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Water and rice: the virtuous system of rice fields

Water and rice

Everyone is familiar with the “checkered sea,” the characteristic and fascinating landscape that defines the Po Valley, making it unique and closely tied to agriculture, particularly rice farming. Water and rice are strictly connected. Water is an essential element for rice cultivation, as rice fields require vast amounts of water to implement the well-known submersion technique. Contrary to what one might think, it is interesting to discover that, thanks to the very design of rice fields and the constant monitoring by relevant authorities, this practice does not lead to water waste but is instead beneficial for the environment.

The use of water in rice cultivation is not just a means to grow plants; it is a truly virtuous system that integrates agricultural production, environmental protection and sustainable water management. Let’s explore how this complex mechanism works, resulting from  centuries of tradition and innovation.

How Rice Fields Work: Submersion

Submersion is a key practice in rice cultivation. It begins in spring with the preparation of the rice fields and ends in autumn. Each hectare of rice field requires approximately 20,000 liters of water per season, with an average submersion depth of 10 centimeters. This layer of water serves multiple purposes: it protects the plants from weeds, regulates soil temperature and promotes rice growth.

Rice fields draw water from rivers, never from aqueducts intended for domestic use. This approach helps preserve potable water reserves and ensures a responsible use of natural resources. The amount of water drawn is constantly measured and adjusted, with a primary goal: ensuring that the river maintains a minimum vital level for the ecosystem. This balance is monitored daily by irrigation consortia, which manage a complex system of canals and sluices to distribute water efficiently.

A distinctive aspect of submersion is the flow-through system, where water continuously moves from one rice field chamber to another, following the minimal land slope. This process is essential to ensure uniform irrigation and prevent stagnation, which could harm the crops.

The Engineering Behind Water Distribution

Water distribution in rice fields is a prime example of hydraulic engineering applied to agriculture. Sluices serve as the starting point, regulating the water flow into distribution canals. From there, a network of ditches and outlets ensures that each rice field receives the right amount of water.

Each distribution canal has a dedicated outlet that can be manually adjusted to regulate the flow according to specific needs. This task requires constant supervision by specialized technicians, who monitor the outlets daily to ensure optimal water distribution across the entire area.

Water Returning to Nature

One of the most virtuous and sustainable aspects of the rice field system lies in the fact that a significant portion of the water used for submersion is not wasted, but rather returned to the natural environment. This occurs through various mechanisms, making rice fields not only sites of agricultural production, but also active components in regional water management.

Part of the water naturally evaporates or is absorbed by plants through the process of evapotranspiration, while another portion is channelled into collection canals to be recovered, filtered and redistributed to the fields, minimizing waste.

But the contribution of rice fields doesn’t stop there. Throughout the entire submersion season, a portion of the water flows back into natural watercourses, helping maintain the rivers minimum vital flow. In addition, a significant amount infiltrates the ground through the process of percolation, replenishing deep aquifers. These underground water reserves become especially crucial in summer, when they resurface through natural springs and water sources, supporting both agriculture and the local ecosystem.

This cyclical and regenerative system makes rice fields a strategic asset for the region water balance and environmental resilience.

Rice Fields: A Heritage to Preserve

Beyond water recovery, rice fields serve several other crucial functions for the environment and the territory, including:

  • Hydroelectric energy production: The water flowing in the canals is also used to generate renewable energy, contributing to the agricultural system sustainability.
  • Territorial flood control: During rainy seasons, rice fields help manage excess water, preventing floods and hydrogeological risks.
  • Hydrogeological monitoring: Irrigation consortia constantly collect data on water network conditions, ensuring optimal management and rapid response to any issues.

The “water lands” of the Po Valley represent a unique heritage globally. They are not only an outstanding example of sustainable agriculture, but also play a crucial role in environmental conservation and natural resource management. The daily work of irrigation consortia and farmers is essential in maintaining this delicate balance while ensuring the production of one of the most beloved and widely consumed foods in the world: rice.

In the context of climate change and an increasing demand for sustainability, the rice field system demonstrates how tradition and innovation can coexist, offering tangible solutions for a more balanced and environmentally respectful future. Preserving and enhancing this model is a responsibility that involves all of us in a collective effort toward responsible resource management. Rice producers like Mundi Riso play a key role in safeguarding a virtuous and sustainable supply chain.