Water adequacy is central to maximised agricultural production in irrigation schemes. Smallholder Irrigation Schemes (SISs) are designed to distribute water efficiently, adequately and equitably. Water governance, defined as the institutions, processes, procedures, rules and regulations involved in water management, plays an important role in water allocation and subsequently water adequacy. The intersectoral institutions involved in water governance in SISs, i.e., government, Water User Associations (WUAs), Irrigation Management Committees (IMCs) and traditional authorities, interact to formulate and design policies for running SISs. However, multilevel interaction amongst the active stakeholders at multiple levels shapes policy and underlies SIS performance. This research aimed to investigate the impacts water governance had on adequacy of water in irrigation schemes and was premised on the hypothesis that governance had no effect on water adequacy. Water adequacy describes water supply relative to demand. Adequacy indicates whether the water delivery system supplies the required amount to a section in the irrigation scheme over a period of time (daily, monthly or seasonally). Two irrigation schemes, the Mooi-River Irrigation Scheme (MRIS) and Tugela Ferry Irrigation Scheme (TFIS) were used as case studies. A descriptive analysis showed that 86% of the farmers in the TFIS had adequate water, whereas 24% had water adequacy in the MRIS. A Binary Logit model was employed to investigate the factors that influence water adequacy among irrigators. The regression model identified eight statistically significant factors that influenced water adequacy: the irrigation scheme, location of plot within the scheme, training in water management, training in irrigation, SIS irrigators' knowledge about the government's aims, availability of water licences, payment of water fees and satisfaction with the irrigation schedule. The study concluded that governance factors had influence on water adequacy in the selected SISs. The implication is that stakeholders should make irrigators aware of government Irrigation Management Transfer (IMT) policy and strategies. The study recommends that the SISs introduce rules, procedures and protocols to support irrigators to enhance scheme governance and lead to the realisation of government policies.

The AquaCrop model was calibrated and validated for canola (Brassica napus) under Moistube irrigation (MTI) and various water regimes [(i) 100%, (ii) 75%, and (iii) 55% of crop water requirement (ETc)] over two seasons, 2019 and 2020. The normalised root mean square (nRMSE), Model Efficiency (EF), R2, and the Willmot’s index of agreement (d) statistics were used to evaluate the model’s efficiency in simulating biomass (B), canopy cover (CC), yield (Y), and harvest index (HI). The calibration results indicated the model simulated with accuracy the CC (under 100% ETcR2 = 0.99, EF = 0.92, nRMSE = 6.4%, d = 0.98) and 75% ETc (R2 = 0.99, EF = 0.92, nRMSE = 10.3%, d = 0.98). The model simulated CC well for validation for 100% ETc (R2 = 0.97, EF = 0.93, nRMSE = 22.5%, d = 0.98) and 75% ETc (R2 = 0.84, EF = 0.45, nRMSE = 59.2%, d = 0.86) irrigation regimes. Final biomass simulations were reasonably good under 100% ETc, 75% ETc, and 55% ETc irrigation regimes (R2 > 0.90, d > 0.65). The study showed the usefulness of AquaCrop for assessing yield response of canola to full and deficit irrigation scenarios under MTI.

Sustainable agricultural intensification requires irrigation methods and strategies to minimise yield penalties while optimising water, land and energy use efficiencies. We assessed, from a silo-based and integrated water-energy-food (WEF) nexus perspective, the performance of irrigation technologies in different agro-climatic regions. Secondary to this, we assessed the impact of adopting systematic approaches such as the WEF nexus on improving efficiency in irrigated agriculture through irrigation modernization. The evidence-based perspectives of silo-based performances individually considered the metrics of yield (Y), water use efficiency (WUE), and energy productivity (EP). The WEF nexus approach applied sustainability polygons to integrate the three metrics into a nexus index representing the holistic performance of the irrigation technologies. Silo-based performance in temperate regions suggests net gains for WUE (+1.10 kg.m-3) and Y (+6.29 ton.ha-1) when transitioning from furrow to sprinkler irrigation, with a net loss in EP (-3.82 ton.MJ-1). There is potential for net loss on EP (-3.33 ton.MJ-1) when transitioning from furrow to drip system in temperate regions. The best performance of irrigation technologies in dry regions in water, energy and food silos was achieved by sprinkler, drip and furrow irrigation systems, respectively. Thus, appraising irrigation technologies from a silos perspective promotes individual silos, which renders an unsustainable picture of the performance of irrigation systems. The integrative WEF nexus approach successfully highlighted the trade-offs and synergies in the nexus of water, energy and food in irrigated agriculture. Drip irrigation led all irrigation technologies in WEF nexus performance in dry (21.44 unit2), tropical (23.98 unit2), and temperate regions (47.28 unit2). Overall, the irrigation modernisation pathway to drip technology from either furrow or sprinkler systems improves irrigated agriculture's WEF nexus performance in all three regions for more crop per drop per joule per hectare under climate change. This has positive potential to influence the sustainability of planetary boundaries.

Agriculture is the biggest consumer of fresh water in the world accounting for almost 70% of the water use. The burgeoning world population and increased demands to feed the world requires novel technologies that reconcile water consumption and food security. Moistube is a polymeric semi-permeable membrane irrigation technology that is known to improve water use efficiency and boost yields. The technology is relatively new, hence a lack of comprehensive literature regarding Moistube irrigation (MTI) technology warrants empirical investigation of the existing literature. The study performed a systematic review guided by the Preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P) and the scoping studies methodological framework to compile an evidence-based literature review on Moistube irrigation. The study performed search queries in the following over-arching and comprehensive databases for grey literature: Google Scholar, Science Direct, Research Gate, CAB direct, All Journals, CNKI, FAO, SCOPUS, Web of Science, and UKZN-EFWE. DistillerSR software was used for screening, data extraction and data charting. Article screening retained one hundred and 55 (n = 155) articles. Forty-nine articles (n = 49) and information sources were found to be related directly and indirectly to Moistube. Moistube articles (n = 29, 59%) were from China were the technology originated. A bulk of literature reported Moistube irrigation use in the arid regions of China. The review revealed areas for research enquiry into the subject matter. Future research areas were fertigation performance under MTI, effects of waste-water on MTI nanopore plugging, yield response of industrial crops of economic importance under MTI and soil wetting geometries under MTI. This signified the need to perform further research enquiries into the subject matter to improve literature availability. Moistube irrigation technology has a low adoption rate in Africa with reported use in South Africa and Morocco. The technology has massive adoption potential in arid and semi-arid regions of sub-Sahara Africa.

Objective The analytical study systematically reviewed the evidence about the IWRM strategy model. The study analysed the IWRM strategy, policy advances and practical implications it had, since inception on effective water management in East, West and Southern Africa. Methods The study adopted the Preferred Reporting Items for Systematic Review and Meta-analysis Protocols (PRISMA-P) and the scoping literature review approach. The study searched selected databases for peer-reviewed articles, books, and grey literature. DistillerSR software was used for article screening. A constructionist thematic analysis was employed to extract recurring themes amongst the regions. Results The systematic literature review detailed the adoption, policy revisions and emerging policy trends and issues (or considerations) on IWRM in East, West and Southern Africa. Thematic analysis derived four cross-cutting themes that contributed to IWRM strategy implementation and adoption. The identified four themes were donor effect, water scarcity, transboundary water resources, and policy approach. The output further posited questions on the prospects, including whether IWRM has been a success or failure within the African water resource management fraternity.