Effect of water, crop and nitrogen management practices on water productivity, yield and greenhouse gas emission in irrigated lowland rice, eastern Tanzania
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Date
2022
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Abstract
Rice (Oryza sativa L.) is one of the most important grain crops for more than 50%
of the world’s population, providing approximately 20% of total energy intake for
humans (Muthayya et al., 2014).
• Rice is also the largest consumer of water among all crops (Deng et al., 2021;
Bouman and Tuong , 2001).
• The water productivity of rice is lower than those of other crops (Kumar and
Rajitha, 2019).
• In Tanzania, about 90% of rice is grown under continuous flooding (CF), a practice
that requires large amounts of water with less productivity (Katambara et al 2013;
FAO, 2012) and contribute to emission of greenhouse gas emission ( Methane,
carbon dioxide and nitrous oxide (Adounkpe et al .,2021).
• Water productivity of rice that ranges from 0.1 to 0.14 kg m−3 has been recorded
in Tanzania, which is lower when compared to 0.60–1.60 kg m-3 in other parts of
the world (Najmuddin et al .,2018).
• On average, 2500 liters of water is used, ranging from 800 liters to more than 5000
liters to produce one kg of rice (Najmuddin et al .,2018;Bouman and Tuong 2001).
By 2025, 15–20 million ha of irrigated rice is estimated to suffer
from some degree of water scarcity (Bouman and Tuong, 2001).
• Alternate wetting and drying (AWD) irrigation practice has been
demonstrated to provide advantages in terms of reducing water
use and increasing crop productivity.
• In addition to water, nitrogen is one of the most important
nutrients that determine rice yields (Zhang et al., 2021, Djaman et
al., 2018; Saito et al., 2015); its deficiency is a limiting factor for
sustainable rice production.
• However, the use of N fertilizer is generally inefficient, and the
average apparent recovery efficiency of N fertilizer is about 33% for
rice globally (Zhang et al., 2021).
Description
Conference Paper
Keywords
Rice, Crop, Nitrogen management, Gas emission, Greenhouse