Evaluation of Agri-Environmental Measures in the Venice Lagoon Watershed. Nitrogen Budgets and Surplus Indicators

Abstract

SummaryOne of the main concerns of the environmental scientists and policy makers is related to the environmental compatibility of current agricultural systems and, in particular, to the losses of chemical fertilizers and manure in surface and ground-waters, as a consequence of run-off and leaching phenomena. In most cases European recent agrienvironmental schemes envisaged specific measures for the reduction of fertilizer rates and the control of manure applications, in order to limit the releases of nutrients in surface and ground-waters. Substantial financial resources are invested in those measures and therefore the issue raises interest in monitoring and evaluating their effectiveness. Nutrient balance indicators are often used for quantitative assessment of the effectiveness of the measures in limiting the environmental impact of farming activities. N-surplus is one of the most commonly used indicators. The paper refers the results of a research project aimed at assessing the outcomes of agri-environmental measures implemented in the Venice Lagoon Watershed with an approach based upon the gross nitrogen balance, called "Nboxes". The results of applying the Nboxes procedure to a sample of 550 farms set are presented, evidencing the expectations of greater effectiveness in terms of nitrogen surplus reduction from the measure C.5.1.3a and C.5.1.3b (low input farming and buffer strips). Measures supporting improved irrigation systems, controlled drainage and more rational livestock nutritional programmes and technologies, showed instead only limited potential for tangible contributions to the reduction of nitrogen surplus in cultivated soils.

Economic impacts of nitrogen and phosphorus use efficiency on nineteen intensive grass-based dairy farms in the South of Ireland

“…As N (Eckard et al, 2004;Leach and Roberts, 2002;Powell et al, 2010) and P (Jarvis and Aarts, 2000) positive balances are commonly associated with excessive, inefficient N and P use on farms, as well as harmful environmental impacts, they are considered as indicators of potential N and P losses and environmental performance (Carpani et al, 2008;Jarvis and Aarts, 2000;Schröder et al, 2003). Therefore, in the current study, N and P balances were used as indicators of environmental sustainability.…”

Nitrogen balance and use efficiency on twenty-one intensive grass-based dairy farms in the South of Ireland

“…2010), it is considered as an indicator of potential N losses and environmental performance (Schröder et al . 2003; Carpani et al 2008). Nitrogen surplus potentially accumulates in soil organic matter (SOM) (Jarvis 1993) or is lost through denitrification, nitrate (NO 3 ) leaching, ammonia (NH 3 ) volatilization (Jarvis & Aarts 2000; Pain 2000; Del Prado et al .…”

“…2007; Beukes et al . 2012); and (iii) increase farmers’ awareness of environmental regulations on farms and implementation of these regulations to control N losses to the environment (Oenema et al 2003; Carpani et al 2008).…”

Multi-Year N and P Removal of a 10-Year-Old Surface Flow Constructed Wetland Treating Agricultural Drainage Waters

“…In this context, the Venice Lagoon drainage basin (in the northeastern part of the low-lying Padano-Veneta Valley in Italy) offers a suitable location to study the environmental benefits provided by SFCWs. Increasing concerns have been raised in the last decades about N and P surface water pollution of the Venice Lagoon [18][19][20], and the European Directives [21,22] stressed the need to reduce water and nutrient losses from agricultural fields to preserve the ecological status of European river basins [23].…”