Water Management Options for Rice Cultivation in a Temperate Area: A Multi-Objective Model to Explore Economic and Water Saving Results

Abstract

Due to the changing climatic and environmental conditions, modifications in agricultural and water policies have been made, and irrigated agriculture has to face the challenge of making a rational and optimal use of the water resource effectively available. This urges rice farming, strongly and traditionally linked to water, to change the modalities for the use of the resource. If on one hand water saving techniques should be preferred, a different water management in paddy fields may lead to lower yields and higher production costs, with consequent repercussions on farm incomes. The paper recognizes the disagreement between environmental and economic concerns and aims at contributing to the discussion about how to reconcile them by adopting alternative irrigation strategies. From this perspective, a multi-objective linear optimization model is used to explore the trade-offs between conflicting objectives in a rice-growing area in Northern Italy. The model returns the optimal allocation of land subject to three different irrigation strategies, as those previously performed in experimental fields; in addition, a scenario analysis is run to simulate reduced resource availability. Results demonstrate the key role of prioritizing one objective over the other, while introducing cultivars more suitable for dry cultivation enables enlarging the frontier of optimal solutions.

In-season early mapping of rice area and flooding dynamics from optical and SAR satellite data

“…Several rice varieties are cropped over about 227,300 ha (http://www.enter isi.it), which accounts for 90% of the total paddy rice area cultivated in Italy. Traditionally rice is cultivated in paddy fields, thus being a highly water demanding crop; but in recent years, due to water shortage and changes in timing of water availability, driven by climatic and human factors, rice cultivation techniques and systems are changing to make a more rational and sustainable use of resource (Monaco et al, 2016). Among alternative cultivation techniques is rice dry seeding, for which flooding is delayed until tillering, or rice growing as other crops with intermittent irrigation (Monaco et al, 2016;Ranghetti et al, 2016).…”

“…Traditionally rice is cultivated in paddy fields, thus being a highly water demanding crop; but in recent years, due to water shortage and changes in timing of water availability, driven by climatic and human factors, rice cultivation techniques and systems are changing to make a more rational and sustainable use of resource (Monaco et al, 2016). Among alternative cultivation techniques is rice dry seeding, for which flooding is delayed until tillering, or rice growing as other crops with intermittent irrigation (Monaco et al, 2016;Ranghetti et al, 2016). According, to recent figures (ENR, 2016), water seeding rice cultivated area has decreased of about 38% in favour of dry seeding (+53%) reaching more than 50,000 ha in 2015 (Monaco et al, 2016).…”

“…Among alternative cultivation techniques is rice dry seeding, for which flooding is delayed until tillering, or rice growing as other crops with intermittent irrigation (Monaco et al, 2016;Ranghetti et al, 2016). According, to recent figures (ENR, 2016), water seeding rice cultivated area has decreased of about 38% in favour of dry seeding (+53%) reaching more than 50,000 ha in 2015 (Monaco et al, 2016). Ranghetti et al (2018) investigated the variation in irrigation dynamics over the last 17 years in the study area.…”

Improvement and application of the PCPF‐1@SWAT2012 model for predicting pesticide transport: a case study of the Sakura River watershed

“…Exposure to high levels of pesticide can occur not only in the surrounding areas where it was initially applied but also in aquatic bodies located far from rice paddy fields as a result of surface runoff or leaching . Because pesticides are applied in rice paddies under submerged conditions, there is a higher probability of pesticide runoff through drainage, seepage, and/or percolation than in typical agricultural fields . Hence, assessment of the fate and transport of pesticides from rice paddies is required to maintain acceptable water quality and protect aquatic ecosystems.…”

“…[9][10][11] Because pesticides are applied in rice paddies under submerged conditions, there is a higher probability of pesticide runoff through drainage, seepage, and/or percolation than in typical agricultural fields. [12][13][14][15][16] Hence, assessment of the fate and transport of pesticides from rice paddies is required to maintain acceptable water quality and protect aquatic ecosystems.…”