Nitrate evolution in leaching water and plant in sweet pepper and broccoli crops using different fertilizers

Groundwater pollution by nitrate is a serious problem in the European Union and in many developed countries, particularly in those areas with intensive agricultural production, like in the case of the Campo de Cartagena, area in the Murcia Region. The aim of this study was to investigate the effect of different fertilization strategies applied during two successive crop cycles, sweet pepper and broccoli on plant growth and nitrate evolution in leaching water and plant. Four fertilization treatments were compared in both crops: i): Integrated Production Fertilization (IP), ii): Organic Fertilization (ORG), using a product for organic crop production; iii): Slow-release N fertilizers (SRN) using two slow release fertilisers and iv): Plant- Associative Bacteria (PAB), using a product with microbial inoculants. Two pairs of suction lysimeters (one 30 cm and the other 60 cm deep) were placed one week after transplanting each crop cycle. In this study, sweet pepper plants were harvested three times and broccoli plants only once. There was no effect of different fertilizer treatments on the sweet pepper yield and on the nitrate content in the fruits. IP treatment produced the best agronomic results in the broccoli crop and the highest nitrate content in the inflorescence. The nitrate content of the pore-water (at 30 cm deep) decreased towards the end of the cycle in all the treatments in both crops and PAB treatment led to the highest nitrate contents in leaching water at 60 cm in both crops.