Angelo Fiore

YIELD AND SOIL RESPONSES OF MELON GROWN WITH DIFFERENT ORGANIC FERTILIZERS

A three-year field experiment (2006–2008) was carried out in Mediterranean conditions to study the effects of organic fertilizers application on yield performance and plant nitrogen (N) status of melon crops. Soil properties at the end of experiment were further investigated. In a strip-plot experimental design, two irrigations and the following four fertilizer treatments were compared: mineral fertilizer (Min); commercial stable manure (Org); anaerobic digestate (WDD); composted municipal solid organic wastes (SUW). The results showed no statistical differences among the four different treatments on melon yields. Conversely, the highest irrigation treatment showed a significantly higher total yield (34%) and fruits number (26%). During cropping cycles, the Min treatment reached the highest mean nitrate content with an increase of about 59% and 154% respectively compared with Org and mean of WDD and SUW. The WDD and SUW significantly increased soil total, extracted and humified organic carbon of the 14, 22 and 12% compared with Min. Among treatments, no significant difference was found for heavy metals excepted for Cu, which reached the highest level in WDD treatment.

PREVIOUS CROPS AND ORGANIC FERTILIZERS IN LETTUCE: EFFECTS ON YIELDS AND SOIL PROPERTIES

The use of organic amendments in agriculture could sustain crop production and preserve the agroecosystem, due to their importance in the conservation of organic matter in soil. The objective of this research was to evaluate the effects of differing organic fertilizers and of previous crops on lettuce growth, nutritional status and yields. The effects on soil characteristics were further investigated. The research was carried out during two years (2006 and 2007) at Metaponto (MT) in southern Italy, on lettuce crops cultivated after eggplant and melon to avoid their continuous cropping. The effects of application of a mineral fertilizer (MF), and of three treatments with organic fertilizers (commercial stable manure - OM; anaerobic digestate based on wine distillery wastewater - AD; composted municipal solid organic wastes coming from the separate collection - MSW) were studied. Head average weight, leaf area index, nitrate content and SPAD readings during the cropping cycles did not show significant differences among fertilizer treatments. On the contrary, marketable yield and head average weight at the harvest presented significantly different among the three organic fertilizers. The average marketable yield and head average weight of organic fertilizers experimental (AD and MSW treatments) decreased of 16 and 17%, respectively, compared to OM treatment. The previous melon crop influenced positively all analyzed parameters of the lettuce compared with previous eggplant crop. The previous melon crop reached the highest marketable yield with an increase of 59% compared with previous eggplant crop. Compared to the mineral fertilizer, the organic ones significantly increased the extracted fraction of soil organic carbon (6.9, 10.7 and 14.9% for OM, AD and MSW, respectively), without significant changes for the humic and fulvic content.

Minimum tillage and organic fertilization for the sustainable management of Brassica carinata A. (Braun) in the Mediterranean environment

In recent years, the massive exploitation of agricultural land intended to meet growing food demand has led to a reduction in soil fertility through the depletion of nutrients and organic matter. To implement sustainable agriculture, it is necessary to reduce soil tillage and use residual biomasses that are easily available in the region as soil amendments. Furthermore, it is important to test these residual biomasses in order to exclude a possible increase of heavy metals in soils due to the incorporation of the aforementioned biomasses. The current study aimed to evaluate the effects on soil fertility and health following the application of organic fertilizers combined with different soil tillage practices and the agronomic response of Brassica carinata A. (Braun). The soil tillage treatments consisted of conventional (CT) and minimum tillage (MT), whereas the fertilization treatments were mineral fertilizer (Nmin), municipal solid waste compost (Ncomp), mixed compost and mineral fertilizer (Nmix), and sewage sludge (Nss). These treatments were compared with an unfertilized control (N0). The Ncomp and Nss treatments enhanced soil fertility, increasing the organic carbon and available phosphorus concentrations compared with N0 and Nmin, whereas no significant difference was showed between the soil tillage treatments in terms of soil fertility. In addition, Nss did not show any significant difference compared to Nmin in terms of crop biomass, whereas this parameter appeared higher in CT compared with MT. A principal component analysis showed that the concentrations of toxic elements applied by the organic amendments did not change the dynamic equilibrium of the soil–plant system. Over the short term, the replacement of CT and Nmin with MT and Nss can be achieved, thus guaranteeing the sustainable cultivation of Brassica, without significant changes in heavy metal concentration in soil.

Yield and Performance and Soil Properties of Organically Fertilized Fodder Crops

The aim of this study was to evaluate the effects of experimental amendments on yields of Trifolium subterraneum L., Pisum arvense L., and Lolium multiflorum Lam., and on soil characteristics. A two-year research was carried out comparing anaerobic digestate (AD) and olive-pomace compost (OPC) with mineral fertilizer (Min), commercial organic-mineral fertilizer (Org-min), and unfertilized control (Cont). Anaerobic digestate and OPC were firstly analyzed for their chemical characteristics. The most important parameters were recorded and soil properties were investigated. Anaerobic digestate showed the highest dry weight for ryegrass, the best yield in pea, and good level of dry matter in clover. Good responses were achieved by OPC. Anaerobic digestate increased total soil organic carbon by 14.4, 8.1 and 7.6% than Min, Org-min and Cont, respectively. Olive-pomace compost increased the same parameter by 16.3, 10.0, and 9.5%. The findings indicated the possibility to substitute mineral fertilizers with organic ones without decreasing yields and support soil fertility.

Suitability of Untreated and Composted Olive Mill By-Products as Amendments in Organic Olive Orchards

ABSTRACT. In the Mediterranean area, the proper soil application of olive pomace compost (OPC) and olive mill wastewater (OWW) could play a crucial role in replacing the annual losses of organic matter, thus sustaining agriculture. Therefore, the objectives of this five-year field trial were: (i) to investigate the effects of OWW and OPC, applied at different doses, on soil fertility in an organic Mediterranean olive grove; (ii) to assess the influence of treatments on production and quality responses of olive trees. In a randomized block experimental design, the following experimental treatments were compared: (i) OWW; (ii) OPC; (iii) the same olive pomace compost used in treatment (ii) distributed to supply a double rate of N per plant (OPCx2). These treatments were compared to: (a) commercial NPK organic-mineral fertilizer (Org-min); and (b) green manure of broad bean (GM). Soil parameters were analyzed to assess soil fertility at the beginning of the field trial and in the medium and longer term. At harvest, agronomical performance of treatments was also evaluated. At the end of the field trial, olive pomace compost (mean of OPC and OPCx2) significantly increased total organic carbon by 47.5% compared to Org-min, and the humified organic carbon values were significantly higher for OWW, OPC, and OPCx2, as compared to GM. The values for olive yield components in GM were lower than in OPC and OWW. Therefore, results showed that OWW and OPC application could be a suitable substitute of traditional methods (GM) to improve overall soil fertility and sustain yield in organic olive grove.