Vol.2, No.4, 435-442 (2011)
opyright © 2011 SciRes. Openly accessible at http://www.scirp.org/journal/AS/
Agricultural Scienc es
Long-term effect s of management systems on crop yield
and soil physical properties of semi-arid tropics of
Prabhakar Pathak*, Suhas P. Wani, Raghavendra Rao Sudi
International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Andhra Pradesh, India;
*Corresponding Author: p.pathak@cgiar.org
Received 8 September 2011; revised 17 October 2011; accepted 26 October 2011.
Long-term experiments can be used to assess
management induced changes in soil properties
and sustainability of the management system in
terms of the productivity. Such data are scanty,
especially in the semi-arid tropics (SAT) region.
A long-term experiment established in 1976 at
ICRISAT in India on Vertisols with two manage-
ment treatments; improved management (IM),
comprising semi-permanent broadbed and fur-
row (BBF) landform with minimum tillage and
improved cropping practices; and traditional
management (TM) system comprising keeping
the land fallow during the rainy season and
sowing on flat landform during post-rainy sea-
son with traditional cropping practices, was
sampled after 24 and 34 years for soil physical
and hydrological properties. Results showed
that both in short- and long-term the manage-
ment systems had profound effect on crop
yields. Also in the long-term IM and TM man-
agement systems had significant effect on sev-
eral soil physical and hydrological properties.
Throughout the soil profile IM systems had sig-
nificantly low er bulk density, significantly higher
porosity, substantially lower penetration resis-
t ance both at 5 cm (1 and 8 MPa) and 15 cm depths
(8 and 15 MPa), significantly higher infiltration
and sorptivity and significantly larger mean
weight diameter of 4.3 mm compared to 2.8 mm
for soils under TM. However, management sys-
tems had no significant effect on moisture hold-
ing capacities both at 0.033 and 1.5 MPa. Sig-
nificant differences between the improved and
traditional systems were observed in the size and
pattern of soil surface cracks. Over the long-
term, the improved management systems has
very favorable effects on soil physical and hy-
drological properties and on the soil surface
cracking and its patterns, thereby contributing
to higher productivity.
Keywords: Broadbed and Furrow System;
Minimum Tillage; Long-Term Experime nt;
Vertisols are one of the major soil orders found in the
semi-arid tropics (SAT). Due to unreliable and variable
rainfall, proneness to water logging, difficulty in tillage
operations due to sticky nature of wet soils and risk
aversion of farmers in many rainfall zones in Indian SAT,
Vertisols are kept fallow in the rainy season [1].
Crops are grown only in post-rainy season on the stored
moisture in the soil profile. The implications of the rainy
season fallow system are serious both in terms of the
overall productivity and with regard to the frequent oc-
currence of large quantities of runoff and soil loss [2].
The lack of vegetative cover during most of the rainy
season exposes the surface soil to the impact of high
intensity storms, causing severe soil erosion [3]. The
traditional crop production system often results in low
crop yields, high runoff and soil loss, reduced ground-
water recharge and frequent flooding of the downstream
lands [4].
To develop an improved crop production system that
enables crops to be grown in both the rainy and the post-
rainy seasons, and improves agricultural productivity
and rainwater use efficiency on a sustainable basis, a
long-term experiment was initiated on the Vertisols at
ICRISAT research station, Patancheru in 1976. It was
envisaged that substantial gains in total food production
can be attained if the present post-rainy season cropping
can be replaced by systems that permits growing of two
crops in the rainy and post-rainy seasons. However to
enable cropping during the rainy season, an appropriate
P. Pathak et al. / Agricultural Sciences 2 (2011) 435-442
Copyright © 2011 SciRes. Openly accessible at http://www.scirp.org/journal/AS/
tillage and land and water management system that re-
duces the problem of water logging and allow timely till-
age operations was essential. The semi-permanent broad-
bed and furrow system with minimum tillage (BBF/MT)
was found appropriate for the in-situ soil and water con-
servation and reducing water logging problem in these
Vertisols [5]. Long-term experiments with BBF/MT along
with other improved cropping practices, have clearly
demonstrated that advantages and profitability of this
improved system [6,7]. There was also clear evidence of
increased soil organic C, total N and P, available N, P
and K, and microbial biomass C and N in the soil under
improved management system [8].
The objective of this study was to assess the long-term
effects of the improved management system (BBF/MT
with improved cropping practices) and traditional man-
agement system (flat cultivation with traditional tillage
and cropping practices) system on crop yields, physical
and hydrological properties of the Vertisols. The effects
of management systems on soil surface cracking and its
pattern in the Vertisols were also studied. The implica-
tions of these changes in physical and hydrological
properties and cracking pattern for tillage, soil and water
management and crop productivity are discussed.
2.1. Experimental Site
The experiments were conducted in two adjacent
small Vertisol watersheds [3.5 ha Black soil Watershed 1
(BW1) and 3.2 ha Black soil Watershed 4C (BW4C)] to
evaluate the long-term effect of tillage and crop manage-
ment systems on crop productivity and soil quality at IC-
RISAT Center, near Hyderabad, Patancheru, India (17˚36'N,
78˚16'E, 545 m altitude) (Figure 1). Two management
systems (improved and traditional) were studied under
long-term experiments initiated in 1976. The average slope
of the experimental watersheds is about 2.0%.
The mean annual rainfall at the experimental area is
about 800 mm; the average minimum temperature is
17˚C and maximum temperature is 32˚C. Rainfall is
variable temporally and during the experimental period
(1976-2009) annual rainfall ranged from 518 to 1194
mm. Spells of excess moisture and drought during the
crop-growing period are common. About 80% of annual
rainfall occurs between June and September and is
known as the monsoon or kharif, in which rainfed crops
are grown. The post-rainy winter season from October to
January, also known as rabi, is dry and cool and days are
2.2. Soils
The soils at the experimental site belong to the very
fine, clayey, montmorillonitic, calcareous hyper thermic
family of typic pallusterts and are classified as “Verti-
sols” Kasireddipalli series [4]. These Vertisols are high
in montmorillinitic clay (40% to 64%) and undergo
pronounced shrinkage during drying, resulting in large
cracks that close only after prolonged rewetting. These
soils become hard when dry and sticky when wet. Thus,
tillage operations must coincide with the specific range
of soil water contents at which the soil is trafficable.
Drainage during wet periods in the rainy season can be a
serious problem.
Figure 1. Experimental watersheds (BW1 and BW4C) at the ICRISAT research station, Patancheru, India.
P. Pathak et al. / Agricultural Sciences 2 (2011) 435-442
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2.3. Treatment Details
The details of two management systems are given be-
2.3.1. Improved Management System
(BW1 Waters hed)
This system includes a semi-permanent broadbed and
furrow system with minimum tillage (BBF/MT) only in
the beds along with improved cropping practices [4].
The beds are 1.0 m wide with 0.5 m furrows prepared at
0.6% gradient using a bullock drawn bed-maker mounted
on a tropicultor. Field traffic was confined to the furrows.
Excess rainfall drains along the furrows and is discharges
into grassed waterways [9]. Improved agronomic prac-
tices, viz. use of high-yielding varieties, dry sowing
ahead of the rainy season, nutrient management, inte-
grated pest management and other improved practices,
were followed [8]. In view of the difficult workability of
Vertisols both in the very dry and very wet conditions,
primary tillage was done immediately after the harvest
of post-rainy season crop. Final land preparation was
initiated immediately following initial rains so that the
system is again ready for pre-monsoon sowing of the
next year’s crop.
2.3.2. Traditional Management System
(BW4C Watershed)
In this system the land was left as cultivated bare fal-
low during the rainy season and sorghum and chickpea
were grown as sole crop in the post-rainy season [10].
Sowing was done with a local seed drill on a flat surface
when seedbed moisture was adequate. No chemical fer-
tilizers were applied to the crop, but 10 t·ha–1 of farm-
yard manure (FYM) was broadcasted each alternate year
before land preparation (farmers practice). The land was
ploughed every two years; harrowing was done with a
blade harrow to control weeds.
2.4. Soil and Crop Sampling
After 24 (April 1999) and 34 years (April 2009) of
experimental cycles, both watersheds (BW1 and BW4C)
were sampled for detailed physical and hydrological
properties of two profile pits were dug in each watershed
and three replicated samples were collected for texture,
bulk density, and porosity measurements from each pit
up to 1.2 m depth at increments of 15 cm [11]. The soil
samples from both the watersheds at 2 layers (0 - 15 and
15 - 30 cm) were collected for aggregate analysis by wet
sieving method for mean weight diameter of soil aggre-
gates. Infiltration measurements were done at four loca-
tions each at surface on bed and furrow of BW1 and four
locations in BW4C watershed [12]. Penetration resis-
tance readings were made in both the improved (80 ob-
servations) and traditional (20 observations) treatments
depending up on the variations in each of the watersheds.
The samples from BW1 were collected from the centre
of beds and in furrows. Table 1 gives the details of
number of samples collected for various physical prop-
erties of soil.
For estimating the crop yields, samples from 24 ran-
domly selected spots (each 12 m2 area) were collected
from the each treatment. After taking the fresh weight of
grain and biomass, the samples were kept in drier for
obtaining dry weights.
2.5. Statistical Analysis
Soil physical and hydrological data obtained from
watersheds BW1 and BW4C were analyzed using the
analysis of variance method in GENSTAT 5 with man-
agement systems as main treatments and soil depths as
sub-treatments. The significant differences between main
and sub-treatments and interaction effects were studied
by comparing the “F” test of significance and standard
error of means.
Table 1. Details of samples collected for soil physical properties determination.
Number of samples
Soil property
Bed Furrow
Texture 6 6 6 Hydrometer method
Bulk density 6 6 6 Core method
Total porosity 6 6 6 From density measurements
Air-filled porosity 6 6 6 From density measurements
Penetration resistance 80 80 20 Cone penetrometer
Mean weight diameter Wet-sieving method
Sorptivity 4 4 4 Disc permeameter
Steady-state flow rate 4 4 4 Disc permeameter
Cumulative infiltration 4 4 4 Disc permeameter
Moisture retention 6 6 6 Pressure plate apparatus
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3.1. Crop Productivity
The crop yields were higher in the improved system
(semi-permanent broadbed and furrow with minimum
tillage along with improved cropping systems and man-
agement) than in the traditional system (monsoon fallow
with flat landform with traditional cropping practices).
In the improved system the sorghum and pigeonpea to-
gether recorded an average grain yield of 5.3 t·ha–1·yr–1
compared with the 1.2 t·ha–1·yr–1 in traditional system
(Figure 2). The annual gain in grain yield in the im-
proved system was 82 kg·ha–1·yr–1 compared with 23
kg·ha–1·yr–1 in the traditional system. The initial big dif-
ference in crop yields between the two systems was
mainly due to two crops per year in improved system vs
one crop per year in traditional system. Also the im-
proved system had improved varieties and cropping sys-
tem along with other improved management compared
to traditional variety and traditional management prac-
tices in traditional system. Significant contribution had
also come from the improved BBF landform and tillage
system, which facilitated the cropping during the rainy
season by improving surface drainage and reducing wa-
ter logging problem. The improved system of BBF
landform reduced seasonal runoff from 174 mm meas-
ured within the traditional system to 99 mm, improving
soil water content and reducing annual soil losses from
6.46 t·ha–1 to 1.51 t·ha–1 [3]. However, subsequent an-
nual gain in grain yield must have come from the grad-
ual improved soil health. The small annual gain in crop
yield observed in the traditional system can be attributed
to the organic fertilizers (FYM) incorporated into the
system. However, the large annual gain in the crop yield
in the improved system could be attributed to gradual
im- provement in soil health (soil physical, chemical and
biological properties). The improved system [8] reported
the positive changes in the soil chemical and biological
properties from the same experiment. The changes in the
soil physical and hydrological properties are discussed in
the subsequent sections of this paper.
3.2. Soil Physical Properties
3.2.1. Mean Weight Diam eter
Management system had a significant effect on the
mean weight diameter of water stable aggregates (Table
2). After 34 years of experimentation, the soils in im-
proved management had significantly larger mean weight
diameter compared to soils under traditional management.
This trend was seen both at 0 - 15 and 15 - 30 cm soil
layers. This may be attributed to relatively more crop
residue, minimum tillage in the cropping zone and
higher microbial activity in the improved system.
3.2.2. Penetration Resistance
The soils under improved management had lower
penetration resistance at 5 and 15 cm depths compared
to soils under traditional management (Figure 3). For
example, at 5 cm depth the penetration resistance of soils
in the improved system was 1.1 compared to 9.8 MPa in
the traditional system. This suggests a progressive im-
provement in soil tilth occurred in the cropping zone
(bed zone) over time. So in the BBF system the tillage
operations in the bed zone (cropping zone) became pro-
gressively easier, allowing timely tillage operations
which is so crucial for SAT Vertisols in view of their
difficult workability in the dry and wet conditions. There-
fore in the long-term, the semi-permanent BBF system
facilitates land preparation during the summer season
and dry sowing of the rainy season crop, which are pre-
requisites for the double cropping in such SAT environ-
3.2.3. Soil Texture
A significant difference in texture between improved
and traditional management systems was observed only
in top 10 cm soil layer (Table 3). After 24 and 34 years
of experimentation the improved system had signify-
cantly higher clay content (51% and 50%) compared to
Figure 2. Three-year moving average of sorghum and pigeon-
pea grain yield under improved (BW1) and traditional (BW4C)
management systems in deep Vertisol catchment at ICRISAT,
Patancheru, India.
Table 2. Long-term effects of management systems on mean weight diameter (mm) of water stable aggregates.
Improved system Traditional system
(cm) 1976 2009
SEM 1976 2009 SEM
0 - 15 3.0 4.1 0.251 2.9 2.7 0.069
15 - 30 3.1 4.5 0.158 3.0 2.8 0.161
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Table 3. Long-term effects of management systems on soil texture (0 - 10 cm).
Improved system Traditional system
Texture 1976 1999 2009 SEM 1976 1999 2009 SEM
Clay (%)** 52 51 50 0.675 52 46 45
Silt (%) 22 21 21 0.792 22 22 21
Fine sand (%) 15 15 16 0.981 14 15 16
Coarse sand (%)** 12 13 13 0.725 12 17 18
Gravel (%)** 4 5 5
0.133 4 11 13
traditional management (46% and 45%). There was no
significant difference in silt and fine sand contents. The
coarse materials (coarse sand and gravel) were signifi-
cantly higher in traditional management. The texture
analyses indicates the long-term effect of the differential
soil erosion between the improved and traditional man-
agement systems, with higher soil erosion in the tradi-
tional systems (6.5 t·ha–1·yr–1) compared with the im-
proved system (1.5 t·ha–1·yr–1) resulting in greater re-
moval of finer soil particles from the cultivated topsoil
layer [3].
3.2.4. Bulk Density
At beginning of the experiment, the soil bulk density
of different layers in two experimental watersheds was
similar (Figure 4). After 24 and 34 years of experiments,
the bulk density throughout the soil profile (up to 105 cm)
was significantly lower with improved management than
in traditional management. However, the differences in
bulk densities were relatively greater in the top 20 cm
soil layer and the maximum difference in bulk density
between the two treatments was recorded in the top 0 -
10 cm soil layer. These data clearly show the advantage
of improved management system over the traditional
management system in keeping the soil loose which has
major implications for tillage (time, and energy require-
ment), water movement, aeration and root growth. It
appears that the large changes in bulk density in the top
0 - 20 cm soil layer have occurred mainly because of the
different tillage systems, which had been followed in the
improved and traditional systems.
3.2.5. Porosity and Air-Filled Porosity
The long-term effect of improved and traditional
management on total porosity and air-filled porosity are
shown in (Figure 5). Both air-filled porosity and total
porosity recorded from the improved system were sig-
nificantly higher compared to values recorded from tra-
ditional system. In the improved system the air-filled
porosity in top 30 cm soil layer had improved by 46%
during the first 24 years of experiments (1976-1999). In
the traditional management system no significant changes
in porosity and air-filled porosity was recorded even
after 24 and 34 years of experimentations. These data
indicate the effectiveness of the improved management
system in improving soil porosity and air-filled porosity,
thereby improving the internal profile drainage in the
seed and root environment of Vertisols. This has major
implications for Vertisols where during rainy season the
waterlogging is often a serious problem mainly due to
very low saturated hydraulic conductivity and poor in-
ternal profile drainage needed.
Figure 3. Long-term effects of improved vs. traditional man-
agement systems on soil penetration resistance.
Figure 4. Long-term effects of improved vs. traditional man-
agement systems on bulk density of soils.
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3.3. Hydrological Properties
(Moisture Retention, Infiltration
and Sorptivity)
Even after the 24 and 34 years of experimentations, no
significant difference in soil moisture retention properties
both at 0.033 and 1.5 MPa were recorded in the soil
samples from improved and traditional management sys-
tems (Table 4).
After 24 years of experimentations, significantly
higher initial infiltration rate (347 mm·h–1) was recorded
in improved management system compared to traditional
management system (265 mm·h–1). Similar trend in in-
filtration rate was recorded after 34 years of experiments.
The sorptivity value was also significantly higher in im-
proved management system (121 mm·h–1/2) than in tradi-
tional management system (88 mm·h–1/2). These values
indicate the long-term effects of improved and tradi-
tional tillage and crop management systems on hydro-
logical properties of soils. These changes in soil proper-
ties may have contributed in reduced runoff recorded
from the improved management system. On an average
(from 1974 to 1993) the improved tillage and crop man-
agement system reduced annual runoff from 220 mm
measured from the traditional tillage and crop manage-
ment system only to 91 mm [13].
Figure 5. Long-term effects of improved vs. traditional management systems on total and air-filled porosity of soils.
Table 4. Change in the hydrological properties of soils in improved and traditional management system.
Improved management system Traditional management system
Soil properties
1976 1999 2009 1976 1999 2009
Moisture retention (g·g1) of
0 - 10 cm depth at 0.033 MPa 1.5 MPa
Cum. Infiltration in first 1 h (mm)** 289 347 356 292 265 273
Sorptivity (mm·h1/2)* - 121 - - 88 -
*Significant at 0.05 and **highly significant at <0.001 probabilities; -not measured
P. Pathak et al. / Agricultural Sciences 2 (2011) 435-442
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Figure 6. Long-term effects of improved vs. traditional management systems on cracking pattern.
3.4. Surface Cracks and Its Pattern
The development of cracks owing to shrinkage is a
major structural feature of Vertisols. Big cracks, ex-
tending deep into the profile, define major structural
features and play an important role in several soil and
water processes [14].
Significant differences between the two treatments
were observed in the pattern, area and density of cracks.
The total length of cracks (1.17 vs 2.1 m per m2 of land
area) and its area (0.07 vs 0.16 m2 per m2 of land area)
was found significantly lower in the improved mana-
gement system compared traditional management sys-
tem (Figure 6). In watershed with improved manage-
ment (semi-permanent BBF land treatment) most of the
cracks were found in the furrows, which serve as traffic
zone. The presence of cracks in bed or cropping zone
were relatively fewer. Soil compaction due to farm ma-
chinery wheel traffic and human trampling induced
deeper and wider surface cracks in the furrows, which
got developed with further drying into big cracks. Since
compaction was restricted to particular traffic zone, most
large cracks were located in the furrows only. Within the
traditional management system (flat land treatment)
cracks were found all over including in the cropping
zone (Figure 6).
Cracking patterns could affect germination, seedling
establishment, vegetative growth, root development and
crop yields [6,15]. Although the wider and deeper cracks
were found in furrows of semi-permanent BBF in im-
proved management compared to flat land configuration
in traditional management, it may not affect the crop
growth on BBF as the cracks were at a distance from the
crop zone. Where as, in traditional management the crop
growth was affected due to formation of cracks in the
crop zone, which were at a closer distance to the crops
resulting in an uneven moisture distribution and rela-
tively lower available soil moisture in the root zone.
In the improved system however the presence of large
cracks in the furrows could greatly increase the initial
infiltration by intercepting the runoff particularly during
the early parts of the rainy season. The runoff recorded
during the early parts of the rainy season supports this
hypothesis [3]. During high rainfall years the Vertisols
have severe waterlogging problem mainly due to poor
profile internal drainage. Wider and deeper cracks cre-
ated by compacted zone in improved system could pro-
long the useful life of cracks as large drainage voids for
the soil in the neighboring zone. This mechanism may
significantly help in reducing the waterlogging problem
in the improved management system.
The results indicate that in the long-term, the improved
management system (BBF landform along with mini-
mum tillage and appropriate crop management practices)
substantially increased the crop yields as well as im-
proved the physical and hydrological properties of SAT
Vertisols. The results also indicate that with this im-
proved management system it is possible to achieve the
substantially higher crop productivity along with im-
proved soil quality. In the long-term the improved man-
agement system resulted in lower bulk density and pene-
tration resistance and higher porosity compared with
traditional management system (flat cultivation, mon-
soon fallow with traditional practices). Similarly, soil
hydrological properties (infiltration and sorptivity) were
more favorable in improved management system than
traditional management system. The improved manage-
ment system resulted in larger mean weight diameter of
soil particles and better soil aggregation and more fa-
vorable soil surface cracking and its pattern.
The favorable soil physical and hydrological proper-
ties recorded under the improved management system
have positive implications for the cultivation and timely
P. Pathak et al. / Agricultural Sciences 2 (2011) 435-442
Copyright © 2011 SciRes. Openly accessible at http://www.scirp.org/journal/AS/
tillage operations on SAT Vertisols under both dry and
wet soil conditions. The timely tillage is one of the ma-
jor constraints for improved management of Vertisols
particularly during the rainy season. The implications of
traditional with no crops during rainy season (or mon-
soon fallow) are serious both in terms of the overall crop
productivity and with regard to soil degradation through
high runoff and soil loss.
Significantly higher porosity and air-filled porosity
recorded under the improved management system indi-
cate the effectiveness of this system in improving the
waterlogging problem in SAT Vertisols. The favorable
changes in soil physical, hydrological properties and
cracking pattern under improved management system
must have contributed in increasing and sustaining the
crop productivity, which recorded about 5 times higher
compared to traditional management system.
This paper is based on the long-term experiments at Heritage water-
sheds ICRISAT Center, Patancheru, India, financial support provided
by S. M. Sehgal Foundation for Heritage watersheds is gratefully ac-
knowledged. We acknowledge the help and contribution of all the
scientists and staff who have been associated with these experiments.
The authors are highly thankful to Dr. Peter Craufurd for his comments
and suggestions in improving the manuscript.
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