In agriculture, water consumption for crop production represents 69% of all water use. Precision irrigation systems based on available soil water have been developed to improve crop production, reducing water use. Besides the improvements in irrigation management, a better resolution of the optimal water level is required, and revealing the impact of soil matric potential on the soil microbial community may help. Here, the effect of four soil matric potential treatments (−15 kPa, −25 kPa, −30 kPa, and −45 kPa) was evaluated on the soil microbial community across three potato cultivars and two soil types (silt and sand). The results confirmed the soil matric potential with −25 kPa as the optimal irrigation level, which promoted high potato production using the minimal water use. The irrigation levels affected the composition, predicted functionality, and the ecological network of soil bacterial community. Water excess (−15 kPa) and deficit (−30 and −45 kPa) promoted an increase in microbial interaction and alpha-diversity. The results suggested higher Positive/Negative ratio for phyla Proteobacteria, Actinobacteria, and Acidobacteria in optimal irrigation level (−25 kPa) than other irrigation levels. Also, correlation analyses revealed an interesting association between the irrigation levels, potato production, and bacterial functionality, especially in the carbon cycle (fixation and emission). Therefore, this study proposed important associations between the soil bacterial community and water management, focusing on high potato production and minimal water use. The advancement of this knowledge may lead to a more comprehensive assessment of the optimal irrigation levels of others crop production systems. Furthermore, the inclusion of biological mechanisms, especially microbial interactions, in agriculture studies has the potential to contribute to the development of water management practices conducive to both increasing crop yield and maintaining a sustainable soil environment.

Soil organic carbon (SOC) has a significant effect on the carbon cycle, playing a vital role in environmental services and crop production. Increasing SOC stock is identified as an effective way to improve carbon dioxide sequestration, soil health, and plant productivity. Knowing soil water is one of the primary SOC decomposition driver, periods in the crops growth stages with increased water movement might influence the SOC dynamics. Here, we evaluate the temporal effect of four precision irrigation thresholds ( $$-15$$- 15 , $$-30$$- 30 , $$-45$$- 45 , and $$-60$$- 60 kPa) in potato crop on SOC dynamics using the Partial Least Square algorithm and the Tea Bag Index in a sandy soil under potato production. The difference of SOC decomposition rate between the precision irrigation thresholds is developed in the second quarter of the growing season, between 38 and 53 days after planting. This critical period occurred in a stage of strong vegetative growth and rapid irrigation cycles. The precision irrigation threshold affected the decomposition rate of SOC. A faster decomposition of labile organic carbon was promoted by water excess ( $$-15$$- 15 kPa). The dryer ( $$-30$$- 30 , $$-45$$- 45 , and $$-60$$- 60 kPa) precision irrigation thresholds did not show any differences. The advancement of this knowledge may promote soil health conservation and carbon sequestration in agricultural soil.

Potato is one of the most cropped plants worldwide. Hundreds of different varieties are cultivated only in North America. Potato growers usually crop multiple varieties on their farms to answer the market demands for potato’s specific physical properties. However, few pieces of information are available regarding the optimal management of irrigation across potato varieties. Knowing that modern potatoes share genetics similarities, the optimal irrigation comfort zone for the potato crop might be the same for different groups of varieties. This study evaluates the effect of precision irrigation thresholds on the potato yields of three varieties (Envol: very early, Kalmia: early, and Red Maria: mid-late) with different maturity classes. In a greenhouse, a soil matric potential sensor network used in combination with a precise irrigation system allows the identification of a common optimal precision irrigation threshold, allowing optimal yields for the three varieties. This paper presents the first identification of an optimal irrigation threshold, $-15$ kPa, shared by different potato varieties. The optimal irrigation threshold identified in this study is not dependent on the maturity class, plant height or tuber potential production. The determination of an optimal precision irrigation threshold will allow potato growers to adapt their farm management processes to integrate more sustainable water management practices as they will be able to irrigate a field with multiple varieties with the same threshold.

Soil disturbance resulting from tuber crop harvesting is a major threat to soil health. The depth of soil intervention is a critical factor that further strengthens the effects of such disturbance and makes harvest one of the most harmful cropping operations. In the case of potato, soil moisture is a determining factor for root and stolon development, hence, a deeper soil intervention may be required at harvest. While potato ranks as the fourth most cultivated crop worldwide, the impact of soil moisture on potato tuber vertical and horizontal distribution has received very little attention. The objective of this study was to evaluate the effects of four soil matric potential thresholds (SMPTs; –10, –20, –30, and –45 kPa) on the spatial (vertical and horizontal) distribution of potato tubers grown in plastic containers filled with sandy soil using an X-ray computed tomography scanner. The results of the experiments conducted in a greenhouse environment suggest that the horizontal distribution of the tubers did not differ significantly across the irrigation treatments. However, a linear relationship between SMPT, and therefore irrigation threshold, and potato tuber depth was observed. In addition, the deepest tuber position was observed under the –10 kPa SMPT, while the tubers were closer to the soil surface under the –45 kPa SMPT, which could lead to a greater preponderance of tuber diseases such as late blight or greening. Thus, potato irrigation events implementing a SMPT between –20 and –30 kPa could reduce the harvest depth, hence, decreasing the negative impacts of soil disturbance on soil structural stability and soil organic carbon degradation while mitigating the impacts of disease as well as reducing fuel costs, greenhouse gas emissions, soil loss and erosion.

English Wetlands are becoming more and more vulnerable environments. They were, and still are, largely impacted by the expansion of agricultural activities and urbanization. Their substantial loss has had significant repercussions, including on water quality and quantity. Yet, wetlands are remarkable ecosystems. They provide many ecosystem functions that benefit both human beings and biodiversity. For instance, scientific research has shown that wetlands are known to provide flood control, improve water quality, and enhance carbon sequestration. Although many projects focus on wetlands and agriculture, there is a lack of interdisciplinary research in this field. Such an approach would sketch out a more comprehensive portrait and provide a useful analysis with respect to existing knowledge and protection mechanisms relating to wetlands. This is why our report aims at providing an interdisciplinary overview of wetland ecosystems in their relation to agriculture, especially by showing that these ecosystems can be an important asset for a more sustainable Canadian agriculture. We explore, amongst other things, the anthropogenic risks wetlands face, the ecosystem services they provide, the conservation technics that could benefit them and the legal and political mechanisms that relate to them. Based on this analysis, a set of recommendations is suggested. From the perspectives of research, farming, and policy, these recommendations take into consideration the current state of wetland conservation and the potential for future actions. French Les zones humides constituent des milieux de plus en plus vulnérables. Ils ont subi, et continuent de subir, l’impact de l’expansion des activité agricoles et de l’urbanisation. Leur destruction a notamment eu des répercussions importantes sur la qualité, la disponibilité et la distribution de l'eau. Pourtant, les zones humides sont des écosytèmes d’exception. Elles fournissent de nombreuses fonctions écosystémiques qui profitent à la fois aux êtres humains et à la biodiversité. Par exemple, la recherche scientifique a démontré que ces écosystèmes sont reconnus pour leur capacité à contrôler les inondations, à contrôler les éléments nutritifs dans les différentes masses d'eau ou à séquestrer le carbone. Bien que de nombreux projets soient axés sur les zones humides et l'agriculture, il existe un besoin important de recherche interdisciplinaire dans ce domaine. Une telle approche contribuerait à dresser un portrait plus complet et fournirait une analyse pertinente en ce qui concerne les connaissances actuelles et les mécanismes de protection relatifs aux zones humides. C'est pourquoi notre étude vise à fournir un état des lieux interdisciplinaire des terres humides en lien avec l'agriculture, notamment en montrant que la protection de ces écosystèmes peut être perçue comme un atout au profit d’une agriculture canadienne plus durable. Dans ce rapport, nous explorons donc, entre autres, les risques anthropogéniques auxquels les zones humides sont confrontés, les services écosystémiques qu’elles fournissent, les techniques de conservation qui pourraient leur être bénéfiques et les mécanismes juridiques et politiques qui s'y rapportent. Sur la base de cette analyse, un ensemble de recommandations est proposé. Elles dressent, au regard de la recherche, de l'agriculture et des politiques publiques, de l'état actuel de la conservation des zones humides et des possibilités d'actions futures.