An open field Variable Rate Irrigation (VRI) experiment was a carried out on corn at the Vittorio Tadini experimental farm (Piacenza, Italy) on 2008. An Available Water Capacity (AWC) map of the experimental field was estimated using geo-referred measures of soil texture and water potential and using a MSI (Moisture Stress Index) map obtained from a SPOT HRG corn reflectance data collected on 2005 over the same field. Two irrigation water balances, based on standard local crop water requirements for each crop stage and rainfall, were calculated during the growing season for the two estimated extreme AWC values in the field. Variable rate irrigation prescription maps, aimed to maintain a minimum of 20% of AWC and to avoid to exceed the Field Capacity (FC) for each location in the field, were calculated by spatial linear interpolation based on the estimated AWC map of the two irrigation rates assigned for each irrigation turn to maximum and minimum AWC locations. Irrigation turns were set according to estimated minimum AWC depletion (i.e. aimed to maintain a minimum of 20% of AWC in locations with smallest AWC. VRI was carried out in part of the field by GPS-driven traveling sprinkler varying travel speed and gun angular speed to achieve desired rate within management zones, whereas in the other part of the field irrigation was carried out with constant rates corresponding to the spatial average of the VRI area (i.e. the same amounts of water were given to VRI and test –constant rate– areas in each irrigation turn). Grain production of VRI-irrigated corn outperformed that of test area by 20%.
In una prova di irrigazione a rateo variabile (VRI), svolta su mais nel 2008 presso l’azienda sperimentale Tadini (Piacenza), è stata ottenuta una mappa di Riserva Idrica Utile (RIU) dell’appezzamento a partire dall’elaborazione dell’indice MSI (Moisture Stress Index) ottenuta da un’acquisizione SPOT HRG del 2005 mediante l’integrazione con misure georeferenziate della tensione dell’acqua nel terreno e della tessitura in alcuni punti dell’appezzamento. Sulla base dei valori di restituzione idrica sono stati calcolati due bilanci idrici, al netto di eventuali precipitazioni, per i due valori estremi di riserva idrica utile stimati con turni e volumi che assicurassero il mantenimento di un minimo attorno al 20% della riserva idrica utilizzabile ed il non superamento della capacità di campo ad tutte le condizioni di riserva idrica. Le mappe di prescrizione irrigua a rateo variabile sono state ottenute da una interpolazione lineare, sulla base spaziale della mappa di riserva idrica stimata, della delle due dosi irrigue attribuite per le posizioni a massima e minima riserva stimata in ciascun turno irriguo. Il turno è stato stabilito sulle aree a minor riserva idrica. L’irrigazione VRI è stata realizzata mediante un irrigatore per aspersione sviluppato dalla ditta Casella in grado di modificare velocità di recupero e velocità angolare del getto in funzione della posizione GPS. A parità di volumi irrigui per ogni singolo turno la resa produttiva nella parte di appezzamento irrigato in maniera variabile è stata del 20% in più rispetto alla parte irrigata con rateo costante.
Vincini, M., Frazzi, E., Calegari, F., Irrigazione di mais da granella a rateo variabile mediante mappe indice di stress idrico da acquisizione SPOT HRG, in Atti 15° Conferenza Nazionale ASITA, (Colorno, 15-18 November 2011), ASITA, Colorno 2011: 2113-2118 [http://hdl.handle.net/10807/5508]
Irrigazione di mais da granella a rateo variabile mediante mappe indice di stress idrico da acquisizione SPOT HRG
Vincini, Massimo;Frazzi, Ermes;Calegari, Ferdinando
2011
Abstract
An open field Variable Rate Irrigation (VRI) experiment was a carried out on corn at the Vittorio Tadini experimental farm (Piacenza, Italy) on 2008. An Available Water Capacity (AWC) map of the experimental field was estimated using geo-referred measures of soil texture and water potential and using a MSI (Moisture Stress Index) map obtained from a SPOT HRG corn reflectance data collected on 2005 over the same field. Two irrigation water balances, based on standard local crop water requirements for each crop stage and rainfall, were calculated during the growing season for the two estimated extreme AWC values in the field. Variable rate irrigation prescription maps, aimed to maintain a minimum of 20% of AWC and to avoid to exceed the Field Capacity (FC) for each location in the field, were calculated by spatial linear interpolation based on the estimated AWC map of the two irrigation rates assigned for each irrigation turn to maximum and minimum AWC locations. Irrigation turns were set according to estimated minimum AWC depletion (i.e. aimed to maintain a minimum of 20% of AWC in locations with smallest AWC. VRI was carried out in part of the field by GPS-driven traveling sprinkler varying travel speed and gun angular speed to achieve desired rate within management zones, whereas in the other part of the field irrigation was carried out with constant rates corresponding to the spatial average of the VRI area (i.e. the same amounts of water were given to VRI and test –constant rate– areas in each irrigation turn). Grain production of VRI-irrigated corn outperformed that of test area by 20%.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.