depletion of organic carbon, phosphorus, and potassium stock under a pearl millet based cropping...

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Depletion of Organic Carbon,Phosphorus, and Potassium Stock Undera Pearl Millet Based Cropping System inthe Arid Region of IndiaSurendra Kumar Singh a , Mahesh Kumar a , Brij Kishore Sharma a &Jagadish Chandra Tarafdar aa Central Arid Zone Research Institute (CAZRI) , Jodhpur, Rajasthan,IndiaPublished online: 21 Mar 2007.

To cite this article: Surendra Kumar Singh , Mahesh Kumar , Brij Kishore Sharma & Jagadish ChandraTarafdar (2007) Depletion of Organic Carbon, Phosphorus, and Potassium Stock Under a Pearl MilletBased Cropping System in the Arid Region of India, Arid Land Research and Management, 21:2,119-131, DOI: 10.1080/15324980701236101

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Depletion of Organic Carbon, Phosphorus, andPotassium Stock Under a Pearl Millet BasedCropping System in the Arid Region of India

Surendra Kumar SinghMahesh KumarBrij Kishore SharmaJagadish Chandra Tarafdar

Central Arid Zone Research Institute (CAZRI), Jodhpur, Rajasthan, India

Carbon, phosphorus and potassium stock for a meter soil profile were determined in2002 for a 22860 km2 area under pearl millet (pm) -pearl millet (pm) (pennisetumamericanum Linn.) cropping system and the results were compared with the data-base of 1975. The influence of alternate land use systems on organic carbon, phos-phorus and potassium density under the similar set of conditions was also evaluated.Soil organic cabon (SOC), phosphorus, and potassium stocks were depleted by 9.7,17.1, and 9.0% from 1975 to 2002. Typic Torripsamment (19.7%) and Lithic Tor-riorthents (17.7%) suffered from the highest SOC loss, while coarse loamy, TypicHaplocambids registered the lowest (0.9%) SOC depletion. Equivalent CO2 emis-sion was 11.5 Tg, while 0.37 Tg CO2 was sequestered as inorganic carbon. Trends ofphosphorus and potassium depletion was similar to that of SOC. Silvipasture, Silvi-culture, agroforestry and pearl millet-legume sequence on Typic Torripsammentsfrom last thirty years at CAZRI Research Farm contained 185,141,121, and 50%higher SOC and could sequester 9.6, 7.4, 6.3 and 2.6 kg=m2 higher CO2, respectivelythan the similar soils used for pm-pm sequence. Potassium depletion and phosphorusaccumulations were significantly higher in pm-legume than other land use systems.Cropping intensity, fertilizer application, soil texture, initial organic carbon,organic residue recycled and period of canopy cover alone or in combinationexplained the extent of variation. The study reveals that silvipasture and silvicultureare the better option for increasing SOC sequestration. Agroforestry and pearlmillet-legume sequence may be grown for arresting SOC and nutrient depletion.

Keywords arid region, land use, nutrient depletion, SOC density and stock

Soil organic carbon (SOC) is the predominant parameter that affects other physical,chemical, and biological properties of soils (Tiessen et al., 1994; Lal, 1994). Cultivationgenerally depletes 33 to 50% SOC (Vanubgaart et al., 2003), depending upon soil tex-ture, erosion, and vegetative cover (Burke et al., 1989), management regime (Janzen etal., 1987), initial concentration (Mann, 1986), extent of fallowing (Monreal et al.,1992; Doran et al., 1996), and inorganic carbon accumulation (Pal et al., 1999). Avail-able phosphorus (Wang et al., 1995) and potassium were reported to increase with thestability of organic carbon (Keeny et al., 2002) and vice versa (Webb et al., 2000).

Received 3 April 2006; accepted 4 December 2006.Address correspondence to J. C. Tarafdar, Central Arid Zone Research Institute,

Jodhpur, Rajasthan 342003, India. E-mail: [email protected]

Arid Land Research and Management, 21:119–131, 2007Copyright # Taylor & Francis Group, LLCISSN: 1532-4982 print/1532-4990 onlineDOI: 10.1080/15324980701236101

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Sodium adsorption on clay complex increased with SOC depletion (Poonia, 1998).Thus soil organic carbon is dynamic (Parton et al., 2004) and a widely accepted indi-cator (Lal, 2004), changing with land use and management history.

The arid region of India spreads in 38.7 million hectares in a part of Rajasthan,Gujarat, Haryana, and Punjab. Majority of nonarable lands were put up under apearl millet based cropping system with or without support of irrigation in the latesixties. Present degradation status on the account of severe wind erosion, droughti-ness, low biomass production, mounting salinity, and sodicity and an increased levelof inorganic carbon, demands revisiting the soil profiles and systematically analyzingthe influence of a pearl millet based cropping system and management on SOC,phosphorus, and potassium, governing the productivity. The study essentiallyneeded the reformulating of the farming strategies for combating the problems ofsoil degradation related to the present land use system. Therefore, the present inves-tigation is undertaken with the following objectives: (i) to study the variation in car-bon, phosphorus, and potassium stock from 1975 to 2002 under a pearl millet basedcropping system, and (ii) to study the influence of alternate land use systems on soilorganic carbon, phosphorus, and potassium stock for understanding their suitabilityunder the present set of conditions.

Materials and Methods

Study Area

The study area chosen for the present investigation is located between 27�290 to25�290 N latitude and 71�590 to 73�460 E longitude in the Jodhpur district, coveringa 22860-km2 area in western Rajasthan. The area represents most of the soil and landuse variability of the region. Soil survey initially was undertaken during 1975 on1:50,000 scale and soils were mapped in 18 soil series associations (CAZRI, 1975),excluding saline depressions, dunes, and hills. Typic Torripsamments with low-to-high hummocks occupied 49.1% of the area. Typic Haplocambids, including acoarse loamy deep and moderately-deep phase covered another 35% of the area.Fine loamy, Typic Haplocambids were mapped only in 3.8% of the area, whileLithic Torriorthents associated with pediments, foot slope, and shoulders of hills,occupied another 8.7% of the investigated area. The loamy family of Lithic Haplo-cambids, cover only 0.9% of the area. Undulated topography and severe winderosion were the major constraints associated with Typic Torripsamments. Shallowdepth, graveliness, and moderate-to-severe erosion were the constraints linked withLithic Torriorthents. Typic Torripsamments and Lithic Torriorthents were severelydegraded, while extent and severity of degradation declined in Typic Haplocambids(Shyampura and Sehgal, 1995). The typifying pedons of each subgroup under a pearlmillet based cropping system is given in Table 1. Groundwater potential was goodalong the drainage lines, dissecting Typic Haplocambids at places.

Superimposition of soil and rainfall maps in a Geographical Information System(GIS) environment indicated that coarse loamy deep and loamy soils of Haplocam-bids experienced 424 mm mean of annual precipitation, while their counterpartscoarse loamy (moderately deep) and fine loamy, Typic Haplocambids fall in theregion, having 317.9 and 378.0 mm of rainfall, respectively (Table 1). Typic Torrip-samments and Lithic Torriorthents were associated with the area of 250 mm of mean

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annual rainfall (Table 2). Scarcity of water is the major bottleneck for agricultureand drought in the arid region which often occurs once every 2.5 years.

Around 46% of the area is cultivated once a year only on the commencement ofa good monsoon, while 1.8% of the area is used for double cropping with support ofgroundwater irrigation. Cropping intensity was the highest—150 to 200% on the fineloamy, Typic Haplocambids and the lowest (30 to 50%) on the Typic Torripsam-ments and Lithic Torriorthents (Table 2). Lower cropping intensity of the latter sug-gested that a vast stretch of land remained untilled, even in a year of good rainfallbecause of severe erosion and uneven topography. Groundwater is often brackishand very deep. Pm-pm based cropping sequence is the most preferred land use sys-tem of the arid region for fulfilling the dietary needs of the people and the fodderrequirements of the animals. There is no usual practice of manure application. How-ever, animals move in the fields after the harvest of summer crops.

Sampling and Laboratory Analysis

The type location of each soil series was traced again in 2002 and re-examinedaccording to the Soil Survey Staff (1999). Ten additional random profiles in eachof the soil series were also studied about an interval of half a kilometer from the mas-ter profile or at a lesser distance, depending upon soil variability. The procedure wassimilar to that used by Sanchez et al. (1985) and Tan (1996) for studying the chrono-sequential changes in chemical properties. Horizon-wise samples were collected andanalyzed for organic carbon (wet digestion), calcium carbonate equivalent (1N HCldigestion), available phosphorus (0.5 N NaHCO3), and potassium (1N NH4OAc).Bulk density was determined only in the master profile, examined in 2002 by coresamples, while pedotransfer function {Bulk density ¼ 0.0181(100-clay-5)–0.08 OC,r2 ¼ 0.66} was used for the determination of bulk density in the soil samples ana-lyzed during 1975. Mean of soil organic carbon, phosphorus, and potassium for each

Table 2. Soil site characteristics under pearl millet based production system

Mean AnnualRainfall (mm)

�Texture

Area (km2) Surface Subsurface Cropping Intensity (%)

Coarse loamy (deep phase), Typic Haplocambids (n ¼ 30)1506.2 403.0 ls-sl sl-l 70–100

Coarse loamy (mod. deep phase), Typic Haplocambids (n ¼ 40)6506.3 317.9 s-sl sl-l 50–100

Loamy, Lithic Haplocambids (n ¼ 10)218.0 424.0 ls-sl sl-l 50–100

Fine loamy, Typic Haplocambids (n ¼ 40)868.7 378.0 l-scl l-cl 150–200

Loamy-skeletal, Lithic Torriorthents (n ¼ 20)2010.0 247.7 gls-gsl gls-gsl 30–50

Typic Torripsamments (n ¼ 50)11224.3 248.8 s-ls s-ls <50

�

Depletion of Carbon, Phosphorus, and Potassium Stock 123

s-sand, ls-loamy sand, sl- sandy loam, l-loam, cl-clay loam, g- gravelly.

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horizon was considered as representative value for the typifying pedon of each soilseries. Weighted mean for 0–100-cm soils was used for the computation of soilorganic carbon, phosphorus, and potassium stock, which were calculated by multi-plying content (g=g), thickness, bulk density, and area (Batjes, 1996). Inorganic car-bon stock was calculated by multiplying carbonate content (g=g) with thickness, bulkdensity, area, and a factor of carbon (0.12) in CaCO3. Calcium carbonate in the sub-stratum was not considered for the computation unless it is the part of soil taxono-mical classification. Thirty percent or equivalent amounts of gravels were deductedfrom the total nutrient stock of loamy-skeletal soils (Bernoux et al., 2002). Gain orloss of carbon was calculated using the following equation:

Organic carbon stock ð1975Þ � Organic carbon stock ð2002Þ ¼ Loss/gain ð1Þ

Similarly, loss=gain was calculated for inorganic carbon, phosphorus, and potass-ium. Equivalent carbon dioxide emission was calculated by using eq. 2, where a factor3.67 (44 molecular weight of CO2 divided by molecular weight of carbon, 12) wasderived and was multiplied with the loss=gain of organic=inorganic carbon (Eq. 1):

CþO2�!CO2 ð2Þ

A paired t-test was employed for assessing the level of significance between the nutrient’sstock of 1975 and 2002. The results are presented in terms of soil particle size class andsubgroups for better interpretations.

Sampling was done simultaneously at the research farm of the CAZRI, Jodhpur,maintaining a biosequence of pearl millet-legume, silviculture, silvipasture, and agro-forestry on Typic Torripsamments from the last three decades. Ten samples fromeach land-use system were analyzed for gauging their influence on soil organic car-bon, phosphorus, and potassium. Management history was collected from farmrecords, which substantiated that the recommended dose of nitrogenous and phos-phatic fertilizers were used in pearl millet-legume sequence. However, other land-use systems were maintained without a fertilizer application. In the absence of actualarea under each element of biosequence, we have analyzed soil organic carbon andnutrient density {content (g=g)� bulk density� thickness of soil profile} for 0–100-cm soil depth instead of stock and was compared with the corresponding data of apearl millet based cropping system.

Results

Carbon Stock Under pm-pm-Based Cropping System

Soil organic carbon stock in the sampled area was computed 34.1 Tg (1T g ¼ 1012g)during the first appraisal of a natural resource survey in 1975 and it was significantly(p < 0.05) reduced to 30.8 Tg after 27 years (Table 3). A detailed investigationshowed that SOC stock squeezed from 21.8 to 20.9 Tg in Typic Haplocambids(8012.5 km2 covering 35.0% area), 11.49 to 9.22 Tg in Typic Torripsamments(11224.3 km2, constituting 49.1% area), and from 0.82 Tg to 0.62 Tg in Lithic Tor-riorthents (2010.0 km2, comprising 8.7% area) during the period. Soil organic car-bon loss over the area was estimated to 9.7% from 1975 to 2002. Among thesubgroup, Typic Torripsamments suffered from the highest SOC loss (19.6%), whilecoarse loamy, (deep) Typic Haplocambids witnessed the lowest SOC depletion


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(0.9%). Soil organic carbon stock was reduced by 4.2 and 10.4% in coarse loamy(moderately deep) and fine loamy, Typic Haplocambids, respectively. Lithic Haplo-cambids and Lithic Torriorthents mapped in the area showed a SOC loss of 5.1 and14.1%, respectively, during the period of observations.

An equivalent CO2 emission was 11.5 Tg during the investigated period (Table 3),of which Typic Torripsamments (11224.3 km2, constituting 49.1% area) and coarseloamy (moderately deep) Typic Haplocambids (6506.3 km2, comprising 28.46% area)emitted 69.8 and 19.3% of CO2, respectively, while a contribution of Lithic Torriorth-ents (2010.0 km2, comprising 8.2% area) and fine loamy, Typic Haplocambids(868.7 km2, constituting 3.8% area), respectively, was 4.5 and 4.4% in total CO2 emis-sion. Loamy, Lithic Haplocambids (218 km2, constituting 0.9% area) and coarseloamy, (deep) Typic Haplocambids (1506.2 km2, covering 6.5% area) emitted 0.07and 0.15 Tg CO2, which were constituted 0.6 and 1.3% of the total CO2 emission dur-ing the period.

An equivalent quantity of 0.37 Tg atmospheric CO2 was sequestered in thesampled area as inorganic carbon from 1975 to 2002, of which 20.5% became the partof recently precipitated lime in coarse loamy, (deep) Typic Haplocambids (Table 3),while fine loamy, Typic Haplocambids and Typic Torripsamments could be stored0.05 and 4.5% of sequestered CO2 as CaCO3 equivalent. Coarse loamy, (moderatelydeep) Typic Haplocambids could stock the highest around 59.4% of sequestered CO2

as inorganic carbon.

Phosphorus and Potassium Stock Under Pearl Millet Based Production System

Available P2O5 stock was reduced significantly (p < 0.05) from 7.52 to 6.31 Tg from1975 to 2002 (Table 4). The phosphorus depletion was 17.1% during the period.Typic Torripsamments witnessed the highest loss of phosphorus (30.7%), which

Table 3. Carbon stock in soils under pearl millet based production system

SOC (Tg) Emission=Sequestration of CO2(Tg)

1975 2002 SOC Loss (Tg) SIC Gain (Tg) Emission Sequestration

Coarse loamy (deep phase), Typic Haplocambids (n ¼ 30)4.44 4.40 0.04 (0.90) 0.02 0.15 0.08

Coarse loamy (mod. deep phase), Typic Haplocambids (n ¼ 40)14.68 14.07 0.61 (4.15) 0.06 2.22 0.22

Loamy, Lithic Haplocambids (n ¼ 10)0.35 0.33 0.02 (5.7) – 0.07 –

Fine loamy, Typic Haplocambids (n ¼ 40)2.29 2.06 0.23 (10.04) 0.0005 0.52 0.002

Loamy-skeletal, Lithic Torriorthents (n ¼ 20)0.82 0.68 0.14 (17.0) – 0.51 –

Typic Torripsamments (n ¼ 50)11.49 9.22 2.17 (19.7) 0.017 8.02 0.067�34.07 �30.76 �3.21(9.4) �0.09 �11.49 �0.37

�Total; Figure in parentheses represents percentage loss over baseline data of 1975.


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was the lowest (6.9 to 9.7%) in coarse loamy, (deep) Typic Haplocambids. Coarseloamy, (moderately deep) Typic Haplocambids and Lithic Torriorthents showedavailable phosphorus depletion by 18.6 and 15.2%, respectively, during the period.

Available K2O was estimated to 171.3 Tg in the soil samples collected during1975, which was reduced significantly (p < 0.05) to 155.89 Tg in 2002 (Table 4). Per-cent K2O stock depletion during the period was 17.6. The highest loss of potassiumwas estimated in Typic Torripsamments (17.9%) followed by Lithic Torriorthents(15.9%). Moderately deep Typic Haplocambids and Lithic Haplocambids werethe lowest potassium depletion, varying from 0.5 to 3.2% over the baseline dataof 1975. Coarse loamy (deep) and fine loamy, Typic Haplocambids were the identicalin terms of potassium depletion.

Soil Organic Carbon Density Under Alternate Land Use Systems

Soil organic carbon density of Typic Haplocambids for a meter soil profile was 3400,4000, 3100, and 2100 g=m2 under silviculture, silvipasture, agroforestry, and pearlmillet-legume sequence, respectively (Figure 1). These were significantly higher than1400 g=m2, estimated on similar soils under pearl millet based production system.Soil organic carbon density was increased by 141, 185, 121, and 50% under silvicul-ture, silvipasture, agroforestry, and pearl millet-legume sequence, respectively, overthe similar soils used under a pearl millet based production system. These alternateland-use system, respectively, could sequester 7.6, 9.6, 6.3, and 2.6 kg=m2 moreatmospheric CO2 into the soils. Among them silvipasture, silviculture, and agrofor-estry could be able to add 7.0, 4.8, and 3.7 kg=m2 more atmospheric CO2 to the soilsthan pm-legume sequence. Silviculture and silvipasture could sequester 1.1 and3.8 kg=m2 more atmospheric CO2 even from partially cultivated agroforestry system.

Table 4. Phosphorus and potassium stock in soils under pearl millet basedproduction system

P2O5 (Tg) K2O (Tg)

1975 2002 % Loss Over 1975 1975 2002 % Loss Over 1975

Coarse loamy (deep phase), Typic Haplocambids (n ¼ 30)0.82 0.80 9.7 14.98 14.2 5.2

Coarse loamy (mod. deep phase), Typic Haplocambids (n ¼ 40)2.45 2.28 6.9 50.17 49.9 0.5

Loamy, Lithic Haplocambids (n ¼ 10)0.07 0.06 14.2 1.55 1.5 3.2

Fine loamy, Typic Haplocambids (n ¼ 40)0.43 0.35 18.6 8.55 8.19 4.21

Loamy-skeletal, Lithic Torriorthents (n ¼ 20)0.33 0.27 15.2 4.29 3.6 16.1

Typic Torripsamments (n ¼ 50)3.42 2.37 30.7 91.8 75.3 17.9�7.52 �6.23 �(17.1) �171.34 �155.89 �(9.01)

�Total; Figure in parentheses represents percentage loss over baseline data of 1975.


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Soil organic carbon density under silvipasture was significantly higher (p < 0.05;p < 0.01) than any other land use system tested in biosequence.

Phosphorus and Potassium in Alternate Land Use Systems

Unlike organic carbon, pm- legume sequence had 47.6, 43.6, 14.6, and 70% higheravailable phosphorus (9.0 g=m2) in a meter soil profile (Figure 2) than the similarsoils used for silvipasture, silviculture, agroforestry, and pearl millet, respectively.Available potassium was the lowest 106.1 g=m2 in pm-legume sequence as comparedto any other land use systems (Figure 3). Soils under silvipasture and agroforestrymaintained around 42% higher available potassium than the soils under pm-legumesequence. Silviculture and pm-pm based system contained around 14.1 and 29.0%higher available potassium than soils under the pm-legume sequence.

Discussion

Soil organic carbon depletion in the arid region of India was comparatively lowerthan the similar agroclimatic situation of Iran and China (Habbasi et al., 1997;Wu and Tiessen, 2002) and from most of the agricultural soils of the world (Scholesand Hall, 1996) because of lower cropping intensity and the presence of perennialvegetation like Prosopis cineraria, Tecomella undulata, arid shrubs, and grasses.However, among the soils of arid region of India, nonarable Typic Torripsamments,having <50% cropping intensity and a thin biomass cover were depleted the mostfor SOC from 1975 to 2002, whereas similar soils could attain the highest SOCdensity under alternate land use of silviculture and silvipasture having a canopycover year-round with a minimum disturbance on account of the tillage. Assuming

Figure 1. Organic carbon density (g=m2) for 0–100 cm soil depth in different land use systemsof arid region on Typic Torripsamments. Bars represent least significant difference (LSD) foreach treatment (p ¼ 0.05).


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identical rainfall within the geographic settings of Typic Torripsamments, one couldeasily conclude that an absence of canopy cover (Murty et al., 2002) and lower veg-etative inputs (Doran et al., 1996) in the soils were the crucial for SOC depletionunder a pearl millet based cropping sequence. Tillage during monsoon further expe-dites the process of SOC depletion by increasing erosion severity (Wu and Tiessen,2002) and by opening the soils for microbial decomposition (Shephered et al.,2001). A lower SOC density on Typic Torripsamments under pearl millet-legumesequence at the research farm than silviculture and silvipasture further endorsedthe influence of canopy cover and tillage on SOC accumulations. Intermittentdrought once in 2.5 years further accentuated the problem of organic residuerecycling. Explanations coincide with the findings of Monreal et al. (1992), Doranet al. (1996), and Vanubgaart et al. (2003).

A lower quantity of silt and clay in Typic Torripsamments and Lithic Torriorth-ents may be the another reason for a higher SOC depletion, while higher silt and clayin Typic Haplocambids may be the reason for higher SOC accumulations. A highaggregation on account of increased silt and clay protects SOC from decompositionby trapping them between the aggregates (Jolivet et al., 1997). A negative correlation(r ¼ �0.59) between silt þ clay and SOC depletion further endorsed the presentcontention as well. However, this relationship may not be always true. A higherinitial SOC modified the impact of texture (Mann, 1986) that could be verified fromhigher absolute SOC depletion in fine loamy, Typic Haplocambids than their coarseloamy counterparts. Based on a higher canopy cover and a higher silt and claycontent, SOC depletion should theoretically be higher in coarse loamy, Typic Hap-locambids than their fine loamy counterparts. However, the reverse had emerged inthe present investigation. This means initial concentration overshadowed the influ-ence of soil texture and cropping intensity.

Figure 2. Available phosphorus (g=m2) for 0–100 cm soil depth in different land use systems ofarid region on Typic Torripsamments. Bars represent least significant difference (LSD) foreach treatment (p ¼ 0.05).


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Carbon dioxide emission was the function of total soil organic carbon stock overthe area, as indicated by a higher flux of CO2 from severely eroded Typic Torripsam-ments. Quirogo et al. (1999) also noted a higher emission of CO2 from highlydegraded sandy soils.

Frequently, application of carbonate- and bicarbonate-rich irrigation water onmoderately deep Typic Haplocambids induced a higher inorganic carbon sequestration.However, the process of carbonate accumulations was not an exception on Typic Hap-locambids; these also prominently appeared on an irrigated part of Typic Torripsam-ments. Irrigation with high Residual Sodium Carbonate (RSC) groundwater, rich incarbonates and bicarbonate of sodium and calcium, might have raised the soil pH,which ultimately enhanced calcium carbonate precipitation. The increase of soil pH by0.2 units from 1975 to 2002 in these soils further substantiated our explanations.

No phosphorus fertilizer was applied and crops were solely dependent on naturestock of these nutrients. Cropping from the last 27 years exploited phosphorus andpotassium stock significantly. Loss of potassium was also reported from the inten-sively cultivated Frazer Valley of Canada (Keeny et al., 2002). Intensity of croppingand severity of erosion further modified the extent of nutrient depletion. Loss of top-soils caused more removal of phosphorus from Lithic Torriorthents, while landscapemodification reduced phosphorus stock substantially on Typic Torripsamments.Leaching and erosion were the factors for greater potassium depletion on Typic Tor-ripsamments. However, comparatively better managed soils under a pearl millet-leg-ume sequence showed phosphorus building and a depletion of potassium. Croppinghistory at CAZRI Research Farm indicated that phosphatic fertilizer was not thepart of management. However, the application of potassic fertilizers was not in prac-tice. Thus inadequate fertilization was the crucial factor for nutrient depletion undera pm-pm based cropping system of arid region.

Figure 3. Available potassium (g=m2) for 0–100 cm soil depth in different land use systems ofarid region on Typic Torripsamments. Bars represent least significant difference (LSD) foreach treatment (p ¼ 0.05). No potassium fertilizer was added in any of the treatment.


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Conclusion

The present results demonstrated that organic carbon, phosphorus, and potassiumstock have been depleted in soils of arid zones from 1975 to 2002 under a pearl milletbased cropping sequence. Summer and winter fallowing and tillage were the cause ofSOC depletion and carbon dioxide emission. Canopy cover year-round was the prin-cipal factor, holding organic carbon in its place. However, SOC concentrations at theinitial stage have modified the influence of canopy cover to an extent. Carbonate- andbicarbonate-rich irrigation water was the source of inorganic carbon sequestration,while inadequate fertilization was the reason for nutrient depletion. Silvipastureand silviculture are the better option on severely eroded Typic Torripsammentsand Lithic Torriorthents for increasing SOC sequestration and for arresting losseson account of erosion. However, agroforestry and cultivation of pearl millet-legumesequence are the other options in minimizing SOC depletion and CO2 emission.

References

Batjes, N. H. 1996. Total carbon and nitrogen in the soils of the world. European Journal ofSoil Science 47:151–163.

Bernoux, M., M. C. S. Carvalho, B. Volkoff, and C. C. Cerri. 2002. Brazil’s soil carbon stock.Soil Science Society of American Journal 66:888–896.

Burke, I. C., C. M. Yonker, W. J. Parton, C. V. Cole, K. Flach, and D. S. Schimel. 1989. Tex-ture, climate and cultivation effects on organic matter content in U.S. grassland Soils. SoilScience Society of American Journal 53:800–805.

Central Arid Zone Research Institute (CAZRI). 1975. Basic and human resources of Jodhpur.Central Arid Zone Research Institute, Jodhpur, India.

Doran, J. W., M. Sarrantanio, and M. A. Liebig. 1996. Soil health and sustainability.Advances in Agronomy 56:1–54.

Habbasi, M. A., A. Lalalian, and R. Karimzadeh. 1997. Desertification effects on soil physicaland chemical properties, Lordegan, Iran. Plant and Soil 190:301–308.

Janzen, H. H., C. A. Campbell, I. B. H. Ellert, N. Juma, W. V. Mcgill, and R. P. Zentner. 1987.Management effects on soil C storage on Canadian prairies. Soil Tillage Research 55:31–42.

Jolivet, C., D. Arrouays, F. Andreux, and J. Leveque. 1997. Soil organic carbon dynamicsin cleared temperate forest spodosols converted to maize cropping. Plant and Soil191:225–231.

Keeny, E. A., J. W. Hall, and C. Wang. 2002. Temporal trends in soil properties at soil qualitybenchmark site in the Frazer Valley, British Columbia. Canadian Journal of Soil Science82:499–509.

Lal, R. 1994. Methods and guidelines for assessing sustainable use of soil and water resources inthe tropics. SCS Technical Monograph No. 21, Soil Management Support Services,Washington, DC.

Lal, R. 2004. Soil quality industrialized and developing countries – similarities and differences,pp. 297–313, in P. Schjønning, S. Elmholt, and B. T. Christensen, eds., Managing soilquality; challenges in modern agriculture. CAB International, Wallingford, UK.

Mann, L. K. 1986. Changes in soil carbon storage after cultivation. Soil Science 142:279–288.Monreal, C. M., R. P. Zenter, C. A. Campbell, M. Nyborg, K. Greer, E. G. Gregorich, and D.

W. Anderson. 1992. Simulating the dynamics of soil organic matter in long-term rotationplots of Saskatchewan and Alberta, pp 206–234. in Management of agriculture science,soils and crops workshop. University of Saskatchewan, Saskatoom, SK.

Murty, D., M. U. F. Krischbaum, R. E. MxMurtie, and H. McGilvray. 2002. Does conversionof forest to agriculture land change soil carbon and nitrogen? A review of the literature.Global Change Biology 8:105–123.


Dow

nloa

ded

by [

Uni

vers

ity o

f K

ent]

at 1

1:15

16

Dec

embe

r 20

14

Pal, D. K., G. S. Dasog, S. Vadivelu, R. L. Ahuja, and T. Bhattacharyya. 1999. Secondarycalcium carbonate in soils of arid and semi arid regions of India, pp. 149–185, in R.Lal, J. M. Kimble, H. Eswaran, and B. A. Stewart, eds., Global climate change and pedo-genic carbonates. Lewis Publishers, Boca Raton, FL.

Parton, W., G. Tappan, D. Ojima, and P. Tschakert. 2004. Ecological impact of historical andfuture land use pattern in Senegal. Journal of Arid Environments 59:409–425.

Poonia, S. R. 1998. Sorption=exchange of some nutrients and non-nutrient cations in soils.16th Prof. J. N. Mukherjee – ISSS Foundation Lecture, 63th Annual Convention of IndianSociety of Soil Science, Hissar, India.

Quirogo, A. R., D. E. Buschiazzo, and N. Peinemann. 1999. Soil compaction is related tomanagement practices in the semi arid Argentine pampas. Soil Tillage Research 52:21–28.

Sanchez, P. A., C. A. Palm, C. B. Davey, L. T. Sazoti, and C. E. Russel. 1985. Tree crops assoil improvers in the humid tropics?, pp. 79–124, in Attributes of trees as crop plants. Insti-tute of Terrestrial Ecology, Huntingdon, U.K.

Scholes, R. J. and D. O. Hall. 1996. The carbon budget of tropical savannas, woodlands andgrassland, pp. 69–155, in A. I. Breymeyer, D. O. Hall, J. M. Melillo, and G. I. Agren,eds., Global change. Effects on coniferous forests and grasslands. Wiley, Chichester, UK.

Shephered, T. G., S. Saggar, R. H. Newman, C. W. Ross, and J. L. Dando. 2001. Tillageinduced change to soil structure and soil organic carbon fraction in Newzeland soils. Aus-tralian Journal of Soil Research 39:465–489.

Shyampura, R. L. and J. L. Sehgal. 1995. Soil of Rajasthan for optimizing land use. NationalBureau of Soil Survey (NBSS) and Land Use Planning (LUP) Publication (Soils of IndiaSeries), Nagpur, India.

Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for making andinterpreting soil survey, pp. 1–869, in USDA Agriculture Handbook 436, 2nd ed. U.S.Govt. Printing Office, Washington, DC.

Tan, K. H. 1996. Soil sampling, preparation and analysis. Marcel Dekkar, New York.Tiessen, H., E. Cuevas, and P. Chancaon. 1994. The role of soil organic matter in sustaining

soil fertility. Nature 371:783–785.Vanubgaart, A. J., E. G. Gregorich, and D. A. Angers. 2003. Influence of agricultural man-

agement on soil organic carbon: A compendium and assessment of Canadian studies.Canadian Journal of Soil Science 83:363–380.

Wang, C., L. J. Gregorich, H. W. Rees, B. D. Walker, D. A. Holmstrom, E. A. Keeny, D.King, L. M. Kozak, W. Michalyna, M. C. Nolin, K. T. Webb, and F. E. Woodrow.1995. Benchmark sites for monitoring agricultural soil quality, pp. 31–40, in D. F. Actonand L. J. Gregorich, eds., The health of our soil – Towards sustainable agriculture inCanada. Center for Land and Biological Resource Research, Agriculture Canada andAgriculture Food Canada, Ottawa, ON.

Webb, K. T., C. Wang, T. Astatkie, and D. R. Langille. 2000. Spatial and temporal trends insoil properties at a soil quality benchmark site in central Nova Scotia. Canadian Journalof Soil Science 80:567–575.

Wu, R. and H. Tiessen. 2002. Effect of land use on soil degradation in alpine grassland soils ofChina. Soil Science Society of America Journal 66:1648–1655.


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depletion of organic carbon, phosphorus, and potassium stock under a pearl millet based cropping...

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