Water Use and Rice Productivity for Irrigation Management Alternatives in Tanzania

Stanslaus Materu,Andrew Tarimo,Rajendra Sishodia,Siza Tumbo,Sanjay Shukla

doi:10.3390/w10081018

Stanslaus Materu, Andrew Tarimo + Show 3 more

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https://doi.org/10.3390/w10081018

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Journal: Water	Publication Date: Aug 1, 2018
Citations: 25	License type: CC BY 4.0

Affiliation: Sokoine University of Agriculture, University of Florida

Abstract

Rice production is important for global food security but given its large water footprint, efficient irrigation management strategies need to be developed. Expansion of rice growing area is larger than any other crop in Africa due to increasing demand for rice. Three rice irrigation management alternatives with the system of rice intensification (SRI) were field-evaluated against the conventional continuously flooded system (CF) in Tanzania. Production systems included: (1) CF (50 mm ponding depth for the entire season); (2) SRI (40 mm ponding for 3 days and no irrigation for next 5 days); (3) 80% SRI (80% of the SRI ponding); and (4) 50% SRI (50% of the SRI ponding). Experimental evaluation of the four systems was conducted for both wet and dry seasons. For the dry season, the SRI and 80% SRI produced higher yields of 9.68 tons/ha and 11.45 tons/ha and saved 26% and 35% of water, respectively compared to the CF (8.69 tons/ha). The yield advantage of the 80% SRI and SRI over the CF was less during the wet season with 6.01 tons/ha and 5.99 tons/ha of production, and water savings of 30% and 14%, respectively compared to the CF (5.64 tons/ha). The 50% SRI had lowest yield of all for both seasons, 7.48 tons/ha and 4.99 tons/ha for the dry and wet seasons, respectively. Statistically, the 80% SRI treatment outperformed all other treatments over the two seasons with an additional yield of 1.57 tons/ha and 33% (345 mm) water savings compared to the CF. Economic productivity of water (US$/ha-cm) over two seasons was highest for the 80% SRI ($20.27/ha-cm), while it was lowest for the CF ($12.89/ha-cm). Water saved by converting from the CF to the 80% SRI (1.98 million ha-cm) can support a 50% expansion in the current rice irrigated area in Tanzania. Even without irrigation expansion, the 80% SRI can increase rice production by 1.5 million tons annually while enhancing water availability for industrial and environmental uses (e.g., ecological preserves) and help achieve food security in Tanzania and the greater sub-Saharan Africa.

Highlights

Water is a valuable resource that is becoming increasingly scarce due to growing population and intensifying agriculture [1]
Expansion of rice growing area is larger than any other crop in Africa due to its increasing demand
Plant height for the continuous flooding (CF) and system of rice intensification (SRI) treatments were significantly (p < 0.05) higher than both the 80%

Summary

Introduction

Water is a valuable resource that is becoming increasingly scarce due to growing population and intensifying agriculture [1]. Water scarcity is challenging the ability of countries to meet the increasing food demand [2]. Of the three main food crops (maize, wheat, and rice), rice is the most important crop especially in developing countries [5]. Water 2018, 10, 1018 reduce water inputs for rice production such as deficit irrigation need to be explored. Deficit irrigation is a technique used to minimize water losses and increase water efficiency, especially in areas where there is insufficient water supply for irrigation. Deficit irrigation management involves inducing marginal stress, except in critical growth stages where crop yield might be negatively affected [6]

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