Soil Organic Matter Management: The Roles of Residue Quality in C Sequestration and N Supply - Sustainable Management of Soil Organic Matter - page 193

S.K. Whiteet al. Low-input Ecological Rice Farming

3.13

Low-input Ecological Rice
Farming in Bangladesh

S.K. W HITE 1 , M.F. H OSSAIN 3 , N. S ULTANA 3 , S.F. E LAHI 3 ,
M.H. C HOUDHURY 2 , S. S ARKER 2 , Q.K. A LAM 2 , J.A.
R OTHER 4

AND J.L. G AUNT 1

1
IACR-Rothamsted,Harpenden, Hertfordshire AL5 2JQ, UK;
2
PROSHIKA, Mirpur 2, Dhaka; 3 Soil Science, Dhaka University,
Dhaka 1000, Bangladesh; and 4 NRI, Chatham, Medway, UK

Introduction

The population in Bangladesh is 120.8 million people and currently grow-
ing at an annual rate of 1.8% (Bangladesh Bureau of Statistics, 1997). With
a reduction in the per capita availability of cultivatable land, productivity
must be increased. Modern cereal varieties introduced throughout Asia
during the 1960s differed from the traditional varieties in their short stature
and stiffer straw. These plants do not lodge when N fertilizer is applied,
allowing them to produce higher yields. Generally farmers have sought
to maximize economic gain through the use of fertilizers and agricultural
chemicals to control weeds, diseases and pests. Modern varieties are less
sensitive to day length than traditional varieties, and where other climatic
factors and water supply are not constraints, continuous rice cropping is
possible. Using pumps to extract groundwater for irrigation, modern variet-
ies are now grown in the dry season in addition to the crop traditionally
grown in the monsoon season between July and September. The emergence
of the double-cropped rice system was central to the green revolution.
However, there is concern that rice yields may be declining under such
intensive cultivation in several Asian countries including Bangladesh
(Cassman and Pingali, 1995). There is some evidence for this from
experimental stations, but the anecdotal evidence from farmers - who are
more constrained by productivity factors such as labour, fertilizer and
pesticide - supports the view that greater inputs are required to maintain
the same level of yield.