RESEARCH ARTICLE

Soil Physical Quality as Affected by Management PracticesUnder Maize–Wheat System

Nishant K. Sinha • Usha K. Chopra • Anil K. Singh •

M. Mohanty • J. Somasundaram • R. S. Chaudhary

Received: 16 October 2012 / Revised: 15 August 2013 / Accepted: 22 October 2013 / Published online: 7 February 2014

� The National Academy of Sciences, India 2014

Abstract Soil physical quality is one of the three

important aspects of soil quality, besides biological and

chemical quality. Decline in soil physical quality can have

serious consequences on biological and chemical proper-

ties thereby making it relevant to study soil physical quality

for maintaining soil health in long run. Changes in this

property of soil affect the productivity of crops. In this

investigation, Dexter S theory has been applied to evaluate

the soil physical quality in maize–wheat system under two

tillage/land configurations namely raised bed planting (BP)

and conventional tillage (CT) and nine nutrient treatments

viz (1) T1—control (crop without fertilizer), (2) T2—

100 % recommended dose of nitrogen (N), phosphorous

(P) and potassium (K), (3) T3—100 % NPK (25 % N

substituted by farmyard manure (FYM)), (4) T4—100 %

NPK ? green manure (Sesbania), (5) T5—100 % NPK

(25 % N substituted by biofertilizer), (6) T6—100 % NPK

(25 % N substituted by sewage sludge), (7) T7—100 %

NPK ? crop residue incorporated (from previous crop), (8)

T8—100 % organic source (50 % FYM ? 25 % bio-fer-

tilizer ? 25 % crop residue), and (9) T9—no crop no fer-

tilizer; were identified for this study. BP significantly

improved the soil physical quality compared to CT. Within

nutrient treatments, S index was highest in T8 followed by

the T5, whereas lowest in T1. There is high and significant

correlation between S index and soil physical parameter

and crop yield which shows that S index can be used

effectively for quantifying soil physical quality under

diverse environments vis-a-vis crop yield.

Keywords Soil physical quality � S index � Tillage �Nutrient management

Introduction

Soil quality has been a matter of great concern in recent

years. It is usually considered to have three main compo-

nents: physical, chemical, and biological. Researchers have

highlighted the importance of physical [1], chemical [2]

and biological [3] environment for plant growth. Soil

physical quality is manifested in various ways. It is con-

sidered to be poor when soil exhibits one or more of the

following symptoms viz. poor water retention, infiltration,

aeration, rootability and workability and hard-setting and

runoff. Often, soil exhibits several or all of these physical

problems simultaneously which occur due to poor soil

structure [4–6].

Maize (Zea mays)–wheat (Triticum aestivum) (M–W) is

the third most important cropping system after rice (Oryza

sativa)–wheat (RW) and rice–rice in India and covers

about 1.13 million ha land each year [7]. Tillage along with

water and nutrients is the most crucial monetary inputs in

crop production. The conventional practice of tillage,

involving 6–8 tillage operations for maize and wheat,

consumes a high proportion (25–30 %) of the total opera-

tional energy in maize and wheat production [8]. Conser-

vation tillage practices, such as zero tillage and raised bed

may reduce the production costs and other constraints

N. K. Sinha (&) � M. Mohanty � J. Somasundaram �R. S. Chaudhary

Division of Soil Physics, Indian Institute of Soil Science (IISS),

Nabibagh, Berasia Road, Bhopal 462038, Madhya Pradesh, India

e-mail: nishant.sinha76211@gmail.com

U. K. Chopra

Division of Agricultural Physics, IARI, New Delhi 110012, India

A. K. Singh

RVSKVV, Gwalior, Madhya Pradesh, India

123

Natl. Acad. Sci. Lett. (January–February 2014) 37(1):13–18

DOI 10.1007/s40009-013-0194-3

associated with land preparation [9]. Conventionally maize

and wheat are planted on the flat surface and water man-

agement is by low efficiency flood irrigation. Raised beds

were introduced as a resource-conserving technology to

address the economic, water and soil constraints of con-

ventional flat sowing [10, 11]. The potential benefits of

raised beds in terms of higher yield and water-use effi-

ciency have been studied [12, 13] but evaluation of soil

physical quality through a unified index has received very

little attention.

Several researchers have attempted to incorporate soil

physical parameters into soil quality indices following

different approaches. Some examples are non-limiting

water range [14], least limiting water range [15], tilth index

[16]. Recently, Dexter [4] proposed the use of a single-

value ‘‘S-index’’ to quantify soil physical and structural

ability and defined it as slope of the soil water retention

curve (SWRC) at its inflection point. Tormena et al. [17]

and Chakraborty et al. [18] evaluated Dexter’ S-index and

explained the potential of S index to quantify soil physical

modification under different tillage, fertilizer and manure

applications. The theoretical development of S index was

presented by Dexter [4] from the definition of the SWRC as

the relationship between the water content on mass basis

(h, kg kg-1) and the logarithm (base e) of the soil water

potential (W, hPa), with a single common inflection point.

The applicability of S-theory has been illustrated with real

measurements on soils with predictions obtained from the

use of pedo-transfer functions. However, the theory should

still be tested with more data from soils formed under

diverse soil forming factors and processes to evaluate its

usability [19]. In this study, soil physical quality has been

evaluated using Dexter S index under different manage-

ment practices in M–W system. Further relations between

S and bulk density (BD), organic matter content (OM) and

saturated hydraulic conductivity (Ks) of the representing

soil (Typic Haplustepts) formed over Indo-Gangetic allu-

vium have also been investigated to examine the applica-

bility of S index vis a vis the established soil physical

parameters.

Materials and Methods

Disturbed and undisturbed soil samples were collected

during 2006 from 0–15 cm at Indian Agricultural Research

Institute (IARI) research farm, New Delhi, India (28�370N77�090E, 228.7 m above mean sea level). The climate is

semiarid with warm summer and mild winter and the

average maximum and minimum temperatures ranges from

32 to 35 �C and 13 to 15 �C, respectively. The mean

annual rainfall is 787 mm, of which 75–80 % occurs dur-

ing the monsoon season (July–September). The experiment

was initiated in 2001 and composed of nine nutrient

treatments and two tillage/land configuration systems in a

split plot design, replicated three times. Two tillage sys-

tems viz bed planting (BP) and conventional tillage (CT)

and nine nutrient treatments viz. (1) T1—control (without

fertilizer), (2) T2—100 % recommended dose of nitrogen

(N), phosphorous (P) and potassium (K), (3) T3—100 %

NPK (25 % N substituted by farmyard manure (FYM)), (4)

T4—100 % NPK ? green manure (sesbania), (5) T5—

100 % NPK (25 % N substituted by biofertilizer), (6) T6—

100 % NPK (25 % N substituted by sewage sludge), (7)

T7—100 % NPK ? crop residue incorporated (from pre-

vious crop), (8) T8—100 % organic source (50 %

FYM ? 25 % bio-fertilizer ? 25 % crop residue), and (9)

T9—no crop no fertilizer; considered as main plot and sub-

plot respectively in split plot design. The recommended

fertilizer rate is 120 kg N, 60 kg P, and 40 kg K ha-1 for

both maize and wheat. The full dose of P and K were

applied as basal at the time of sowing, whereas 50 % N

was applied as basal during sowing and rest as top dressing

in two applications. The soil is sandy loam (Typic hap-

lustepts), non-calcareous and slightly alkaline in reaction.

Disturbed soil samples were air-dried and sieved

through a 2-mm sieve and analyzed for textural compo-

nents (sand, silt and clay) by Bouyoucos method, mean

weight diameter (MWD) by Yoder’s wet sieving method

and OM by the Walkley–Black procedure. Undisturbed soil

samples were collected using core with 5.0 cm diameter

and 5.5 cm length. These undisturbed soil samples were

analyzed for BD by core method and saturated hydraulic

conductivity with a constant head permeameter. Water

retentions of soils were analyzed using the disturbed soil

sampled with a pressure plate apparatus. To obtain water

retention curves, volumetric water content was measured at

-10, -33, -50, -75, -100, -300, -500, -1,000 and

-15,000 kPa soil water pressures. The values of the water

content corresponding to each level of suction were then

fitted to the Van Genuchten [20] equation:

h ¼ ðhSat � hResÞ � 1 þ / hð Þn½ ��mþ hRes ð1Þ

where: h water content at the suction h (m3 m-3); hSat

water content at saturation (m3 m-3); hRes residual water

content (m3 m-3); a adjustable scaling factor (kPa-1); h

water suction (kPa-1); m, n adjustable shape factors,

m = 1-1/n [21].

The value of van Genuchten water retention parameter

was obtained using measured water retention data with

inverse function of computer program RETC, and then

these values were used with Eq. 2 to calculate S value [4].

S ¼ �nðhSat � hresÞ 2n � 1=n � 1

h i 1n�2ð Þ

ð2Þ

where the terms have the same meaning as in Eq (1).

14 N. K. Sinha et al.

123

Results and Discussion

Soil Physical Quality Index

Soil physical quality index ‘S’ varied with the treatments.

Analysis of variance (ANOVA) indicated the tillage

(P \ 0.05) and nutrient (P \ 0.01) treatments significantly

affected the soil physical quality (Table 1). Relatively

higher values of S were observed in BP than CT (Table 2),

representing better soil physical environment for crop

growth. The better soil physical environment in BP com-

pared to CT attributed to decrease in BD

(1.44–1.34 Mg m-3), increase in porosity (45–49 %), and

MWD (0.53–0.62 mm), available water capacity

(13.77–15.70 m3 m-3) and saturated hydraulic conductiv-

ity (0.68–0.72 cm h-1). Other studies have also shown that

the bedding process can increase soil aggregate formation

and maintain optimal ratios of solid, liquid, and gaseous

phase in agricultural soils [22]. Raised-bed planting also

optimizes water holding capacity and conductivity of soil

solutions to flat planting via enhanced aeration/porosity of

soil [23].

Under both the tillage systems, nutrient treatments

recorded significantly higher S value compared to control.

Maximum S value was observed in T8 (100 % organic

source through 50 % FYM ? 25 % bio-fertilizer ? 25 %

crop residue) in both the tillages. All other treatments

where nitrogen supply was substituted by organic source

viz. T3 to T8 showed better physical quality compared to

T1 (control) and T2 (100 % nitrogen supplied through

inorganic source). This indicates that organic source of

nitrogen not only supplies available N, but also improves

the soil physical quality compared to N supplied by inor-

ganic source. Benbi et al. [24] suggested that application of

organic manure significantly improved the soil physical

environment by increasing the soil organic carbon (OC),

infiltration rate, water retention, and soil aggregate stabil-

ity. Chakraborty et al. [18] also advocated that the organic

sources of N like green manure, FYM etc. were effective in

improving the soil physical quality, whereas continuous

fertilization with or without organic sources of nutrient

could also maintain a better soil physical quality compared

with control.

Effect of Bulk Density on S Index

A negative but significant correlation was observed

between BD and S (Fig. 1a). SWRC depends on structural

Table 1 Analysis of variance (ANOVA) results for tillage and nutrient management

Source DF Sum of square Mean of square F-ratio P value Significant

Tillage 1 0.0030 0.0030 56.70 0.0172 *

Error (tillage) 2 0.0001 0.0001

Nutrient management 8 0.0129 0.0016 18.58 \.0001 **

Tillage 9 nutrient management 8 0.0004 0.0000 0.51 0.8364 NS

Error (nutrient) 32 0.0028 0.0001

Total 53 0.0191

NS Non Significant

* Significant at 5 %

** Significant at 1 %

Table 2 S-value as affected by nutrient management under BP and CT

Bed planting Conventional tillage

T1—control (no fertilizer ? with crop) 0.062d 0.045d

T2—100 % NPK (recommended dose) 0.084c 0.072c

T3—100 % NPK (25 % N substituted by FYM) 0.104a 0.088b

T4—100 % NPK ? green manure (Sesbania). 0.105ab 0.087cb

T5—100 % NPK (25 % N substituted by biofertilizer) 0.111ab 0.090ba

T6—100 % NPK (25 % N substituted by sewage sludge) 0.098bc 0.081cb

T7—100 % NPK ? crop residue incorporated (from previous crop) 0.106ab 0.089b

T8—100 % organic source (50 % FYM ? 25 % bio-fertilizer ? 25 % crop residue) 0.117ab 0.105a

T9—blank plot 0.097bc 0.095ba

a–d values followed by different letters in the same column are significantly different among various treatments at the P \ 0.01 level

Management Practices Under Maize–Wheat System 15

123

and textural porosity, any change in BD changes porosity

and pore size distribution and thus the shape of water

retention curve. Similar results have been observed by

various researchers including Tormena et al. [17] for

tropical oxisol and Dexter [4] for temperate soils with

different textural classes. Dexter [4] conducted experi-

ments with distinct soils from different countries and

suggested a typical S value of 0.035 to specify critical BD

value for each of the textural classes. In the present study

the critical BD value i.e. the BD that corresponds to

S = 0.035 is 1.68 Mg m-3. Kutlu and Erashim [19]

reported that the critical BD values where root growth

could stop completely were 1.5–1.6 Mg m-3 for clayey

soils and 1.6–1.8 mg m-3 for loamy and sandy soils.

Effect of Soil Organic Matter on S Index

The S index was positively correlated with OM content

(Fig. 1b), indicating the OM content improves the soil

physical condition. Kutlu and Erashim [19] have also

reported the similar relationship between S and OM

content and concluded that OM improves the formation of

pores and microstructures, thereby increasing the soil

physical quality. Further, they concluded that besides

OM, other factors such as CaCO3, sesquioxides, plant

roots, soil clay minerals and microbial population also

contribute to the formation and features of soil structure.

Therefore, it seems quite challenging to specify a critical

value for soil OM content in the aspect of soil physical

quality.

Saturated Hydraulic Conductivity and S Index

Ks is the function of water content, porosity, continuity of

pores and pore size distribution. Porosity is often conceptu-

ally partitioned into two components, most commonly called

textural and structural porosity [25]. The textural component

of porosity is determined by the grain size or soil texture and

the way in which the primary soil particles naturally pack

together. Structural porosity consists of micro cracks, cracks,

biopores and voids within and between soil aggregates.

Textural porosity is largely unaffected by soil management,

whereas structural porosity is readily influenced by tillage,

compaction and biological activity [4]. Ks is mainly con-

trolled by structural macropores such as worm holes, root

channels, cracks and fissures that are too large to be featured

on water retention curve [6]. Thus, it is not expected that Ks

would correlate with S [19]. In this study too, very poor and

non-significant correlation was found between saturated

hydraulic conductivity and S-index (Fig. 1c). In general,

more root channels and biological activities including worm

holes is associated with better soil condition. We consider

that correlation between Ks and S may improve if instead of

disturbed sample undisturbed sample is used for developing

moisture characteristic curve on which S index is based. We

propose to explore this in our future studies.

Fig. 1 S Index as function of a bulk density b organic carbon c saturated hydraulic conductivity and d mean weight diameter

16 N. K. Sinha et al.

123

MWD and S Index

MWD is a sensitive index of measure of the aggregate

stability of soils and is used in quantitative evaluation of

soil structure and the influences on soil physical properties

[26]. Any changes in soil aggregate stability may serve as

early indicators of recovery or degradation of soils.

Therefore, aggregate stability is one of the important soil

properties that are used to evaluate the soil physical qual-

ity. In the present investigations, we have found a signifi-

cantly positive correlation between MWD and S index

(Fig. 1d).

Crop Yield and S index

During recent past, soil quality has received great attention

from soil scientists. However, their main focus has been on

defining the concept of soil quality rather than evaluating soil

quality [27]. Crop productivity is one of the reliable ways to

evaluate the soil quality [28]. In the present investigation,

correlation analysis showed that S-index was significantly

correlated with maize and wheat yield under both the tillage

practices (Fig. 2). High and significant correlation between

S index and crop yield, indicate that the status of soil physical

quality under different management practices can be effec-

tively evaluated using the S index.

Conclusion

1) S Index can be effectively used to quantify the changes

in the soil physical quality, which occurs due to dif-

ferent soil management practices.

2) Tillage systems such as BP, CT, and nutrient management

practices significantly affect the soil physical quality.

3) Application of organics is one of the best option to

improve soil physical quality.

4) S index is highly correlated with BD, OM, and MWD

but very poorly correlated with Ks. Use of undisturbed

sample for moisture characteristic curve may improve

correlation between Ks and S index and this needs

further investigation.

5) From this study, it has been found that, critical BD for

root development in loamy soil of North Indian

Inceptisol is 1.68 Mg m-3.

6) A high and significant relationship between crop yield

and S index has been found. This indicates importance

of practical applicability of S index.

Fig. 2 Correlation between S-index and a Maize yield under BP b Maize yield under CT c Wheat yield under BP d Wheat yield under CT

Management Practices Under Maize–Wheat System 17

123

References

1. Silva AP, Kay BD (1996) The sensitivity of shoot growth of corn

to the least limiting water range of soils. Plant Soil 184:323–329

2. Drury CF, Zhang TQ, Kay BD (2003) The non-limiting and least

limiting water range for soil nitrogen mineralization. Soil Sci Soc

Am J 67:1388–1404

3. Allmaras RR, Fritz VA, Pfleger FL, Copeland SM (2002)

Impaired internal drainage and Aphanomyces euteiches root rot

of pea caused by soil compaction in a fine-textured soil. Soil

Tillage Res 1740:1–12

4. Dexter AR (2004) Soil physical quality. Part I. Theory, effects of

soil texture, density and organic matter, and effects on root

growth. Geoderma 120:201–214

5. Dexter AR (2004a) Soil physical quality. Part II. Friability, till-

age, tilth and hard-setting. Geoderma 120:215–225

6. Dexter AR (2004b) Soil physical quality. Part III. Unsaturated

hydraulic conductivity and general conclusions about S-theory.

Geoderma 120:227–239

7. Yadav RL and Subba Rao AVM (2001) Atlas of cropping sys-

tems of India. PDCSR Bulletin Project Directorate of Cropping

Systems Research, Modhopuram, Meerut, India No. 2001–2

8. Sidhu HS, Singh S, Singh T, Ahuja SS (2004) Optimization of

energy usage in different crop production systems. J Inst Eng

85:1–4

9. Hobbs PR (2001) Tillage and crop establishment in South Asian

rice–wheat system: present practices and future options. J Crop

Prod 4:1–22

10. Painuli DK, Tomar SS, Tembe GP, Sharma SK (2002) Raised-

sunken bed technology for rainfed vertisols of high rainfall areas.

In: AICRP on soil physical constraints and their amelioration for

sustainable crop production. IISS, Bhopal, p 19

11. Connor DJ, Timsina J, Humphreys (2003) Prospects for perma-

nent beds for the rice–wheat system. Improving the productivity

and sustainability of rice–wheat systems: issue and impact, vol

65. American Society of Agronomy Special Publication, Wis-

consin, pp 197–210

12. Jat ML, Srivastva A, Sharma SK, Gupta RK, Zaidi PH, Srini-

vasan G (2005) Evaluation of maize–wheat cropping system

under double-no-till practice in Indo-Gangetic plains of India.

Paper presented in the 9th Asian regional maize workshop, Bei-

jing, China, 6–9 September 2005

13. Ram H, Singh Y, Saini KS, Kler DS, Timsina J, Humphreys J

(2012) Agronomic and economic evaluation of permanent raised

beds, no tillage and straw mulching for an irrigated maize–wheat

system in northwest India. Exp Agric 48:21–38

14. Letey J (1985) Relationship between soil physical properties and

crop production. Adv Soil Sci 1:277–294

15. De Silva AP, Kay BD, Perfect E (1994) Factors influencing least

limiting water range of soils. Soil Sci Soc Am J 58:1775–1781

16. Singh KK, Colvin TS (1992) Tilth index and crop yield. ASAE

paper no. 92–1023. ASAE, St. Joseph

17. Tormena CA, Da Silva AP, Imhoff SDC, Dexter AR (2008)

Quantification of the soil physical quality of a tropical oxisol

using the S index. Sci Agric (Piracicaba, Braz.) 65:56–60

18. Chakraborty D, Garg RN, Tomar RK, Dwivedi BS, Aggarwal P,

Singh R, Behera UK, Thangasamy A, Singh D (2010) Soil

physical quality as influenced by long-term application of fertil-

izers and manure under maize–wheat system. Soil Sci

175:128–136

19. Kutlu T, Ersahin S (2008) Evaluation of soil physical quality in

mollic ustifluvent, typic ustifluvent and typic ustorthent using

Dexter’s S-theory. J Food Agric Environ 6:450–455

20. van Genuchten MTH (1980) A closed-form equation for pre-

dicting the hydraulic conductivity of unsaturated soils. Soil Sci

Soc Am J 44:892–898

21. Mualem Y (1986) Hydraulic conductivity of unsaturated soils:

prediction and formulas. In: Klute A (ed) Methods of soil ana-

lysis: part 1. physical and mineralogical methods, 2nd edn.

American Society of Agronomy Monograph, Madison, WI,

pp 799–823

22. Zhang X, Li Ma, Gilliam FS, Wang Q, Li C (2012) Effects of

raised-bed planting for enhanced summer maize yield on rhizo-

sphere soil microbial functional groups and enzyme activity in

Henan Province, China. Field Crop Res 130:28–37

23. Patino-Zuniga L, Ceja-Navarro JA, Govaerts B, Luna-Guid M,

Sayre KD, Dendooven L (2009) The effect of different tillage and

residue management practices on soil characteristics, inorganic N

dynamics and emissions of nitrous oxide, carbon dioxide and

methane in the central highlands of Mexico: a laboratory study.

Plant Soil 314:231–241

24. Benbi DK, Biswas CR, Bawa SS, Kumar K (1998) Influence of

farmyard manure, inorganic fertilizers and weed control practices

on some soil physical properties in a long-term experiment. Soil

Use Manag 14:52–54

25. Nimmo JR (2004) porosity and pore size distribution. In: Hillel D

(ed) Encyclopedia of soils in the environment, vol 3. Elsevier,

London, pp 295–303

26. Bavel Van (1950) Mean weight-diameter of soil aggregates as a

statistical index of aggregation. Proceedings Soil Sci Soc Am J

14:20–23

27. Fernandes JC, Gamero CA, Rodrigues JGL, Miras-Avalos JM

(2011) Determination of quality index of a Paleudult under

sunflower culture and different management systems. Soil Tillage

Res 112:167–174

28. Mohanty M, Painuli DK, Misra AK, Ghosh PK (2007) Soil

quality effects of tillage and residue under rice–wheat cropping

on a Vertisol in India. Soil Tillage Res 92:243–250

18 N. K. Sinha et al.

123