Agroforestry systems combine the cultivation of woody plants with agricultural crops or livestock farming on the same area. There are different types, and one of them is the alley-cropping systems, that is systems composed of tree rows alternating with arable cultivation. The interactions that arise between the components of the system are varied and still poorly known and quantified. The aim of this thesis work was to study water relations and productivity in a silvoarable system with clones of poplar with High Environmental Sustainability (HES) in its seventh growing season and barley as a consociated herbaceous crop. The study was carried out at the pilot and demonstration farm “Sasse Rami” of Veneto Agricoltura in Ceregnano (RO) and aimed at analysing (i) the basic (ᴪPD leaf) and minimum (ᴪMD leaf) leaf water potentials of poplar plants, (ii) resistance to cavitation and (iii) the growth in diameter and height of three clones of poplar with High Environmental Sustainability (HES: Aleramo, Moncalvo and Tucano), grown both in a specialised 6 x 6m planting system and in an alley-cropping system with 40m row spacing. In addition, (i) the basic (ᴪPD leaf) and minimum (ᴪMD leaf) leaf water potentials were measured, (ii) the seasonal dynamics of leaf greenness and (iii) the yield and grain quality at harvest of barley plants at different distances from the tree row, both on the east and west sides. Finally, the main microclimatic parameters of both cropping systems were monitored during the season in comparison. The results showed that the agroforestry system maintained a higher soil water content during the season than the poplar grove. In agroforestry, poplars showed more negative minimum leaf water potentials (ᴪMD leaf) (-5%, -26%, -21%, -10% on the different measurement dates), which together with an increased stem diameter growth (+30% Aleramo, +32% Moncalvo, +45% Tucano) suggest a longer stomatal opening and so a higher assimilation of CO₂ in this system. In the poplar grove, on the other hand, the minimum potentials (ᴪMD leaf) are less negative and the diametric growths are smaller than in agroforestry. These observations can be explained by a preventive stomatal closure to maintain a better water status. Overall, all three HES clones showed higher diametrical growths in the agroforestry system (Aleramo 32,8 cm, Moncalvo 32,1 cm and Tucano 36,5 cm), compared to those found in the poplar grove. It is therefore confirmed that the greater availability of resources in agroforestry, such as water content in the soil, results in faster plant growth. Regarding barley, the study confirmed the high aptitude of this cereal for intercropping in silvoarable systems. In general all HES clones studied lend themselves to agroforestry. Overall, the thesis demonstrated excellent adaptability and productivity of barley and HES clones to agroforestry cultivation. Furthermore, it showed a different water use efficiency compared to specialised systems. So it can be considered that silvoarable systems offer more solutions than specialised systems to ensure greater resilience against water stress and climate change more generally. As this is one of the first works dealing with water relations in a silvoarable system with barley and HES poplar clones, further studies will have to be carried out in the future to compare the results obtained and expand knowledge in this regard, in years and/or sites characterised by greater water scarcity and at different times in the poplar crop cycle.
I sistemi agroforestali combinano sulla stessa superficie la coltivazione di piante legnose con colture erbacee o l’allevamento. Esistono diverse tipologie, e una di esse è rappresentata dai sistemi silvoarabili di tipo alley-cropping, ovvero sistemi composti da filari alberati alternati alla coltivazione di seminativi. Le interazioni che si originano tra le componenti del sistema sono di varia natura e ancora poco conosciute e quantificate. Il presente lavoro di tesi ha avuto l’obiettivo di studiare le relazioni idriche e la produttività in un sistema silvoarabile con cloni di pioppo a Maggior Sostenibilità Ambientale (MSA) alla settima stagione vegetativa e orzo come coltura erbacea consociata. Lo studio si è svolto presso l’azienda pilota e dimostrativa “Sasse Rami” di Veneto Agricoltura a Ceregnano (RO) e ha inteso analizzare (i) i potenziali idrici fogliari di base (ᴪPD leaf) e minimi (ᴪMD leaf) delle piante di pioppo, (ii) la resistenza alla cavitazione e (iii) gli accrescimenti in diametro e in altezza di tre cloni di pioppo a Maggior Sostenibilità Ambientali (MSA: Aleramo, Moncalvo e Tucano), coltivati sia in una sistema specializzato con sesto d’impianto 6 x 6m che in un sistema alley-cropping con interfilare di 40m. Inoltre, sono stati misurati (i) i potenziali idrici fogliari di base (ᴪPD leaf) e minimi (ᴪMD leaf), (ii) la dinamica stagionale della greenness fogliare e (iii) la resa e la qualità della granella alla raccolta delle piante di orzo a diverse distanze dal filare alberato, sia al lato Est che al lato Ovest. Infine, sono stati monitorati durante la stagione i principali parametri microclimatici di entrambi i sistemi colturali a confronto. Dai risultati è emerso che il sistema agroforestale ha mantenuto durante la stagione un contenuto idrico del suolo maggiore rispetto al pioppeto. In agroforestazione, i pioppi hanno mostrato potenziali idrici fogliari minimi (ᴪMD leaf) più negativi (-5%, -26%, -21%, -10% nelle diverse date di misurazione), che insieme a una maggior crescita del diametro del fusto (+30% Aleramo, +32% Moncalvo, +45% Tucano) ci suggeriscono una più prolungata apertura stomatica e quindi una maggiore assimilazione di CO₂ in questo sistema. Nel pioppeto, invece, i potenziali minimi (ᴪMD leaf) sono meno negativi e le crescite diametriche sono minori rispetto all’agroforestazione. Tali osservazioni possono essere spiegate con una preventiva chiusura stomatica per mantenere uno stato idrico migliore. Nel complesso, tutti e tre i cloni MSA hanno mostrato accrescimenti diametrici maggiori nel sistema agroforestale (Aleramo 32,8 cm, Moncalvo 32,1 cm e Tucano 36,5 cm), rispetto a quelli rilevati nel pioppeto. Si conferma quindi che la maggior disponibilità di risorse dell’agroforestazione, come il contenuto d’acqua nel suolo, determina un accrescimento più rapido delle piante. Per quanto riguarda l’orzo, lo studio ha confermato l’elevata attitudine di questo cereale alla consociazione nei sistemi silvoarabili. In generale tutti i cloni MSA studiati si prestano all’agroforestazione. La tesi complessivamente ha dimostrato un’ottima adattabilità e produttività dell’orzo e dei cloni MSA alla coltivazione in agroforestry. Inoltre, ha evidenziato un’efficienza d’uso dell’acqua diversa rispetto ai sistemi specializzati. Quindi si può ritenere che i sistemi silvoarabili offrano più soluzioni rispetto ai sistemi specializzati per garantire maggiore resilienza nei confronti dello stress idrico e più in generale dei cambiamenti climatici. Essendo uno dei primi lavori che trattano le relazioni idriche in un sistema silvoarabile con orzo e cloni di pioppo MSA, sarà necessario in futuro realizzare ulteriori studi per confrontare i risultati ottenuti e ampliare le conoscenze a riguardo, in annate e/o siti caratterizzati da una maggiore carenza idrica e in momenti diversi del ciclo colturale del pioppo.
Analisi delle relazioni idriche e della produttività in un sistema silvoarabile con orzo e cloni di pioppo a Maggior Sostenibilità Ambientale
BONGIOVANNI, GIACOMO
2023/2024
Abstract
Agroforestry systems combine the cultivation of woody plants with agricultural crops or livestock farming on the same area. There are different types, and one of them is the alley-cropping systems, that is systems composed of tree rows alternating with arable cultivation. The interactions that arise between the components of the system are varied and still poorly known and quantified. The aim of this thesis work was to study water relations and productivity in a silvoarable system with clones of poplar with High Environmental Sustainability (HES) in its seventh growing season and barley as a consociated herbaceous crop. The study was carried out at the pilot and demonstration farm “Sasse Rami” of Veneto Agricoltura in Ceregnano (RO) and aimed at analysing (i) the basic (ᴪPD leaf) and minimum (ᴪMD leaf) leaf water potentials of poplar plants, (ii) resistance to cavitation and (iii) the growth in diameter and height of three clones of poplar with High Environmental Sustainability (HES: Aleramo, Moncalvo and Tucano), grown both in a specialised 6 x 6m planting system and in an alley-cropping system with 40m row spacing. In addition, (i) the basic (ᴪPD leaf) and minimum (ᴪMD leaf) leaf water potentials were measured, (ii) the seasonal dynamics of leaf greenness and (iii) the yield and grain quality at harvest of barley plants at different distances from the tree row, both on the east and west sides. Finally, the main microclimatic parameters of both cropping systems were monitored during the season in comparison. The results showed that the agroforestry system maintained a higher soil water content during the season than the poplar grove. In agroforestry, poplars showed more negative minimum leaf water potentials (ᴪMD leaf) (-5%, -26%, -21%, -10% on the different measurement dates), which together with an increased stem diameter growth (+30% Aleramo, +32% Moncalvo, +45% Tucano) suggest a longer stomatal opening and so a higher assimilation of CO₂ in this system. In the poplar grove, on the other hand, the minimum potentials (ᴪMD leaf) are less negative and the diametric growths are smaller than in agroforestry. These observations can be explained by a preventive stomatal closure to maintain a better water status. Overall, all three HES clones showed higher diametrical growths in the agroforestry system (Aleramo 32,8 cm, Moncalvo 32,1 cm and Tucano 36,5 cm), compared to those found in the poplar grove. It is therefore confirmed that the greater availability of resources in agroforestry, such as water content in the soil, results in faster plant growth. Regarding barley, the study confirmed the high aptitude of this cereal for intercropping in silvoarable systems. In general all HES clones studied lend themselves to agroforestry. Overall, the thesis demonstrated excellent adaptability and productivity of barley and HES clones to agroforestry cultivation. Furthermore, it showed a different water use efficiency compared to specialised systems. So it can be considered that silvoarable systems offer more solutions than specialised systems to ensure greater resilience against water stress and climate change more generally. As this is one of the first works dealing with water relations in a silvoarable system with barley and HES poplar clones, further studies will have to be carried out in the future to compare the results obtained and expand knowledge in this regard, in years and/or sites characterised by greater water scarcity and at different times in the poplar crop cycle.File | Dimensione | Formato | |
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https://hdl.handle.net/20.500.12608/80366