Improving Soil Functions for

Sustainable Agriculture- a case study

from South India A Nexus of Soils-Environment-Livelihoods

E.V.S.Prakasa Rao

Independent(Formerly, Chief Scientist, CSIR-Centre for

Mathematical Modelling and Computer Simulation,

Bengaluru and Head, Central Institute of Medicinal and

Aromatic Plants, Research Centre, Bengaluru, India)

evsprakasarao@gmail.com

S12 Assessing the role of soil functions

for achieving SDGs

Soil- Environment- Economics- Equity Nexus

Equity

Economics

Environment

Soil Soil

Physiographic Regions in south India

Soil groups in south India

LCC in Southern States

Soil constraints In South India

Andhra Pradesh

Black soils: pH 8.5 – 9.0, poor in organic matter and nitrogen but sufficient in P and K.

Red soils: pH 6.8 – 8.0, light, dry and rain fed crops with poor yields. , poor in organic matter, N and available P, moderate in K.

Coastal alluvial soils: Sandy, Poor in plant nutrients. and organic matter.

River alluvial soils: Rich in plant nutrients.

Karnataka

Laterite soils: pH 4.5 – 6.0, low in bases, poor in plant nutrients in organic matter and N.

Kerala

.

Peaty soils (black): pH as low as 3.9, 10 to 40 % organic matter, 0.4% K2O, poor in P2O5

Tamil Nadu

Deltaic alluvial soils: pH 7.0 – 8.2, low in bases, poor in organic matter and N and P but rich in K.

Forest and hill soils: pH 4.5 – 6.5, 0.1 – 0.7% N, poor in bases.

WHY A NEXUS AMONG SOILS –LIVELIHOODS-ENVIRONMENT?

“ Economic survival and viability are the primary goals of land managers, and while most appreciate the need for environmental conservation, the simple fact remains that ‘it is hard to be green when you are in the red’ ”.

(JW Doran & MR Zeiss, 2000. Appl. Soil. Ecol. 15, 3-11)

Nexus of farmers’ needs and soil environment

Farmer’s needs

Soil environmental

conservation

Yields

Profits

Stability

Benefit cost ratio

(energy and

costs)

Soil organic matter

Top soil depth

Soil fertility

Soil reaction

Physical properties

of soil

Estimates of soil degradation in India

Process

GLASOD (Mha)

Others (Mha)

Water erosion

32.8

74-77

Wind erosion

10.8

13-39

Soil fertility decline

29.4

26

Waterlogging

3.1

7-9

Salinization

4.1

7-26

Lowering of water table

0.2

NA

GLASOD – Global Assessment of Soil Degradation

(R.Lal, Soil carbon sequestration in India. Climatic Change, 65, 277-296, 2004)

Demography of sample villages

Literacy

13.4%

Average land holding

1-3 ac

Economic status

Poor

Delicate soil ecosystems supporting livelihoods

Crops and economics in western

ghats region in India

Crop

Net income

(Rs/ha)

Rice

12 000

Arecanut

49 000

Cashew nut

53 000

Vetiver

123 000

Vetiver with banana

Rice cultivation in valleys

Vetiver; arecanut and a distillation unit in the background

E.V.S.Prakasa Rao et al., 2015.Sust. Agric. Rev. (in press)

Carbon should be sequestered to

maintain soil functions and also to protect environment

Such systems planted in 10% of

wastelands can fix up to 200 Tg C

yr -1 in India

(M.Singh, N.Guleria, E. V. S. Prakasa Rao and

P.Goswami(2014)Agronomy for Sustainable

Development 34(3), 603-607 DOI 10.1007/s13593-

013-0184-3.)

Recycling of agro-wastes by vermi-composting ( 20 ftX 6 ft X 1.5 ft pits)

Vermi-compost

produced 300 kg/pit/batch

N(%) 1.4

P(%) 0.12

K(%) 0.22

Organic C (%) 22.9

E.V.S.Prakasa Rao et al., 2015.Sust. Agric.

Rev. (in press)

Effect of organic and conventional

methods of cultivation of medicinal and

aromatic plants on some soil properties (4 yrs)

Treatment Organic

carbon

(%)

Bulk

density

(g/cm3)

Microbial

biomass

(mg/kg)

Available

P2O5

(kg/ha)

Organic 0.63 1.43 90.0 22.95

Inorganic

0.39

1.62

27.4

19.1

(Puttanna,K., E. V. S, Prakasa Rao, C. T. Gopinath, T. N. Parameswaran, Alok Kalra, S. Ramesh and R. P. Singh, International Seminar India Organic 2007, New Delhi, 29 Nov. 2007- 2 Dec. 2007 )

Soil analysis in an Eucalyptus

citriodora plantation (at the end of 10 yrs)

Soil characteristic Fallow soil E. citriodora

plantation

pH 0-15 cm

15-30 cm

5.64

5.70

5.79

5.81

Organic carbon

0-15 cm

15-30 cm

0.35

0.35

0.46

0.45

Available N (kg/ha)

0-15 cm

15-30 cm

310

310

318

278

Available P (kg/ha)

0-15 cm

15-30 cm

6.6

10.3

3.4

7.7

Exchange K (kg/ha)

0-15 cm

15-30 cm

524

408

488

423

CEC (meq/100g)

0-15 cm

2.0

2.6

Prakasa Rao, E,V,S, et al., Fafai J., 1(3), 44-47, 1999

Nirogen being very mobile in tropical

soils, requires proper management to

improve N-use efficiency

Techniques % improvement over

conventional method

Split application

Urea supergranules

Neem cake coated urea

DCD-treated urea

Fe-deficiency correction

Combination of organics

and inorganics

16

12-15

25

31

36

33

E.V.S.Prakasa Rao. Indian Journal of Agronomy 56 (4): 280-296 (2011)

Protection of soil – perennial aromatic grasses provide a way

Cashew nut and citronella grass

Cashew nut

Ammonia volatilization losses

from urea and NCU applied to soil

Prakasa Rao, E.V.S. (1996).In Neem and Environment Vol. 2 eds. R.P.Singh et. al, Oxford & IBH Publ. Co., Ltd., pp 815-819.

Effect of spentgrass : urea-N ratio on release of NO3

- - N

(Puttanna, K., & Prakasa Rao E.V.S.- , Sehgal J. Ed. et al. Red and Lateritic Soils of India – Resource Appraisal and Management, NBSS Publ. 37 NBSS&LUP, Nagpur, India, 346 p., 1993)

In situ soil moisture

conservation in rainfed palmarosa

Method Herb yield (t/ha/6

harvests)

Weed biomass (t/ha)

Mulching

16.1 22.5

Wider interrow-narrow

intrarow spacing

18.5 13.2

Ridges & Furrows

21.5 10.9

Life saving irrigation

21.2 12.1

Normal planting

21.0 12.6

Incorporation of spent

material

25.3 10.0

L.S.D. (P=0.05)

2.98 - E.V.S.Prakasa Rao et al., 2001. European J. Agronomy, 14: 167-172.

P deficiency can be rectified to

increase income and soil P status in rain-fed palmarosa

P applica-

tion (kg/ha/yr)

Net

balance of

available

P(kg/ha) in

soil(0-15

cm)

Palma-rosa

oil yield

(kg/ha)

Extra

income

(Rs/ha)

0 -0.9 38.1

17.5 7.0 40.4 3000

35.0 19.6 44.3 6000

52.5 19.7 47.0 13500

E.V.S.Prakasa Rao et al., 2001. European J. Agronomy, 14: 167-172.

Technology helps economics and environment in vetiver oil distillation

Method of

distillation

Firewood

consumption

(kg/batch)

Man

days/batch

Convention-

al

600 18

Improved 150 3

Method of distillation

Vetiver oil recovery

(%)

Vetiver oil yield

(kg/ha)

Conventional 0.78 17

Improved 1.20 25

Traditional distillation unit

Improved distillation unit E.V.S.Prakasa Rao et al., 2015.Sust. Agric. Rev. (in

press)

Vetiver dry leaves are used to make

temporary hutments for the farm workers in the western ghats area, India

Cultivation of vetiver on hill slopes in

western ghats, India provides

livelihood support besides protecting

the soil from erosion

Alternate uses of farm products can

generate employment and provide

livelihoods

Vetiver by- products

Run off and soil losses need to

be controlled in slopes of high rainfall regions

Method

Run off (% of

rainfall)

Soil loss (t/ha)

Infiltration

(% of rainfall)

Control

23.3

14.4

76.7

Vetiver on contours

15.5

3.9

84.5

Truong(1993)

Man –Soil Nexus

Soil provides

food, fibre, and

also shelter

Key Message,Finding and

Future Agenda

• Message: The nexus among farm income- soil

functions- environment is key to livelihoods in

south India

• Finding: Proper crop diversification, soil

management and technology have contributed

to the livelihoods

• Future agenda: Small farmers have to be made

partners not only in agriculture but also in soil

health and environmental protection through

appropriate institutional mechanisms

Thank you for your attention