soil. Phosphorus was applied at 0 (P0), 30 (P30) and 60 (P60)?mg?kg?1?soil in the form of KH2PO4. Results showed that increasing soil salinity had no effect on shoot N or P concentrations, but increased shoot Na+ and chlorine ion (Cl?) concentrations and reduced dry weights of shoot and root in all treatments of N and P. At each salinity and P level, increasing application of N reduced dry weight of shoot. At each salinity and N level P fertilization increased dry weights of shoot and root and shoot P concentration. Addition of greater than N50 contributed to the soil salinity limiting plant growth, but increasing P addition up to 60?mg?P?kg?1 soil reduced Cl? absorption and enhanced the plant salt tolerance and thus plant growth. The positive effect of the combined addition of N and P on wheat growth in the saline sandy loam is noticeable, but only to a certain level of soil salinity beyond which salinity effect is dominant.  相似文献   

10.
For understanding the effects of soil salinity and nitrogen (N) fertilizer on the emergence rate, yield, and nitrogen-use efficiency (NUE) of sunflowers, complete block design studies were conducted in Hetao Irrigation District, China. Four levels of soil salinity (electrical conductivity [ECe] = 2.44–29.23 dS m?1) and three levels of N fertilization (90–180 kg ha?1) were applied to thirty-six microplots. Soil salinity significantly affected sunflower growth (P < 0.05). High salinity (ECe = 9.03–18.06 dS m?1) reduced emergence rate by 24.5 percent, seed yield by 31.0 percent, hundred-kernel weight by 15.2 percent, and biological yield by 27.4 percent, but it increased the harvest index by 0.9 percent relative to low salinity (ECe = 2.44–4.44 dS m?1). Application of N fertilizer alleviated some of the adverse effects of salinity, especially in highly saline soils. We suggest that moderate (135 kg ha?1) and high (180 kg ha?1) levels of N fertilization could provide the maximum benefit in low- to moderate-salinity and high- or severe-salinity fields, respectively, in Hetao Irrigation District and similar sunflower-growing areas.  相似文献   

11.
Saline‐sodic water is a by‐product of coalbed natural gas (CBNG) production in the Powder River Basin of Wyoming, USA and is being beneficially used in places as irrigation water. This study evaluated effects of 2 years of natural precipitation on soil properties of a hay field after the cessation of managed irrigation with CBNG water. The hay field had been irrigated with only CBNG water [CBNG(NT)], CBNG water amended with gypsum [CBNG(G)] or gypsum plus sulfur via a sulfur burner [CBNG(GSB)] in combination with soil amendments—gypsum ( +G ), elemental sulfur ( +S ), and both ( +GS ). Results indicated that infiltration rates were the lowest on fields irrigated with CBNG(NT), followed by CBNG(G) and CBNG(NT) +G treatments (12·2, 13·2, and 13·5 cm h−1, respectively). The CBNG(GSB) +GS treatment had the highest infiltration rates (33·5 cm h−1). By the second year, salinity and sodicity of treated soils had decreased in the A‐horizon of most CBNG‐water irrigated plots, whereas in Bt1‐ and Bt2‐horizons salinity generally decreased but sodicity increased; S and GS soil amended plots had higher profile salinities compared with NT and G soil treatments. Although Na+ leaching was observed in all fields that received soil and/or water amendments, CBNG(GSB) +GS plots had the lowest sodicity in the A‐ and Bt1‐horizons. Effective managed irrigation requires knowledge of site‐specific soil properties, plant suitability, water chemistry, and amendments that would be needed to treat the CBNG waters and soils. This study indicates the greatest success was realized when using both soil and water amendments. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

12.
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13.
Potential for carbon dioxide (CO2) biosequestration was determined during the reclamation of highly saline–sodic soils (Aridisols) after rice (2003) and wheat (2003–2004) crops at two sites in District Faisalabad, Pakistan. Two treatments were assessed: T1, tube-well brackish water only; and T2, soil-applied gypsum at 25% soil gypsum requirement?+?tube-well brackish water. The irrigation water used at both sites had different levels of salinity (EC 3.9–4.5 dS m?1), sodicity (SAR 21.7–28.8), and residual sodium carbonate (14.9 mmolc L?1). Composite soil samples were collected from soil depths of 0–15 and 15–30 cm at presowing and postharvest stages and analyzed for pH, ECe, and sodium adsorption ratio (SAR). After rice harvest, there was no significant effect of gypsum application on ECe, pH, and SAR at both sites, except pH at 0–15 cm depth decreased significantly with gypsum at site 1. After wheat harvest, ECe, pH, and SAR decreased significantly with gypsum at site 1, whereas the effect of gypsum on these parameters was not significant at site 2. Compared to initial soil, ECe and SAR in soil decreased considerably after rice or wheat cultivation, particularly at site 1, whereas pH increased slightly due to cultivation of these crops. For rice, the total CO2 sequestration was significantly increased with gypsum application at both sites and ranged from 1499 to 2801 kg ha?1. The total sequestration of CO2 was also significantly increased with gypsum application in wheat at both sites and ranged from 2230 to 3646 kg ha?1. The amounts of CO2 sequestered by crops due to gypsum application were related to seed and straw yield responses of rice and wheat to gypsum, which were greater at site 1 than site 2. Also, the yield response to applied gypsum was greater for rice than wheat at site 1, whereas the opposite was true at site 2. Overall, the combined application of gypsum with brackish water reduced soil ECe and SAR compared to brackish water alone, particularly at site 1. Our findings also suggest that the reclamation strategies should be site specific, depending on soil type and quality of brackish water used for irrigation of crops. In conclusion, the use of gypsum is recommended on brackish water–irrigated salt-prone soils to improve their quality, and for enhancing C biosequestration and crop production for efficient resource management.  相似文献   

14.
In the oldest commercial wine district of Australia, the Hunter Valley, there is the threat of soil salinization because marine sediments underlie the area. To understand the risk requires information about the spatial distribution of soil properties. Electromagnetic (EM) induction instruments have been used to identify and map the spatial variation of average soil salinity to a certain depth. However, soils vary with depth dependent on soil forming factors. We collected data from a single‐frequency and multiple‐coil DUALEM‐421 along a toposequence. We inverted this data using EM4Soil software and evaluated the resultant 2‐dimensional model of true electrical conductivity (σ – mS/m) with depth against electrical conductivity of saturated soil pastes (ECp – dS/m). Using a fitted linear regression (LR) model calibration approach and by varying the forward model (cumulative function‐CF and full solution‐FS), inversion algorithm (S1 and S2), damping factor (λ) and number of arrays, we determined a suitable electromagnetic conductivity image (EMCI), which was optimal (R2 = 0.82) when using the full solution, S2, λ = 3.6 and all six coil arrays. We conducted an uncertainty analysis of the LR model used to estimate the electrical conductivity of the saturated soil‐paste extract (ECe – dS/m). Our interpretation based on estimates of ECe suggests the approach can identify differences in salinity, how these vary with parent material and how topography influences salt distribution. The results provide information leading to insights into how soil forming factors and agricultural practices influence salinity down a toposequence and how this can guide soil management practices.  相似文献   

15.
ABSTRACT

We estimate the electrical conductivity of saturated soil paste extract (ECe) from electrical conductivity of a 1:5 soil-water dilution ratio (EC1:5) in Northeastern Thailand. Soil samples of various textures and salinity collected from Sakhon Nakhon basin were used to develop multiple regression models, from which the linear model was chosen and was validated on soil samples from the Khorat basin. Comparison with previous models indicated that most linear models gave a good fit, but the non-linear models either over or underestimated the measured values. The models performed very well for low values of ECe (<5 dS m?1), while the prediction errors increased significantly for ECe levels >35 dS m?1. The present model performed well at various ECe levels and can be used to predict salinity levels for soils weathered from salt deposits in sedimentary rocks with similar rock formation in countries like Malaysia, Vietnam, Cambodia, and Laos.  相似文献   

16.
Phosphogypsum (PG), which contains Ca, P and S and has an acidic effect, may be applied to manage soil constraints such as alkalinity and salinity. For increasing nutrients bioavailability, biofertilizers are commonly applied. Therefore, the aim of this study was to assess PG effect either alone or in combination with the mixed co-inoculation of plant growth promoting rhizobacteria on a saline soil. In a greenhouse pot experiment with maize (Zea mays L.), the inoculated and non-inoculated saline soils were treated with PG at 10 g kg?1 (PG10), 30 g kg?1 (PG30), and 50 g kg?1 (PG50). The soil pH, electrical conductivity (ECe), and macro-(NPK) and micronutrients (Fe, Mn, Zn, and Cu) availability to mays were examined. Applying PG reduced soil pH and co-inoculation induced significant decreases in soil ECe. Applying PG increased significantly soil available P. Applying PG combined with co-inoculation effectively increased the soil available K. The soil available micronutrients decreased significantly with PG. However, the inoculated maize treated with PG showed significant higher dry weight (82.1–127.4%) and nutrients uptake than the control. It could be concluded that PG along with co-inoculation may be an important approach for alleviating negative effects of salinity on plant growth.  相似文献   

17.
The electrical conductivity of the water within the soil pores (ECp) measured with the WET sensor, appears to be a reliable estimate of soil salinity. A methodology combining the use of the WET sensor along with geostatistics was developed to delimit and evaluate soil salinity within an irrigated area under arid to semiarid Mediterranean climate in SE Spain. A systematic random sampling of 104 points was carried out. The association between ECp and the saturation‐extract electrical conductivity (ECse) was assessed by means of correlation analysis. The semivariograms for ECp were obtained at three different soil depths. Interpolation techniques, such as ordinary kriging and cokriging, were applied to obtain ECp levels in the unknown places. For each one of the soil depths, a model able to predict ECse from ECp was developed by means of ordinary least squares regression analysis. A good correlation (r = 0.818, p < 0.001) between ECp and ECse was found. Spherical spatial distribution was the best model to fit to experimental semivariograms of ECp at 10, 30, and 50 cm soil depths. Nevertheless, cokriging using the ECp of an adjacent soil depth as an auxiliary variable provided the best results, compared to ordinary kriging. An analytical propagation‐error methodology was found to be useful to ascertain the contribution of the spatial interpolation and ordinary least squares analysis to the uncertainty of the ECse mapping. This methodology allowed us to identify 98% of the study area as affected by salinity problems within a rooting depth of 50 cm, with the threshold of ECse value at 2 dS m–1. However, considering the crops actually grown and 10% potential reduction yield, the soil‐salinity‐affected area decreased to 83%. The use of sensors to measure soil salinity in combination with geostatistics is a cost‐effective way to draw maps of soil salinity at regional scale. This methodology is applicable to other agricultural irrigated areas under risk of salinization.  相似文献   

18.
Previous studies have shown that carbon (C) mineralization in saline or sodic soils is affected by various factors including organic C content, salt concentration and water content in saline soils and soil structure in sodic soils, but there is little information about which soil properties control carbon dioxide (CO2) emission from saline-sodic soils. In this study, eight field-collected saline–sodic soils, varying in electrical conductivity (ECe, a measure of salinity, ranging from 3 to 262 dS m−1) and sodium adsorption ratio (SARe, a measure of sodicity, ranging from 11 to 62), were left unamended or amended with mature wheat or vetch residues (2% w/w). Carbon dioxide release was measured over 42 days at constant temperature and soil water content. Cumulative respiration expressed per gram SOC increased in the following order: unamended soil<soil amended with wheat residues (C/N ratio 122)<soil with vetch residue (C/N ratio 18). Cumulative respiration was significantly (p < 0.05) negatively correlated with ECe but not with SARe. Our results show that the response to ECe and SARe of the microbial community activated by addition of organic C does not differ from that of the less active microbial community in unamended soils and that salinity is the main influential factor for C mineralization in saline–sodic soils.  相似文献   

19.
Two approaches have emerged as the preferred means for assessing salinity at regional scale: (i) vegetative indices from satellite imagery (e.g., MODIS enhanced vegetative index, NDVI) and (ii) analysis of covariance (ANOCOVA) calibration of apparent soil electrical conductivity (ECa) to salinity. The later approach is most recent and least extensively validated. It is the objective of this study to provide extensive validation of the ANOCOVA approach. The validation comprised 77 fields in California's Coachella Valley, ranging from 1.25 to 30.0 ha in size with an average size of 12.8 ha. Mobile electromagnetic induction (EMI) equipment surveyed the fields obtaining geospatial measurements of ECa. Soil sample sites selected following ECa‐directed soil sampling protocols characterized the range and spatial variation in ECa across the field. From the data, a regional ANOCOVA model was developed. The regional ANOCOVA model successfully reduced cross‐validated, average log salinity prediction error (variance) estimate by more than 30% across the 77 fields and improved the depth‐averaged prediction accuracy in 58 of the 77 fields. The results show that the ANOCOVA modelling approach improves soil salinity predictions from EMI signal data in most of the surveys conducted, particularly fields where only a limited number of calibration sampling locations were available. The establishment of ANOCOVA models at each depth increment for a representative set of fields within a regional‐scale study area provides slope coefficients applicable to all future fields within the region, significantly reducing ground‐truth soil samples at future fields.  相似文献   

20.
Reforestation of saline sodic soil is increasingly undertaken as a means of reclaiming otherwise unproductive agricultural land. Currently, restoration of degraded land is limited to species with high tolerances of salinity. Biochar application has the potential to improve physical, biological and chemical properties of these soils to allow establishment of a wider range of plants. In a glasshouse trial, we applied biochar made from Acacia pycnantha (5 Mg ha−1) or no biochar to either a low (ECe 4·75 dS m−1, ESP 6·9), a moderate (ECe 27·6 dS m−1, ESP 29·3) or a high (ECe 49·4 dS m−1, ESP 45·1) saline sodic soil. The regional common reforestation species Eucalyptus viminalis and Acacia mearnsii were planted as tubestock in to the soils. Early establishment indicators, including growth, plant condition and nutrition, were assessed at the end of a simulated growing season, 108 days after biochar application. Application of biochar increased height, and decreased root : shoot and the concentration of Mn, N and S in plants of E. viminalis when grown in the highly saline sodic soil. Biochar application increased the concentration of B in leaves of E. viminalis and increased the concentration of P, K and S in leaves of A. mearnsii when grown in the low saline sodic soil. The results confirm that there is potential for biochar to assist in reforestation of saline sodic soils. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

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