Changes in the chemical properties of acid soil and aggregate stability in the whole profile under long-term management history

ABSTRACT

The effects of long-term (1959–2005) liming in combination with cattle manure application on the chemical properties and aggregate stability of acid soil were investigated in the whole soil profile to a 100 cm depth. Investigations were performed in a long-term liming and fertilizing field trial at Vezaiciai Branch of Lithuanian Research Centre for Agriculture and Forestry situated in West Lithuania. The soil of the study site is Bathygleyic Distric Glossic Retisol (WRB 2014) with a texture of moraine loam. Acid soil had been periodically limed and manured at different intensity for 47 years. The experiment involved the following treatments: (1) unlimed and unfertilized (control); (2) unlimed and 60 t ha⁻¹ manure; (3) limed and unfertilized; and (4) limed and 60 t ha⁻¹ manure. During the 47-year period, liming was performed using pulverized limestone at a rate 1.0 (by hydrolytic soil acidity) every 7 years. During the whole study period, the soil received 38.7–36.5 t ha⁻¹ CaCO₃; 840 t ha⁻¹ cattle manure, 2740 kg ha⁻¹ mineral nitrogen; 3030 kg ha⁻¹ phosphorus and 3810 kg ha⁻¹ potassium. The data showed that long-term (47 years) periodic liming of different intensities in combination with cattle manure application significantly changed the chemical properties of the whole soil profile. The soil acidification was neutralized in the topsoil and subsoil to the 60 cm depth when the soil had been systematically limed with 1.0 rate every 7 years in combination with 60 t ha⁻¹ manure application every 3–4 years. Periodic long-term liming in combination with manuring had a positive effect on the improvement of chemical properties of acid soil profile in the ElB₁ and ElB₂ horizons. The data of the soil structure in the topsoil and subsoil showed that such liming practice together with manuring had a positive effect on soil aggregate stability.

KEYWORDS:

• Liming
• manuring
• aluminium
• calcium
• phosphorus and potassium
• soil pH
• soil structure

Introduction

Soil acidification management includes both neutralization of soil acidity and regulation of the acidification of limed soil (Eidukeviciene et al. 2010; Jaskulska et al. 2014). These processes are influenced by agricultural activities such as liming (Mazvila et al. 2004; Marcinkonis & Tripolskaja 2008) and usage of organic fertilizers in combination with mineral fertilizers (Celic et al. 2010). Application of organic manure with high alkalinity (thermophilic straw compost or barnyard manure) mitigated soil acidification in croplands (Meng et al. 2012) and increased the amount of mobile phosphorous in the whole soil profile (Nest et al. 2014).

The combination of long-term liming and fertilization with cattle manure ensured improvement of topsoil aggregate stability and maintenance of soil chemical indicators at an optimal level for better crop performance (Karcauskiene & Repsiene 2009; Veremeenko & Furmanets 2014). Fertilization is one of the main yield-forming factors. When applied properly, it helps to maintain or increase soil fertility and productivity in an environment-friendly way. When used improperly, especially for a long time, it results in unfavourable changes in soil properties and other agroecosystem components as well as decreased productivity of plants and deterioration of yield quality (Gamzikov et al. 2007). Various researchers have reported that the changes of soil morphological, chemical and physical properties of deeper horizons are influenced by more intensive anthropogenic load like drainage, afforestation, deep soil loosening, compaction by heavy traffic and long-term liming (Eidukeviciene et al. 2001; Wang et al. 2014). According to Sramek et al. (2012) the one-time liming by a total dose of 3 tons of dolomitic limestone per hectare influenced topsoil chemical properties to 30 cm depth. However, a long-term periodic liming by pulverized limestone at a rate of 2.0 every 3–4 years hindered acidification in the A₂B horizon to the 40 cm depth and mitigated this process in deeper horizons up to one metre depth. Evaluation of these data by the criteria of base saturation (more than optimal 70%) has revealed a problem of soil over-liming. Some research evidence has suggested that in the over-limed soil the leaching of calcium is the highest and the soil structure is deteriorated (Ozeraitiene 2002). Considering this, the intensity of soil liming in combination with other agronomic practices must be strictly controlled in the agroecosystem.

The aim of the current study was to estimate the changes in soil aggregate stability and the main chemical properties in the whole soil profile as influenced by long-term management (liming, manuring and their combination) under natural humid climate conditions of West Lithuania.

Materials and methods

Study site

The study site is LRCAF Vezaiciai Branch situated in West Lithuania, eastern fringe of the coastal lowland (55°43′N, 21°27′E). The current research was done in a crop rotation field under a long-term liming and fertilization experiment carried out since 1959.

Study conditions

The soil under study is Bathygleyic Distric Glossic Retisol (WRB 2014) whose chemical and physical properties morphologically are typical of acid soils prevalent in West Lithuania. According to the content of clay particles, the soil profile is differentiated into alluvial and illuvial horizons whose diagnostic horizons: Ah – ElB – ElBt – BtEl – BCg. According to its profile differentiation and all acidity parameters, the soil under study is in the priority in terms of the need for liming. The soil reaction in the continuous one metre thick layer is very acid (pH_KCl =  3.8–4.0) and the content of toxic aluminium in the plough horizon (A) exceeds phytotoxicity limit 9-fold (185.6 mg kg⁻¹), and in the alluvial horizon (ElB) the content of mobile aluminium is close to the maximum (305 mg kg⁻¹) limit characteristic of such soil group.

Climate is moderately warm and humid. The region’s mean annual amount of precipitation is more than 800 mm, the average annual air temperature is 6.7°C.

The experimental design

The effects of long-term management (liming, organic fertilization and their combination) on the soil properties in the whole profile were estimated using the following experimental design: (1) unlimed and unfertilized (control); (2) unlimed and 60 t ha⁻¹ manure every 3–4 years; (3) limed with 1.0 rate every 7 years and unfertilized and (4) limed with 1.0 rate every 7 years and 60 t ha⁻¹ manure every 3–4 years. Periodic liming during was carried out using pulverized limestone at a rate 1.0 (by hydrolytic soil acidity) every 7 years. The primary soil tillage was conventional-deep (23–25 cm) ploughing. The effects of liming and manuring on the soil chemical properties and structure were investigated in the crop rotation with the following mineral fertilization: winter wheat (N₆₀P₆₀K₆₀), mixture of peas and bareley (N₆₀P₆₀K₆₀), oat (N₆₀P₆₀K₆₀), forage beets (N₁₂₀P₉₀K₁₅₀), bareley with undercrop (N₄₀P₆₀K₆₀) and perennial grasses of two years usage (P₆₀K₉₀; N₆₀P₆₀K₉₀). The acid soil was periodically limed and manured for 47 years. During the study period the soil received: 38.7–36.5 t ha⁻¹ CaCO₃; 840 t ha⁻¹ cattle manure, 2740 kg ha⁻¹ mineral nitrogen; 3030 kg ha⁻¹ phosphorus and 3810 kg ha⁻¹ potassium.

Methods of soil sampling and analyses

Soil samples for chemical analyses were collected from the wall of the soil profile every 10 cm by the grid method. The samples were taken in triplicate taking into account the soil horizons. For soil structure analysis, the samples were collected in the wall of the profile from separate horizons in triplicate.

Laboratory methods of soil analyses:

pH 1 mol/l KCl suspension – ISO 10390:2005.

Mobile Al – ISO11260 and ISO14254 Sokolov method.

Exchangeable calcium (Ca) – LVP D-13:2011, edition 1. pH of the buffer solution – 3.7.

Organic C – (dry combustion) Dumas method.

Mobile P₂O₅ and mobile K₂O – LVP D-07:2012, edition 4. Egner-Riehm-Domingo (A–L) method.

Composition of soil aggregates (dry sieving) and water stability of soil aggregates (wet sieving) were determined by the Savinov method (Vadiunina & Korchagina 1986).

The significance of studied parameters was analysed by using analysis of variance (Clewer & Scarisbrick 2001).

Results and discussion

Soil chemical properties

The data of the current study showed that long-term (47 years) periodic liming of different intensities in combination with cattle manure application significantly changed the chemical properties of the whole soil profile (Table 1). The greatest changes in the soil pH_KCl (from 3.97 to 6.08), mobile Al (from 185.616 to 2.2 mg kg⁻¹), exchangeable Ca (from 795 to 2457 mg kg⁻¹) and mobile P₂O₅ (from 131 to 220 mg kg⁻¹) and K₂O (from 219 to 266 mg kg⁻¹) were estimated in the topsoil at the 0–30 cm depth. In the unlimed soil fertilized with cattle manure the pH_KCl changed from 3.97 to 4.19, in the limed soil it increased to 5.58, and in the limed and manure-applied soil it increased to 6.08. The unlimed soil had a very high content of mobile Al 186 mg kg⁻¹, in the treatments fertilized with cattle manure its content decreased by 2.5 times to 72.9 mg kg⁻¹. The Ca and Mg present in manure bind mobile Al (Hossain et al. 2016). However, liming is the most efficient practice to reduce soil acidity since it eliminates aluminium toxicity and increases calcium content (Fageria & Baligar 2008). Our study corroborated this finding. In limed soil, the content of mobile Al decreased to a very low value of 3.19 mg kg⁻¹, while in limed and manure-applied soil its reduction was even greater to 2.2 mg kg⁻¹. In the unlimed soil, exchangeable Ca content was 131.08 mg kg⁻¹, and in the unlimed and periodically manure-applied soil its content in the topsoil increased by 1.4 times, and in the limed and manure-applied soil its content increased by 3.2 times to 2457 mg kg⁻¹ (Table 1). The data obtained by Basak and Biswas (2016) also suggest that in limed soil the content of calcium increases, which in turn enhances phosphorus availability to plants. The data of our study show that both unlimed and limed soil was moderate in phosphorus 131 and 142 mg kg⁻¹, respectively. The highest mobile P₂O₅ content 220 mg kg⁻¹ was in the soil which had been limed and fertilized with 60 t ha⁻¹ manure. In the unlimed and limed soil the contents of mobile K₂O were 219 and 199 mg kg⁻¹, respectively, and in both of these soils applied with manure K₂O increased to 266 mg kg⁻¹. The highest concentration of organic C (1.85%) was determined in the limed and manure-applied soil (Table 1).

Table 1. Changes in the soil chemical properties in the soil profile up to 1 metre depth.

Treatment	pHKCl	Mobile Al (mg kg^−1)	Exchangeable Ca (mg kg^−1)	Mobile P2O5 (mg kg^−1)	Mobile K2O (mg kg^−1)	Organic C (%)
Horizon Ah (0–30 cm)
Unlimed and unfertilized (control)	3.97	186	759	131	219	1.26
Unlimed and 60 t ha^−1 manure	4.19**	72.9**	1030**	168**	266**	1.42**
Limed and unfertilized	5.58**	3.19**	177.2**	142	199	1.62**
Limed and 60 t ha^−1 manure	6.08**	2.20**	2457**	220**	267**	1.85**
LSD05	0.110	14.677	163.434	14.011	33.171	0.08
Horizon ElB (30–60 cm)
Unlimed and unfertilized (control)	3.93	305	988	29.9	212	–
Unlimed and 60 t ha^−1 manure	3.95	247**	931	37.5	19.4	–
Limed and unfertilized	5.40**	3.57**	1629**	106	125*	–
Limed and 60 t ha^−1 manure	5.98**	3.94**	1839.67**	192	189	–
LSD05	0.101	23.661	247.759	31.896	23.860	–
Horizon ElBt (60–100 cm)
Unlimed and unfertilized (control)	3.82	326	1128	35.2	163.	–
Unlimed and 60 t ha^−1 manure	3.86	277	891*	27.1	193**	–
Limed and unfertilized	4.79**	30.6**	1350**	34.2	80.1*	–
Limed and 60 t ha^−1 manure	4.54**	69.9**	1307**	34.0	108*	–
LSD05	0.267	50.209	84.669	8.557	14.487	–

*Significantly different from control (p < .005).

**Significantly different from control (p < .001).

These data agree with those obtained by other researchers. According to the data of long-term experiments, liming and manure application had significant and positive changes on soil agrochemical properties – pH, organic carbon, mobile phosphorus and potassium (Manna et al. 2007; Jaskulska et al. 2014).

Changes caused by the long-term liming and manuring were established in the deeper horizons (ElB and ElBt) of soil profile as well. In the profile from 30 to 100 cm depth of unlimed soil the pH remained relatively stable 3.93–3.82, but the content of mobile aluminium markedly increased by 1.6–1.8 times and that of phosphorus decreased by 4.4 times going deep in the profile. In the unlimed, manure-fertilized soil, a significant reduction in the mobile Al content was identified in the ElB horizon.

However in the same ElB horizon of limed and manure-applied soil a reduction in the mobile aluminium to non-toxic content (3.57 and 3.94 mg kg⁻¹) was determined, but in the deeper ElBt horizon an increase (30.6 and 69.9 mg kg⁻¹) in the mobile Al content was observed. An increase in exchangeable calcium content in the limed soil and in the limed and manure-fertilized soil was established in the whole soil profile to 100 cm depth compared with the unlimed soil (Table 1).

The soil acidification was neutralized in the topsoil and subsoil to the 60 cm depth when the soil had been periodically limed with 1.0 rate every 7 years in combination with 60 t ha⁻¹ manure application every 3–4 years in a 7-field crop rotation. Eidukeviciene et al. (2001) indicated that the long-term (over 50 years) intensive liming (2.0 rates every 3–4 years) with no application of manure had a significant effect on the acidity parameters up to the 40-50 cm depth. The data obtained in the current study suggest that long-term periodic liming in combination with manuring had a positive effect on the improvement of chemical properties of acid soil profile in the ElB and ElBt horizons.

Soil aggregate stability

Any agricultural activity which increases organic matter content in the soil has a direct effect on the increase of soil aggregate stability. Manna et al. (2007) have reported that long-term fertilization with 30–60 t ha⁻¹ farmyard manure and its combinations with mineral fertilizers increased organic carbon content by 42–73% and the share of small (0.25–2.0 mm) macroaggregate fraction in the soil. Similar trends were observed in the current study. The data of the soil structure in the topsoil and subsoil showed that long-term manuring had a positive effect on water stability of soil aggregates (Figure 1). Under the effect of long-term manure fertilization, the content of water-stable aggregates >0.25 mm increased by 48.1% and amounted to 52.3%, compared with the treatment with no manure application. An 81.6% increase in the aggregate content was observed in the soil which had been fertilized with manure for a long time and optimal pH had been maintained through the application of periodic liming.

Figure 1. Effects of long-term liming, manuring and their combination on the change of water-stable aggregates on the soil profile.

The amount of water-stable aggregates both in the naturally acid and limed soil was by 30.3% higher in the upper Ah horizon compared with the deeper lying ElBt (30–60 cm) (Figure 1). This is associated with the effect of plant roots present in the upper topsoil layer as well as with higher organic matter content, which as (Bouajila & Gallali 2008; Karcauskiene & Repsiene 2009) indicate are important factors for the formation of water-stable aggregates. Liming and its combination with manure application had a positive impact on the formation of water-stable aggregates in the deeper 30–60 cm soil layer as well. In the limed and limed and manure-applied ElBt soil horizon, the content of water-stable aggregates was by 33.5% and 57.2% respectively higher than in the unlimed and unfertilized one, which was related to a slight increase in calcium ions and organic carbon resulting from the long-term application of crop and soil management practices. The highest content of water-stable aggregates (59.4%) was determined in the limed and manure-applied soil. Manure application alone did not have any effect on the formation of water-stable aggregates in the soil of this layer.

In general, the data of the study showed that long-term (47 years) periodic liming of different intensity in combination with cattle manure application significantly changed the soil chemical properties within the whole soil profile. The largest changes in the soil pH_KCl (from 3.97 to 6.08), mobile Al (from 186 to 2.20 mg kg⁻¹), exchangeable Ca (from 795 to 2457 mg kg⁻¹) and mobile P₂O₅ (from 131 to 220 mg kg⁻¹) and K₂O (from 219 to 267 mg kg⁻¹) were estimated in the topsoil at the 0–30 cm depth. The soil acidification was neutralized in the topsoil and subsoil to the 60 cm depth when the soil had been periodically limed with 1.0 rate every 7 years in combination with 60 t ha⁻¹ manure application every 3–4 years in a seven-field crop rotation. Long-term periodic liming in combination with manure application had a positive effect on the improvement of chemical properties of acid soil profile in the ElB and ElBt horizons. Long-term liming combined with manure application had a significant positive effect on water stability of soil aggregates in moraine loam in both upper (Ah) and deeper (ElB) horizons.

Acknowledgements

The paper presents research findings, obtained through the long-term research programme ‘Productivity and sustainability of agricultural and forest soils’ implemented by Lithuanian Research Centre for Agriculture and Forestry.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes on contributors

Dr Regina Repsiene works at Vezaičiai Branch of Lithuanian Research Centre for Agriculture and Forestry as a scientific worker and is the head of Department of Acid, eroded soils and crop production. She has published 10 research papers in the international journals. Presently he is involved in research in the area of soil acidification process analysis and management: acid soil liming, mineral and organic fertilization, soil chemical changes, plant–soil optimization.

Dr Danute Karcauskiene works at Vezaičiai Branch of Lithuanian Research Centre for Agriculture and Forestry as a Directress and senior researcher. She has published 16 research papers in the international journals. Presently she is involved in research in the area of soil acidification process analysis and management; system: plant–soil optimization; the physical condition of the soil; and degradation prevention of bio-energy resources.