Medium-Term Effects of Sprinkler Irrigation Combined with a Single Compost Application on Water and Rice Productivity and Food Safety

Overview

This multi-year field experiment (2015 to 2019) in a semiarid Mediterranean region of Spain evaluated six rice management systems combining sprinkler or flooding irrigation with conventional tillage or no-tillage (direct seeding), with or without a single compost application (composted two-phase olive mill waste, 80 Mg per ha). The study measured grain yield, water use, and grain arsenic and cadmium concentrations.

Sprinkler irrigation saved 55% of total water compared to flooding. The highest arsenic in grain was found under the ST (sprinkler + conventional tillage) treatment. Sprinkler irrigation reduced grain arsenic compared to flooding, but compost application (FT-C) decreased grain arsenic under flooding. Sprinkler irrigation favored cadmium uptake by plants, though this was reduced under SNT (sprinkler + no-tillage) compared to ST, and especially under amended compost treatments.

Key numbers

Grain yield: highest under ST at 10,307 and 11,625 kg per ha in 2018 and 2019; mean across study approximately 8,140 kg per ha (p. 1 abstract).

Water savings: sprinkler irrigation saved 55% of total water applied compared to flooding (p. 1 abstract).

Grain arsenic: highest under ST; decreased with compost application (FT-C) and with sprinkler irrigation overall. Specific grain arsenic concentrations not quoted in the abstract; the paper reports that sprinkler irrigation reduced arsenic compared to flooding (p. 1).

Grain cadmium: sprinkler irrigation favored cadmium uptake, but this was reduced under SNT and amended compost treatments (p. 1 abstract).

Evidence Fitness

EF-2 (reconstructable dataset). Multi-year field experiment with grain-level arsenic and cadmium data across six management systems. Mediterranean context may not generalize to Asian rice production systems with different soil types and climate. Demonstrates the arsenic/cadmium trade-off with irrigation method and the potential of compost to modify metal uptake.

Methods

Field experiment, 180 m2 blocks, triplicate, Gevora, Southern Spain. Soil classified as Hydragric Anthrosol, loam texture. Rice monocropping. Grain arsenic and cadmium measured (analytical method details in full paper). Compost: composted two-phase olive mill waste at 80 Mg per ha, single application April 2015.

LOD/LOQ: not reported in abstract. CRM/Recovery: not reported in abstract.

Implications

Certification: Demonstrates that sprinkler irrigation reduces grain arsenic but may increase cadmium, a key trade-off for rice mitigation strategies. Compost amendment modulated both metals. Relevant to understanding irrigation-based mitigation for European rice production.

Courses: Multi-year field data showing the interaction of irrigation method, tillage, and organic amendment on both arsenic and cadmium in rice grain provides a teaching case for the complexity of mitigation in practice.

Provenance notes

Open access (CC BY 4.0). MDPI journal (Plants). Deposit: HMI-MIT-rice.

Related evidence

• Rice

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