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A four-year field experiment to evaluate the effects of different types of organic fertilizers on yield and quality of processing tomato and on soil chemical evolution, was carried out in Southern Italy during the 2002–2005 period on a siltyclay soil. The fertilization treatments aimed to supply 100 kg ha -1 of N and were: 1) an organic biological fertilizer (BIO); 2) an experimental compost composed by olive residues, sludge and straw (COMP); 3) a mix (MIX) of an organic fertilizer (50%) and ammonium nitrate (50%); 4) a traditional chemical fertilizer (ammonium nitrate, MIN). At harvest the main productive and qualitative parameters were assessed (fresh and dried yield; biomass and marketable yield). Chemical analyses of the soil were made at the start and at the end of experiment. Fruit yield did not differ among the fertilization treatments, but unripe fruit yield was higher in the MIN and BIO treatment; MIN showed also smaller fruit than BIO and COMP. The N availability during crop cycle influenced the mean fruit weight, date, and simultaneity of maturity during the ripening process. Soil characteristics changed during the four years of application for mineral N and among treatments (P2O5 for BIO and COMP and mineral N for MIN and MIX fertilization treatments). Heavy metals: cupper and zinc did not increase their concentration in the soil; instead, lead increased below the Italian law’s limit in COMP. The possibility to use organic fertilizer for processing tomatoes has been evaluated and the conclusions are that organic fertilization is, in same cases, more suitable than mineral one from a productive and soil fertility standpoint of view.

Nitrogen (N) is one of the most growth restricting nutrients in cereal grain and represents one of the highest input costs in agricultural systems; therefore, environmental and economic considerations require the effective use of N fertilizer in plant production. This study was conducted for three years to better understand wheat plant response to optimize N fertilizer and how to reduce the risk of ground water pollution. Two of the most important durum wheat cultivars in Southern Italy and four N fertilization levels (0, 60, 120, and 180 kg N ha− 1, indicated as N0, N60, N120, and N180, respectively) were compared in this experiment. During plant growth, fresh and dry matter, plant nutritional state (SPAD readings and stem nitrate content), and N uptake were determined. At harvest, plant N content, N uptake, grain yield, yield components and quality were determined, allowing the calculation of the pre- and postanthesis N uptake and the N utilization efficiency indices. Furthermore, at the beginn...

A 3-year experiment was carried out in Mediterranean conditions on two maize–barley rotations to determine the effect of different levels and sources of nitrogen (N) fertilizer on the N uptake, efficiency, soil N deficit and crops yield. The potential for N savings by the use of N indicators was also studied. Five strategies of maize N fertilization were compared on plots laid out in a complete randomized design with three blocks: mineral N (200 kg N ha −1 ); organic-mineral N (100 kg N ha −1 as olive pomace compost plus 100 kg ha −1 of mineral N); mineral N (100 kg N ha −1 ); organic N (100 kg N ha −1 as olive pomace compost); unfertilized control. Winter barley was cultivated without fertilization. The use of organic fertilizer, as a partial substitution of mineral N, achieved the same yield of the highest mineral fertilizer treatment in maize (8.8 and 8.9 t ha −1 , respectively) and barley (3.2 and 3.5 t ha −1 ), ensured the highest increases of total organic carbon and the least N mineral soil deficit at the end of the experiment. Furthermore, N utilization efficiency indices did not change between the highest N treatments (mineral and organic-mineral N supply) in both crops, reflecting no difference in N utilization. High level of available N in the soil during the growing seasons strongly affected the total N uptake in both crops and, consequently, yield and N utilization efficiency. In fact, as mean of N treatments, the available N contributed to total N uptake for the 57.4% in the first growing period (maize 2000 and barley 2001) and 45.2% in the second one (maize 2001 and barley 2002). The findings of this research also indicate that the postanthesis N uptake was higher than preanthesis in maize (59.1 and 40.9% of the total N uptake, respectively) but lower in barley (32.8 and 67.2%), although it was correlated with yield in both crops, confirming that the reproductive stage is more important than the vegetative one in Mediterranean conditions. Finally, the results showed that the more reliable N indicator tests of yield for maize were the pre-sowing soil mineral N and the mean of SPAD readings, which presented a linear relationship. In barley, the best N indicator was the mean stem nitrate content, which showed a high correlation and linear relationship with yield.

Agronomic value and environmental impact of two composts were evaluated in a three-year field experiment (2002, 2003 and 2004) on alfalfa and cocksfoot in Southern Italy. The effects of Municipal Solid Waste compost (MSW), Olive Pomace Compost (OPC), mineral fertilizer (Min) (phosphorus as 75 kg ha−1 for alfalfa and nitrogen as 50 kg ha−1 for cocksfoot) and an unfertilized treatment (Contr) were compared on crop yield, soil characteristics and environment impact. During the cropping cycles, fresh and dry weights, plant nitrogen status (leaves SPAD readings and petiole nitrate content) and plant total N content were determined for calculating the protein content and the plant N uptake. Moreover, at the beginning and the end of the research, chemical soil characteristics and heavy metal levels were also determined. The results indicated that in cocksfoot fertilized with MSW and OPC composts, the mean cumulative dry weight increased by 20.85 and 16.51%, respectively compared to the control, but it was signif...

A two-year experiment was carried out to study the effects of applying untreated Olive Wastewater (OWW), treated OWW and olive pomace compost as soil amendments on both rye-grass growth and soil characteristics. We analysed growth parameters (Leaf Area Index, and fresh and dry weight), leaf green colour (SPAD readings), N uptake of the rye-grass and chemical soil characteristics. The results indicate that the highest untreated OWW application increased growth parameters by 18.2% in 2001 and by 41.1% in 2002, indicating the possible use of OWW as an amendment to rye-grass. We observed a significant increase in total, extracted and humified organic carbon, and humification parameters. No accumulations of heavy metals in the soil were observed. Furthermore, the N content in OWW was used by the rye-grass for plant growth that increases N uptake, and consequently, dry matter accumulation.

The N uptake by crops, soil distribution and recovery of 15N labelled urea-N (100 kg N ha-1) were investigated in a sorghum-wheat rotation in two silty clay soils (Foggia and Rieti Casabianca) and one silt loam soil (Rieti Piedifiume) under different mediterranean conditions. Non-exchangeable labelled NH4-N represented an important pool at both Rieti sites with higher values (p

The research, started 1993, was carried out at Foggia (Southern Italy) on a silty-clay soil with “accentuated thermo-Mediterranean” climate. The field experiment was laid out in randomized blocks with three replications, comparing three types of fertilizer (Al: mineral fertilizer, A2: organic + mineral fertilizer, A3: municipal solid waste compost) and three N doses (40, 80, 120 kg N ha−1) on Autumn-sown sugar beet, and durum wheat, both cropped each year on adjacent plots. Product quality was evaluated determining polarization angle and α-amino N, Na+ and K+ concentrations of sugar beet pulp and the protein content of durum wheat grain. The best yield responses and quality characteristics of sugar beet and durum wheat in MSW-amended soil depend on differing previous crops and agronomical inputs used over many years in the experimental field. Agronomical benefits of MSW-compost applied to the vertisol type soil used were observed also in relation to mineralization of organic N contained in MSW-compost that gradually released N during the cropping season. When MWS-compost was applied for 4 years the a-amino N and Na+ contents of sugar beet pulp decreased but the supply of mineral N to durum wheat plants provided adequate requirements for grain d.m. accumulation.