Land-water-energy nexus and long-term climatic trends in smallholder irrigation schemes: evidence from Vhembe District, South Africa

Résumé

Sustainable irrigation for smallholders requires strategies that minimize and optimize land, water, and energy use while remaining resilient to climate change. The study uses the Land-Water-Energy (LWE) nexus and long-term climate trends to assess smallholder irrigation performance. The Land-Water-Energy Nexus Index (LWENI) assesses the sustainability of four smallholder irrigation systems in Vhembe District. Six normalized indicators for the availability and accessibility of land, water, and energy resources were scored on a 0–1 scale and then aggregated with equal weighting. The standardized composite LWENI scores ranged from 0.53 (Rambuda) to 0.74 (Mphaila), indicating performance ranging from moderately unsustainable to moderately sustainable. These results suggest that smallholder irrigation farmers operate in a zone of functional yet fragile resource integration. The spider diagram visualization shows substantial internal imbalances, with distorted forms indicating inadequate integration of LWE resources, notably land dependency at the expense of electricity infrastructure and a dependable water supply. These trends highlight irrigation issues for smallholders, including siloed management that limits production and resilience. Climatic data analysis (1980–2024) revealed significant seasonal precipitation variability with weak linear increases (3.89 mm/year, R 2 = 0.01, p < 0.04), while maximum temperatures showed a significant warming trend (0.04 °C/year, R 2 = 0.10, p < 0.01), contributing to increased aridity, as indicated by a 0.01 decline in the Climate Moisture Index. The correlation analysis between LWENI components and climate variables revealed significant positive associations between local maximum temperature trends and both water availability (R 2 = 0.98, p = 0.022) and water accessibility (R 2 = 0.99, p = 0.013), a pattern interpreted as a monitoring signal rather than a causal finding, given the small sample of four schemes. The combined LWENI and climatic evaluations show that Vhembe District irrigation schemes face resource imbalances, inconsistent energy supply, and increasing climatic unpredictability. Land tenure provides some stability, but water and energy shortages, rising temperatures, and erratic precipitation threaten agricultural production and food security. Infrastructure rehabilitation, solar-powered systems, climate-smart practices, and integrated LWE nexus planning may increase resource efficiency, resilience, and sustainability for these semi-arid smallholder farmers.

Citer ce document

Accès au document

Texte intégral en lecture en ligne, réservé aux abonnés SPHAERO et aux membres de l'institution. Se connecter

Auteur(s)

Statistiques

Consultations : 1

Téléchargements : 0