Extent of Salt-Affected Soils and Their Effects in Irrigated and Lowland Rain-Fed Rice Growing Areas of Southwestern Tanzania

Kashenge-Killenga, S.; Meliyo, Joel L.; Urassa, Goodluck Charles; Kongo, Victor

doi:10.1007/978-3-319-41238-2_6

Cited by 9 publications

(9 citation statements)

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“…Rising aquifer levels due to over-irrigation are contributing to soil-salinization across the Rufiji River Basin [98] and other agricultural areas [99,100]. Moreover, groundwater is increasingly polluted as a result of human activities, notably by nitrates from poor sanitation and fertilizer use [101][102][103].…”

Section: (7) Risk and Resilient Decision-makingmentioning

confidence: 99%

The Water Governance Reform Framework: Overview and Applications to Australia, Mexico, Tanzania, U.S.A and Vietnam

Grafton

Garrick

Manero

et al. 2019

Water

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The world faces critical water risks in relation to water availability, yet water demand is increasing in most countries. To respond to these risks, some governments and water authorities are reforming their governance frameworks to achieve convergence between water supply and demand and ensure freshwater ecosystem services are sustained. To assist in this reform process, the Water Governance Reform Framework (WGRF) is proposed, which includes seven key strategic considerations: (1) well-defined and publicly available reform objectives; (2) transparency in decision-making and public access to available data; (3) water valuation of uses and non-uses to assess trade-offs and winners and losers; (4) compensation for the marginalized or mitigation for persons who are disadvantaged by reform; (5) reform oversight and "champions"; (6) capacity to deliver; and (7) resilient decision-making. Using these reform criteria, we assess current and possible water reforms in five countries: Murray-Darling Basin (Australia); Rufiji Basin (Tanzania); Colorado Basin (USA and Mexico); and Vietnam. We contend that the WGRF provides a valuable approach to both evaluate and to improve water governance reform and, if employed within a broader water policy cycle, will help deliver both improved water outcomes and more effective water reforms. will need to lower its projected 2050 total water demand by almost 40% (292 Billion Cubic Meters, BCM), the rest of South Asia by 43% (100 BCM), the Middle East by 42% (168 BCM) and North Africa by 17% (30 BCM), if water extractions are not to exceed the current total renewable water resources of these regions.Aeschbach-Hertig and Gleeson [6] argue that current food production in key farming regions of India, China and the USA cannot be maintained unless groundwater levels are stabilized. Another concern is that Wada et al. [7] estimate that, in 2000, non-renewable groundwater extraction contributed to 20% of global irrigation water extraction. This has important implications for food production because, globally, irrigation accounts for about 70% of global freshwater extractions and provides 40% of total human food calories. This tension between water for food production and other purposes is likely to be exacerbated into the future. For instance, by 2050: (1) the current water supply is projected to be less than the projected water applied for irrigation in major food-producing countries with production methods, and (2) a plateau is projected in terms of crop food production from water extractions if there are no further increases in the global irrigated agriculture area [8]. The key point is that in the absence of reform that includes: (1) better water governance and (2) how water is currently extracted and consumed, there are large, and with climate change, increasing risks to future food security [9].Government responses to the global water crises have, typically, been to adopt a "hard" infrastructure or engineering solutions to increase water supply that has sometimes been part of "water natio...

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Section: (7) Risk and Resilient Decision-makingmentioning

confidence: 99%

The Water Governance Reform Framework: Overview and Applications to Australia, Mexico, Tanzania, U.S.A and Vietnam

Grafton

Garrick

Manero

et al. 2019

Water

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“…Consequently, addressing the challenges facing food production, including soil salinization has become a major focus in recent decades (29,30). In Tanzania, the alarming condition of salt-affected soils has been reported by several researchers (31)(32)(33). Kashenge-Killenga et al (31) found that 7-15% of rice irrigation schemes were affected by salts, and about 2-10% of rice fields were abandoned.…”

Section: Introductionmentioning

confidence: 99%

Assessment of salt-affected soil in selected rice irrigation schemes in Tanzania: understanding salt types for optimizing management approaches

Omar,

Massawe,

Shitindi

et al. 2024

Front. Soil Sci.

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Salt-affected soils have serious implications for agricultural land quality and productivity, leading to a reduction in the net cultivable area available for food production. This issue has emerged as one of the foremost global challenges in recent years, impacting both food security and environmental sustainability. This research focuses on soil characterizations conducted in three irrigation schemes to understand the types, distribution, and nature of salt-affected soils. Auger observations served as the basic methodology for soil unit delineation in this study. Twelve representative soil pits with a depth of more than 160 cm were described, and undisturbed and disturbed samples were collected and analyzed for physical and chemical properties. The schemes were characterized by low levels of available phosphorus, organic carbon, and total nitrogen, as well as variations in exchangeable bases. Furthermore, 37.5% of the analyzed horizons highlighted the presence of salt-affected soils. Sodium was the predominant cation, followed by magnesium, potassium, and calcium. Likewise, HCO3− was the dominant anion, followed by Cl− and SO42−. The results of this study reveal the existence of two types of salt-affected soil. Uturo irrigation scheme had sodic soils, while the Ndungu irrigation scheme had saline-sodic soils. Additionally, both sodic and saline-sodic soils have been discovered in the Mawala irrigation scheme. The root cause of this challenge is inherent soil conditions, exacerbated by inadequate drainage infrastructure. Therefore, measures such as the application of gypsum followed by salt leaching, improving soil drainage by incorporating organic matter, improving drainage infrastructure, and using rice-tolerant varieties are recommended to mitigate salt stress and improve soil fertility. It is imperative to establish a robust framework for continuous monitoring and regular assessment of soil health to enable timely interventions and informed decisions for sustainable agricultural management.

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“…Alteration of these successive electrons transfers electrons to oxygen molecules which leads to the formation of reactive oxidative species that normally act as signaling molecules and may induce oxidative damage at high concentrations and reduce the rate of photosynthesis [13]. Saline soils are estimated to cover about 5-10 % of the world's arable land [9]. However, 20% of the world's irrigated land is adversely influenced by salinity and the problem is further increasing because of poor drainage and climate changes [22], [9].…”

Section: Introductionmentioning

confidence: 99%

“…Saline soils are estimated to cover about 5-10 % of the world's arable land [9]. However, 20% of the world's irrigated land is adversely influenced by salinity and the problem is further increasing because of poor drainage and climate changes [22], [9]. In Tanzania, the challenge is increasing rapidly as reported by FAO in 2003 about 3.5 million hectares are prone to salinity covering both the semi-arid, low land and irrigated and non-irrigated areas [14].…”

Section: Introductionmentioning

confidence: 99%

“…Salinity will be a constraint to sustainable rice production, therefore combating salinity is urgently needed to reduce the risk. Developing saline adaptive plants and a better understanding of its mechanism, especially rice, is urgently needed since mere soil remediation management will be difficult in Tanzania [9], [19]. Unfortunately, the tolerant mechanism to salt stresses not fully understood.…”

Section: Introductionmentioning

confidence: 99%

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Morphogenetic Response of Assorted Rice Genotypes to Salinity in Tanzania

Sitta

Kashenge²,

Lee

et al. 2022

EJFOOD

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Salinity, where salts concentrate on the soil surface causing severe decline of crop yields, is a worldwide problem. In Tanzania salinity is one of the major soil degradation challenges affecting over 3.5 million hectares limiting agriculture productivity of various crops including rice. Most of the varieties grown are sensitive to salts and inadequate tolerant cultivars available in the country. A hydroponics mass screening technique using Yoshinda Solution was used to test the 102 genotypes in NaCl- saline treated and non-treated solution at Tanzania Agricultural Research Institute (TARI-Dakawa Centre). Different salt concentrations (4 dSm-1, 6 dSm-1, 8 dSm-1 and 10 dSm) were used and the experiment was done in three replications. The genotypic variability for salinity tolerance was observed as less salt injury symptoms, low Na+ accumulation and Na+/K+ ratio in plant tissues and high biomass accumulation (fresh weight and dry weight). Results revealed further those 28 genotypes (28.45%) out of 102 showed tolerance to salinity, at high salinity level of 10dSm-1. Lines namely SR35266-2-18-2-1, SR35250-1-19-1-1, SR23364-128-1762-1-HV-1-1, SR35230-1-12-1-1, SR23364-128-1986-1-HV-1-1, SR34590-HB3433-4-1-1, SR35266-2-7-1-1, PBR1000922-1 and SR34053 (#5-52)-1-4-2-10-3-3 showed high performance under high salt conditions. Others includes SR35266-3-1-5-1, SR34574-2-10-3-1-2-1, SR35278-2-10-1-1, SR35250-2-3-1-1, SR35266-3-2-3-1, SR35266-3-2-4-1, SR23364-133-184-1-HV-1-1, SR34592-HB-1-HV-1, and SR34042F3-22-1-1-5-3 indicated tolerance to salt and had high dry matter as well. All the genotypes had increased levels of Na+ and differential performance was observed in some genotypes under saline and non-saline conditions. Among these three lines namely SR35266-2-7-1-1, SR23364-128-1762-1-HV-1-1, and SR34590- HB3433-4-1-1expressed high dilution ability as the K+ and Na+ concentrations were lower compared to other genotypes. The study, therefore, suggests that the lines can be used in breeding programs to develop varieties with potential to salt tolerance and other traits.

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Extent of Salt-Affected Soils and Their Effects in Irrigated and Lowland Rain-Fed Rice Growing Areas of Southwestern Tanzania

Cited by 9 publications

References 10 publications

The Water Governance Reform Framework: Overview and Applications to Australia, Mexico, Tanzania, U.S.A and Vietnam

The Water Governance Reform Framework: Overview and Applications to Australia, Mexico, Tanzania, U.S.A and Vietnam

Assessment of salt-affected soil in selected rice irrigation schemes in Tanzania: understanding salt types for optimizing management approaches

Morphogenetic Response of Assorted Rice Genotypes to Salinity in Tanzania

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