Soil quality as affected by long-term cattle manure application in solonetzic soils of Songnen Plain

Meng Qingfeng, Zhang Juan, Li Xinlun, Qu Xiaoze, Li Weitong, Zeng Xiannan, Ma Xianfa



Soil quality as affected by long-term cattle manure application in solonetzic soils of Songnen Plain

Meng Qingfeng1, Zhang Juan1, Li Xinlun1, Qu Xiaoze1, Li Weitong1, Zeng Xiannan2, Ma Xianfa1※

(1.150030;2.150086)

Poor soil structural properties and nutrient status, and low enzyme activities are common in the solonetz. This is caused by excessive exchangeable Na+and high soil pH value in soils. Long-term application of cattle manure is an important management practice that can affect soil quality in the solonetzic soils. Experiments were carried out in a randomized complete block design comprising 5 treatments according to the cattle manure application history: Corns (L.) with manure applied for 2, 6, 13, and 18 years were used as the experimental treatments and corn without manure application was used as a control treatment. Soil physic-chemical properties and enzyme activities were measured across all treatments. The effects of long-term manure application on soil quality were assessed using factor analysis. Results indicated that long-term manure application significantly improved soil physic-chemical properties and enhanced soil enzyme activities. Two factors were selected for the measured soil attributes, which were “soil structural properties” (Factor 1) and “saline-alkaline properties” (Factor 2), respectively. Compared to untreated soils, soils treated with manure for 13 and 18 years were characterized by improved soil structural properties (Factor 1) and decreased soil saline-alkaline properties (Factor 2), while soils treated with manure for 2 and 6 years were characterized by decreased soil saline-alkaline properties (Factor 2). Soil quality was increased with the number of years of manure application judging from the soil quality indices, with the highest value observed for 18 years of manure application. We conclude that soil structural and saline-alkaline properties are the key factors that limit soil quality, and promotion of soil quality is characterized by the decrease in bulk density, pH value and electrical conductivity in the solonetz, especially for bulk density.

organic fertilizer; soils; quality; factor analysis; long-term location experimentation

0 Introduction

Soil is a key natural resource that provides several important ecosystem functions, including a medium for plant growth, regulation and partition of water flow in the environment and an environmental buffer[1]. Soil quality refers to the capacity of the soil to sustain productivity and maintain environmental quality and has three distinct components: chemical, physical, and biological. However, a significant decline in soil quality has occurred worldwide by adverse changes in its physical, chemical and biological properties[2], which results in arable land becoming unsuitable agriculture use.

Salt-affected soils are formed in arid or semi-arid areas of the world and are widely distributed in Europe, North America, South America, Asia and Australia, such as Russia, United States, India and China, etc[3]. China has a large area of salt-affected soil resource. Salt-affected soils are mainly concentrated in inland basins and alluvial plains in the arid and semi-arid regions of northern China, and coastal plains in humid and semi-humid monsoon region. The soluble salts accumulated in these soils have a negative influence on soil properties, enzyme activities and plant growth. Furthermore, the ability of plants to uptake water is reduced by the osmotic potential of these soils[4-5]and plant nutrition deficit can be caused by the low availability of nutrients, such as P, Fe, Zn, and Mn[6]. Most of the Songnen Plain in northeastern China is characterized by typical sodic soils and low crop productivity due to degradation of soil physic-chemical properties and microbiological processes.

Sustainability of agricultural systems, in developing countries, has been considered as an important issue[7]. In China, the largest developing country all over the world, there is a sharp contradiction between reduction of arable land and growth of population in recent years. However, salt-affected soils are considered as reserved land resources, and are likely to be the future growing point of the national agricultural economy of China.

Gong et al.[8]pointed out that reasonable land use practices and scientific management patterns can improve and maintain soil quality in the human-disturbed land-use systems. Soil amendment with manure is a common habitual practice in order to improve soil fertility and productivity, particularly in agroecosystems with naturally low soil organic matter (SOM) that are very susceptible to soil degradation[9]. The improvement in SOM can be achieved through the use of organic amendments. Application of organic amendments is a reliable management practice to improve soil quality[10]. Liu et al.[11]reported that long-term additions of organic manure have the most beneficial effects on grain yield and soil quality in dry land of north China. The achievement has been made in improvement and utilization of salt-affected soils by organic manure applied to soils. Yang et al.[12]conducted a field experiment of sodic soil improvement using organic manure application, and found a decrease in soil pH value and an increase in total N, P and K contents, SOM and crop yield.

Sustainable agricultural production requires prudent management backed by reliable information that accurately illustrates the complex relationships between land management practices and soil quality trends[13]. Soil physical, chemical and biological properties, known as soil quality indicators, are used to soil quality assessment and these measured soil attributes are used to detect changes in soils as a result of soil management practices[14-16]. This study aimed to assess the effects of long-term cattle manure application on soil quality in the solonetz of the Songnen Plain in Northeast China. Furthermore, we also ascertain how the long-term manure application affects soil quality caused by key soil attributes in the solonetz.

1 Material and methods

1.1 Study site

The study was performed in a long-term experimental field of salinization soil amelioration, established in Songnen Plain in 1995, located in the Yongle Village of Zhaozhou county, Heilongjiang Province, China (longitude 125.06° E, latitude 45.4° N, and altitude 149 m). The site is in a temperate zone with a continental monsoon climate. The mean annual precipitation in the area is 434.5 mm, occurring mostly in summer. The mean annual evaporation is 1 800.0 mm and the mean annual temperature is 3.7 ℃. The topography in the area is a plain terrain. The quaternary fluvio-lacustrine deposits are the main soil parent materials. Soil horizons are weakly developed and the natric horizon is within the upper 100 cm of the soil profile in the area. The soil type in the area is classified as solonetz based on the FAO World Reference Base for Soil Resources[17]and the soil texture is clay according to the International Society of Soil Science classification (26.2% sand, 21.5% silt, 52.3% clay). Before soil reclamation, the landscape was a meadow steppe, and alkaline spots without vegetation were distributed sporadically in its natural state. Soil physic-chemical properties prior to experimentation in the study area at the 0-20 cm depth were illustrated as follows: Soil pH value was 9.56; electrical conductivity (EC) was 6.23 dS/m; SOM was 10.95 g/kg; soil total nitrogen (TN) and phosphorus (TP) were 0.37 and 0.25 g/kg, respectively; available N, P and K were 39.11, 12.08 and 125.18 mg/kg, respectively; bulk density (b) was 1.35 g/cm3; total porosity (t) was 49.06%; water-holding capacity (WHC) was 18.23%.

1.2 Experimental design

In the long-term experimental field trial of salinization soil amelioration that was used as the current study site, ridge tillage combined with cattle manure at the rate of 10 000 kg/hm2on oven-dry weight basis was carried out annually in late April. Basic properties of manure illustrated that it had 342.63 g/kg OM, 12.01 g/kg N, 11.34 g/kg P and 14.92 g/kg K on oven-dry weight basis (data from 2013 experimentation). Based on the history of manure application, 5 treatments were defined in a randomized complete block design with 3 replicates in late April of 2013. These treatments included corn (L.) without manure application as a control treatment (CK) and corn with manure application for 2 year (Y2), 6 years (Y6), 13 years (Y13), and 18 years (Y18). Urea (N=46%) was applied as a top dressing to corn in the elongation stage at the rate of 400 kg/hm2.

1.3 Soil sampling

Soils were sampled at the 0−20 cm depth in each plot in October of 2013 after the corn harvest. Each sample was a composite of soils taken from 5 points for soil chemical properties. Moist soil samples were stored at 4 ℃ prior to analysis of enzyme activities. Cores with volume of 100 cm3were performed and replicated 5 times for soil physical properties.

1.4 Laboratory methods

Soil samples were air-dried, pushed though a 1 mm diameter sieve and stored at room temperature prior to analysis of chemical properties. Soil pH value and EC were measured at 1:5 soil-to-water ratio using pH-meter electrode and conductivity meter, respectively. SOM was determined by dichromate oxidation with heating (K2Cr2O7–H2SO4)[18]. TN was determined using the flow analyzer procedure. TP was determined using colorimetric analysis at 700 nm after treatment with HClO4–H2SO4. Available N was determined using the method described by Lu[18]. Available P was determined by NaHCO3extraction and subsequent colorimetric analysis at 700 nm. Available K was determined using atomic absorbance after extraction with 1 mol/L NH4OAC.bwas measured using core method by undisturbed soil cores and dried for 48 h at 105 ℃. WHC was measured using the gravimetric method by equilibrating the soil with water through capillary action[19].twas calculated using bulk density (b) and particle density (d) according to the equation:t=(1−b/d)×100%, whered= 2.65 g/cm3[20]. Urease, phosphatase and catalase activities were determined using the methods described by Zhou et al.[21]and Li et al.[22]Invertase activity was determined using the method of Guan[23].

1.5 Statistical analysis

All the statistical analyses were carried out using SPSS 17.0 for Windows software. Significant differences of all the measured soil attributes and soil quality indices (SQIs) among treatments were tested with one-way analysis of variance (ANOVA) followed by least significant differences (LSD) at<0.05.

Factors were extracted from original variables for assessing soil quality by factor analysis, using covariance and correlation matrix, which interpreted amounts of raw data[24-25]. By the correlation matrix, factors with eigenvalues >1 were retained and maximized using varimax rotation correlation between factors and measured soil attributes[18]. For this assessment, the measured soil attributes were selected across all treatments.

SQI was determined by 3 steps, which were (1) definition of a minimum data set (MDS) that represented soil function, (2) score assignation to each MDS indicator based on mathematical functions and (3) MDS indicators scores integration in a comparative index. We selected significant variables to step in the MDS formation using factor analysis and defined principal components (factors) for a data set as linear combinations of variables. Principal components (factors) with eigenvalue >1 and explained at least 5% of the variation of the data were examined[26-27]. We defined the absolute values with 10% of the highest factor loading as the highly weighted factor loadings, and only retained variables with highly weighted factor loadings in the MDS. When retained variables were more than one in a single principal component (factor), multivariate correlation coefficients were used to determine if the variables could be considered redundant, and eliminated from the MDS[28]. If the highly weighted variables were correlated, then each was important and was retained in the MDS. Well-correlated highly weighted variables were redundant, and only variable with the highest factor loading was retained in the MDS[29].

Each MDS indicator was transformed using linear scoring technique. The variable scores, ranging from 0 to 1, were assigned to the MDS indicators depending on “more is better” or “less is better” function. A certain amount (%) of the variation was explained by each principal component (factor) in the total data set. This percentage as the weight, standardized to unity, was assigned to variables chosen under a given principal component (factor)[23]. The weighted MDS variable scores were summed and the equation was calculated as:

SQI=（1）

whereSis score assigned to each variable;Wis weighing factor derived from factor analysis.

2 Results

2.1 Soil physic-chemical properties

Soil pH value was alkaline across all treatments, ranging from 10.51 in the CK treatment to 8.26 in the Y6 treatment, and was significantly higher in the CK treatment compared with the other treatments (<0.05). No significant difference was observed for soil pH value among the Y6, Y13 and Y18 treatments. Similar to EC, the highest EC was observed in the CK treatment, and was significantly higher than that in the treatments with manure application (<0.05). However, no significant difference was observed for EC in soils treated with manure (Table 1).

No significant difference was observed forrbacross all treatment, although it was lower in the Y18 treatment. WHC was significantly higher in the Y18 treatment compared with the other treatment except for the Y6 and Y13 treatments (<0.05), whereas no significant difference was observed for WHC among the CK, Y2, Y6 and Y13 treatments. Similarly, there was no significant difference among the CK, Y2, Y6 and Y13 treatments as well as the Y13 and Y18 treatments fort(Table 1).

The highest SOM and TN were observed in the Y18 treatment, whereas the lowest were in the CK treatment, respectively. SOM and TN were significantly higher in the Y18 treatment than those in the other treatments except for the Y13 treatment, respectively (<0.05). The highest available N was also found in the Y18 treatment, and was significantly higher in the Y18 treatment than that in the other treatments (<0.05). Significant difference was also observer for available N among the rest of treatments (<0.05). TP and available P were significantly higher in the treatments with manure application than those in the CK treatment except for the Y2 treatment (<0.05), respectively. Available K in the treatments with manure application was 4.66-54.10 mg/kg higher than that in the CK treatment, and was significantly higher in the Y18 treatment than that in the Y2, Y6 and CK treatments (<0.05).

2.2 Soil enzyme activities

Soil enzyme activities were significantly (<0.05) affected by manure application in the Y2, Y6, Y13 and Y18 treatments. Urease activity was significantly higher in the treatments with manure application compared with the CK treatment. Invertase activity was the highest in the Y6 treatment, followed by the Y2, Y13 and Y18 treatments, the lowest was in the CK treatment. Invertase activity was significantly higher in the Y6 treatment than that in the Y18 and CK treatments. Catalase activity was significantly higher in the Y13 treatment than that in the other treatments, except for the Y18 treatment. Phosphatase activity was significantly higher in the Y18 treatment than that in the Y2 and CK treatments and did not significantly differ from the Y6, Y13 and Y18 treatments (Table 1).

Table 1 Mean values ± standard deviations of soil properties under different treatments for long-term experimentation (P<0.05)

Note: CK, corn without cattle manure application; Y2, corn with cattle manure application for 2 years; Y6, corn with cattle manure application for 6 years; Y13, corn with cattle manure application for 13 years; Y18, corn with cattle manure application for 18 years. EC, electrical conductivity;b,bulk density; WHC, water-holding capacity; ƒt, total porosity; SOM, soil organic matter; TN, total nitrogen; TP, total phosphorus. Mean values in the same row followed by the same letter are not significantly different using LSD test at<0.05. Same as below.

2.3 Results of factor analysis

In factor analysis of 15 soil properties, the first 2 factors with eigenvalue>1 explained 85.13% of the total variance of data (Table 2). Factor analysis showed that the first and most important factor (Factor 1) explained 71.73% of total variance (Table 2) and only had a highly positive factor loading fromt(Table 3). Moderately positive factor loadings for Factor 1 were observed from WHC, available N, P and K (Table 3). It also had negative factor loadings fromb(the minimum value), EC and pH (Table 3). Factor 1 was in response to soil structural properties. Factor 2 accounted for 13.40% of total variance (Table 2), and only had the highest negative factor loading from pH value as well as the highest positive factor loading from invertase activity, respectively (Table 3). Similarly, moderately positive and negative factor loadings were also observed from SOM, TN and urease activity as well as EC, respectively (Table 3). This suggested that Factor 2 mainly explained the variances in soil saline-alkaline properties.

Table 2 Total variance explained among soil quality parameters under different treatments for long-term experimentation

Table 3 Component matrix and communality for soil properties of retained factors under different treatments for long-term experimentation

A high communality for soil properties suggested that the factor explained a high portion of variance. Thus, it would obtain higher performance in comparison with a lower communality[30]. The communities of >0.90 were pH value, SOM, TN, available N and P as well as urease activity; >0.80 were EC,b,t, TP, available K and invertase activity; <0.70 were WHC, catalase and phosphatase activities, respectively (Table 3).

2.4 Soil quality assessment

Two factors with eigenvalues>1 were retained from 15 measured soil attributes by factor analysis at 0-20 cm soil depth, and related to one or more functions of soil features. Assessing the effects of long-term manure application on extracted 2 factors with eigenvalues>1, factor scores were calculated using the resulting component scores coefficient matrix and standardized variables, and clustered for homogeneous groups in response to the number of years of manure application.

Distribution of different treatments in the first 2 factors with eigenvalues>1 was shown in Fig.1. Across all treatments, 3 distinct groups of soils were identified. The Y13 and Y18 treatments were clustered into Group 1 due to improved soil structural properties (Factor 1) and decreased soil saline-alkaline properties (Factor 2) in soils treated with long-term manure application than those in untreated soils (CK). Group 2 included the Y2 and Y6 treatments due to decreased soil saline-alkaline properties in these treatments than those in the CK treatment. Group 3 only consisted of the CK treatment. Thus, the number of years of manure application significantly affected separating groups based on improved soil structural properties and decreased soil saline-alkaline properties.

2.5 Soil quality index

Highly weighted variables were obtained using factor analysis, which wereb,t, EC, pH value, available K and invertase activity (Table 3). In Factor 1, the highly weighted variables wereb, ƒtand available K, and were significantly correlated (<0.05, Table 4). Thus,bwas firstly retained in MDS due to absolute value of the highest factor loading and its importance in soil structural properties (Table 3). In Factor 2, EC, pH value and invertase activity were highly weighted (Table 3), whereas pH value was significantly related to EC and invertase activity, respectively (Table 4). Thus, pH value was chosen into MDS owing to absolute value of the highest factor loading and its importance in soil saline-alkaline properties (Table 3). The recent study reported when EC was as an important soil quality indicator in soils with high pH value (>7.5), the variations in EC were likely to reflect management decision[31]. In our study, soil pH value was alkaline (pH>8.0) and variations in EC ranged from 0.17 to 2.04 dS/m across all treatments. Thus, EC was also selected to MDS. In general, SOM is considered as the universal indicator of soil quality[32]. Simultaneously, long-term manure application significantly affected SOM owing to input of C in the soils. For this reason, SOM was also selected to MDS although its factor loading was less than absolute value within 10% of the highest factor loading. The final MDS consisted of pH value,b, EC and SOM based on logic and interpretability of variables.

In order to synthesize all the information provided by selected variables and to assess the soil quality, SQIs were calculated using Eq.(1) under different treatments for long-term experimentation. In our study,bwas the predominant attribute for SQI across all treatments, followed by EC and SOM, the contribution of pH value towards SQIs was the lowest. This suggested thatbwas the dominant variable affecting soil quality in the solonetz.

Table 4 Correlation matrix among soil quality parameters under different treatments for long-term experimentation

Note: ** means correlation is significant at the 0.01 level (two tailed); * means correlation is significant at the 0.05 level (two tailed)

SQI ranged from 0.85 in the Y18 treatment to 0.25 in the CK treatment, and was significantly higher in the Y18 treatment than that in the CK, Y2 and Y6 treatments (<0.05, Fig.2). Judging from SQIs, soil quality increased in sequence of the CK, Y2, Y6, Y13 and Y18 treatments due to an increase in SQIs with better soil properties or functions (Fig.2). This suggested that soil quality increased with the number of years of manure application in the solonetz of the study area, which resulted from the better soil quality or greater performance of soil function with long-term manure application. This was likely due to that annual manure application resulted in better soil structural properties (b) and the decrease in soil saline-alkaline properties (EC and pH value).

3 Discussion

In the study area, solonetz is a degraded soil and has poor soil properties prior to long-term manure application experimentation, such as high soil pH value (>8.0), high salt content (EC>2.0 dS/m) as well as poor soil physical properties, nutrient status and enzyme activities. In our study, manure applied to solonetz significantly improved soil quality by increasing SOM[33]as well as improving soil physic-chemical properties and enzyme activities[34-36].

The result from correlation analysis indicated that SOM was significantly correlated to all the measured soil attributes (<0.05; Table 4). Thus, SOM is a key attribute of soil quality owing to its important sink and source of main plant and microbial nutrients, and it significantly influences soil physical, chemical and biological functions[37].

The large input of C was supplied from long-term manure application, which could cause a significant increase in SOM in soils treated with manure compared with untreated soils. This accumulation of SOM is likely a result of the direct manure application, the increased amount of roots and crop residues and higher humification rate constant[38-39], whereas effects of chemical fertilizer on SOM are related to the amount of biomass C produced or returned to soils and its humification rate[40].

Based on the properties of manure and the amount of manure applied to field on dry weight basis, soils received a large of macronutrients annually, such as N, P and K. This suggested that annual manure application caused significant increase in TN, available N, TP, available P and available K in soils treated with manure compared with untreated soils. Simultaneously, SOM could provide a large pool of macronutrients, which also caused an increase in macronutrients in the solonetz. In addition, urease catalyzes the hydrolysis of urea to CO2and NH3[11], and plays an important role in the N cycling[41]. Phosphatase supplies plant uptake of P by releasing PO43+from immobile organic P[11].

bis an indicator of soil physical condition, and is related to soil porosity, hydraulic conductivity, compaction, and SOM etc. Significant correlations were observed betweenb,t, WHC and SOM by correlation analysis, respectively (<0.05; Table 4). Reduction ofbin manured soils is probably due to soil aggregation with more root biomass by manure application[42], dilution effect of adding less dense organic manure[37]as well as high SOM which led to better soil aeration[43]. Furthermore, crop residues return and roots input to surface soil could result in a decrease inbassociated with an increase int[39]as well as an increase in WHC through soil C input[28]. This suggested that an increase in SOM can result in greater soil porosity and better soil structure[44-45].

A decrease in soil pH value with continued annual manure application is attributed to nitrification of NH4+and organic acid that derived from the decomposition of the organic manure fraction[46]. Furthermore, EC was significantly decreased with soil pH value decreasing (=0.86;<0.01; Table 4) because of the reduction of soluble salts, especially Na+, resulted from its leaching from topsoil due to improvements in soil structural properties, probably.

Soil enzyme involves in soil nutrient transformation, and its activity is considered as a key indicator of soil quality and is mainly affected by microbial activities, SOM, and plant growth[47-49]. In our study, soil enzyme activities, including urease, catalase, phosphatase and invertase, were significantly higher in soils treated with manure than those in untreated soils. An increase in soil enzyme activities in soils treated with manure was attributed to greater input of C from manure application over the years as well as root biomass and crop residues due to better crop productivity. Correlation analysis illustrated that soil enzyme activities were positively and significantly related to SOM (<0.05; Table 4). This suggested that SOM was determinant attribute affecting soil enzyme activities due to SOM supplying soil enzymes of substrates, enhancing microbial activity and protecting soil enzymes by forming complexes with clay and humus[11,50]. We observed that soil enzyme activities were also positively and significantly correlated with each other in long-term manure application. This suggested that all the measured soil enzyme activities were closely interrelated and could be potential indicators for the fertilization effects on soil quality[51].

4 Conclusions

Long-term application of cattle manure on solonetz significantly improved soil physic-chemical properties and enhanced soil enzyme activities. “Soil structural properties” (Factor 1) and “soil saline-alkaline properties” (Factor 2) were obtained using factor analysis, respectively. Based on homogeneous group, improved soil structural properties (Factor 1) and decreased soil saline-alkaline properties (Factor 2) were in response to the number of years of manure application. Soil quality was increased with the number of years of manure application judging from the SQI values. We conclude that soil structural and saline-alkaline properties are the key factors that limit soil quality, and promotion of soil quality is characterized by decrease inb, pH value and EC in the solonetz, especially forb.

[1] Larson W E, Pierce F J. Conservation and enhancement of soil quality[C]//In: Evaluation for sustainable land management in the developing world. Bangkok, Thailand: International Board for Soil Research and Management, 1991, 12: 175－203.

[2] Arshad M A, Martin S. Identifying critical limits for soil quality indicators in agro-ecosystems[J]. Agriculture Ecosystems & Environment, 2002, 88(2): 153－160.

[3] Guo G, Zhang H, Araya K, et al. Improvement of salt-affected soils[M]. Part 4: Heat transfer coefficient and thermal conductivity of salt-affected soils. Biosystems Engineering, 2007, 96(4): 593－603.

[4] Brady N C, Wells R R. The Nature and Properties of Soil[M]. Prentice Hall, Upper Saddle River, New Jersey, 2001.

[5] Gawel L J. A Guide for Remediation of Salt/Hydrocarbon Impacted Soil[M]. Bismarck, U SA: North Dakota Industrial Commission, Department of Mineral Resources, 2009.

[6] Ci L J, Yang X H. Desertification and its control in China[M]. Beijing: Higher Education Press, 2010.

[7] Masto R E, Chhonkar P K, Singh D, et al. Soil quality response to long-term nutrient and crop management on a semi-arid inceptisol[J]. Agriculture, Ecosystems & Environment, 2007, 118(1-4): 130－142.

[8] Gong L, Ran Q Y, He G X, et al. A soil quality assessment under different land use types in Keriya river basin, Southern Xinjiang, China[J]. Soil & Tillage Research, 2015, 146: 223－229.

[9] Domingo-Olivé F, Bosch-Serra À D, Yagüe M R, et al. Long term application of dairy cattle manure and pig slurry to winter cereals improves soil quality[J]. Nutrient Cycling in Agroecosystems, 2016, 104(1): 39－51.

[10] Scotti R, Pane C, Spaccini R, et al. On-farm compost: A useful tool to improve soil quality under intensive farming systems[J]. Applied Soil Ecology, 2016, 107: 13－23.

[11] Liu E K, Yan C R, Mei X R, et al. Long–term effect of chemical fertilizer, straw, and manure on soil chemical and biological properties in northwest China[J]. Geoderma, 2010, 158(3-4): 173－180.

[12] Yang M, Sun Y, Gao Y S, et al. Effects of organic manure on improving soda saline-alkali soil[J]. Journal of Jilin Agricultural Sciences, 2013, 38(3): 43－46, 62. (in Chinese with English abstract)

[13] Vincent de Paul Obade, Lal R. Soil quality evaluation under different land management practices[J]. Environmental Earth Sciences, 2014, 72(11): 4531－4549.

[14] Rahmanipour F, Marzaioli R, Bahrami H A, et al. Assessment of soil quality indices in agricultural lands of Qazvin Province, Iran[J]. Ecological Indicators, 2014, 40(5): 19－26.

[15] Gong L, Ran Q Y, He G X, et al. A soil quality assessment under different land use types in Keriya river basin, Southern Xinjiang, China[J]. Soil & Tillage Research, 2015, 146: 223－229.

[16] Adolfo C C, Klaudia O L, Jorge E B, et al. Exploring the effect of changes in land use on soil quality on the eastern slope of the Cofre de Perote Volcano (Mexico)[J]. Forest Ecology and Management, 2007, 248(3): 174－182.

[17] IUSS Working Group W R B. World reference base for soil resources 2006 (2nd ed) [S].World Soil Resources Report NO. 103. FAO, Rome, 2006.

[18] Lu R K. Soil agricultural chemical analysis method[M]. Beijing: China Agriculture Press, 1999.

[19] Bao S D. Soil and agricultural chemistry analysis[M]. Beijing: China Agriculture Press, 1999.

[20] Huang C Y. Soil Science[M]. Beijing: China Agriculture Press, 2000.

[21] Zhou L K, Zhang Z M. Soil enzyme activity determination method[J]. Chinese Journal of Soil Science, 1980, 11(5): 37－38, 49. (in Chinese with English abstract)

[22] Li Z G, Luo Y M, Teng Y. Soil and environmental microbiology research method[M]. Beijing: Science Press, 2008.

[23] Guan S Y. Soil Enzymes and its Methodology[M]. Beijing: Agricultural Press, 1986.

[24] Tan R B, Mei X R. SPSS statistical analysis of practical course[M]. Beijing: Science Press, 2007.

[25] Zhang L. SPSS application on biological statistics[M]. Xiamen: Xiamen University Press, 2008.

[26] Brejda J J, Moorman T B, Karlen D L, et al. Identification of regional soil quality factors and indicators: I. Central and southern high plains[J]. Soil Science Society of America Journal, 2000, 64(6): 2115－2124.

[27] Wander M M, Bollero G A. Soil quality assessment of tillage impacts on Illinois[J]. Soil Science Society of America Journal, 1999, 63(4): 961－971.

[28] Augé R M, Stodola A J W, Tims J E, et al. Moisture retention properties of mycorrhizal soil[J]. Plant and Soil, 2001, 230(1): 87－97.

[29] Andrews S S, Karlen D L, Mitchell J P. A comparison of soil quality indexing methods for vegetable production systems in Northern California[J]. Agriculture Ecosystems & Environment, 2002, 90(1): 25－45.

[30] Johnson R A, Wichern D W. Applied Multivariate Statistical Analysis[M]. New Jersey: Prentice-Hall, Englewood Cliffs, 1992.

[31] Andrews S S, Mitchell J P, Mancinelli R, et al. On farm assessment of soil quality in California’s Central Valley[J]. Agronomy Journal, 2002, 94: 12－23.

[32] Rasmussen P E, Collins H P. Long-term impacts of tillage, fertilizer and crop residue on soil organic matter in temperate semi arid regions[J]. Advances in Agronomy, 1991, 45: 93－134.

[33] Kaur T, Brar B S, Dhillon N S. Soil organic matter dynamics as affected by long term use of organic and inorganic fertilizers under maize–wheat cropping system[J]. Nutrient Cycling in Agroecosystems, 2008, 81(1): 59－69.

[34] Fraser D G, Doran J W, Sahs W W, et al. Soil microbial populations and activities under conventional and organic management[J]. Journal of Environmental Quality, 1988, 17(4): 585－590.

[35] Clark M S, Horwath W R, Shennan C, et al. Changes in soil chemical properties resulting from organic and low–input farming practices[J]. Agronomy Journal, 1998, 90(5): 662－671.

[36] Hao X, Chang C, Travis G R, et al. Soil carbon and nitrogen response to 25 annual cattle manure applications[J]. Journal of Plant Nutrition and Soil Science, 2003, 166(2): 239－245.

[37] Nieder R, Benbi D K. Carbon and Nitrogen in the Terrestrial Environment[J]. Springer Science Business Media B V, 2008, 35(3): 87–108.

[38] Bhattacharyya R, Chandra S, Singh R D, et al. Long-term farmyard manure application effects on properties of a silty clay loam soil under irrigated wheat–soybean rotation[J]. Soil & Tillage Research, 2007, 94(2): 386－396.

[39] Jagadamma S, Rattan L, Hoeft R G, et al. Nitrogen fertilization and cropping systems effects on soil organic carbon and total nitrogen pools under chisel-plow tillage in Illinois[J]. Soil & Tillage Research, 2007, 95(1-2): 348－356.

[40] Lal R. Soil carbon sequestration impacts on global climate change and food security[J]. Science, 2004, 304(5677): 1623－1627.

[41] Bremner J M, Mulvaney R L. Urease activity in soils[C]// In: Burns R G (ed), Soil enzymes. London: Academic Press, 1978.

[42] Bhattacharyya R, Pandey S C, Chandra S, et al. Fertilization effects on yield sustainability and soil properties under irrigated wheat-soybean rotation of an Indian Himalayan upper valley[J]. Nutrient Cycling in Agroecosystems, 2010, 86(2): 255－268.

[43] Kundu S, Bhattacharyya R, Prakash V, et al. Carbon sequestration and relationship between carbon addition and storage under rain-fed soybean–wheat rotation in a sandy loam soil of the Indian Himalayas[J]. Soil & Tillage Research, 2007, 92(1/2): 87－95.

[44] Herencia J F, Garcia-Galavis P A, Maqueda C. Long-term effect of organic and mineral fertilization on soil physical properties under greenhouse and outdoor management practices[J]. Pedosphere, 2011, 21(4): 443－453.

[45] Celik I, Gunal H, Budak M, et al. Effects of long–term organic and mineral fertilizers on bulk density and penetration resistance in semi–arid Mediterranean soil conditions[J]. Geoderma, 2010, 160(2): 236－243.

[46] Chang C, Sommerfeldt T G, Entz T. Soil chemistry after eleven annual applications of cattle feedlot manure[J]. Journal of Environmental Quality, 1991, 20(2): 475－480.

[47] Masto R E, Chhonkar P K, Singh D, et al. Changes in soil biological and biochemical characteristics in a long-term field trial on a sub–tropical inceptisol[J]. Soil Biology & Biochemistry, 2006, 38(7): 1577－1582.

[48] Roldán A, Salinas-García J R, Alguacil M M, et al. Soil enzyme activities suggest advantages of conservation tillage practices in sorghum cultivation under subtropical conditions[J]. Geoderma, 2005, 129(3-4): 178－185.

[49] Kong L G. Maize residues, soil quality, and wheat growth in China: A review[J]. Agronomy for Sustainable Development, 2014, 34(2): 405－416.

[50] Saha S, Prakash V, Kundu S, et al. Soil enzymatic activity as affected by long term application of farm yard manure and mineral fertilizer under a rainfed soybeanewheat system in N-W Himalaya[J]. European Journal of Soil Biology, 2008, 44(3): 309－315.

[51] Liang Q, Chen H Q, Gong Y S, et al. Effects of 15 years of manure and mineral fertilizers on enzyme activities in particle-size fractions in a north China Plain soil[J]. European Journal of Soil Biology, 2014, 60: 112－119.

长期施用牛粪对松嫩平原盐渍化土壤质量的影响

孟庆峰1，张娟1，李欣伦1，屈晓泽1，李伟彤1，曾宪楠2，马献发1※

（1. 东北农业大学资源与环境学院，哈尔滨 150030； 2. 黑龙江省农科院耕作与栽培研究所，哈尔滨 150086）

在盐渍化土壤中，普遍存在土壤结构性和养分状况差以及土壤酶活性低等现象。这种现象主要是由于土壤中过量的交换性钠离子和较高的土壤pH所引起。长期施用有机肥（牛粪）是一项提升盐渍化土壤质量的重要措施。本研究依托东北农业大学盐碱土改良长期定位试验站，以腐熟的牛粪为改良材料，依据牛粪施用年限共设置5个处理，采用完全随机区组设计，每处理3次重复，供试作为玉米，各处理分别为：施用牛粪2年、6年、13年和18年，以不施用牛粪的盐渍化土壤作为对照。分别测定各处理的土壤理化指标和酶活性。采用因子分析法与土壤质量指数法评价长期施用有机肥对盐渍化土壤质量的影响。研究结果表明：长期施用有机肥能够改善盐渍化土壤的物理性状、提高土壤养分状况、降低土壤pH和盐分以及增加土壤酶活性。根据特征根>1原则，经因子分析后可提取2个公因子，分别表征“土壤结构性”（因子1）和“土壤盐碱性质”（因子2）。与未施用有机肥的土壤相比，施用有机肥13年和18年的土壤具有较好的土壤结构性和较低的盐碱性质，而施用有机肥2年和6年的土壤仅具有较低的盐碱性质。比较土壤质量指数（SOI）可知：盐渍化土壤质量随有机肥施用年限而增加，有机肥施用18年处理的土壤质量最高。总之，土壤结构性差和盐碱性质高是影响松嫩平原盐渍化土壤质量的关键限制因子，其中以土壤结构性差最为主导；土壤容重、pH和盐分的降低是长期有机培肥措施下盐渍化土壤质量得以提升的重要特征，尤其是以土壤容重的降低最为重要。

有机肥；土壤；质量；因子分析；长期定位试验

10.11975/j.issn.1002-6819.2017.06.011

S156.4; S158.5

A

1002-6819(2017)-06-0084-08

2016-07-03 Revised date：2017-01-23

National Natural Science Foundation of China (41501315 and 41501316); Special Funds for the “Young Talents” Project of Northeast Agricultural University (14QC31 and 16QC11); Key Technology Research of Efficient Fertilization of Farmland and Promotion of Land Productivity in Songnen Plain of China (YS15B15); Fund of Postdoctor in China (2014M551207)

Meng Qingfeng, male, lecturer, mainly engaged in amelioration of salt-affected soils, School of Resources and Environment, Northeast Agricultural University, Harbin 150030, China. Email: qfengmeng@hotmail.com

Ma XianFa, male, associate professor, mainly engaged in amelioration of salt-affected soils, School of Resources and Environment, Northeast Agricultural University, Harbin 150030, China. Email: xianfama@yeah.net