褐煤基改良剂对石灰性土壤复合体铅赋存形态的影响

为了解褐煤基材料对土壤复合体铅形态的影响和污染退化修复机制,将褐煤以及褐煤基改性材料,混入铅污染的土壤中培养4个月,提取其中的土壤复合体,测定各组复合体中的各形态铅.结果表明:施用褐煤基有机材料后,水稳性复合体增加.1)6种铅化学形态在各复合体中分布状况不同.各改良剂处理的离子交换态、铁锰氧化物结合态和碳酸盐结合态铅在复合体中分布的大小顺序均为:G0＞G1＞G2,各处理从G0到G1,交换态铅质量分数下降了8.74％ ～ 32.22％,从G1到G2各处理下降了2.73％ ～ 26.74％;弱有机态和强有机态、残渣态铅分布顺序为:G0＜G1、G2.2)施用有机材料均引起了3组复合体中交换态铅质量分数的下降,各处理交换态铅质量分数平均下降了2.73％ ～32.22％;普遍提高了弱有机态和强有机态铅质量分数,弱有机态铅最高提高51.23％,强有机态铅最高提高67.65％,对残渣态铅没有显著影响.3)所有改性材料改性后均提高了G2组中的交换态铅,普遍降低强有机态铅质量分数,碳酸盐态铅质量分数未有显著变化.因此,施用褐煤基有机改良剂,促进了水稳性复合体的形成,降低了复合体中交换态铅质量分数,对土壤铅起到了钝化作用.褐煤有机材料对交换态和有机态铅影响较大,对铁锰氧化物态、碳酸盐态和残渣态影响较小.     

湖南某铅锌矿污染土壤稳定化修复研究

使用海泡石、磷酸二氢钙、钙镁磷肥、氧化钙和氧化镁等土壤改良剂及其组合,对湖南省某铅锌矿冶炼厂附近的重金属污染土壤进行了稳定化修复试验,利用BCR连续提取法进行形态分析,并进行稳定化效果的评价。结果表明,各改良剂组合均能够有效改变土壤中Zn、Cd和Pb的形态分布,弱酸提取态含量的减少率分别为Zn:17.03%~83.13%,Cd:45.03%~99.17%,Pb:54.05%~99.44%,降低重金属的不稳定形态和生物可利用性,稳定化效果显著。改良剂对Zn元素的稳定化效果影响程度为:钙镁磷肥+氧化钙钙镁磷肥+氧化镁钙镁磷肥海泡石+磷酸二氢钙海泡石;对Cd元素的稳定化效果影响程度为:钙镁磷肥+氧化钙钙镁磷肥+氧化镁钙镁磷肥海泡石+磷酸二氢钙海泡石;对Pb元素的稳定化效果影响程度为:海泡石+磷酸二氢钙钙镁磷肥+氧化镁钙镁磷肥+氧化钙钙镁磷肥海泡石。该复合污染土壤中,Zn、Cd、Pb稳定效果最优处理为10%钙镁磷肥+5%氧化钙组合。     

褐煤基改良剂对石灰性土壤复合体镉赋存形态的影响

为筛选和评估褐煤基材料对镉污染的修复效果,降低通过垂直入渗进入地下水或通过地面径流污染更大面积水土的镉通量,通过将3％各种材料均匀混入污染土壤并培养120 d,提取其胶散分组复合体并测定镉化学形态变化.结果表明:1)各改良剂处理的离子交换态、碳酸盐结合态、铁锰氧化物结合态镉质量分数在复合体中分布均为G0＞G1＞G2,而弱有机态、强有机态质量分数分布的顺序相反.残渣态镉质量分数具有G0组复合体低于G1组和G2组复合体内镉质量分数的趋势,除钙化处理,其他处理3组复合体中残渣态之间均无显著差异.2)施用褐煤基材料普遍提高土壤中弱有机结合态镉质量分数,主要提高水稳性复合体中弱有机态镉,G0、G1和G2中施用材料的比对照分别提高5.27％、20.74％和17.82％.褐煤、硝化褐煤、腐植酸显著提高水稳性复合体强有机态镉质量分数,平均分别提高27.26％、23.90％和40.05％,显著降低交换态镉质量分数和水稳性复合体碳酸盐态镉质量分数,平均降低幅度分别为14.63％～22.79％和14.31％ ～ 34.56％.硝化褐煤和腐植酸显著降低G1和G2中铁锰氧化物结合态镉的质量分数.3)褐煤改性后多数提高了交换态镉和碳酸盐态镉质量分数,以碱化、钙化、去矿化和活性炭在改性后提高交换态镉质量分数的幅度较大,较褐煤提高幅度最大值分别是29.41％、34.03％、33.82％和43.32％.改性后所有材料普遍降低土壤弱有机结合态镉的质量分数,除腐植酸外,强有机态镉质量分数均比改性前降低.残渣态镉质量分数有向易利用态转化的趋势.总之,非水稳性复合体主要由离子交换态和碳酸盐结合态等易效性镉赋存,水稳性复合体中主要由有机态和残渣态等难效性镉赋存.褐煤、硝化、腐植酸处理显著降低污染土复合体中离子交换态、碳酸盐态、铁锰氧化物态镉质量分数,显著提高水稳性G1和G2复合体强有机态镉质量分数,腐植酸还提高残渣态镉质量分数,起到对镉的钝化作用,但改性后多数是削弱了钝化效果.     

Desorption behaviour of lead in two calcareous soils as affected by Pb level without and with compost supply

A laboratory study was performed to investigate the influence of soil texture (sandy loam vs. clay loam), Pb supply (as Pb(NO₃)₂ without or with compost) and Pb levels on the extraction of available Pb by diethylene triamine pentaacetic acid (DTPA) and its desorption patterns at ten shaking periods. The soils were polluted with five Pb levels without or with compost and incubated for 1 month. Kinetic models commonly used to study the release of the nutrients were used in this study. Results showed that Power function model described the pattern of Pb desorption better than other models. The amount of extracted Pb increased as the Pb levels increased and was found to be higher in sandy loam soil treated with Pb without compost than that of clay loam soil treated with Pb with compost. The a value (Pb desorption constant) was the highest in sandy loam soil amended with Pb without compost. The lowest value of a, however, was observed in clay loam soil amended with Pb with compost. The ab coefficient (initial desorption rate of Pb) was higher in sandy loam than clay loam soil, demonstrating higher initial release rates of Pb in the coarser-textured soil. Addition of Pb without compost resulted in a higher increase in ab value in comparison with Pb with compost, in both the soils.     

Aggregation in a surface layer of a hardsetting and crusting soil as influenced by the application of amendments and grass mulch in a South African semi-arid environment

Hardsetting and crusting are forms of soil structure degradation associated with the collapse of macroaggregates during wetting and are responsible for poor seedling emergence, crop establishment and yields of food crops especially in semi-arid environments. This study investigated the effects of applying of 3.0 t ha⁻¹ phosphogypsum, 1.0 t ha⁻¹ polymer gel, 3.0 t ha⁻¹ grass mulch and 5.0 t ha⁻¹ cattle manure to the topsoil (0–15 cm) of a soil with hardsetting and crusting behavior and observed changes on aggregation under field conditions for two consecutive seasons. There were significant improvements in soil aggregate properties in the amended soil over the control. Both aggregate size distribution and wet aggregate stability showed significant differences between the amendments in the two seasons. The mean weight diameters of aggregates were 4.23 mm (mulch), 3.31 mm (manure), 2.17 mm (polymer gel), 2.23 mm (phosphogypsum) and 1.36 mm (control). The aggregates (2–4 mm) from amended soil were consistently more stable than the control and were in the order polymer gel = manure > mulch > gypsum > control. Tensile strength and bulk density of aggregates, on the other hand, were significantly higher (P < 0.05) in the unamended than amended soil.The application of soil amendments, especially mulch, significantly increased the soil water content over the two seasons and this was associated with lower soil penetration resistance in the latter. The reduced soil strength in the amended soils contributed to higher pegging, podding and grain yields of bambara groundnut (Vigna subterranean). This was confirmed by significantly higher correlations between soil aggregate characteristics, soil water, penetrometer resistance and growth and yield of bambara groundnut. The study concluded that significant improvements in soil aggregation can be obtained over a relatively short period and this can improve the yield of food crops.     

腐殖酸对磷在石灰性土壤中迁移的影响

When humic acid (HA) and phosphorus (P) fertilizer are simultaneously applied to soil, HA may affect the movement of P. A laboratory incubation experiment was conducted to quantify the effects of a commercial HA product co-applied with monocalcium phosphate (MCP) on the distance of P movement and the concentration of P in various forms at different distances from the P fertilizer application site in a calcareous soil from northern China. Fertilizer MCP (at a rate equivalent to 26.6 kg P ha-1 ) was applied alone or in combination with HA (at 254.8 kg HA ha-1 ) to the surface of soil packed in cylinders (150 mm high and 50 mm internal diameter), and then incubated at 320 g kg-1 moisture content for 7 and 28 d periods. Extraction and analysis of each 2 mm soil layer in columns showed that the addition of HA to MCP increased the distance of P movement and the concentrations of water-extractable P, acid-extractable P and Olsen P in soil. The addition of HA to MCP could enhance P availability by increasing the distance of P movement and the concentration of extractable P in soil surrounding the P fertilizer.     

Nutrients in a calcareous soil affected by Cadmium

A calcareous soil (Haploxeroll calcic) was amended in two different forms according with the standard nutritional requirements of tomato plant. The treatments applied were: i) an organic fertilization applying sewage sludge (SS), ii) an inorganic fertilization (IN) using mineral fertilizers (NPK), and iii) a treatment called W where no fertilizer was applied. For each treatment, cadmium (Cd) pollution was added to the soil establishing different concentrations (0, 3, 30 and 100 mg kg^‐1 d.w.). The availability of macronutrients and micronutrients were analyzed in the soil. Phosphorus (P), iron (Fe), and copper (Cu) were the nutrients more affected by Cd. In general, sewage sludge favored the availability of nutrients in the same degree of the inorganic fertilization.     

Phytoextractability of lead from soil by some oilseed crops as affected by sewage sludge and farmyard manure

Abstract

Screenhouse experiments were conducted to study the phytoextractability of lead (Pb) by three oilseed crops (Brassica juncea, Brassica napus and Eruca sativa) from Pb enriched (i.e. 0, 200, 400, 600 and 800 mg Pb kg^?1 soil) unamended, sewage sludge-amended (SS-amended) and farmyard manure-amended (FYM-amended) sandy loam soil. Chlorotic symptoms and stunted growth were observed at Pb₆₀₀ and Pb₈₀₀ treatments. Sewage sludge and FYM slightly decreased chlorosis. The biomass production for amendment treatments followed the order: FYM-amended > SS-amended > Unamended soil, and for species: Brassica juncea > Brassica napus > Eruca sativa. The Pb concentration followed the order: leaf > stem > seed, Brassica napus > Brassica juncea > Eruca sativa, and SS-amended > Unamended > FYM-amended soils. The Pb uptake followed the order: Brassica juncea > Brassica napus > Eruca sativa, and SS-amended > Unamended > FYM-amended soils. Exchangeable and Fe-Mn oxide bound fractions decreased and organic matter bound fraction increased with sewage sludge and FYM. The carbonate bound fraction considerably decreased with FYM.     

四种土壤调理剂对镉、铅的吸附效果研究

采用等温吸附试验研究了主要原料为麦饭石(M)、蒙脱石(T)、牡蛎壳(O)和硅钙矿(S)4种土壤调理剂对溶液中镉和铅的吸附效果。结果表明,4种土壤调理剂对镉和铅的吸附均可用Langmuir方程进行描述;相比而言,4种土壤调理剂对镉吸附量的大小顺序为O调理剂>S调理剂>M调理剂>T调理剂,对铅吸附量的大小顺序为M调理剂>S调理剂>O调理剂>T调理剂;随溶液pH值的增大各调理剂的吸附量逐渐减小,尤其当Cd溶液pH值>8,Pb溶液pH值>6,各调理剂的吸附量迅速降低。     

Adsorption kinetics of zinc in a calcareous soil as affected by pH and temperature

Abstract

Sorption of zinc (Zn) in a calcareous soil was studied using a miscible displacement procedure. Sorption of Zn in soil can be described by a second‐order equation and by a diffusion equation based on the overall higher value of correlation coefficient and the lower value of standard error. The results show that the sorption of Zn in soil was increased by elevated temperature and pH. The maximum of Zn sorbed in soil increased, but the rate coefficient decreased with increasing pH. The maximum of sorbed Zn and rate coefficient tended to increase with elevated temperature. The value of activation energy (E_a) estimated with different kinetic equations was found to be variable and in the range of 5.0–17 kJ.mol^‐1. The relative diffusion rate coefficient (D/r²), estimated using a diffusion equation, was found to be in the order of 10^‐6 sec^‐1. The intra‐aggregate diffusion and/or film diffusion of Zn may be a rate‐limiting process in the sorption of Zn in soils.     

Rice yield nutrient uptake as affected by cyanobacteria soil amendments—a pot experiment

Rice production and cyanobacterial N in acid soil can be improved by liming. There is evidence that the organic amendments can increase the soil pH. The aim of this study was to find appropriate combination of soil amendments and cyanobacteria capable for enhancing nutrient uptake and improving rice yield in acidic paddy soil. Three soil amendments (rice straw, sewage‐sludge composts, NPK) with and without inoculation of cyanobacteria were studied for rice plants (Oryza sativa L.) in a pot experiment. The sludge compost had significantly reduced soil acidity from 5.44 to 6.67. The plant N and K uptake increased significantly with sludge and cyanobacteria application. The yield components increased significantly with sludge, but decreased thereafter, an exception was the number of panicles, with straw compost. These characters were also significantly affected by inoculation with cyanobacteria except 100‐grain weight, filled‐grain percentage, and harvest index. The combination of sludge compost and cyanobacteria improved the yield components and consequently grain yield (138 g pot^–1) compared with sludge treatment only (132 g pot^–1). The amount of cyanobacterial N absorbed (N‐difference method) by rice plant under sludge compost was higher than that of soils amended with either rice straw or NPK treatments. Therefore, the addition of sewage sludge to acid paddy soil not only amended the soil properties but also activated the cyanobacteria and consequently improved rice plant nutrition and grain yield.     

Energy balances and SOC and N stocks as affected by organic amendments and inorganic N fertilization in a semi-arid environment (IOSDV-Madrid)

A long-term field experiment (1984–2011), was conducted on a Calcic Haploxeralf from semi-arid central Spain to evaluate the combined effect of three treatments: farmyard manure (FYM), straw and control without organic amendments (WOA) and five increasing rates of mineral N on: (1) some energetic parameters of crop production, and (2) the effect of the different treatments on soil organic carbon (SOC) and total N stocks. Crop rotation included spring barley, wheat and sorghum. The energy balance variables considered were net energy produced (energy output minus energy input), the energy output/input ratio and energy productivity (crop yield per unit energy input). Results showed small differences between treatments. Total energy inputs varied from 9.86 GJ ha^?1 year^?1 (WOA) to 11.14 GJ ha^?1 year^?1 in the FYM system. For the three crops, total energy inputs increased with increasing rates of mineral N. Energy output was slightly lower in the WOA (33.40 GJ ha^?1 year^?1) than in the two organic systems (37.34 and 34.96 GJ ha^?1 year^?1 for FYM and straw respectively). Net energy followed a similar trend. At the end of the 27-year period, the stocks of SOC and total N had increased noticeably in the soil profile (0–30 cm) as a result of application of the two organic amendments. Most important SOC changes occurred in the FYM plots, with mean increases in the 0–10 cm depth, amounting an average of 9.9 Mg C ha^?1 (667 kg C ha^?1 year^?1). Increases in N stocks in the top layer were similar under FYM and straw and ranged from 0.94 to 1.55 Mg N ha^?1. By contrast, simultaneous addition of increasing rates of mineral N showed no significant effect on SOC and total N storage.     

Soil microbial activity after restoration of a semiarid soil by organic amendments

Unsuitable agricultural practices together with adverse environmental conditions have led to degradation of soil in many Mediterranean areas. One method for recovering degraded soils in semiarid regions, is to add organic matter in order to improve soil characteristics, thereby enhancing biogeochemical nutrient cycles. In this study, the effect of adding the organic fraction of urban wastes (both fresh and composted) on different carbon fractions and on microbiological and biochemical parameters (microbial biomass C, basal respiration and different enzymatic activities) of a degraded soil of SE Spain has been assessed in a 2 year experiment. Three months after the addition of the organic material, spontaneous plant growth occurred and the plant cover lasted until the end of the experiment. Organic soil amendment initially increased the levels of soil organic matter, microbial biomass, basal respiration and some enzyme activities related to the C and N cycles These values decreased but always remained higher than those of the unamended soil. The results indicate that the addition of urban organic waste is beneficial for recovering degraded soils, the microbial activity of which clearly increases with amendment. The incorporation of compost seemed to have a greater positive effect on the soil characteristics studied than the incorporation of fresh organic matter.     

Changes in recovery of native and applied phosphorus with time as affected by soil properties in some calcareous soils

In an attempt to investigate variations in availability of native and applied phosphorus (P) with time, twenty five calcareous soil samples were treated with 0, 50 and 500 mg P kg^?1 soil and incubated at 80–90% of field capacity moisture content in an open door glasshouse for a period of one year. Soil samples were taken out at certain intervals for P extraction with Olsen extractant under moist condition. Results indicated that following wetting the mean value of native Olsen-P decreased initially and then increased gradually with time of incubation. Generally, the short term (24 h) recoveries were not correlated with long term ones. The recovery of added P with time was described properly by the following new proposed model: R = 100/(1 + kt^b), where R is percent recovery at time t, and k and b are empirical parameters. The values of k constant at 50 and 500 mg P kg^?1 were in the ranges of 0.40 to 1.22 (0.84 ± 0.25, on average) and 0.04 to 0.52 (0.23 ± 0.14, on average), respectively. The corresponding respective values of b constant also ranged from 0.05 to 0.32 (0.15 ± 0.06, on average) and 0.12 to 0.92 (0.46 ± 0.23, on average).     

Transport of zinc,copper, and lead in a sewage sludge amended calcareous soil

The application of sewage sludge on farmland is practised in many countries since sludge is rich in macro- and micro- nutrients. However, increasing use of sewage sludge on farmland has raised concerns about the potential transport of heavy metals into food chains and groundwater. This study determined for a calcareous soil the effects of sludge application on soil physical properties and transport of zinc (Zn), copper (Cu), and lead (Pb). Secondary anaerobic digested sewage sludge was applied at rates of 0, 25, 50, and 100 t/ha (on a dried weight basis) for four consecutive years and mixed in the top 20-cm of soil. Corn (Zea mays L.) was planted as a spring crop, followed by wheat (Triticum aestivum) as a winter crop. Sludge application increased the dissolved organic matter content and modified the soil structure, increased the soil infiltration rate, saturated hydraulic conductivity, and aggregate stability, and decreased the bulk density. Sludge application greatly increased DTPA (diethylenetriamine pentaacetic acid)-extractable soil metal concentrations to 50 cm depth and significantly to 1 m. In the plots that received four application of 100 t/ha sewage sludge, the mean concentrations of Zn, Cu, and Pb in subsoil increased by 1600, 7, and 4.5 times, respectively, compared with the control. The results indicate that a combination of enhanced soil physical properties, heavy and inefficient irrigation and high organic matter content with heavy metals cause significant metal mobility. High sludge applications pose risks of groundwater and food chain contamination and rates are best restricted to those reflecting the nutrient demand of crops (20 t/ha every 4 to 5 yr or an average of 4 to 5 t/ha/yr).     

Lead stabilization in a polluted calcareous soil using cost-effective biochar and zeolite amendments after spinach cultivation

Biochar has been shown to be an effective organic soil amendment for the in-situ immobilization of lead (Pb).Little research has been done on the effects of biochar and zeolite interactions on Pb immobilization in contaminated calcareous soils.Therefore,the aim of this study was to investigate the effects of different levels of zeolite (2% and 4%,weight:weight) and biochars (3%,weight:weight) prepared from green compost (GB),poultry manure (PB),and municipal waste (MB) on the content of Pb in sp...     

Phosphorus leaching in a calcareous soil treated with plant residues and inorganic fertilizer

Column experiments were conducted over 45 d to determine the degree of P mobility. The sandy loam soil was spiked with 200 mg P kg^–1 and 5% organic residues. The treatments included: control without any water‐soluble P and plant residues, potato, wheat, water‐soluble P fertilizer, wheat + water‐soluble P, and potato + water‐soluble P. Each column was leached with distilled water, and leachates were collected and analyzed for P, K⁺, Ca²⁺, Mg²⁺, along with pH and EC. Sequential extraction was performed on soil samples at the end of leaching column experiments. The relatively high initial concentration of P in the leachates decreased to more stable values after 15 d which can be attributed to the colloid‐bound P. The P concentrations in the leachates fluctuated between 8 and 220 mg L^–1 in the water‐soluble–P fertilizer treatment, between 0.80 and 230 mg L^–1 in the potato + water‐soluble‐P treatment, and between 0.90 and 214 mg L^–1 in the wheat + water‐soluble P treatment. Leaching loss of P mainly occurred in the 15 d of leaching, accounting for 94%, 88%, and 65% of total P leached in wheat + water‐soluble‐P, potato + water‐soluble‐P, and water‐soluble‐P treatments, respectively. Maximum amount of P leached was found from an exponential kind model and was in the range 0.45 mg kg^–1 to 125.4 mg kg^–1 in control and potato + water‐soluble‐P treatments, respectively. Sequential extraction results showed that in control and amended soils the major proportion of P was associated with Ca. The leachate samples in all treatments were saturated with respect to hydroxyapatite, β‐tricalcium phosphate, and octacalcium phosphate up to 20 d of leaching, whereas they were undersaturated with respect to Mg‐P minerals through the entire leaching experiment.     

Soil metal immobilization and ryegrass uptake of lead, copper and zinc as affected by application of organic materials as soil amendments in a short-term greenhouse trial

Green waste compost, peat, coir and wood bark were applied to metal-contaminated mine waste at the rates of 1%, 10% and 20% on dry weight basis, and perennial ryegrass grown over a period of 6 weeks. Addition of amendments led to increased biomass yield in all soils when compared with the non-amended soil. EDTA extractable Pb, Cu and Zn was significantly reduced in amended soil, while leaf and root metal concentrations were also significantly reduced by the application of amendments, especially at applied rates of 10% and 20%. Coir, green waste compost and wood bark stood out as amendments which were consistent in reducing soil extractable and plant tissue Pb, Cu and Zn; while peat rates above 10% enhanced solubility of Cu and Zn because of a lowering of the soil pH.     

Effects of greenhouse intensive cultivation and organic amendments on greenhouse gas emission according to a soil incubation study

Soil cultivation changes and usage of agricultural wastes can have profound impacts on greenhouse gas (GHG) emission from soil. In this study, the effects of soil cultivation and organic amendment on GHG emission were investigated using aerobic incubation. Surface soil (0–20 cm) from (1) rice–legume consecutive rotation (Rice) and (2) recently (<3 years) converted from rice field to plastic-covered intensive vegetable and flower production (VegC) were collected in Kunming, P.R. China. Rose (Rosa rugosa Thunb.) residues and cattle manure were applied at 5% by weight. Results indicated that N₂O and CO₂ fluxes were significantly influenced by soil cultivation, organic amendment, incubation time and their interaction (p <0.05). Applying cattle manure increased, while rose residue decreased, cumulative N₂O emissions from soil (84 days). Rose residue application significantly increased cumulative CO₂ emissions with peak values of 6371 (Rice) and 7481 mg kg^?1 (VegC), followed by cattle manure addition figure of 2265 (VegC) and 3581 mg kg^?1 (Rice). Both were significantly higher (p <0.05) than the un-amended Control at 709 (VegC) and 904 mg kg^?1 (Rice). Our study demonstrates that a low C/N ratio in cattle manure is better than a high C/N ratio in rose residue in regard to reducing the global warming potential of agricultural soil.     

Effects of plant residues and calcite amendments on soil sodicity

The effects of wheat, potato, sunflower, and rape residues and calcite were evaluated in soil that received sodic water. These materials were added to a sandy‐loam soil at a rate of 5%, after which the treated soils were incubated for 1 month at field‐capacity moisture and a temperature of 25°C–30°C. Column leaching experiments using treated soils were then conducted under saturated conditions using water with three sodium‐adsorption ratios (SAR) (0, 10, 40) with a constant ionic strength (50 mmol L^–1). The results indicated that the application of plant residues to soils caused an increase in cation‐exchange capacity and exchangeable cations. Leaching experiments indicated that the addition of plant amendments led to increased Na⁺ leaching and decrease in exchangeable‐sodium percentage (ESP). The ESP of the control soil, after leaching with solutions with an SAR of 10 and 40, increased significantly, but the level of sodification in soils treated with plant residue was lower. Such decreases of soil ESP were greatly affected by the type of plant residues, with the order of: potato‐treated soil > sunflower‐treated soil > rape‐treated soil > wheat‐treated soil > calcite‐treated soil > control soil.