Geographical description

Location: Legnaro, Padova, Italy (Exp. 1: 45° 20' 52'' N, 11° 57' 17'' E, Exp. 2: 45° 21' 04'' N, 11° 56' 51'' E), 5 m a.s.l., Fluvi-Calcaric Cambisol (CMcf).

The study area is located in the low venetian plain and is characterized by sedimentary loamy soils with shallow groundwater (<2 m). The local climate is sub-humid, with annual rainfall of about 850 mm. Temperatures increase from January (minimum average: 1.5 °C) to July (maximum average: 27.2 °C). SOM content is strongly affected by the peculiar texture (low physical protection) and climatic conditions, and usually ranges from 10 to 20 g kg-1 in the top layer.

Pedo-climatic zone
Mediterranean North, Cambisol 

Location of the study study in NE Italy Overview of part of the long-term experiment (50-yrs old).

Cropping systems

Cropping intensity: Conventional.

Types of crop
Exp. 1: wheat, maize, soybean, sugarbeet, alfalfa, permanent meadow, 7 crop rotations: six-years (maize, sugarbeet, maize, wheat, alfalfa, alfalfa), four year (sugarbeet,soybean, wheat, maize), two years (wheat, maize), continuous maize, continuous wheat, continuous silage maize, permanent meadow
Exp. 2: wheat, maize, tomato, sugarbeet, four-year rotation Management of soil, water, nutrients and pests
Exp. 1: Moldboard ploughing in autumn; due to the shallow water table (ranging from 60 to 200 mm) irrigation is used occasionally; nutrient status is regulated through organic (cattle slurries or farmyard manure) and mineral inputs + introduction of soybean and alfalfa in 4-year and 6-year rotation respectively; chemical weed and pest control.
Exp. 2: Moldboard ploughing in autumn; due to the shallow water table (ranging from 60 to 200 mm) irrigation is used occasionally; nutrient status is regulated through organic (residue incorporation or residue incorporation + poultry manure) and mineral inputs; chemical weed and pest control.

Soil improving cropping system and techniques currently used
Rotation, organic fertilisers (different types and amounts)

Problems that cause yield loss or increased costs
The main threat considered is the loss of organic matter (SOM) in mineral soils. It causes both GHG emissions and a worsening of soil functions (e.g. soil nutrient supply, hydraulic properties), pushing farmers to rely on external chemical input. In the last fifty years, SOM in NE Italy decreased at rates ranging from 0.02 to 0.58 t C/ha/year as a consequence of the intensification and simplification of cropping systems (e.g. monoculture) and the uncoupling of crop and livestock production. Most recently, the removal of crop residue for bioenergy production raises concern about its potential impact on SOM evolution. Application of EU conditionality measures (i.e. mandatory crop rotations) has had only a marginal effect on SOM recovery while other voluntary measures supported by the Regional Government (e.g. input of organic amendant, no-tillage) showed low acceptance by the farmers. Indeed, implementation of measures has been hindered by a) technical, logistic and economic constraints (e.g. distance between amendant source and potential users); b) farmer’s cultural diffidence; c) uncertainties of their bio-physical effectiveness, due to a large variability in pedo-climatic conditions which strongly affect the interaction between
organic input and C cycle.

External drivers and factors

Institutional and political drivers
The area is included in the Vulnerable Zone of Veneto Region for the Nitrate Directive. Veneto Region has recently implemented a specific agro-environmental measure to increase SOM content through amendant input and conservative tillage. However these measures showed low acceptance.

Societal drivers
The agricultural system of Veneto region is struggled by different external factors. A first constraint is a strong competition for land by industrial and urbanisation, leading to a prevalence of highly fragmented and small farms with a relatively low technological level. This reduces the competitiveness, in particular considering the dynamic of product prices in the last years, and frequently pushes toward a simplification of cropping systems.

Bio-physical drivers
In the last years the increase of inter-annual variability of climatic variability is becoming an important constraint for the main summer crops; this is partially mitigated in maize anticipating sowings from mid-april to the end of March, thus allowing an earlier flowering, before droughts normally occurring in July. Frequent summer droughts tends to increase pest incidence, particularly for micotoxins-producing fungi.