Agricultural Water Management 161 (2015) 65–76
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Enhancing water and cropping productivity through Integrated
System of Rice Intensification (ISRI) with aquaculture and horticulture under rainfed conditions
Amod K. Thakur ∗, Rajeeb K. Mohanty, Rajbir Singh1, Dhiraj U. Patil
ICAR-Directorate of Water Management, Chandrasekharpur, Bhubaneswar 751023, Odisha, India a r t i c l e i n f o
Received 16 March 2015
Received in revised form 6 July 2015
Accepted 18 July 2015
Available online 7 August 2015
Rice (Oryza sativa)
Water management a b s t r a c t
The System of Rice Intensification (SRI), based on modifications in the management practices for rice cultivation, is being utilized inmany countries, although notwithout some controversy. One reason cited for non-adoption or disadoption of SRI is difficulties with water management under rainfed conditions with unreliable or aberrant rainfall distribution, which causes either flooding or long dry spells, or both. These constraints could be dealt with by tapping groundwater resources or by capture and use of rainwater runoff and/or by diversification of the farming system.
A 2-year field experiment was conducted in Odisha, India to evaluate SRI under rainfed conditions and also to explore options for enhancing the economic productivity of land andwater under such conditions.
Four rice cropping systems were evaluated: (i) conventional rice cultivation under rainfed conditions, (ii) SRI methods as adapted to rainfed cultivation, (iii) rainfed SRI methods with drainage facilities and supplementary pump-irrigation, and (iv) integrated SRI (ISRI) where rainwater runoff was harvested and stored for aquaculture and horticulture crops while also providing supplementary irrigation for the rice crop.
The rice crop grown with adapted SRI practices under rainfed condition showed significant improvements in the plants’ morphology and physiology. Phenotypic changes included: greater plant height and tillering, more number of leaves, and expanded root systems. These changes were accompanied by changes in plants’ physiological functions like greater xylem exudation rate and more light interception by the canopy, increased chlorophyll content in the leaves, andhigher light utilization andphotosynthetic rates during flowering. These factors were responsible for improved yield-contributing characteristics and for higher grain yield (52%) as compared with crops grown by conventional production methods.
Comparing yield from rainfed conventional vs. SRI methods between drought and normal-rainfall years indicated that the lattermethods aremore drought-tolerant and productive; greatly expanded and active root systems with SRI have been important contributing factors.
Introducing drainage and supplementary irrigation improved both the grain yield (by 29%) and water productivity for rainfed SRI. Further, integrating aquaculture and horticulture with SRI management and rainwater harvesting increased the rice yield further (by 8%) and the net water productivity. This integrated system was found to raise the net income per unit of water by more than 60-fold compared to conventional rainfed rice cultivation. This option looks promising for improving food security for smallholders under erratic or diminished rainfall conditions. © 2015 Elsevier B.V. All rights reserved. ∗ Corresponding author.
E-mail addresses: amod email@example.com, firstname.lastname@example.org (A.K. Thakur). 1 Present address: NRM Division (ICAR), New Delhi 110012, India. 1. Introduction
Food security is threatened by continuing population growth, declining arable land per capita, and water scarcity (Fedoroff et al., 2010; Satterthwaite et al., 2010), with these effects being exacerbated by the phenomena of climate change (Wheeler and von Braun, 2013). In recent years farmers have been experiencing declining growth of productivity, which is associated with several widespread phenomena such as land degradation, soil http://dx.doi.org/10.1016/j.agwat.2015.07.008 0378-3774/© 2015 Elsevier B.V. All rights reserved. 66 A.K. Thakur et al. / Agricultural Water Management 161 (2015) 65–76 fertility loss, salinization, erratic rainfall, and extreme weather events (IFPRI, 2009). In the near future, farmers and their agricultural systemsneed tobeable to copewithmore frequent incidences of extreme weather events due to climate change (Gornall et al., 2010; Lobell et al., 2009; Meinke et al., 2009; Naylor et al., 2007).
In rainfed areas, which amount to about 54 million ha worldwide, with a lack of irrigation facilities, rainfall is the only source of water for a rice crop that is grown just once a year, during the rainy season (Bouman et al., 2007). Due to uneven and unreliable rainfall distribution over the cropping season, either most of the rainwater from heavy downpours runs off and is lost from the rice fields, or long dry spells result in lowproductivity. Common features of rainfed rice production include lowproductivity (both crop andwater), poor fertilizer use-efficiency, and environmental pollution.
To meet rising food demand we need to increase the sustainability of food production in socially acceptable ways and from diminishing land and water resources (Schneider et al., 2011;
Swaminathan, 2007). Agriculture systems will need to evolve by intensifying production from available land, while practicing water-efficient techniques that will sustain also the associated ecosystems (Fedoroff et al., 2010; Giovannucci et al., 2012) under a changing climate (Gornall et al., 2010; Meinke et al., 2009; Naylor et al., 2007). 1.1. Water management alternatives in rice cultivation
A number of rice production systems that use various watersaving irrigation practices have been proposed to deal with such constraints, including alternate wetting and drying (Belder et al., 2004, 2007; Bouman and Tuong, 2001; Zhang et al., 2008); continuous soil saturation (Tuong et al., 2004); sprinkler irrigation (Muirhead et al., 1989); direct-dry seeding systems that use less water (Tabbal et al., 2002); and aerobic rice culture (Kato et al., 2009; Nie et al., 2012). However, they all too often involve some reduction in grain yield, increased costs of production, and a need for very precise control over irrigation water (Bouman et al., 2007).