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RESEARCH
R E P O R T
Trees and Water:
122
Smallholder Agroforestry on
Irrigated Lands in Northern India
Robert J. Zomer, Deborah A. Bossio, Antonio Trabucco, Li Yuanjie,
Diwan C. Gupta and Virendra P. Singh
International
Water Management

I n s t i t u t e IWMI is a Future Harvest Center
supported by the CGIAR
Research Reports
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Research Report 122
Trees and Water: Smallholder Agroforestry
on Irrigated Lands in Northern India
Robert J. Zomer, Deborah A. Bossio, Antonio Trabucco,
Li Yuanjie, Diwan C. Gupta and Virendra P. Singh
International Water Management Institute
P O Box 2075, Colombo, Sri Lanka
i
IWMI receives its principal funding from 58 governments, private foundations, and
international and regional organizations known as the Consultative Group on International
Agricultural Research (CGIAR). Support is also given by the Governments of Ghana,
Pakistan, South Africa, Sri Lanka and Thailand.
The authors: Robert J. Zomer is a Senior Researcher at the World Agroforestry Centre
(ICRAF), P. O. Box 30677, Nairobi, Kenya (e-mail: [email protected]); Deborah A. Bossio
is Director - Research Programs at the International Water Management Institute (IWMI),
P. O. Box 2075, Colombo, Sri Lanka (e-mail: [email protected]); Antonio Trabucco and
Li Yuanjie are former Research Associates at the International Water Management Institute
(IWMI), P. O. Box 2075, Colombo, Sri Lanka (e-mail: [email protected]
and [email protected], respectively); Diwan C. Gupta is Group Leader-Socio Consult B-6,
Kamla Nehru Nagar, Khurram Nagar, Lucknow – 226022, Uttar Pradesh, India (e-mail:
[email protected]); Virendra P. Singh is a Principal Researcher and Coordinator at
the South Asian Regional Office of the World Agroforestry Centre (ICRAF), Regional Office
for South Asia, 1st Floor, CG-Block, NASC Complex, Dev Prakash Shastri Marg, Pusa
Campus, New Delhi - 110 012, India (e-mail: [email protected]).
Acknowledgments: The authors would like to acknowledge the support of the International
Water Management Institute (IWMI) and the World Agroforestry Centre (ICRAF). The field
survey was conducted by Socio-Consults, Lucknow, Uttar Pradesh, India. The authors
thank, especially Dr. Hammond Murray-Rust for his early support that allowed this work to
proceed. Also, they extend their thanks to ICRISAT for performing soils analysis, to
Dr. Jan Larman of World Agroforestry Centre for helping to facilitate the soils work,
Dr. Hugh Turral of IWMI for providing input and support, and Oliver van Straaten for providing
technical and fieldwork assistance.
Zomer, R. J.; Bossio, D. A.; Trabucco, A.; Yuanjie, L.; Gupta, D. C.; Singh, V. P. 2007.
Trees and water: Smallholder agroforestry on irrigated lands in Northern India. Colombo,
Sri Lanka: International Water Management Institute. 47p. (IWMI Research Report 122)
/ trees / Populus deltoides / agroforestry / models / water balance / evapotranspiration /
remote sensing / irrigation requirements / India /
ISSN 1026-0862
ISBN 978-92-9090-685-8
Copyright © 2007, by IWMI. All rights reserved.
Cover picture: Over the last several decades, poplar agroforestry has been adopted by
tens of thousands of small farmers, with poplar trees now a common site throughout the
irrigated rice-wheat farmlands of northern India (photo credit: Oliver van Straaten).
Please send inquiries and comments to: [email protected]
Contents
Acronyms iV
Summary v
Introduction 1
Research Objectives 6
Methods 7
Results and Discussion 23
Hydrologic Impact of Agroforestry in Irrigated Areas 29
Conclusion 36
References 38
iii
iii
Acronyms and Abbreviations
AET Actual Evapotranspiration
AI Aridity Index
EC Electrical Conductivity
ET Evapotranspiration
ETP Entire Tree Plant
FAO Food and Agriculture Organization of the United Nations
FCD Forest Canopy Density
GIS Geographic Information System
GPS Global Positioning System
ICRAF World Agroforestry Centre
ICRISAT International Crops Research Institute for the Semi-Arid Tropics
IWMI International Water Management Institute
MODIS Moderate Resolution Imaging Spectrometer
NASA National Aeronautics and Space Administration
NDVI Normalized Difference Vegetation Index
PET Potential Evapotranspiration
WHO World Health Organization
WIMCO Western India Match Company
iv
Summary
Trees are increasingly grown on-farm to supply located within the study area in northern India. The
wood and biomass needs, in both temperate and study observed that poplar plantation increased
tropical climates, as well as in developed and water productivity and profitability of the smallholder
developing countries. Over the last several decades, farmers. As this agroforestry system replaces an
within the irrigated rice-wheat growing lands of already intensively irrigated cropping system, the
northern India, a considerable number of fast- establishment of poplar agroforestry on 10% of the
growing poplar trees have been planted on tens of area adds only a very marginal increase to the
thousands of small farms. This trend is driven by existing water use for crops in this region. The
economic incentives (as wood production is often impact on annual irrigation requirement for the
more valuable or less labor intensive) and by region (at the current level of adoption for poplar
national policies (as they aim to limit further agroforestry) is estimated to be minimal (1.6%
deforestation in regional forests). Recent debate increase), whereas the contribution of poplar trees
regarding tree plantings has raised the issue that to the local economy and farmer livelihoods is quite
water use is often increased when trees are planted. significant and well established. This study
This ongoing debate focuses primarily on concludes that the widespread adoption of poplar
afforestation or reforestation of upland and rain-fed agroforestry and other tree-based systems has
agricultural areas, and on resulting off-site impacts created a substantial improvement in the water
such as reduced streamflow. Adoption of poplar productivity of this intensively irrigated region. In
agroforestry in northern India, in contrast, is particular, it was found that boundary plantings had
occurring in areas where land and water are already little or no impact on regional water use, but could
intensively used and managed for agricultural add significantly to ‘farmer-livelihood and economic-
production. security’. The importance of growing trees outside
This study used farmer-survey data, remote of forests, in general, for domestic and industrial
sensing, and hydrological modeling of the prevalent uses, and growing trees on-farm, in particular, to
cropping systems to investigate the importance and directly reduce pressure on forests, wildlife habitat
role of the poplar trees within the agricultural and biodiversity, is highlighted in the study. Overall,
landscape, and to estimate their water use. It was these results illustrate a potential for meeting the
found that trees are currently grown on increasing global demand for wood from trees grown
approximately 10% of the irrigated lands, which are on-farm in irrigated agroforestry systems.
v
Water and Trees: Smallholder Agroforestry on
Irrigated Lands in Northern India
Robert J. Zomer, Deborah A. Bossio, Antonio Trabucco, Li Yuanjie, Diwan C. Gupta and
Virendra P. Singh
Introduction
The role of trees within landscapes has been given crops, has been promoted for many years as a
much attention recently, in contexts ranging from partial solution to rising demand. In India, this
local watersheds to regional impacts and global concept has received widespread support (Puri and
cycles. As an example, trees, forests and Nair 2004); so that a significant proportion of the
reforestation are specifically identified as viable national wood demand is currently met by what is
climate change mitigation measures by the Kyoto produced on-farm. Various fast-growing species
Protocol (IPCC 2000), but have also been identified have been introduced across India specifically to
both as carbon sinks and sources. It is evident meet the local and regional wood needs. Several of
that widespread and continuing deforestation has these trees, notably various species of Eucalytpus
significantly reduced the extent of forests globally, and Prosopsis, have given rise to much
in general, and across the tropics, in particular controversy due to a general impression that their
(FAO 2006). Increasing population pressure, and increased water use has a negative impact on
demand for both food and wood have led to the water balances (Calder 1992, 2000, 2002).
conversion of large areas of forest to agriculture, Across northern India (Figure 1), from Punjab
industrial, urban, and other uses reducing not only through Haryana and Uttar Pradesh to West
terrestrial carbon stocks, but also the supply of Bengal, poplar (Populus deltoides) trees, which
easily available wood. The resulting scarcity of were introduced in the early 1970s to supply wood
fuelwood, timber for construction and wood for a to a local match factory, have been widely
huge array of industrial and commercial uses has adopted. These trees are planted on irrigated land
imposed significant constraints on the rapidly traditionally used for cereal production in a rice/
growing rural societies and the national economies wheat rotation. It has been proposed that including
of many developing countries. This is particularly a tree component within the farming system, either
true in the drier and semi-arid regions of the on bunds and boundaries (sequentially with crops)
tropics. The rising concern over these issues and or intercropped in an agroforestry type
the increasing awareness of the important role of configuration, can lead to increased land
trees and forests within terrestrial biogeochemical productivity while diversifying the farming enterprise
cycles, have led many countries to impose (Atta-Krah et al. 2004; Huxley 1999; Young 1989),
substantive measures to conserve their remaining and increase economic security for small farmers
forests, further reducing the supply of local wood. (Russell and Franzel 2004). In light of prevailing low
Driven both by population growth and increasing grain prices, due in part to successive abundant
standards of living, the demand for wood, as well harvests from these intensively cultivated lands,
as the demand for agricultural land, will continue to poplar agroforestry has become increasingly
grow in the future. Producing wood on-farm, either attractive to farmers. In this agroforestry system,
in woodlots or intercropped with other agricultural poplar and sometimes other trees are planted in
1
FIGURE 1. Map showing the location of the study area in northern India. Poplar agroforestry stretches in a belt from the
Punjab, through Haryana and western Uttar Pradesh states.
association with a variety of crops, including rice, Trees and Water
wheat, sugarcane, berseem clover, and sorghum;
and, at times, other tree crops such as mango or Numerous projections with regard to water supply
citrus (Figure 2). These systems provide various and scarcity focus on the rising global population
products, which contribute to commercial and and the increasing need for domestic, industrial,
subsistence agricultural productivity as well as to agricultural and recreational water (e.g., IWMI’s
farm family livelihoods. For example, within the Global PODIUM online interactive model at http://
study area, as in many parts of South Asia, cattle podium.iwmi.org). Over 1.1 billion people currently
manure is commonly burned for fuel (Figure 3). lack access to safe and affordable water for their
Hopefully, increased regional availability of on-farm domestic use (WHO 2006). The majority of these
woody biomass might allow for a shift to increased people are the rural poor who lack water not only
use of fuelwood, and the recycling of farm animal for domestic purposes, but also to sustain their
manures back into compost and soil to improve agricultural livelihoods (Rijsberman et al. 2006). To
farm fertility. meet growing food demand, water diversion for
2