Long-term rice-based cropping system effects on near-surface soil compaction

doi:10.4236/as.2011.22017

Paper Menu >>

Journal Menu >>

Vol.2, No.2, 117-124 (2011)

doi:10.4236/as.2011.22017

Agricultural Sciences

Long-term rice-based cropping system effects on

near-surface soil compaction

Jill M. Motschenbacher, Kristofor R. Brye*, Merle M. Anders

Department of Crop, Soil, and Environmental Sciences, University of Arkansas, Fayetteville, USA;

*Corresponding Aut hor: kbrye@uark.edu

Received 7 February 2011; revised 3 March 2011; accepted 30 March 2011.

ABSTRACT

Irrigated rice (Oryza sativa L.) production is as-

sociated with frequent cycling between anaero-

bic and aerobic conditions, which can lead to a

greater rate of soil organic matter (SOM) decom-

position, thus potentially increasing soil bulk de-

nsity (BD) over time. A study was conducted in

the Mississippi River Delt a region of eastern Ark-

ansas, USA to evaluate the long-term effects of

rice-based crop rotations, tillage [conventional

tillage (CT) and no-tillage (NT)], soil fertility re-

gime (optimal and sub-optimal), and soil depth

(0-10 and 10-20 cm) after 10 years of consistent

management on near-surface soil compaction,

as measured by BD. Soil BD was greater under

NT than CT in the top 10 cm, but was similar

between NT and CT in the 10- to 20-cm depth

interval. Soil BD differed among common rice-

based cropping systems with corn, soybean,

and winter wheat, but few consistent trends

were evident. It appears that, even after 10 years

of continuous CT or NT rice production on a silt-

loam soil, substantially increased near-surface

soil BD has not occurred to the point where soil

compaction would be a likely culprit respon-

sible for a reduced early season stand estab-

lishment or crop yield differences among rice-

based copping systems.

Keywords: Bulk Density; Crop Rotation; Soil

Organic Matter; Tillage

1. INTRODUCTION

The enhancement of soil quality is vital to sustaining

and improving long-term agricultural productivity, na me ly

crop yields [1,2]. Soil bulk density (BD), the ratio of the

dry soil mass to th e volume it occup ies, is often one of a

suite of measured soil properties that is an indicator of

soil quality [1,3,4 ]. Soil BD is related to soil compaction

in that BD is relatively greater in compacted than in

non-compacted soil. Compacted soil with a relatively

large BD can negatively affect numerous soil and plant

properties and processes. Soil BD has been shown to be

directly related to soil streng th [5-9] and soil penetration

resistance [10-14], which is another soil property that is

often used to quantify soil compaction. In contrast, soil

BD has been shown to be inversely related to soil or-

ganic matter (SOM) [6,15], water-holding capacity [6,14,

16], soil particle size [17], total porosity [18-20], infil-

tration capacity [6,21,22], hydraulic co nductivity [14,18,

20], gas exchange [23], nutrient mobility [6,24], and

invertebrate movement [12,25]. Similarly, soil BD has

been shown to be inversely related to seedling emer-

gence [19,26] and root penetration [6,12,14,16], both of

which can negatively affect yield if soil compaction is

severe.

Soil BD has also been shown to be affected by several

crop management practices, particularly tillage and crop

rotation [14,27-30]. Soil BD is generally greater under

reduced tillage, specifically no-tillage (NT), due to ma-

chinery traffic and the lack of surface soil disruption and

mixing accomplished by annual plowing [16,18,20,29,

31,32]. Since soil BD has been shown to be inversely

related to SOM [6,15], where increasing SOM generally

decreases soil BD by adding additional pore space

without adding much additional mass, crop rotations

with a large frequency of high-residue-producing crops

that are managed using cultural practices that return crop

residues to the soil could consequently at least maintain

a near-surface soil BD that is favorable for gas exchange,

water infiltration, and plant growth.

Rice (Oryza sativa L.) is one of several high-residue-

producing crops, along with corn ( Zea mays L.) and win-

ter wheat (Triticum aestivum L.), that is capable of pro-

ducing 8.1 Mg·ha–1 of above-ground biomass under op-

timal nitrogen fertilization [33,34]. Of the roughly 1.2

million ha of rice planted and 9.3 million Mg of rice

grain produced in the United States annually, over 46%

of the total rice area (566,800 ha) and over 45% of the

J. M. Motschenbacher et al. / Agricultural Sciences 2 (2011) 117-124

118

total grain production (4.2 million Mg) occur in th e Mis-

sissippi River Delta region of eastern Arkansas [35].

However, rice is unlike all other row crops in that rice is

most frequently grown under flood-irrigated conditions

after about one month post-emergence, where the upper-

most part of the soil profile is nearly to co mpletely satu-

rated [36]. To harvest rice, the flood must be released

several weeks prior to the targeted harvest window in

order to allow the soil to drain and dry out to achieve

enough structural stability to support heavy harvesting

machinery. If the soil is too wet and not sufficiently dry

to provide structur al support for a large harvest combine,

rice fields are often severely rutted, which can result in

elevated soil BD and compaction in many areas of a

field [37].

Furthermore, the decomposition of SOM is generally

slower in waterlogged soil than in well-aerated soil [2,

36]. However, flood-irrigated rice fields are unique from

other wetland soils in that they are often relatively dry

between successive rice crops in the rotation. Aerobic

soil conditions also exist during the dry periods between

flooding and heavy precipitation, which stimulates the

rapid breakdown of accumulated SOM. This decline in

SOM can, in turn, adversely affect soil productivity, soil

quality, and the overall sustainability of rice production

[38]. The frequent cycling between anaerobic and aero-

bic conditions can potentially lead to a greater rate of

SOM decomposition [39], which could essentially in-

crease the BD of the soil. Increasing soil BD over time is

a reasonable concern because compacted soil may hinder

short-term plant growth and long-term crop yield.

Since the nature of soil physical properties are gener-

ally of little concern during a rice crop-growing season

due to the flooded-soil conditions, relatively few studies

have examined the potential effects of rice rotations on

soil physical properties, particularly soil BD. Therefore,

the objective of this study was to evaluate the long-term

effects of rice-based crop rotations, tillage [conventio nal

tillage (CT) and no-tillage (NT)], soil fertility regime

(optimal and sub-optimal), and soil depth (0-10 and 10-

20 cm) after 10 years of consistent management on near-

surface soil compaction, as measured by soil BD, in the

Mississippi River Delta region of eastern Arkansas. It

was hypothesized that soil BD would be i) similar

among soil depths under CT due to the mixing action of

mechanical cultivation, but greater in the 10-20 than in

the 0-10 cm depth interval under NT, ii) different among

rice-based cropping systems and that the difference

would be related to the frequency of rice and other

high-residue-producing crops in the rotation, and iii)

generally lower under optimal than sub-optimal fertiliza-

tion due to greater SOM.

2. SITE DESCRIPTION

This study was conducted at the University of Arkan-

sas Rice Research and Extension Center (RREC) near

Stuttgart, AR (34o27' N, 91o24' W), which is located in

the Mississippi River Delta region of eastern Arkansas in

an area known as the Grand Prairie. This study was ini-

tiated in 1999 on a Dewitt silt loa m (fine, smectitic, ther-

mic, Typic Albaqualf) [40], which is characteristic of

Grand Prairie soils used for rice production.

Prior to 1999, the study area had been fallow for sev-

eral years due to a lack of irrigation capability. Vegeta-

tion present consisted of a mixture of grasses and weeds

that were managed by periodic mowing during the

summer. In preparation for this study, the site was

land-leveled to a 0.15% grade in fall 1998. Land-level-

ing consisted of removing and piling the top 10 cm of

soil off to the side of the area to be leveled, cutting the

field to grade, and redistributing the topsoil uniformly

over the field. Land-leveling is a common practice in the

Mississippi River Delta region, especially in areas where

rice production dominates, to facilitate uniform distribu-

tion of flood-irrigation water [41].

The climate of the region is warm and wet with a

30-yr mean annual temperature minimum of 0.22˚C in

January and maximum of 33.1˚C in July. The 30-yr

mean annual precipitation is 131.6 cm [42].

3. FIELD TREATMENTS AND EXPERI-

MENTAL DESIGN

This field study consisted of two tillage treatments

[conventional tillage (CT) and no-tillage (NT)], two soil

fertility treatments (optimal and sub-optimal), and 10

rice-cropping systems arranged in a randomized com-

plete block with four replications (i.e., blocks) of treat-

ment combinations. Each block occupied an area of 120-

m long by 76-m wide (9120 m2). Soil fertility treatments

were imposed as a split of each tillage treatment, while

the rice rotations were horizontally stripped across the

tillage-fertility combinations. Each tillage-fertility-rota-

tion combination represented the experimental unit and

had dimensi on s of 19 - by 6- m.

The optimal soil fertility treatment followed a stan-

dard fertility recommendation based on the analysis of

soil samples that were collected in sp ring 1999 (Table 1).

The annual soil fertility treatment consisted of P2O5 ap-

plied as triple super phosphate and K2O applied as muri-

ate of potash, with both fertilizers broadcast pre-plant

and pre-tillage with a spreader. Nitrogen as urea was

applied with a hand-spreader pre-flood at the 5-leaf stage

of rice growth approximately one month after planting.

Phosphorous and potassium were incorporated into the

soil under CT and were left at the surface under NT.

J. M. Motschenbacher et al. / Agricultural Sciences 2 (2011) 117-124

119

Table 1. Summary of the N, P

2O5, and K2O added to corn,

soybean, rice, and wheat to comprise the sub-optimal and op-

timal soil fertility treatments in a long-term rotation study at

the RREC near Stuttgart, AR on a silt-loam soil.

Soil Fertility (kg·ha–1)

Crop Nutrient

Sub-Optimal Optimal

N 224 337

P2O5 67 90

Corn

K2O 112 168

N 0 0

P2O5 45 67

Soybean K2O 67 135

N 112 168

P2O5 45 67

Rice K2O 67 101

N 112 168

P2O5 34 67

Wheat K2O 34 67

Following nitrogen fertilization, a 5- to 10-cm deep

permanent flood was established, which was maintained

annually on all of the rice plots until the rice reached

physiological maturity. All other summer crops present

in a given year were furrow-irrigated on an as-needed

basis approximately 3 to 4 times annually, which was

effectively based on the amount of rainfall received and

the growth of the crop. Winter wheat was rain fed only

without irrigation.

Crop varieties included in the rotation treatment of

this study consisted of the maj or agronomic crops grown

in Arkansas. Crop rotations included: continuous rice (R),

rice-soybean (RS), soybean-rice (SR), rice-corn (RC),

corn-rice (CR), rice (winter wheat) [R(W)], rice (winter

wheat)-soybean (winter wheat) [R(W)S(W)], soybean

(winter wheat)-rice (winter wheat) [S(W)R(W)], rice-

soybean-corn (RSC), and rice-corn-soybean (RCS).

‘Wells’ was the rice cultivar grown based on its local

popularity among rice producers. Rice, soybean, and

wheat were sown into 19-cm rows in tillage treatments

using an Almaco NT drill (Almaco, Nevada, IA). The

rice was drill-seeded at a rate of 100 kg seed ha–1, soy-

bean at a rate of 56 kg seed ha–1, and wheat at a rate of

67 kg seed ha–1. Corn was planted in 76-cm rows at a

plant populat i o n of 79,040 seeds ha–1 [43].

Rice management practices closely followed the Uni-

versity of Arkansas Cooperative Extension Service rec-

ommendations for stand establishment, irrigation man-

agement, and pest management [44]. In CT plots, crop

residues were burned and incorporated into the soil gen-

erally one to two months following harvest by disking

twice. Prior to planting in the spring, plots were tilled by

disking once, followed by multiple passes of a light field

cultivator (i.e., Triple-K) to achieve the desired seedbed

for rice planting. In NT plots, crop residues were left on

the surface after harvest and were not manipulated by

any means prior to planting in the spring.

Weed management for rice [44], soybean [45], corn

[46], and wheat [47] followed recommendations made by

the Arkansas Cooperative Service. Weed management for

rice consisted of a pre-emergence application of 0.34

kg·ha–1 of clomazone [2-[(2-chlorobenzyl)methyl]-4, 4-

dimethyl-3-isoxaolidinone] and a post-emergent applica-

tion of halosulfuron [3-chloro-5-[[[[(4,6-dimethoxy-2-

pyrimidinyl)amino]carbonyl]amino]sulfonyl]-1-methyl-

1H-pyrazole-4-carcoxylic acid] at 0.06 kg·ha–1 for both

tillage treatmen ts. Soybean and corn were treated of 0.06

kg·ha-1 of glyphosate [N-(phosphonomethyl)glycine] in

the spring and applications of paraquat [1,1’-dimethyl-4,

4’-bipyridinium ion] and flumioxazin [2-[7-fluro-hydro-3

-oxo-4-(2-propynyl)-2H-1,4-benzoxazin-6-yl]-4,5,6,7-tet-

rahydro-1H-isoindole-1,3(2H)-dione] in the fall follow-

ing harvest and winter-wheat planting. Corn also received

a treatment of 2.3 L·ha–1 of glufosinate-ammonium [2-

amino-4-(hydroxymethylphosphinyl)butanoic acid mono-

ammonium salt] and 0.07 L·ha–1 of halosulfuron [3-

chloro-5-[[[[(4,6-dimethoxy-2-pyrimidinyl)amino]carbo-

nyl]amino]sulfonyl]-1-methyl-1H-pyrazole-4-carcoxylic-

acid]. Wheat was treated with 0.35 L·ha–1 of mesosulfu-

ron-methyl [methyl 2-[[[[(4,6-dimethoxy-2-pyrimidinyl)

amino]car-bonyl]amino]sulfonyl]-4-[[(methylsulfonyl)a-

mino]methyl] benzoate].

4. SOIL SAMPLING

At the time of soil sampling, the R an d R(W) rotations

had produced a total of 10 rice crops, the RS, SR, RC,

CR, R(W)S(W), and S(W)R(W) rotations had produced

five rice crops with five crops in the respective rotation

with corn or soybean, and the RSC and RCS rotations

had produced four rice crops with three crops in the re-

spective rotations with corn and soybean (Table 2). Fur-

thermore, the plots that were rotated with winter wheat

produced a total of 10 wheat crops. The CT treatment

was imposed on all plots five months (late-October 2008)

prior to soil BD sampling. Soil BD samples were col-

lected in mid-March 2009 from the 0- to 10- and 10- to

20-cm depth intervals using a 4.7-cm diameter, stainless

steel core chamber that was beveled to the outside to

minimize compaction upon sampling. One BD sample

was collected from each depth (0- to 10-cm and 10- to

20-cm) per plot at a random location between previously

planted rows, for a total of 320 samples. Soil samples

were oven-dried at 70˚C for 3 days and weighed to de-

termine soil BD by dividing the oven-dry soil mass by

the sample volume. After weighing, samples were grou nd

to pass a 2-mm mesh screen to determine SOM concen-

tration by wei g ht -l oss-on-ignition at 360˚C for 2 hours.

Though soil BD was not measured at the onset of the

study in spring 1999, land-leveling activities uniformly

affected the entire study area and 10 years of consistent

J. M. Motschenbacher et al. / Agricultural Sciences 2 (2011) 117-124

120

Table 2. Summary of the crop rotations and the number of rice

crops and the respective rotations grown during the 10-yr study

period at the RREC near Stuttgart, AR on a silt-loam soil.

Crops in parentheses were grown during the winter.

Number of Crops

Rotation Rice Corn SoybeanWheat

Continuous Rice 10 - - -

Rice-Soybean 5 - 5 -

Soybean-Rice 5 - 5 -

Rice-Corn 5 5 - -

Corn-Rice 5 5 - -

Rice-(Wheat) 10 - - 10

Rice-(Wheat)-Soybean-(Wheat) 5 - 5 10

Soybean-(Wheat)-Rice-(Wheat) 5 - 5 10

Rice-Soybean-Corn 4 3 3 -

Rice-Corn-Soybean 4 3 3 -

management has elapsed. Therefore, it was reasonably

assumed that any observed differences in soil BD among

treatment combinations from the 2009 sampling repre-

sented actual treatment effects rather than residual ef-

fects from inherent differences among plots from the

beginning of the study.

5. DATA ANALYSES

The effects of tillage, fertility, crop rotation, soil dep th,

replication and their interactions on soil BD and SOM

were evaluated by analysis of variance (ANOVA) using

the Mixed Model procedure in SAS (version 9.2, SAS

Institute, Inc., Cary, NC). When appropriate, means were

separated using Fisher’s protected least significant dif-

ference (LSD) at the 0.05 level. In addition, linear cor-

relation analyses were conducted to identify the rela-

tionship between soil BD and SOM for each soil depth

interval separate and combined within rotation treat-

ments (version 13.31, Minitab, Inc., State College, PA).

6. RESULTS AND DIS CUS SION

After 10 years of consistent rotation and fertility

management and nine years of CT or NT, soil BD was

affected by all treatments evaluated in this study. Statis-

tical analyses showed that soil BD differed among till-

age-soil depth treatment combinations (P = 0.021; Table

3) and rotation-tillage-fertility treat ment combinations (P

= 0.002; Ta ble 3). There were no statistically significant

block effects caused by treatment replications, so all

interactions observed were exclusively a result of the

imposed treatments.

In the 0- to 10-cm depth interval, soil BD was 2.38%

greater (P = 0.021) under NT (1.29 g/cm3) than CT (1.26

g/cm3; Figure 1). Since SOM concentration did not dif-

fer between tillage treatments (Ta ble 3 ), the greater BD

near the soil surface under NT can be explained by the

Table 3. Analysis of variance summary of the effects of tillage,

soil fertility, crop rotation, and soil depth on soil bulk density

(BD) and soil organic matter content (SOM) during the 10-year

rotation study at the RREC near Stuttgart, AR on a silt-loam

soil.

Treatment Effectz BD SOM

_________ P _________

Tillage 0.229 0.110

Fertility 0.452 0.029

Tillage *Fertility 0.797 0.702

Rotation < 0.0010.333

Rotation *Tillage 0.020 0.613

Rotation *Fertility 0.995 0.792

Rotation *Tillage *Fertility 0.002 0.296

Depth 0.001 < 0.001

Depth *Tillage 0.021 0.081

Depth *Fertility 0.598 0.268

Depth *Rotation 0.160 0.050

Depth *Tillage *Fertility 0.767 0.530

Depth *Tillage *Rotation 0.301 0.215

Depth *Fertility *Rotation 0.969 0.078

Depth *Tillage *Fertility *Rotation 0.585 0.765

z Block effects were not significant in both analyses.

lack of soil loosening associated with annual tillage. As

would be expected, soil BD was greater in the 10- to 20-

than in the 0- to 10-cm depth interval under NT (Figure

1). However, in contrast to that expected, soil BD was

also greater in the 10- to 20- than in the 0- to 10-cm

depth interval under CT (Figure 1). Soil BD was similar

in the 10- to 20-cm depth interval between tillage treat-

ments, averaging 1.41 g/cm3 across both tillage treat-

ments (Figure 1). Though the 10- to 20-cm soil depth

interval typically has a greater clay content than in the

top 10 cm in the alluvial soils of the Mississippi River

Delta region of eastern Arkansas, and since soil BD has

been shown to be directly related to clay content [17], it

appears that the mixing of soil due to mechanical culti-

vation in CT was not substantial enough to eliminate

dissimilarities among depth intervals as expected. The

elevated BD in 10- to 20-cm depth interval in CT, in

relation to the top 10 cm, can be partially explained by

the presence of a prominent plow pan within the sam-

pled depth. A prominent plow layer of approximately the

10 cm depth is common throughout much of the row-

crop cultivated area in the Delta region of eastern Ar-

kansas due the long h istory of annual mechanical disrup-

tion by tillage [48]. The assumption of a plow pan pre-

sent in CT plots is consistent with previous observations

made in this same study in spring 2006, which showed

that CT had significantly greater penetration resistance

than to NT beginning at the 12.7-cm depth (P < 0.001)

and continuing through the 25.4-cm depth (P = 0.031)

[43].

A subsurface compacted layer can be created when

fine soil particles dispersed during tillage settle into

spaces of the soil matrix that were previously occupied

J. M. Motschenbacher et al. / Agricultural Sciences 2 (2011) 117-124

121

Table 4. Crop rotation-soil depth treatment combination effects

on soil organic matter percentage averaged across tillage and

fertility treatments after 10 years of consistent management.

Crops included rice (R), soybean (S), corn (C), and winter

wheat (W). Soil depths included 0-cm to 10-cm and 10-cm to

20-cm.

Soil Organic Matter (%)a

Rotation 0-10 cm 10-20 cm

R 2.085 1.428

RS 1.952 1.533

SR 1.982 1.479

RC 2.152 1.473

CR 2.237 1.499

R(W) 2.388 1.528

R(W)S(W) 2.192 1.535

S(W)R(W) 2.201 1.469

RSC 2.117 1.446

RCS 1.984 1.478

Figure 1. Tillage and soil depth effects on soil bulk density

averaged across crop rotations and soil fertility levels after 10

years of consistent management. Tillage treatments included

no-tillage (NT) and conventional tillage (CT). Bars with dif-

ferent letters are significantly different at the 0.05 level. a.The least significan t difference at t he 0.05 l evel (LSD0.05) to co mpare

among different rotations at the same depth is 0.240. All values of the

same rotation with a different depth and different rotation with a dif-

ferent depth are significantly different.

by air, thus elevating soil BD. Furthermore, this subsur-

face compacting effect of the soil can be increased by

repeated machinery traffic [20] and prolonged flooded

conditions for rice production, which causes the slaking

of soil aggregates [49].

(1.38 g·cm–3) than NT (1.33 g·cm–3) in both soil fertility

regimes (Ta ble 5), which, as mentioned previously, may

presumably be caused by the settlement of fine soil par-

ticles as a result of soil disruption from tilla ge combined

with flooded growing conditions. This outcome suggests

that greater BD associated with negative effects on plant

growth and/or yield may have a greater tendency to de-

velop in time under CT than under NT regardless of soil

fertility regime. In addition, compared to contin uous NT

(R) (1.33 g·cm–3), soil BD was 3.00% greater in the NT

R(W) rotation (1.37 g·cm–3) under both soil fertility re-

gimes and SOM was greater in the R(W) rotation in the

0- to 10-cm depth (2.388%) under both tillage treatments

and fertility regimes than (R) (2.085%; Table 4). This

result demonstrates that, despite producing a greater

amount of aboveground residue in the R(W) rotation

compared to continuous rice due to twice the number of

high-residue-producing crops per year (Table 2), the

effects of greater surface SOM decreasing soil BD are

not quickly realized. However, with twice the number of

crops grown per year, the R(W) rotation also experi-

enced twice the number of machinery passes compared

to continuous rice, so the elevated BD in the R(W) rota-

tions may possibly be associated with compaction due to

machinery traffic. Furthermore, penetration resistance

data collected in 2006 showed that the R(W) rotation

had greater resistance in the 5- to 15-cm depth (ranging

from 2.5 to 4.4 MPa) than any other rotation in the study,

whereas the CR rotation had the lowest resistance

(ranging from 1.6 to 2.8 MPa) over the same depth

Another possible contribution to greater BD in 10-to

20-cm depth in both tillage treatments was likely related

to numerically lower SOM compared to the top 10 cm.

Similar to previous research [6,15], the SOM concentra-

tion was 43.17% greater in the 0- to 10- (2.129%) than

in the 10- to 20-cm depth (1.487%) when averaged

across all other treatment combinations (P < 0.001; Ta-

ble 3; Table 4). Although SOM concentration did not

differ significantly among tillage treatments, there was a

significant interaction effect between crop rotation and

sampling depth on SOM (P < 0.050; Tab le 3). Soil OM

differed among crop rotations in the top 10 cm, but was

similar among all crop rotations in the 10- to 20-cm

depth interval. Overall, soil BD magnitudes measured in

this study were well-below the typical 1.60 g/cm3

threshold at which root penetration has been reported to

become limited when the soil is dry [17]. The results of

this study were similar to those reported from a 3-yr

rice-wheat rotation in a sandy-loam soil in Ind ia [50 ] and

from a rice-rotation study in a clay-loam soil in India

[51].

Averaged across soil depth, soil BD also differed (P =

0.002) among rotation-tillage-fertility treatment combi-

nations (Table 3). However, few consistent trends

among treatment combinations and their effect on soil

BD existed. It is interesting to note that after 10 years of

continuous rice, soil BD was 3.76% greater under CT

Openly accessible at

J. M. Motschenbacher et al. / Agricultural Sciences 2 (2011) 117-124

122

Ta b le 5 . Crop rotation-tillage-fertility treatment combination effects on soil bulk density averaged across soil depths after

10 years of consistent management. Crops included rice (R), soybean (S), corn (C), and winter wheat (W). Tillage treatments

included no-tillage and conventional tillage. Soil fertility treatments included optimal and sub-optimal.

Soil Bulk Density (g/cm3) a

No-Tillage Conventional Tillage

Rotation

Optimal Sub-Optimal Optimal Sub-Optimal

R 1.32 1.35 1.37 1.39

RS 1.39 1.41 1.34 1.35

SR 1.36 1.36 1.32 1.34

RC 1.38 1.35 1.35 1.36

CR 1.31 1.36 1.33 1.30

R(W) 1.35 1.39 1.37 1.34

R(W)S(W) 1.40 1.37 1.35 1.39

S(W)R(W) 1.33 1.34 1.30 1.32

RSC 1.34 1.33 1.32 1.32

RCS 1.34 1.32 1.33 1.35

aThe least si g ni ficant differen ce at t h e 0.05 lev el ( LSD0.05) to compare among same tillage, same fertility, and different rotation combinations is 0.04.

The LSD0.05 to compare among same tillage, different fertility, and same rotation combinations is 0.04. The LSD0.05 to compare among different

tillage, same or different fertility, and same rotation combinations is 0.03. The LSD0.05 to compare among same tillage, different fertility, and differ-

ent rotation combinations is 0.07. The LSD0.05 to compare among different tillage, same or different fertility, and different rotation combinations is

0.05.

interval [43]. The greater resistance in the R(W) was re-

ported to be caused from a lack of a strong, deep-penetra-

ting root system as is present in the CR rotation [43].

With the exception of in the CR rotation under NT,

where soil BD was greater with the sub-optimal than

with the optimal soil fertility regime, soil fertility regime

did not affect soil BD within tillage treatments in any

rotation (Table 5). Despite differences from the hy-

pothesized outcome of BD in relation to fertility level,

SOM concentration was 4.18% greater in optimal

(1.845%) than in the sub-optimal (1.771%) fertility re-

gime (P = 0.029). Soil BD within the same fertility re-

gime differed between tillage treatments in all rotations

except in the RC, S(W)R(W) and RCS rotations (Table

5). In contrast to that hypothesized, soil BD was unre-

lated to the number of times a rice or high-residue-

producing crop (i.e., rice, corn, and wheat; Table 2) was

grown over the 10-yr study period in either soil depth

interval separately or averaged across both soil depths.

However, as might be expected, SOM concentration was

highly correlated with the number of times a high-

residue-producing crop (i.e., rice, corn, and wheat; Table

2) was grown over the 10-yr study period in the top 10

cm (r = 0.89, P = 0.001) an d when averaged across bo th

soil depths (r = 0.90, P < 0.001).

7. AGRONOMIC IMPLICAT IONS

This study demonstrated that after 10 years of consis-

tent management soil BD was slightly greater under NT

than CT in the top 10 cm, but soil BD was similar be-

tween NT and CT in the 10- to 20-in depth interval.

These results indicate that, despite BD values observed

in this study being lower than the common thresho ld BD

above which it is believed that root penetration is nega-

tively affected, an infrequent deep-tillage operation may

be needed to disrupt the developing zone of relatively

compacted soil below the plow layer under CT. This

study also demonstrated that soil BD differed among

common rice-based cropping systems, but that differ-

ences in near-surface soil BD were not clearly related to

the number of high-residue-producing crops, such as rice,

corn, and wheat, that were produced in a given time pe-

riod. The frequent cycling between relatively dry and

nearly to completely saturated soil conditions over the

course of the rice growing season likely contributes to a

more complex relationship between soil BD and residue

returned to the soil and/or SOM accumulation. It appears

that, even after 10 years of continuous CT or NT rice

production on a silt-loam soil in the Mississippi River

Delta region of eastern Arkansas, sub stantially increased

near-surface soil BD has not developed to the point

where soil compaction would be a likely culprit respon-

sible for potential early season stand establishment or

crop yield differences among rice-based copping sys-

tems.

8. ACKNOWLEDGEMENTS

This research was partially funded by the Arkansas Rice Research

and Promotion Board. Field assistance provided by Terry Sells and

Daniel McCarty is gratefully acknowledged.

REFERENCES

[1] Karlen, D.L., Andrews, S.S., Wienhold, B.J. and Zobeck,

T.M. (2008) Soil quality assessment: Past, present, and

future. Journal of Integrated Biosciences, 6, 3-14.

[2] Pulleman, M.M., Bouma, J., van Esse n, E.A. and Meijles,

J. M. Motschenbacher et al. / Agricultural Sciences 2 (2011) 117-124

123

E.W. (2000) Soil organic matter content as a function of

different land use history. Soil Science Society of America

Journal, 64, 689-693. doi:10.2136/sssaj2000.642689x

[3] Karlen, D.L., Mausbach, M.J., Doran, J.W., Cline, R.G.

Harris, R.F. and Schuman, G.E. (1997) Soil quality: A

concept, definition, and framework for evaluation. Soil

Science Society of America Journal, 61, 4-10.

doi:10.2136/sssaj1997.03615995006100010001x

[4] Wolf, B. and Snyder, G.H. (2003) Sustainable soils: The

place of organic matter in sustainable soils and their

productivity. Food Products Press, New York.

[5] Carter, M.C., Dean, T.J., Wang, Z. and Newbold, R.A.

(2006) Impacts of harvesting and post harvesting treat-

ments on soil bulk density, soil strength, and early

growth of Pinus taeda in the Gulf Coastal Plain: A

long-term soil productivity affiliated study. Canadian

Journal of Forest Research, 36, 601-614.

doi:10.1139/x05-248

[6] Diana, G., Beni, C. and Marconi, S. (2008) Organic and

mineral fertilization: Effects on physical characteristics

and boron dynamic in an agricultural soil. Communica-

tions in Soil Science and Plant Analysis, 39, 1332-1351.

doi:10.1080/00103620802004037

[7] Elliot, W.J., Page-Dumroese, D.S. and Robichaud, P.R.

(1998) The effect of forest management on erosion and

soil productivity. In: Lal, R., Ed., Soil quality and erosion.

St. Lucie Press, Boca Raton, Florida, 195-209.

[8] Page-Dumroese, D.S., Jurgensen, M.F., Tiarks, A.E.,

Ponder, Jr.F., Sanchez, F.G., Fleming, R.L., Kranabetter,

J.M., Powers, R.F., Stone, D.M., Elioff, J.D. and Scott,

D.A. (2006) Soil physical property changes at the North

American long-term soil productivity study sites: 1 and 5

years after compaction. Canadian Journal of Forest Re-

search, 36, 551-564. doi:10.1139/x05-273

[9] Souch, C.A., Martin, P.J., Stephens, W. and Spoor, G.

(2004) Effects of soil compaction and mechanical dam-

age at harvest on growth and biomass production of short

rotation coppice willow. Plant and Soil, 263, 173-182.

doi:10.1023/B:PLSO.0000047734.91437.26

[10] Amuri, N. and Brye, K.R. (2008) Residue management

practice effects on soil penetration in a wheat-soybean

double-crop production system. Soil Science, 173, 779-

791. doi:10.1097/SS.0b013e31818a54b4

[11] Ehlers, W., Köpke, U., Hesse, F. and Böhm, W. (1983)

Penetration resistance and root growth of oats in tilled

and untilled loess soil. Soil and Tillage Research, 3,

261-275. doi:10.1016/0167-1987(83)90027-2

[12] Hirth, J.R., McKenzie, B.M. and Tisdall, J.M. (2005)

Ability of seedling roots of Lolium perenne L. to pene-

trate soil from artificial biospores is modified by soil

bulk density, biospore angle and biospore relief. Plant

and Soil, 272, 327-336.

doi:10.1007/s11104-004-5764-1

[13] Krizek, D.T., Ritchie, J.C., Sadeghi, A.M., Foy, C.D.,

Rhoden, E.G., Davis, J.R. and Camp, M.J. (2003) A

four-year study of biomass production of eastern gama-

grass grown on an acid compact soil. Communications in

Soil Science and Plant Analysis, 34, 457-480.

doi:10.1081/CSS-120017832

[14] Lampurlanés, J. and Cantero-Martínez, C. (2003) Soil

bulk density and penetration resistance under different

tillage and crop management systems and their relation-

ship with barley root growth. Agronomy Journal, 95,

526-536. doi:10.2134/agronj2003.0526

[15] Son, Y., Yang, S.Y., Jun, Y.C., Kim, R.H., Lee, Y.Y.,

Hwang, J.O. and Kim, J.S. (2003) Soil carbon and nitro-

gen dynamics during conversion of agricultural lands to

natural vegetation in central Korea. Communications in

Soil Science and Plant Analysis, 34, 1511-1527.

doi:10.1081/CSS-120021293

[16] Karamanos, A.J., Bilalia, D. and Sidiras, N. (2004) Ef-

fects of reduced tillage and fertilization practices on soil

characteristics, plant water status, growth and yield of

upland cotton. Journal of Agronomy and Crop Science,

190, 262-276. doi :1 0. 1111/ j.1439-037X.2004.00101.x

[17] Brady, N.C. and Weil, R.R. (2008) The nature and prop-

erties of soil, 14th Edition, Prentice-Hall, Upper Saddle

River, New Jersey.

[18] Afyuni, M. and Wagger, M.G. (2006) Soil physical prop-

erties and bromide movement in relation to tillage system.

Communications in Soil Science and Plant Analysis, 37,

541-556. doi:10.1080/00103620500449393

[19] Chan, K.Y. (2002) Bulk density. In: Lal, R. Ed., Ency-

clopedia of Soil Science, Marcel Dekker, New York,

128-130.

[20] Mahboubi, A.A., Lal, R. and Fausey, N.R. (1993)

Twenty-eight years of tillage effect on two soils in Ohio.

Soil Science Society of America Journal, 57, 506-512.

doi:10.2136/sssaj1993.03615995005700020034x

[21] Radcliffe, D.E., Toller, E.W. and Hargrove, W.L. (1988)

Effect of tillage practice on infiltration and soil strength

of a Typic Hapludult soil after ten years. Soil Science So-

ciety of America Journal, 52, 798-804.

doi:10.2136/sssaj1988.03615995005200030036x

[22] Vervoort, R.W., Dabney, S.M. and Romkens, M.J.M.

(2001) Tillage and row position effects on water and sol-

ute infiltration characteristics. Soil Science Society of

America Journal , 65, 1227-1234.

doi:10.2136/sssaj2001.6541227x

[23] Khan, A.R., Chandra, D., Quraishi, S. and Sinha, R.K.

(2000) Soil aeration under different soil surface condi-

tions. Journal of Agronomy and Crop Science, 185, 105-

112. doi:10.1046/j.1439-037X.2000.00417.x

[24] Girma, K., Martin, K.L., Anderson, R.H., Arnall, D.B.,

Brixey, K.D., Casillas, M.A., Chung, B., Dobey, B.C.,

Kamenidou, S.K., Kariuki, S.K., Katsalirou, E.E., Morris,

J.C., Moss, J.Q., Rohla, C.T., Sudbury, B.J., Tubana, B.S.

and Raun, W.R. (2006) Mid-season prediction of

wheat-grain yield potential using plant, soil, and sensor

measurements. Journal of Plant Nutrition, 29, 873- 897.

doi:10.1080/01904160600649187

[25] Townshend, J.L. and Webber, L.R. (1971) Movement of

Pratylenchus penetrans and moisture characteristics of

three Ontario soils. Nematologica, 17, 47-57.

doi:10.1163/187529271X00404

[26] Soyelu, L.O., Ajayi, S.A., Aluko, O.B. and Fakorede,

A.B. (2001) Varietal differences in development of maize

(Zea mays L.) seedlings on compacted soils. Journal of

Agronomy and Crop Science, 186, 157-166.

doi:10.1046/j.1439-037X.2001.00467.x

[27] Cassel, D.K., Raczkowski, C.W. and Denton, H.P. (1995)

Tillage effects on corn production and soil physical

properties. Soil Science Society of America Journal, 59,

1436-1443.

J. M. Motschenbacher et al. / Agricultural Sciences 2 (2011) 117-124

124

doi:10.2136/sssaj1995.03615995005900050033x

[28] Grevers, M.C.L. and Bomke, A.A. (1986) Tillage prac-

tices on a northern clay soil: Effect of sod breaking

methods on crop production and soil physical properties.

Canadian Journal of Soil Science, 66, 385-395.

doi:10.4141/cjss86-041

[29] Lal, R., Mahboubi, A.A. and Fausey, N.R. (1994)

Long-term tillage and rotation effects on soil properties

of a central Ohio soil. Soil Science Society of America

Journal, 58, 517-522.

doi:10.2136/sssaj1994.03615995005800020038x

[30] NeSmith, D.S., Radcliffe, D.E., Hargrove, W.L., Clark,

R.L. and Toller, E.W.. (1987) Soil compaction in dou-

ble-cropped wheat and soybean on an Ultisol. Soil Sci-

ence Society of America Journal, 51, 183-186.

[31] Myers, J.L. and Wagger, M.G. (1996) Runoff and sedi-

ment loss from tillage systems under simulated rainfall.

Soil and Tillage Research, 39, 115-129.

doi:10.1016/S0167-1987(96)01041-0

[32] Wagger, M.G. and Denton, H.P. (1989) Influence of cover

crop and wheel traffic on soil physical properties in con-

tinuous no till corn. Soil Science Society of America

Journal, 53, 1206-1210.

doi:10.2136/sssaj1989.03615995005300040036x

[33] United States Department of Agriculture (USDA) (2009)

Crop Explorer: United States—area, yield, and produc-

tion.

http://www.pecad.fas.usda.gov/cropexplorer/default_pop

win.cfm?obj_name=util/new_get_psd_data.cfm&regioni

d=us.

[34] Wilson, C.E.Jr. and Runsick, S.K. (2008) Trends in rice

production. In: Norman, R., Meullenet, J.-F. and

Moldenhauer, K.A.K., Eds., B. R. Wells, Rice Research

Studies 2007, Research Series 560, University of Arkan-

sas Agricultural Experiment Station, Fayetteville, 11-20.

[35] National Agricultural Statistics Service (NASS) (2009)

U.S. and all states data—Crops: Planted, harvested, yield,

production, price (MYA), value of production.

http://www.nass.usda.gov/Data_and_Statistics/Quick_Stats/.

[36] Norman, R.J., Wilson, C.E.Jr. and Slaton, N.A. (2003)

Soil fertilization and mineral nutrition in U.S. mecha-

nized rice cu lture. In: Smit h, C.W. and Dilday, R.H., Eds.,

Rice: Origin, History, Technology, and Production, John

Wiley & Sons, Inc., New Jersey, 331-411.

[37] Lima, A.C.R., Hoogmoed, W.B., Pauletto, E.A. and Pinto,

L.F.S. (2009) Management systems in irrigated rice af-

fect physical and chemical properties. Soil and Tillage

Research, 103, 92-97. doi:10.1016/j.still.2008.09.011

[38] Salinas-Garcia, J.R., Hons, F.M. and Matocha, J.E. (1997)

Long-term effects of tillage and fertilization on soil or-

ganic matter dynamics. Soil Science Society of America

Journal, 61, 152-159.

doi:10.2136/sssaj1997.03615995006100010023x

[39] Xu, Y., Chen, W. and Shen, Q. (2007) Soil organic car-

bon and nitrogen pools impacted by long-term tillage and

fertilization practices. Communications in Soil Science

and Plant Analysis, 38, 347-357.

doi:10.1080/00103620601172332

[40] National Resources Conservation Service (NRCS) (2008).

Web soil survey. Data from survey from November 12,

2008.

http://websoilsurvey.nrcs.usda.gov/app/WebSoilSU-vey.a

spx.

[41] Brye, K.R., Slaton, N.A. , Savin, M.C., Norman, R.J. and

Miller, D.M. (2003) Short-term effects of land leveling

on soil physical properties and microbial biomass. Soil

Science Society of America Journal, 67, 1405-1417.

doi:10.2136/sssaj2003.1405

[42] Southern Region Climate Center (SRCC) (2009) Tem-

perature (F) and precipitation (in) normals (1971-2000):

Stuttgart 9 ESE. Louisiana State University. Baton Rouge,

Baton Rouge.

http://www.srcc.lsu.edu/stations/index.php?action=meta

&network_station_id=030240.

[43] Schmid, B.T. (2008) Conservation tillage effects on soil

physical and chemical properties in rice production in the

Arkansas delta. Master’s Thesis, University of Arkansas,

Fayetteville.

[44] Slaton, N.A. (2001) Rice production handbook. Hand-

book. MP 192. University of Arkansas Cooperative Ex-

tension Service, Little Rock.

[45] Ashlock, L. (2000) Arkansas soybean handbook. Hand-

book. MP 197. University of Arkansas Cooperative Ex-

tension Service, Little Rock.

[46] Espinoza, L. and Ross, J. (2003) Corn production hand-

book. Handbook. MP 437. University of Arkansas Coop-

erative Extension Service, Little Rock.

[47] Johnson, W.F.Jr. (1999) Arkansas wheat production and

management. Handbook. MP 404. University of Arkan-

sas Cooperative Extension Service, Little Rock.

[48] Harper, T.W., Brye, K.R., Daniel, T.C., Slaton, N.A. and

Haggard, B.E. (2008) Land use effects on runoff and wa-

ter quality on an eastern Arkansas soil under simulated

rainfall. Journal of Sustainable Agriculture, 32, 231-253.

doi:10.1080/10440040802170806

[49] Hillel, D. (2004) Introduction to soil physics. Elsevier

Academic Press, San Diego.

[50] Gangwar, K.S., Singh, K.K., Sharma, S.K. and Tomar,

O.K. (2006) Alternative tillage and crop residue man-

agement in wheat after rice in sandy loam soils of

Indo-Gangetic plains. Soil and Tillage Research, 88,

242-252. doi:10.1016/j.still.2005.06.015

[51] Kar, G. and Kumar, A. (2009) Evaluation of post-rainy

season crops with residual soil moisture and different

tillage methods in rice fallow of eastern India. Agricul-

tural Water Management, 96, 931-938.

doi:10.1016/j.agwat.2009.01.002