Resource Use Efficient and Productive Rice-Based Systems for South Asia

JIRCAS International Symposium Proceedings

In South Asia, rice is the topmost, followed by wheat and maize in terms of area, production and yield. While
rice and wheat are grown for grain, maize may be grown for grain, green cobs or fodder for animals. Three
cereals are cultivated either as a mono crop in irrigated areas or a mixed crop in dryland, mostly in fixed
sequences. Maize is cultivated in homesteads in both monsoon and winter seasons on the hills of Nepal and
Pakistan and in eastern India. Rice-wheat (R-W) is the predominant cropping system (CS) with 12.6 m ha in
the sub-tropical areas of the Indo-Gangetic Plains (IGP); double (R-R) or triple (R-R-R) rice crops with 9.5
and 0.34 m ha, respectively, are common in tropical irrigated or favourable rainfed lowlands of eastern IGP
with distinct dry and wet seasons. The intensively cultivated irrigated rice?wheat system is fundamental to
employment, income, and livelihoods for hundreds of millions of rural and urban poor of South Asia.
However, yield stagnation/decline together with large yield gap; water and labor scarcity; and soil, water, and
air pollution are the emerging threats to the sustainability of rice-wheat systems. Therefore, the design and
implementation of alternative production systems with increased resource use efficiency, profitability and
productivity, and reduced adverse environmental impact, are urgently required. One of the strategies to
address emerging problems, specifically shortages of water and labor, is to grow rice and wheat in
direct-seeding without tillage utilizing integrated crop and resource management (ICRM) strategies.
Integrated crop and resource management for enhancing productivity and resource use
Two types of trials were conducted to evaluate and refine various technological options. Well-planned
on-station research trials were conducted at selected research farms where detailed measurements were made.
From on-station trials, successful technologies were introduced to farmers’ fields for further evaluation and
eventually wider dissemination. Numerous trials were conducted to evaluate various technologies in rice and
wheat at various sites of four IGP countries which includes optimal (1) land preparation, (2) water
management, (3) crop establishment (time and method of seeding/transplanting, age, number of seedlings, and
plant density in the case of rice and seeding rate and depth in the case of upland crops such as wheat), and (4)
nutrient, pest, and weed management.
We measured the following four groups of performance indicators in both on-station and on-farm trials: (1)
crop productivity, (2) pattern of resource (labor, water, agro-chemicals) use, (3) partial budgeting (various
costs and profit), and (4) global-warming potential (GWP). The on-station trials followed proper experimental
design and replications; hence, adequate statistical analyses were done. But, for on-farm trials, for which
proper experimental designs are often not possible, data were analyzed using SAS mixed model procedure, in
which treatment was used as a fixed effect and farmer as a random effect.
On-station technology performance
The productivity of the RW system has been stagnant in recent years because of (1) contrasting tillage
requirements for rice and wheat, (2) delayed wheat sowing, (3) poor maintenance of soil structure, and (4)
poor management of irrigation water, agro-chemicals, including fertilizer, and crop residues. On-farm technology performance
Farmers can effectively reduce their yield gaps and enhance farm income by adopting ICRM in rice. ICRM
in rice, which also included crop need-based N management with the help of an LCC for transplanted rice
(CT-TPR-LCC), increased grain yield by 0.24 to 0.75 t ha?1 and net income by $41 to $49 ha?1 and reduced
fertilizer cost because of efficient N use. Likewise, ICRM in zero-till drill-seeded wheat (ZT-DSW-ICRM)
increased mean grain yield by 1.06 t ha?1. So far, crop management has largely been developed and promoted
in a conventional rice system (CT-TPR). However there is an urgent need for a full package of crop
management together with conservation tillage for both rice and wheat. Crop residue is another missing link
that should be factored in ICRM. The adoption of a full package of ICRM is essential to maximize system
productivity (reduce yield gap) and profit, and save resources.
Reduced-till and zero-till drill-seeded wheat either on flat (RT-DSW/ZT-DSW/RT-DSW-PTOS) or raised
beds (Bed-DSW) was productive and profitable, with a yield advantage of 0.14 to 0.46 t ha?1 and net income
from $76 to $200 ha?1. Therefore, minimum- or zero-tillage is becoming increasingly popular among farmers
in parts of the IGP. Reduced or zero-tillage facilitates timely wheat planting. Reduced- or zero-till wheat is
established by tractor-operated drill seeding with or without crop residues in combine-harvested rice fields.
Retaining crop residues as mulch would reduce the perceived need to burn rice residues in the northwest IGP
and likely enhance the scope of organic matter accumulation in the soil, and move the system toward
conservation agriculture.
A number of ICRM modules which encompass following practices were developed and promoted (1) enhance
resource- or input-use efficiency; (2) provide immediate, identifiable, and demonstrable economic benefits
such as reductions in production costs, and savings in water, fuel, and labor requirements; and (3) ensure
timely crop establishment and uniform crop stands, resulting in higher crop yields. Indirect benefits include
(1) effective control of Phalaris minor, a major weed in wheat by zero-tillage; (2) replacement of residue
burning by retention of crop residues, resulting in some improvement in certain soil quality parameters,
including short-time accumulation of carbon in surface soil; (3) a reduction in methane emissions from
nonpuddled and nonflooded rice fields; (4) buildup of soil fertility over the long term, leading to sustainability
of intensive rice-wheat cultivation; and (5) the generation of rural employment by training and empowering
local farm machine manufacturers, custom-hire service providers, retailers and traders, and seed producers.
Although ICRM with tillage and crop establishment options has been more successful in wheat, the next
frontier will be to make similar headway in rice. In short, integrating new RCTs into the portfolio of farmers’
current technologies using the framework of ICRM (good agronomy) will continue to be a key to improving
productivity and production (thereby reducing yield gap) and eventually attaining national food security.

作成者 Jagdish K. Ladha

Rice-based cropping system



integrated crop resource management


conservation agriculture

公開者 Japan International Research Center for Agricultural Sciences
開始ページ 146
終了ページ 151
権利 Japan International Research Center for Agricultural Sciences
言語 eng