Nitrate Leaching During a 4-Year Period in a Maize Monoculture Trial in Friuli-Venezia Giulia G
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Nitrate leaching during a 4-year period in a maize monoculture trial in Friuli-Venezia Giulia G. PARENTE, S. VENERUS, M. SCIMONE, M. TACCHEO BARBINA and A. DELUISA Summary ther with the Regional Agency for Agri- GATO and LEITA, 2001). Among the- This paper presents the results of a mul- culture of Friuli Venezia Giulia (ERSA). se, high annual rainfall, permeable soil ti-annual experimental trial carried out This trial was established at Fiume Ve- with gravels (easily leached by water) in in the Friulian plains (N-E Italy), to com- neto (Friuli Venezia Giulia, Province of the Northern zone, and the presence of pare the environmental impact on water Pordenone), in the experimental farm "F. surface ground water in the Southern and nitrate leaching of the most im- Ricchieri", in order to study the impact zone. The objective of the trial was to portant crop system of the region (Mai- of the most important crop systems of verify if the best practices in agriculture ze-Maize succession) with a rotation the region on leached water quality, as a established by the European Union with system using cover crop (Maize-Rye- consequence of fertilisers application the Nitrate Directive 676/91, the Regu- grass). Field lysimeters were used to col- (PARENTE et al., 1996, 1997a, 1997b). lations 2078/92 and 1257/99 and inclu- lect leached water, which was then ana- This issue is particularly relevant for the ded into the recent Regional Develop- lysed for evaluating the amount of per- Friuli Venezia Giulia plain, where high- ment Plan (2000) could result into posi- colation, the nitrate concentration and impact agricultural activity and environ- tive effects on water pollution. With this the nitrate load of leaching. The results mental characteristics make the whole purpose the field lysimeter stations, esta- indicate good efficiency of the rotation area very vulnerable (CUCCHI, 2001a, blished in Fiume Veneto since 1992, system to limit nitrate leaching of 5 to10 2001b; PECCOL, 2001; CICOGNA, were used to collect the leached water times compared to maize monoculture, 2001; MICHELUTTI et al., 2001; BRA- from the soil. at values of about 20-30 kg/ha per year. The effect of cover crops resulted also Table 1: Experimental crop systems characteristics during the trial years when both systems were set-aside for YEAR Maize-Maize monoculture Maize-Ryegrass rotation two consecutive years, with a reduction (MM system) (MR system) of nitrate leaching of 50-60%. Because of the high temporal and spatial variati- 1996 Maize cv: DAVIDA (Fao 400) Maize cv: DAVIDA (Fao 400) on of the leaching data, it is anyway stres- Seeding date : 03.06.96 Seeding date: 03.06.96 -2 -2 sed that, for monitoring purposes, some Seeding rate: 7,2 p m Seeding rate: 7,2 p m Fertilisation (kg/ha): Fertilisation (kg/ha): other techniques, like diffused suction N 162 - P 96 - K 96 N 162 - P 96 - K 96 cups integrated by territorial models, Ryegrass not seeded could be more effective. 1997 Set-aside, no tillage Introduction 1998 Set-aside, no tillage Cover crops seed in Autumn Maize monoculture is the main produc- Ryegrass cv: ASSO tive system in Friuli Venezia Giulia. It is Seeeding date: 17.11.98 characterised by a high environmental Seeding rate: 45 kg ha-1 impact for two main reasons: the high- 1999 Maize cv: DK 502 (Fao 500) Maize cv: DK 502 (Fao 500) impact agricultural activity and the high Seeding date: 02.06.99 Seeding date: 02.06.99 level of simplification of the productive Seeding rate: 7,2 p m-2 Seeding rate: 7,2 p m-2 system. A possibility to moderate this Fertilisation (kg/ha): Fertilisation (kg/ha): N 211 - P 106 - K 100 N 211 - P 106 - K 100 effect is represented by the rotation of Ryegrass cv: ASSO maize with a winter cover crop. In order Seeding date: 08.10.99 to verify the efficiency of the cover crop Seeding rate: 45 kg ha-1 in reducing the environmental impact, 2000 Maize cv: CECILIA (Fao 500) Maize cv: CECILIA (Fao 500) the maize monoculture system was com- Seeding date: 28.04.00 Seeding date: 28.04.00 pared with the maize-cover crop system. Seeding rate: 7,2 p m-2 Seeding rate: 7,2 p m-2 Fertilisation (kg/ha): Fertilisation (kg/ha): For this reason a multi-annual experi- N 211 - P 106 - K 100 N 211 - P 106 - K 100 ment with field lysimeters was carried Ryegrass cv: ASSO out by the Agricultural Service of the Seeding date: 30.10.00 Seeding rate: 45 kg ha-1 Province of Pordenone (SAASD), toge- Autoren: Dr. Giuseppe PARENTE, Dr. Sonia VENERUS, Province of Pordenone, SAASD - viale Martelli 51, I-33170 PORDENONE; M. SCIMO- NE, SISSAD snc, - v.le Campi Elisi 62, I-34100 TRIESTE; M. TACCHEO BARBINA and A. DELUISA, Regional Agency of Agriculture of Friuli-Venezia Giulia (ERSA) - via Sabbatini 5, Udine, I-33100 POZZUOLO DEL FRIULI 10. Gumpensteiner Lysimetertagung, 29. und 30. April 2003 Bundesanstalt für alpenländische Landwirtschaft Gumpenstein, A-8952 Irdning 63 G. PARENTE, S. VENERUS, M. SCIMONE, M. TACCHEO BARBINA and A. DELUISA Materials and methods 30 cm diameter, distributed in two 3-pla- To the aim of this paper, the analysis tes blocks per each crop, at depths of 70 concerns only the data collected from The trial was carried out at the experi- cm, 100 cm and 140 cm. The samples of 1997 to 2000. mental farm "F. Ricchieri" in Fiume Ve- leaching water were collected each 15 neto (Pordenone), 30 m asl, on medium- days on the average, plus / minus one textured clayey (sand 43%, loam 37%, Results week, depending on the rainfall of the clay 20%), basic soil (Ph in H O 7.9 and 2 period. The data have been analysed as Leached water Ph in KCl 7.3), with 0.92% of organic C average values of the 6 plates per crop and 0.11% of total N. The annual avera- The correlation between the cumulated system at each collection date. ge rainfall is 1260 mm, mainly distribu- amount of leached water and the corre- ted in spring and autumn. Both systems were provided of irrigati- sponding cumulated rainfall is an esti- mation of the water loss by percolation Two crop systems were compared: on in the hottest periods, 3 times per year on the average, for a total amount of 75 during the season in each crop system. • a monoculture cash crop with potenti- mm. This amount of water was not inte- This correlation is well indicated by li- ally high environmental impact (Mai- grated to the rainfall in the analysis, as- near regressions (Figure 1 a-b) that re- ze-Maize succession with no winter sulted in each case significant at p<0.01. soil tillage); suming that it was not relevant with re- gard to leaching. In particular, the slope of regression • a cash crop -cover crop rotation (Mai- functions (i.e. rate of water loss per rain- The variables analysed are the following: ze - Ryegrass). fall unit received) is given in order to In both systems fertilisation was applied • Amount of collected water [litre/pla- differentiate the crop systems (Table 2). only to Maize, whereas Ryegrass, sown te] as indicator of leaching; It can be remarked that: immediately after the Maize harvest, was •NO concentration in leached water 3 • the rate of water loss recorded in the never fertilised. The total amount of fer- [mg/l]; Maize-Ryegrass system is less than the tilisers was in conformity with the ma- • Amount of leached nitrates [g/m²]. half of the Maize-Maize system in the ximum rates indicated by EU Reg. 2078/ years of crop re-establishment (1999- 92 and by the Regional Plan of Rural The analysis was carried out to search 2001), and slightly less than the half Development, applied from 1996 and for differences in the behaviour of the in the set-aside years (1997-98); from 1999, respectively. crop systems during the years of trial, by means of: The crop experimental design during the Table 2: Slope values of the regressi- period 1996-2000 is described in Table 1. • Correlation of the collected leached on curves of Figure 1, per year and The N fertilisation was always provided water with the cumulated rainfall du- crop system (MM=maize-maize; in 3 rates, i.e. 20% of the total at the ring the season; MR=maize-ryegrass). Slopes show the water loss rate (l/plate) per mm of rain- Maize seeding, 30% at the stage of 4th - • Trend of water NO concentration with 3 fall. 5th leaf, 30% at the stage of 8th leaf. The time; crops were established in 1992 and after Year Crop system Slope • Correlation of water NO concentrati- 4 complete vegetative seasons, the field 3 on with the rainfall of the same peri- 1997 MR .017 data collection started. In 1997 and 1998 MM .027 od; both systems were set aside with no soil 1998 MR .009 tillage; after wards the crops were re- • Trend of the amount of leached nitra- MM .013 1999 MR .005 established. te with time; MM .012 Experimental data were collected from • Correlation with leached nitrate with 2000 MR .005 MM .013 2 series of 6 lysimeter ceramic plates of rainfall, cumulated along the season. Maize-Maize Maize-Ryegrass 1997 1997 1998 1998 50 30 1999 1999 45 2000 25 2000 40 35 20 30 25 15 20 10 15 10 5 5 0 0 0 300 600 900 1200 1500 0 300 600 900 1200 1500 Figure 1a, b: Seasonal curves of the cumulated water loss through leaching (l/plate) in function of the cumulated rainfall (mm) 64 10.