ADOPTION OF CONSERVATION AGRICULTURE IN WINTER WHEAT (TRITICUM AESTIVUM L.) WITH THE AIM OF SAVING WATER, PROTECTING THE ENVIRONMENT, IMPROVING SOIL HEALTH AND REDUCING CO2 EMISSIONS.

Conservation Agriculture (CA) is an ecological approach to regenerative sustainable agriculture and ecosystem management based on the practical application of context-specific and locally adapted three interlinked principles of: (i) Continuous minimum or no mechanical soil disturbance (no-till seeding/planting and weeding, and minimum soil disturbance with all other farm operations including harvesting); (ii) permanent maintenance of soil mulch cover (crop biomass, stubble and cover crops); and (iii) diversification of cropping system (economically, environmentally and socially adapted rotations and/or sequences and/or associations involving annuals and/or perennials, including legumes and cover crops). These essential practices are combined and enhanced with other complementary practices of integrated crop, soil, nutrient, water, pest, labour, energy and land management practices to generate and sustain optimum performance of ecosystem services. This PhD project seeks to demonstrate the effect of CA in the short term after its implementation and its effect on soil fertility with one of the major crops in the study area, winter wheat. The hypothesis proposed is that the reduction of soil tillage favors the physico-chemical and biological characteristics of the soil, and the quality and yield of the wheat crop. To test this hypothesis, a three-year experiment was carried out in the lowland plain of Veneto (northern Italy). Three tillage intensities were considered: conventional tillage (CT), minimum tillage (MT) and no-tillage (NT). In a first phase, the effect of tillage on different soil and wheat crop parameters was evaluated. The results indicated that the reduction of soil tillage improved soil physico-chemical parameters and did not influence the yield and quality of the wheat crop, with an equal behavior in the three tillage treatments. A higher percentage of moisture in the soil under NT was observed, bulk density in the upper horizon had similar values for NT and CT and lower values for MT. An increase in soil organic carbon of 25% and 31% was observed for MT and NT respectively, which corresponds to 5.41 and 6.75 t C ha-1 respectively. These tests showed that, in the short term, this practice positively influences important soil parameters and does not generate negative effects in terms of crop production. The overall sustainability of the system was measured using a multivariate approach to calculate a Relative Sustainability Index (RSI), using the information collected within this research project and those obtained in the preceding years in the experimental system here considered. This analysis showed that reduced tillage systems (MT and NT) are more sustainable than CT, which with the passing of time decreased its RSI. On the other hand, in the face of adverse climatic conditions, such as those suffered in 2022 with a marked drought and extreme temperatures, the reduced tillage systems showed no negative effects in terms of grain yield and quality, the results were competitive with those of conventional tillage. Finally the results obtained in this research were analysed with the results obtained since 2018, the beginning of the implementation of conservative agriculture in the field under study, where the focus was on the nutritional factor, its evolution over time and the soil's capacity for carbon sequestration, with positive results framed within the 4 per mille initiative exceeding the carbon sequestration value of 4‰ per year in the reduced tillage practices for the soil under study.