A long-term study was carried out concerning the use and depletion of phosphate reserves on agricultural land in the region, funded by the Emilia-Romagna Region. The agronomic experiment started in 1987 and was continued for 15 years. This report covers the period 1997 – 2001, while a monographic study covering the first 10 years of testing has already been published (Paris et al., 1997). The aim of the study was to find out how many years soils rich in P Olsen (P extractable in sodium bicarbonate at pH 8.5), if unfertilized, would maintain the same yield as those receiving fertilizer. Given that the rate of depletion of phosphate reserves in soil was found to be slower than predicted, and that at the end of the first decade the yields of the crops tested were not sufficiently clear, it was decided to continue for a further five years. Testing continued only in two of the three original experimental sites: a) Quarantoli near Mirandola (MO), on loam-clayey soil with a pH of 7.6, classified as fine silty over clayey, mixed, mesic (Aquic) Udifluventic Ustochrepts (Soil Taxonomy, 1992); b) Taneto near Gattatico (RE), on clay-silt soil of pH 7.5, classified as fine, mixed, mesic Udertic Ustochrepts. The crops were maize, wheat and lucerne. In each field, three phosphate rates were tested: P 0 (control), P 1 (26.2 kg ha 1 year 1 of P) and P 2 (52.4 kg ha 1 year 1 of P). The Olsen P concentration in the P 0 plots decreased continuously as a result of its removal by the different crops. At Quarantoli, from starting figures of 19.3-23.8 mg kg 1 of P there was a decrease over the 15-year period to 6.8-7.0 mg kg 1 with a fall of 12.5-16.9 mg depending on the crops sequence , with average annual losses of between 0.83 e 1.13 mg kg 1. At Taneto the values decreased from 23.2 to 7.3 mg kg 1 with a fall of 15.9 mg, equal to an average annual loss of 1.06 mg kg 1 of P. Even at the end of this five-year period of testing, there was still no clear deficiency of available P in the soil. As regards the yield of the various crops in the two fields, of a total of 74 cases, P 0 was significantly below the other two only in 8 cases, of which 6 were due to the lucerne. As regards P concentration in plants, out of a total of 54 cases 23 were significant, of which 16 were lucerne; finally, as regards P depletion, out of 74 cases there were only 20 significant ones, of which 16 were the fodder crop. When compared with the first 10 years, the frequency of situations where there are significant differences between the control and one or both of the fertilized treatments increased. With specific reference to lucerne, which proved to be the most sensitive crop, the yield reached approx. 1/4 positive cases, P concentrations almost 4/5 and P removal by crops over 2/3.

Con il finanziamento della Regione Emilia-Romagna, è stato condotto uno studio di lungo termine sull’utilizzazione e l’esaurimento delle riserve fosfatiche nei terreni agrari della regione. La sperimentazione agronomica, iniziata nel 1987, è durata un quindicennio; questo rapporto riguarda il periodo 1997-2001, mentre è già comparsa una monografia riguardante i primi dieci anni di prova (Paris et al., 1997). Lo scopo dell’indagine era quello di verificare per quanti anni terreni ricchi in P Olsen (P estraibile in sodio bicarbonato, a pH 8,5) avrebbero consentito, in assenza di concimazione, rese colturali non diverse da quelle delle tesi concimate. Poiché il ritmo di attenuazione delle riserve fosfatiche nei terreni si è rivelato più lento del previsto e, alla fine del decennio iniziale, le risposte delle colture saggiate non sono risultate sufficientemente chiare, si è deciso di continuare per un altro quinquennio. La prova è proseguita soltanto in due delle tre località iniziali: a) Quarantoli di Mirandola (MO), su terreno a granulometria di medio impasto tendente all’argilloso, con pH 7,6, appartenente ai fine silty over clayey, mixed, mesic (Aquic) Udifluventic Ustochrepts (Soil Taxonomy, 1992); b) Taneto di Gattatico (RE), su terreno a granulometria argillosa tendenzialmente limosa e pH 7,5, ascrivibile ai fine, mixed, mesic Udertic Ustochrepts. Le colture utilizzate sono state mais, frumento tenero ed erba medica; in ogni campo sono state confrontate tre tesi fosfatiche, siglate P 0 (controllo), P 1 (26,2 kg ha 1 anno 1 di P ) e P 2 (52,4 kg ha 1 anno 1 di P). Il tenore in P Olsen nelle parcelle P 0 è andato man mano diminuendo sotto l’azione delle asportazioni operate dalle diverse colture. A Quarantoli, dai valori iniziali di 19,3-23,8 mg kg 1 di P si è scesi, nel quindicennio, a 6,8-7,0 mg kg 1 con un calo di 12,5-16,9 mg secondo la sequenza colturale, facendo registrare perdite medie annue comprese fra 0,83 e 1,13 mg kg 1. A Taneto si è passati da 23,2 a 7,3 mg kg 1 con una riduzione di 15,9 mg, pari ad una perdita media annua di 1,06 mg kg 1 di P. Nemmeno alla fine di questo quinquennio sperimentale si è evidenziato uno stato di conclamata carenza nella disponibilità di P nel terreno. Per quanto riguarda le rese delle varie colture nei due campi, su 74 casi complessivi, quelli in cui la tesi P 0 è risultata significativamente inferiore alle altre due sono stati otto, di cui sei attribuibili all’erba medica. Per le concentrazioni dei prodotti vegetali, su 54 casi totali, ventitre risultano significativi, dei quali sedici riguardano l’erba medica; infine, per quanto concerne le asportazioni, su 74 casi, quelli significativi sono venti, di cui sedici riferibili alla foraggera. Rispetto al primo decennio, è aumentata la frequenza di situazioni nelle quali si sono riscontrate differenze significative fra tesi controllo ed una o entrambe le tesi concimate. In particolare, per l’erba medica che si è rivelata la coltura più sensibile, le rese hanno raggiunto circa 1/4 di casi positivi, le concentrazioni quasi i 4/5 ed infine le asportazioni oltre i 2/3.

Tabaglio, V., Gavazzi, C., La riutilizzazione delle riserve fosfatiche in alcuni tipi di terreni emiliani - Un terzo quinquennio di indagine (1997-2001), Tecnograf, Reggio Emilia 2003: 74 [http://hdl.handle.net/10807/43148]

La riutilizzazione delle riserve fosfatiche in alcuni tipi di terreni emiliani - Un terzo quinquennio di indagine (1997-2001)

Tabaglio, Vincenzo;Gavazzi, Carolina
2003

Abstract

A long-term study was carried out concerning the use and depletion of phosphate reserves on agricultural land in the region, funded by the Emilia-Romagna Region. The agronomic experiment started in 1987 and was continued for 15 years. This report covers the period 1997 – 2001, while a monographic study covering the first 10 years of testing has already been published (Paris et al., 1997). The aim of the study was to find out how many years soils rich in P Olsen (P extractable in sodium bicarbonate at pH 8.5), if unfertilized, would maintain the same yield as those receiving fertilizer. Given that the rate of depletion of phosphate reserves in soil was found to be slower than predicted, and that at the end of the first decade the yields of the crops tested were not sufficiently clear, it was decided to continue for a further five years. Testing continued only in two of the three original experimental sites: a) Quarantoli near Mirandola (MO), on loam-clayey soil with a pH of 7.6, classified as fine silty over clayey, mixed, mesic (Aquic) Udifluventic Ustochrepts (Soil Taxonomy, 1992); b) Taneto near Gattatico (RE), on clay-silt soil of pH 7.5, classified as fine, mixed, mesic Udertic Ustochrepts. The crops were maize, wheat and lucerne. In each field, three phosphate rates were tested: P 0 (control), P 1 (26.2 kg ha 1 year 1 of P) and P 2 (52.4 kg ha 1 year 1 of P). The Olsen P concentration in the P 0 plots decreased continuously as a result of its removal by the different crops. At Quarantoli, from starting figures of 19.3-23.8 mg kg 1 of P there was a decrease over the 15-year period to 6.8-7.0 mg kg 1 with a fall of 12.5-16.9 mg depending on the crops sequence , with average annual losses of between 0.83 e 1.13 mg kg 1. At Taneto the values decreased from 23.2 to 7.3 mg kg 1 with a fall of 15.9 mg, equal to an average annual loss of 1.06 mg kg 1 of P. Even at the end of this five-year period of testing, there was still no clear deficiency of available P in the soil. As regards the yield of the various crops in the two fields, of a total of 74 cases, P 0 was significantly below the other two only in 8 cases, of which 6 were due to the lucerne. As regards P concentration in plants, out of a total of 54 cases 23 were significant, of which 16 were lucerne; finally, as regards P depletion, out of 74 cases there were only 20 significant ones, of which 16 were the fodder crop. When compared with the first 10 years, the frequency of situations where there are significant differences between the control and one or both of the fertilized treatments increased. With specific reference to lucerne, which proved to be the most sensitive crop, the yield reached approx. 1/4 positive cases, P concentrations almost 4/5 and P removal by crops over 2/3.
2003
Italiano
Monografia o trattato scientifico
Tabaglio, V., Gavazzi, C., La riutilizzazione delle riserve fosfatiche in alcuni tipi di terreni emiliani - Un terzo quinquennio di indagine (1997-2001), Tecnograf, Reggio Emilia 2003: 74 [http://hdl.handle.net/10807/43148]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10807/43148
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