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1.
This investigation was conducted by using alkaline slag and crop straw biochars to reduce acidity of an acidic Ultisol through incubation and pot experiments with lime as a comparison. The soil was amended with different liming materials： lime（1 g kg^-1）,alkaline slag（2 and 4 g kg^-1）, peanut straw biochar（10 and 20 g kg^-1）, canola straw biochar（10 and 20 g kg^-1） and combinations of alkaline slag（2 g kg^-1） and biochars（10 g kg^-1） in the incubation study. A pot experiment was also conducted to observe the soybean growth responses to the above treatments. The results showed that all the liming materials increased soil p H and decreased soil exchangeable acidity. The higher the rates of alkaline slag, biochars, and alkaline slag combined with biochars, the greater the increase in soil p H and the reduction in soil exchangeable acidity. All the amendments increased the levels of one or more soil exchangeable base cations. The lime treatment increased soil exchangeable Ca^2＋, the alkaline slag treatment increased exchangeable Ca^2＋ and Mg^2＋ levels, and the biochars and combined applications of alkaline slag with biochars increased soil exchangeable Ca^2＋, Mg^2＋ and K^＋ and soil available P. The amendments enhanced the uptake of one or more nutrients of N, P, K, Ca and Mg by soybean in the pot experiment. Of the different amendments, the combined application of alkaline slag with crop straw biochars was the best choice for increasing base saturation and reducing soil acidity of the acidic Ultisol. The combined application of alkaline slag with biochars led to the greatest reduction in soil acidity, increased soil Ca, Mg, K and P levels, and enhanced the uptake of Ca, Mg, K and P by soybean plants.  相似文献   

2.
Temporal changes in soil chemical and nutritional properties were evaluated in a long-term experiment conducted on Alfisols in West Africa. Effects of land use and cropping duration on soil chemical properties at 0–5 cm and 5–10 cm depths were evaluated for five treatments: (1) alley cropping with Leucaena leucocephala established on the contour at 4-m intervals; (2) mucuna (Mucuna utilis) fallowing for 1 year followed by maize (Zea mays)-cowpea (Vigna unguiculata) cultivation for 2 years on severely degraded land; (3) fallowing with mucuna on moderately degraded soils; (4) ley farming involving growing improved pastures for 1 year, grazing for the second year, and growing maize-cowpea for the third year on severely degraded land; (5) ley farming on moderately degraded soils. Soil chemical properties were measured once every year from 1982 through 1986 during the dry season, and included pH, soil organic carbon (SOC), total soil nitrogen (TSN), Bray-P, exchangeable cations, and effective cation exchange capacity (CEC). Regardless of the cropping system treatments, soil chemical quality decreased with cultivation time. The rate of decrease at 0–5 cm depth was 0·23 units year−1 for pH, 0·05 per cent year−1 for SOC, 0·012 per cent year−1 for TSN, 0·49 cmol kg−1 year−1 for Ca2+, 0·03 cmol kg−1 year−1 for Mg2+, 0·018 cmol kg−1 year−1 for K+, and 0·48 cmol kg−1 year−1 for CEC. Although there was also a general decrease in soil chemical quality at 5–10 cm depth, the trends were not clearly defined. In contrast to the decrease in soil properties given above, there was an increase in concentration at 0–5 cm depth of total acidity with cultivation time at the rate of 0·62 cmol kg−1 year−1, and of Mn3+ concentration at the rate of 0·081 cmol kg−1 year−1. Continuous cropping also increased the concentration of Bray-P at 0–5 cm depth due to application of phosphatic fertilizer. Trends in soil chemical properties were not clearly defined with regards to cropping system treatments. In general, however, soil chemical properties were relatively favorable in ley farming and mucuna fallowing treatments imposed on moderately degraded soils. Results are discussed in terms of recommended rates of fertilizer use, in view of soil test values, expected yields, and critical limits of soil properties.  相似文献   

3.
Most tropical soils have high acidity and low natural fertility. The appropriate application of lime and cattle manure corrects acidity, improves physical and biological properties, increases soil fertility, and reduces the use of chemical and/or synthetic fertilizers by crops, such as soybean, the main agricultural export product of Brazil. This study aimed to assess the effects of the combination of the application of dolomite limestone (0, 5, and 10 Mg ha?1) and cattle manure (0, 40, and 80 Mg ha?1) on grain yield and the chemical properties of an Oxisol (Red Latosol) cultivated with soybean for two consecutive years. The maximum grain yield was obtained with the application of 10 Mg ha?1 of lime and 80 Mg ha?1 of cattle manure. Liming significantly increased pH index, the concentrations of calcium (Ca2+) and exchangeable magnesium (Mg2+), and cation exchange capacity (CEC) of soil and reduced potential acidity (H+ + Al3+), while the application of cattle manure increased pH level; the concentrations of potassium (K+), Ca2+, and exchangeable Mg2+; and CEC of the soil. During the 2 years of assessment, the greatest grain yields were obtained with saturation of K+, Ca2+, and Mg2+ in CEC at the 4.4, 40.4, and 17.5 levels, respectively. The results indicated that the ratios of soil exchangeable Ca/Mg, Ca/K, K/Mg, and K/(Ca+Mg) can be modified to increase the yield of soybean grains.  相似文献   

4.
The increasing demand for fertilizers and the fact that the world reserves of phosphorus (P) and potassium (K) are depletable make appropriate soil management a critical factor in agriculture. Techniques for the fertilizer use and soil acidity corrective are becoming increasingly necessary to minimize the cost of yield and increase the nutrient efficiency. In view of the aforementioned, the present study aimed to assess the effects of gypsum application on the leaching of cations in the soil profile. A completely randomized design in a 5 × 4 factorial arrangement, with five replicates, was used. The treatments corresponded to five gypsum rates (0, 1, 2, 4, and 8 magnesium (Mg) ha?1) applied on broadcast of soil and at four depth sampled (0–5, 6–10, 11–15, and 16–20 cm). Gypsum application increased the fertility in depth, with the leaching of cations. There was an increase in soil pH, exchangeable K+ and calcium (Ca2+), sulfur (S–SO42?), P, boron (B), and manganese (Mn) concentration, cation exchange capacity (CEC), K+ and Ca2+ saturation, Ca2+/Mg2+, Ca2+/K+, and K+/(Ca2+ + Mg2+) ratios, and electrical conductivity in soil depth. On the other hand, there was a decrease in exchangeable Mg2+ and potential acidity hydrogen and aluminum (H+ + Al3+), available silicon (Si), Mg2+ saturation, and Ca2+/K+ and Mg2+/K+ ratio. These results demonstrate that the gypsum application in an Oxisol with 690 g kg?1 of clay improves the root system with a significant increase in the soil fertility in the profile.  相似文献   

5.
One of the main environmental impacts of concentrated animal feeding operations is soil degradation in the vicinity of the livestock breeding facilities due to substances such as ammonia emitted from the various stages of the process. In this research, the soil degradation effects of an intensive hog farming operation (IHFO) located at a Mediterranean limestone soil coastal area have been investigated. Soil samples of the upper mineral soil were taken in various distances and directions from the IHFO boundaries. Thirteen experimental cycles were carried out in the duration of 1.5?years starting in March 2009 until October 2010. The soil samples were analysed on total, exchangeable and water-soluble Ca, Mg and K as well as water-soluble ammonium concentrations. Significantly lower concentrations of the exchangeable and water-soluble base cations were observed on soil samples at increasing proximity downwind from the farm (south). Southern soil average concentrations of exchangeable base cations ranged between 78.6 and 128.52?mmol Ca2+?kg?1 soil, 8.42?C21.39?mmol?Mg2+?kg?1 soil and 4.25?C8.1?mmol?K+?kg?1 soil, respectively. Southern soil average concentrations of water-soluble base cations ranged between 0.57 and 2.17?mmol Ca2+?kg?1 soil, 0.16?C0.89?mmol?Mg2+?kg?1 soil and 0.48?C0.95?mmol?K+?kg?1 soil, respectively.  相似文献   

6.
Soil acidity is the principal limiting factor in crop production in Oxisols, and deficiency of micronutrients has increased in recent years because of intensive cropping. A field experiment was conducted over three consecutive years to assess response of common bean (Phaseolus vulgaris L.) to lime and iron (Fe) applications on an Oxisol in a no-tillage system. Changes in selected soil chemical properties in the soil profile (0- to 10- and 10- to 20-cm depths) with liming were also determined. Lime rates used were 0, 12, and 24 Mg ha–1, and Fe application rates were 0, 50, 100, 150 200, and 400 kg ha–1. Both lime and Fe were applied as broadcast and incorporated in the soil. Grain yields of common bean were significantly increased with the application of lime. Iron application, however, did not influence bean yield. There were significant changes in soil profile (0- to 10-cm and 10- to 20-cm depths) in pH, calcium (Ca2+), magnesium (Mg2+), hydrogen + aluminum (H+ + Al3+), base saturation, acidity saturation, cation exchange capacity (CEC), Ca2+ saturation, Mg2+ saturation, potassium (K+) saturation, and ratios of Ca/Mg, Ca/K, and Mg/K. These soil chemical properties had significant positive association with common bean grain yield. Averaged across two depths and three crops, common bean produced maximum grain yield at pHw 6.3, Ca2+ 3.8 cmolc kg–1, Mg2+ 1.1 cmolc kg–1, 3.5 H+ + Al3+ cmolc kg–1, acidity saturation 41.8%, CEC 7.5 cmolc kg–1, base saturation 57.4%, Ca saturation 45.2%, Mg saturation 14.2%, K saturation 9.1%, Ca/Mg ratio 3.1, Ca/K ratio 22.6, and Mg/K ratio 6.7.  相似文献   

7.
A study was conducted to examine the impact of land use on soil fertility in an Entisol in the Jalpaiguri District of humid subtropical India. The natural forest served as a control against which changes in soil properties were compared. Soil samples were collected from four different depths (0–25, 25–50, 50–75, and 75–100 cm) of soil from four land uses (viz. forest, home garden, arecanut plantation, and agriculture) and examined for pH, organic carbon (OC), electrical conductivity (EC), cation exchange capacity, available nitrogen (N), phosphorus (P), exchangeable calcium (Ca), magnesium (Mg), potassium (K), aluminum (Al), microbial biomass carbon (MBC), microbial biomass nitrogen (MBN) and dehydrogenase activity (DHA). Soil pH (5.7), OC (2.29%), N (386 kg ha?1), and P (22.54 kg ha?1) were greatest in forest soil, followed by soil from arecanut plantation, agriculture, and home garden. The greatest Ca (0.892 cmol kg?1), Mg (0.527 cmol kg?1), and Al (1.86 cmol kg?1) were found in the arecanut plantation, whereas K (0.211 cmol kg?1) was greatest in forest. The greatest content of diethylenetriaminepentaacetic acid–extractable copper, zinc, manganese, and iron (2.25, 1.66, 4.86, and 7.65 ppm, respectively) were found in forest. MBC (558 mg kg?1), MBN (26.67 mg kg?1), and DHA (33.03 μg TPF 24 h?1 g?1) was greatest in forest soil. Soil fertility index varied from 13.13 in arecanut plantation to 18.49 in forest. The soil evaluation factor ranged from 5.32 in agriculture to 6.56 in forest. Pearson's correlation matrix revealed strongly significant positive correlation of soil fertility index and soil evaluation factor with soil properties.  相似文献   

8.
ABSTRACT

Orchard efficiency (OE) is one of the indices of evaluating the sustainability in production behavior of citrus orchards. A wide range of soil properties broadly categorized into particle size distribution, water soluble and exchangeable cations, and soil available nutrients were investigated in relation to efficiency of Nagpur mandarin (Citrus reticulata Blanco) orchards established on smectite rich three soil orders (Entisols, Inceptisols, and Vertisols) representing 18 locations of central India. The soil properties, viz., free calcium carbonate (CaCO3), clay content, water soluble- and exchangeable-calcium (Ca2 +), available nitrogen (N), phosphorus (P), and zinc (Zn) contributed significantly towards variation in OE. The threshold limit of these limiting soil properties was further established using multivariate quadratic regression models as: 132.1 g kg? 1 free CaCO3, 418.1 g kg? 1 clay, 149.9 mg L? 1 water soluble Ca2 +, 25.9 cmol(p+) kg? 1 exchangeable Ca2 +, 114.6 mg kg? 1 available N, 12.8 mg kg? 1 available P, and 0.96 mg kg? 1 available Zn in relation to optimum OE of 82.1%. These reference values were very close to those obtained from best fit models, and could be effectively utilized in addressing soil related production constraints for precision-aided citriculture.  相似文献   

9.
Understanding of tillage effects on soil chemical properties and cations in soil solution dynamics is essential for making appropriate land-management decisions. Measurements were made after more than 25 years of different tillage treatments: conventional tillage (CT) and conservation tillage, which includes no-till (NT) and minimum tillage (MT). pH and bulk density did not show important changes but exchangeable cations and cations in soil solution were affected by depth and different tillage. The highest concentration of exchangeable Ca2+ and Mg2+ was found in NT, decreased in MT and the lowest concentration was found in CT (mean values were 26.0, 24.4 and 23.3 cmolc kg?1 for exchangeable Ca2+ and 4.2, 3.7 and 3.3 cmolc kg?1 for exchangeable Mg2+ in NT, MT and CT, respectively). In addition, the highest concentration of exchangeable Na+ was found in NT, decreased in CT and the lowest concentration was found in MT. However, the highest concentration of exchangeable K+ was found in MT. A significant depth effect was observed for cations in soil solution: Na+ increased with depth whereas K+ and Ca2+ decreased with depth. This study aims to demonstrate the effect of tillage on the distribution and concentration of certain chemical soil properties.  相似文献   

10.
Abstract

Hardsetting soil properties are undesirable in agricultural soils because they hamper moisture movement and soil aeration. The soils of the floodplain of Niger River in eastern Nigeria hardsets upon drying, following dispersion, puddling, and slaking during the waterlogged period. Ten soil samples collected from a depth of 0–20 cm were analyzed for their properties. The soils are classified as Fluvaquentic Eutropepts or Dystric Gleysol (FAO). The objective was to investigate the influence of some soil properties on water‐dispersible clay (WDC) of the soils, which is the precursor of the hardsetting process. The total clay content (TC) correlated significantly with WDC (r=0.94??), whereas the water‐dispersible silt (WDSi) was higher than its corresponding total silt content. The WDC showed a positive correlation with dithionite extractable Fe (Fed), Al (Ald), and oxalate extractable Fe (Feo) (r=0.75?, 0.89??, and 0.76? respectively). Exchangeable Mg2+ correlated significantly with WDSi (r=0.70). Principal component analysis of the soil variables indicates that 15 soil components, which influence WDC as hardsetting properties, were reduced to 5 orthogonal components. The parameters that influence hardsetting properties are exchangeable Na+, K+, Ca2+, Mg2+, Fed, Alo, and Feo. Other soil properties are kaolinite, smectite, illite, and WDC, including soil organic carbon (OC), electrical conductivity (EC), and ESP. Therefore, those soil properties, which explain hardsetting characteristics most, are exchangeable Na+, Fed, OC, Mg2+, and Alo. There are negative consequences on the erodibility, runoff, infiltration and tillage of the soils at both submerged and dry conditions due to clay dispersion, low OC, and hardsetting behavior of the soil.  相似文献   

11.
Abstract

Soils collected from 15 locations from SE Nigeria at the 0‐ to 20‐cm depth were studied for the nutrient elements of fine fractions and their role in the stability of the soils. The objective was to understand the role of these elements in the stability of the aggregates. The fine fractions were clay and silt, and elements measured in the fine fractions were exchangeable sodium (Na+), potassium (K+), calcium (Ca2+), magnesium (Mg2+), exchangeable acidity (EA), cation exchange capacity (CEC), and available phosphorus (P). The aggregate stability was measured at the microlevel with clay dispersible indices and water‐stable aggregate (WSA) <0.25 mm, and at macrolevel with other WSA indices and mean‐weight diameter (MWD). Soils varied from loamy sand to sandy clay. There were more exchangeable cations, CEC, EA, and available P in clay than in the silt fraction. Whereas EA values ranged from 2.8 to 10.4 cmol kg?1, they were between 1.6 and 9.2 cmol kg?1 in silt. The CEC in the clay fraction was from 7.4 to 70 cmol kg?1 and between 4.0 and 32.8 cmol kg?1 in the silt fraction. The WDC were from 50 to 310 g kg?1 while the average dispersion ratio (DR) was generally higher than the corresponding clay‐dispersion ratio (CDR), and the MWD ranged from 0.45 to 2.68 mm. Soils with WSA skewed mostly to higher WSA (>2–1.00 mm) had a higher MWD. Exchangeable Ca2+ in clay correlated significantly with CDR and WSA sizes 1.0–0.5 mm and 0.5–0.25 mm (r=0.45,* 0.51,* and 0.60*), respectively, but negatively correlated with clay flocculation index (CFI) (r=?0.45*). Also, available P in clay correlated respectively with CDR and CFI (r=0.45*, ?0.45*), whereas K+ in silt correlated significantly with WDSi (r=0.64*), CFI (r=0.62*), and CDR (r=?0.65*). Principal component analysis revealed that elemental contents in the silt fraction can play very significant roles in the microaggregate stability.  相似文献   

12.
We measured soil chemical and microbial properties at a depth of 0–20 cm among mine tailings, abandoned mined land, contaminated cropland, and uncontaminated cropland around a magnesite mine near Haicheng City, Liaoning Province, China. The objective was to clarify the impact of Mg on the soils. We found that soluble Mg2+ concentration and pH were significantly higher in contaminated soils (266–345 mg kg−1 and 9·9–10·3, respectively) than in uncontaminated soils (140 mg kg−1 and 7·1, respectively). Soil nutrients (total N, total P, mineral N, available P and soluble Ca) and microbial biomass C and N decreased as pH and soluble Mg2+ concentration increased. In addition, an increase of microbial metabolic quotient and a decrease of N mineralization rate were found in contaminated soils. Soluble Mg2+/Ca2+ ratios in contaminated soils were 3·5–8·9‐times higher than in uncontaminated soils. Our results indicate that soil contamination in such magnesite mine regions is characterized by high pH, Mg2+ concentration and soluble Mg2+/Ca2+ ratio, and low microbial activity and N and P availability. Future soil amelioration in the magnesite regions should consider applying acid ameliorants to neutralize high pH and applying calcareous ameliorants to increase Ca2+ concentration. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

13.
A soil column laboratory experiment was carried out at the central campus, Mahatma Phule Agricultural University, Rahuri, India during 2008–2009 to study the accumulation and mobility of salts in Typic Haplusterts as influenced by primary biomethanated spentwash (PBSW). The PBSW was applied in three different levels (0.5, 1.0, and 2.5 cm) and then tap water with low salinity and low sodium hazard (C1S1 class) was used to carry out leaching in four different levels of water at the pore volume of soil (WPVS) (0.5, 1.0, 1.5, and 2.0). The electrical conductivity (EC) in the soil increased significantly with increasing levels of PBSW and decreased with increasing levels of WPVS in surface (0–15 cm deep) and subsurface (15–30 cm deep) soil layers. The exchangeable calcium (Ca2+), magnesium (Mg2+), and potassium (K+) increased, whereas exchangeable sodium (Na+) decreased with increasing levels of PBSW and WPVS in surface and subsurface layers of soil. The organic carbon content increased with increasing levels of PBSW and decreased with increasing levels of WPVS in both the soil layers. The cation exchange capacity (CEC) increased with increasing levels of PBSW and WPVS in both the soil layers. The exchangeable sodium percentage (ESP) decreased with increasing levels of PBSW and WPVS over the initial values of soil in both the layers. The pH of saturated paste (pHs) was reduced and electrical conductivity of extract (ECe) was increased with increasing levels of PBSW and WPVS in both the layers. The Na+ content of saturation paste extract increased significantly with increasing levels of PBSW and WPVS in both the soil layers.  相似文献   

14.
Abstract

In Oxisols, acidity is the principal limiting factor for crop production. In recent years, because of intensive cropping on these soils, deficiency of micronutrients is increasing. A field experiment was conducted on an Oxisol during three consecutive years to assess the response of common bean (Phaseolus vulgaris L.) under a no‐tillage system to varying rates of lime (0, 12, and 24 Mg ha?1) and boron (0, 2, 4, 8, 12, 16, and 24 kg ha?1) application. Both time and boron (B) were applied as broadcast and incorporated into the soil at the beginning of the study. Changes in selected soil chemical properties in the soil profile (0- to 10‐ and 10- to 20‐cm depths) with liming were also determined. During all three years, gain yields increased significantly with the application of lime. However, B application significantly increased common bean yield in only the first crop. Only lime application significantly affected the soil chemical properties [pH; calcium (Ca2+); magnesium (Mg2+); hydrogen (H+)+ aluminum (Al3+); base saturation; acidity saturation; cation exchange capacity (CEC); percent saturation of Ca2+, Mg2+, and potassium (K+); and ratios of exchangeable Ca/Mg, Ca/K, and Mg/K] at both soil depths (0–10 cm and 10–20 cm). A positive significant association was observed between grain yield and soil chemical properties. Averaged across two depths and three crops, common bean produced maximum grain yield at soil pHw of 6.7, exchangeable (cmolc kg?1) of Ca2+ 4.9, Mg2+ 2.2, H++Al3+ 2.6, acidity saturation of 27.6%, CEC of 4.1 cmolc kg?1, base saturation of 72%, Ca saturation of 53.2%, Mg saturation of 17.6%, K saturation of 2.7%, Ca/Mg ratio of 2.8, Ca/K ratio of 25.7, and Mg/K ratio of 8.6. Soil organic matter did not change significantly with addition of lime.  相似文献   

15.
Purpose

The majority of biochar studies use soils with only a narrow range of properties making generalizations about the effects of biochar on soils difficult. In this study, we aimed to identify soil properties that determine the performance of biochar produced at high temperature (700 °C) on soil pH, cation exchange capacity (CEC), and exchangeable base cation (Ca2+, K+, and Mg2+) content across a wide range of soil physicochemical properties.

Materials and methods

Ten distinct soils with varying physicochemical properties were incubated for 12 weeks with four rates of biochar application (0.5, 2, 4, and 8% w/w). Soil pH, CEC, and exchangeable base cations (Ca2+, K+, and Mg2+) were determined on the 7th and 84th day of incubation.

Results and discussion

Our results indicate that the highest biochar application rate (8%) was more effective at altering soil properties than lower biochar rates. Application of 8% biochar increased pH significantly in all incubated soils, with the increment ranging up to 1.17 pH unit. Biochar induced both an increment and a decline in soil CEC ranging up to 35.4 and 7.9%, respectively, at a biochar application rate of 8%. Similarly, biochar induced increments in exchangeable Ca2+ up to 38.6% and declines up to 11.4%, at an 8% biochar application rate. The increment in CEC and exchangeable Ca2+ content was found in soils with lower starting exchangeable Ca2+ contents than the biochar added, while decreases were observed in soils with higher exchangeable Ca2+ contents than the biochar. The original pH, CEC, exchangeable Ca2+, and texture of the soils represented the most crucial factors for determining the amount of change in soil pH, CEC, and exchangeable Ca2+ content.

Conclusions

Our findings clearly demonstrate that application of a uniform biochar to a range of soils under equivalent environmental conditions induced two contradicting effects on soil properties including soil CEC and exchangeable Ca2+ content. Therefore, knowledge of both biochar and soil properties will substantially improve prediction of biochar application efficiency to improve soil properties. Among important soil properties, soil exchangeable Ca2+ content is the primary factor controlling the direction of biochar-induced change in soil CEC and exchangeable Ca2+ content. Generally, biochar can induce changes in soil pH, CEC, and exchangeable Ca2+, K+, and Mg2+ with the effectiveness and magnitude of change closely related to the soil’s original properties.

  相似文献   

16.
The aim of this study was to verify if the application of silicate or lime, in association with gypsum, on sugarcane residue can lead to amendment of subsurface soil acidity, increasing sugarcane yield and profitability. The treatments were: 1 – control (without application of amendments), 2 – gypsum, 3 – dolomitic limestone, 4 – silicate, 5 – dolomitic limestone + gypsum, and 6 – silicate + gypsum. The surface application of gypsum led to reduction in Al (aluminum) contents and Al saturation, and increase in Mg+2, Ca+2, K+, S–SO4?, and base saturation in deeper soil layers, as well as increased yield of stalks, sugar, trash, bagasse, and energy, and greater profit. The application of limestone and silicate, alone or in association with gypsum, amend soil acidity throughout the soil profile. It likewise leads to an increase in stalk, sugar, trash, bagasse, and energy yield, however, application of silicate in association with gypsum leads to the greatest profitability.  相似文献   

17.
Soybean is one of the most important legume crops in the world. Two greenhouse experiments were conducted to determine the influence of liming and gypsum application on yield and yield components of soybean and changes in soil chemical properties of an Oxisol. Lime rates used were 0, 0.71, 1.42, 2.14, 2.85, and 4.28 g kg?1 soil. Gypsum rates applied were 0, 0.28, 0.57, 1.14, 1.71, and 2.28 g kg?1 soil. Lime as well as gypsum significantly increased grain yield in a quadratic fashion. Maximum grain yield was achieved with the application of 1.57 g lime per kg soil, whereas the gypsum requirement for maximum grain yield was 1.43 g per kg of soil. Lime significantly improved soil pH, exchangeable soil calcium (Ca) and magnesium (Mg) contents, base saturation, and effective cation exchange capacity (ECEC). However, lime application significantly decreased total acidity [hydrogen (H) + aluminum (Al)], zinc (Zn), and iron (Fe) contents of the soil. The decrease in these soil properties was associated with increase in soil pH. Gypsum application significantly increased exchangeable soil Ca, base saturation, and ECEC. However, gypsum did not change pH and total acidity (H + Al) significantly. Adequate soil acidity indices established for maximum grain yield with the application of lime were pH 5.5, Ca 1.8 cmolc kg?1, Mg 0.66 cmolc kg?1, base saturation 53%, Ca saturation 35%, and Mg saturation 13%. Soybean plants tolerated acidity (H + Al) up to 2.26 cmolc kg?1 soil. In the case of gypsum, maximum grain yield was obtained at exchangeable Ca content of 2.12 cmolc kg?1, base saturation of 56%, and Ca saturation of 41%.  相似文献   

18.
砒砂岩区不同退耕还林措施土壤颗粒及交换性能分布特征   总被引：3，自引：2，他引：1  
为研究砒砂岩区退耕还林还草措施下林地和草地的土壤结构及土壤交换性能对其措施的响应,选取柠条林、油松林、小叶杨林和本氏针茅草地为研究对象,并以荞麦坡耕地为对照,通过野外取样与室内试验相结合的方式,采用分形理论探究土壤粒径分布(PSD)、阳离子交换量(CEC)和交换性盐基总量(ECEC)及其组成(Na~+、K~+、Ca~(2+)、Mg~(2+))的分布特征,并分析其相关性关系。结果表明:(1)实施退耕还林措施后,草地和林地的PSD分布范围、非均一性、离散程度均高于坡耕地,且柠条林的土壤粉粒含量、PSD分布范围的增幅效果最显著(P0.05);土壤剖面垂直层次上,草地有利于增加表层土壤的细粒组分和粒径的分布范围,而林地更有利于对深层土壤粒径的改良与细化;(2)研究区交换性盐基组成主要以碱土金属为主(Ca~(2+)、Mg~(2+)),不同措施的土壤ECEC和CEC值由大到小依次为柠条林油松林小叶杨林草地坡耕地。草地表层土壤交换性能优于底层土壤,而林地与之相反;(3)黏、粉粒和细砂是决定研究区土壤交换性能的细粒土壤和粗粒土壤,粉粒是CEC、ECEC的主要贡献因子,多重分形维数可较好地描述土壤交换性能与土壤颗粒间的关系。不同措施以柠条林对土壤颗粒组成和土壤交换性能的改良效果最优。  相似文献   

19.
The effects of salinity on four faba bean (Vicia faba L) cultivars [Giza 429, Giza 843, Misr 1 (Orobanche-tolerant), and Giza 3 (Orobanche-susceptible)] and soil properties were investigated in a pot experiment with addition of 0, 50, and 100 mM sodium chloride (NaCl) for 9 weeks. Salinity significantly decreased calcium (Ca2+), magnesium (Mg2+), potassium (K+), bicarbonate (HCO3 ?), and sulfate (SO4 2?) while significantly increasing sodium (Na+), chloride (Cl?), pH, and electrical conductivity (EC; dS m?1). Root length density (cm cm?3), root mass density (mg cm?3), total dry weight, and salt-tolerance indexes were significantly reduced as a result of application of salinity. The results presented support evidence on the positive relationship between Orobance tolerance and salt tolerance in the three cultivars (Giza 429, Giza 843, and Misr 1). This adaptation was mainly due to a high degree of accumulation of inorganic nitrogen (N), phosphorus (P), K+, Ca2+, and Mg2+ and lesser quantities of Na+ and Cl?, as well as greater K+/Na+ and Ca2+/Na+ ratios.  相似文献   

20.
This study investigated general physicochemical properties of tea garden soils at the alluvial plain of Cong River in Tan Cuong commune, Vietnam. Four gardens were selected as study sites on three transect lines established perpendicularly to the river. Soil samples were collected from the surface (0–10 cm) and subsurface (20–30 cm). Soil texture classes varied from sandy loam to light clay, which was affected by different terrains along the transect lines as well as severe disturbance such as terracing and earth excavation. The levels of total C and total N were correlated with increasing garden age, suggesting the replenishment of soil organic matter pool by the addition of plant residue and manure. Meanwhile, the soils showed strongly acidic nature with the average pH(H2O) of 3.7 at the surface and 3.9 at the subsurface. The effective cation exchange capacity (ECEC) was low at 4.7 and 4.9 cmolc kg?1, respectively, and dominated by exchangeable Al3+. Soil acidification was exacerbated with increasing garden age. However, a relatively large saturation of exchangeable calcium (Ca2+), potassium (K+), and magnesium (Mg2+) on the ECEC was found in the surface soils. The levels of available P were high, occasionally exceeding 1000 and 500 mg kg?1 at the surface and subsurface, respectively. In spite of strongly acidic condition, ammonium (NH4-N) applied as fertilizer was converted to nitrate (NO3-N) to move down to deeper layers. The levels of the bases, P, and mineral N seem to be principally determined by management practices. Significant portion of these nutrients was likely to exist in water soluble forms without adsorption onto soils. It should be required to develop proper schemes and to educate the owners for adequate fertilizer managements.  相似文献   

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