Valutazione della variabilità spaziale e temporale del lavoro per la gestione sito specifica delle colture agrarie

The soil varies from place to place, and many of its properties vary in time too. Within-field variation is the result of both spatial and temporal variation of biological, edaphic, climatic, topographic and anthropogenic factors. There is a need in modern agriculture of understanding spatial and temporal variability within fields. The objective of this study was to analyze, to quantify and to assess the within agricultural field spatial and temporal variability for site specific management. Some soil physical-chemical parameters were investigated by means of georeferenced samplings in order to study the variability of multiple soil variables and to find soil indicators. Performance of machineries during soil tillage and agricultural operations were also investigated and analyzed with the aim of finding field efficiency indicators. Geostatistical analyses were implemented to interpolate the acquired data and to perform the cluster analysis. The results of tests performed during the whole experimentation highlighted the presence of high spatial variability of soil physical-chemical properties within the agricultural fields examined. Georeferenced sampling of soil physical-chemical parameters allowed to identify soil quality and soil strength indicators, furthermore monitoring the performance of machineries during soil tillage and agricultural operations allowed to identify field efficiency indicators (i.e.: area specific consumption, global energy employed and fuel energy requirements). The assessing process of spatial variability within agricultural fields, the identification of soil indicators and the definition of management zones can be considered as an adaptation technique to Climate Change enhancing the efficiency of agriculture. In fact, the defined management zones could provide information for sitespecific management, including the application of different soil tillage methods. Furthermore, variable-rate application (VRA) instead of uniform-rate application (URA) of inputs might be carried out, decreasing fertilization in the more productive area and minimizing the application of chemical substances as a strategy to obtain a more costeffective field management.Il suolo varia da luogo a luogo e molte delle sue proprietà variano anche nel tempo. La variabilità all’interno dei campi coltivati è il risultato della variazione spaziale e temporale di fattori biologici, edafici, climatici, topografici e antropogenici. L’agricoltura moderna deve studiare e valutare la variabilità spaziale e temporale all’interno dei campi coltivati. L’obiettivo della presente ricerca è stato quello di analizzare, quantificare e valutare la variabilità spaziale e temporale all’interno dei campi coltivati al fine di stabilire un sistema di gestione sito specifico. Alcuni parametri fisico-meccanici del suolo sono stati studiati, per mezzo di campionamenti georeferenziati, al fine di studiare la variabilità di diverse variabili del suolo e di trovare degli indicatori. Sono state studiate anche le prestazioni delle trattrici durante le lavorazioni del suolo e le operazioni colturali con lo scopo di trovare indicatori di efficienza delle stesse. I risultati dei test effettuati durante l’intera sperimentazione hanno evidenziato la presenza di un’elevata variabilità spaziale dei parametri fisico-meccanici del suolo nei campi esaminati. Inoltre i campionamenti georeferenziati hanno permesso di identificare indicatori della qualità e della tenacità del suolo, il monitoraggio delle prestazioni delle trattrici ha permesso di trovare indicatori di efficienza (consumo specifico, energia globale impiegata, richiesta di carburante) Il processo di valutazione della variabilità spaziale all’interno dei campi coltivati, l’identificazione degli indicatori del suolo e la definizione delle zone omogenee possono essere considerati come tecniche di adattamento ai Cambiamenti Climatici, in quanto forniscono informazioni per la gestione sito specifica delle colture agrarie come ad esempio la distribuzione a regime variabile dei prodotti fitosanitari (VRA) e la differenziazione delle lavorazioni del suolo.Dottorato di ricerca in Ingegneria dei sistemi agrari e forestal

Soil Tillage Systems and Wheat Yield under Climate Change Scenarios

In this study, the effects of three different main preparatory tillage operations: ploughing at 0.4 m (P40) and 0.20 m (P20) depth and harrowing at 0.20 m depth (MT) were investigated. The tillage operations were carried out at two different times, as the soil water content increased over time from rainfall: (low, 58% (LH) and high, 80% (HH) of field capacity). Results obtained from the soil monitoring carried out before and after tillage showed high values of soil strength in terms of Penetration resistance and shear strength particularly in deeper soil layers at lower water content. During tillage, fossil-fuel energy requirements for P40 LH and P20 LH were 25% and 35% higher, respectively, with respect to the HH treatments and tractor slip was very high (P40 LH = 32.4%) with respect to the P40 HH treatment (16%). Soil water content significantly influenced tractor performance during soil ploughing at 0.40 m depth but no effect was observed for the MT treatment. The highly significant linear relations between grain yield and soil penetration resistance highlight how soil strength may be good indicator of soil productivity. We conclude that ploughing soil to a 0.20 m depth or harrowing soil to a 0.20 m depth is suitable for this type of soil under climate change scenarios

Equipping a Combine Harvester with Turbine Technology Increases the Recovery of Residual Biomass from Cereal Crops via the Collection of Chaff

In cereal crops, chaff is a valuable lignocellulosic by-product that accounts for more than 50 Mt y−1 in Europe and is suitable for bioenergy purposes. Chaff is usually not collected due to the lack of combine harvesters that have the capability to handle it properly. The present two years experimental study investigated the hypothesis that the overall biomass collected in wheat crop can be increased by equipping the combine harvester with an aftermarket device. Chaff, discharged from the combine harvester-cleaning system, is collected by the turbine that delivers it either on the swath or on a lateral trailer towed by a tractor. The performance of all machines involved in the harvesting (combine harvester, tractor, baler, and trailer) were assessed. The chaff was collected in bales with the straw (A mode) and separately on a trailer (C mode). Comparisons with non-collected treatment (B mode) were performed in order to estimate the total chaff collected and the biomass losses. The results showed that 1.79 t FM ha−1 per year of chaff could be collected when baled with the straw, whereas 1.27 t FM ha−1 were collected separately on a trailer. Both field and material capacity were not negatively affected by the chaff collection. Therefore, our study confirmed the hypothesis that turbine technology is a valid solution for increasing the total residual biomass collected in cereal cropping for energy purposes

An Innovative System for Maize Cob and Wheat Chaff Harvesting: Simultaneous Grain and Residues Collection

Maize and wheat are two of the most widespread crops worldwide because of their high yield and importance for food, chemical purposes and livestock feed. Some of the residues of these crops (i.e., maize cob and wheat chaff) remain in the field after grain harvesting. In Europe, just maize cob and grain chaff could provide an annual potential biomass of 9.6 Mt and 54.8 Mt, respectively. Collecting such a biomass could be of interest for bioenergy production and could increase farmers’ income. Progress in harvest technology plays a key role in turning untapped by-products into valuable feedstocks. This article presents a study of the performance and the quality of the work of Harcob, an innovative system developed for maize cob collection. Furthermore, the feasibility of using the Harcob system to also harvest wheat chaff during wheat harvesting was also verified. The results showed that it was possible to harvest 1.72 t ha−1 and 0.67 t ha−1 of cob and chaff, respectively, without affecting the harvesting performance of the combine. The profit achievable from harvesting the corn cob was around 4%, while no significant economic benefits were observed during the harvesting of wheat chaff with the Harcob system. The use of cereal by-products for energy purposes may allow the reduction of CO2 from fossil fuel between 0.7 to 2.2 t CO2 ha−1. The Harcob system resulted suitable to harvest such different and high potential crop by-products and may represent a solution for farmers investing in the bioenergy production chain

The Correlation between Proximal and Remote Sensing Methods for Monitoring Soil Water Content in Agricultural Applications

Water shortages have increasingly become a global issue due to the acceleration of climate change. The consumption of freshwater can be reduced to a minimum using water irrigation techniques that are based on conservative methods. For example, one of these is precision irrigation, or PI, which uses advanced digital technology to regulate the amount of water used. The aim is to use the least amount of water necessary for a given purpose. This approach keeps consumption to a minimum while the amount remains effective for its purpose. It is also important to note that the variability which occurs in soil and crops will create different types of conditions. These different conditions will need to be studied so as to determine the correct and adequate dynamics for a water management approach that is efficient. In this study, three investigation methods were developed and compared. The first evaluation was performed on outputs from the geoelectric reading of Automatic Resistivity Profiling (ARP). A second evaluation was performed in real time via a sensor network placed in the soil for the duration of two growing seasons of two different crops. The last evaluation was carried out by using maps of spectral indices obtained by the Sentinel 2 satellites. The correlations between the three methods were evaluated to verify if satellite information may have significant potential in the use of water management in varying conditions. From the results obtained, some correlations have been found from the observations of the three systems under study. This has given a positive input towards using satellite maps which are integrated with simplified proximal sensor networks. The outcome of this technique can improve the efficiency of how to manage water distribution on cultivated land

Effect of Swathing or Direct Combining on Yield, Seed Losses and Costs of Camelina

Camelina is an interesting crop and producers must adopt cultural practices to achieve the highest yield and oil content possible. Considering the size of the seed, the harvesting phase is crucial to reduce losses and maximize income. Furthermore, in recent years, with the worsening of climatic conditions due to global warming, crop management can no longer follow the classic seasonality but must adapt to new climatic conditions. The possibility of double cropping, that is the process of producing two crops in a single season, allows multiple advantages such as weed control, greater remuneration, and less exposure to bare soil which determine greater resilience of the production system. To enable this, especially in recent years, even a few days of difference in the cultivation phases can guarantee the success of double cropping. For these reasons, the authors compared two different harvesting strategies: direct combining at full maturity (DC); swathing + combining at full maturity (SW). The working performance, cost, and seed losses associated with each harvesting method were calculated. The results highlighted how SW reduced the crop cycle length by 11 days, did not influence seed losses and crop yield but showed lower performance and higher cost with respect to DC

Testing Open-Air Storage of Stumps to Provide Clean Biomass for Energy Production

When orchards reach the end of the productive cycle, the stumps removal becomes a mandatory operation to allow new soil preparation and to establish new cultivations. The exploitation of the removed stump biomass seems a valuable option, especially in the growing energy market of the biofuels; however, the scarce quality of the material obtained after the extraction compromises its marketability, making this product a costly waste to be disposed. In this regard, the identification of affordable strategies for the extraction and the cleaning of the material will be crucial in order to provide to plantation owners the chance to sell the biomass and offset the extraction costs. Mechanical extraction and cleaning technologies have been already tested on forest stumps, but these systems work on the singular piece and would be inefficient in the conditions of an intensive orchard, where stumps are small and numerous. The objective of this study was to test the possibility to exploit a natural stumps cleaning system through open-air storage. The tested stumps were obtained from two different vineyards, extracted with an innovative stump puller specifically designed for continuous stump removal in intensively-planted orchards. The effects of weathering were evaluated to determine the fuel quality immediately after the extraction and after a storage period of six months with respect to moisture content, ash content, and heating value. Results indicated interesting storage performance, showing also different dynamics depending on the stumps utilized

Methodology for the Definition of Durum Wheat Yield Homogeneous Zones by Using Satellite Spectral Indices

One of the main questions facing precision agriculture is the evaluation of different algorithms for the delineation of homogeneous management zones. In the present study, a new approach based on the use of time series of satellite imagery, collected during two consecutive growing seasons, was proposed. Texture analysis performed using the Gray-Level Co-Occurrence Matrix (GLCM) was used to integrate and correct the sum of the vegetation indices maps (NDVI and MCARI2) and define the homogenous productivity zones on ten durum wheat fields in southern Italy. The homogenous zones identified through the method that integrates the GLCM indices with the spectral indices studied showed a greater accuracy (0.18–0.22 Mg ha−1 for ∑NDVIs + GLCM and 0.05–0.49 Mg ha−1 for ∑MCARI2s + GLCM) with respect to the methods that considered only the sum of the indices. Best results were also obtained with respect to the homogeneous zones derived by using yield maps of the previous year or vegetation indices acquired in a single day. Therefore, the survey methods based on the data collected over the entire study period provided the best results in terms of estimated yield; the addition of clustering analysis performed with the GLCM method allowed to further improve the accuracy of the estimate and better define homogeneous productivity zones of durum wheat fields

Analysis of the Work Productivity and Costs of a Stationary Chipper Applied to the Harvesting of Olive Tree Pruning for Bio-Energy Production

Pruning residues could represent an important biomass resources for energy production. Only in Italy it has been estimated that an annual quantity of biomass of over 2600 kt of dry matter could be obtained from olive residues. Several machines developed for pruning harvesting are available in the market, most of which are tractor-driven, while limited knowledge is available on performance, quality of work and costs of harvesting logistics based on stationary chippers. The aim of the present paper is to analyze machine performance of a forestry stationary chipper applied to pruning harvesting for what concerns work productivity, quality of the comminuted product and harvesting operating costs. This system is actually applied by Fiusis Company, an Italian enterprise which manages a biomass power plant exclusively powered by olive trees’ pruning residues, and it has never been analyzed in literature. The results obtained showed consistent work productivity, which resulted the highest ever found in olive pruning harvesting systems and equal to 5.23 ± 0.81 tdm·h−1. This high work productivity allowed also to obtain a little economic gain from a matter, which is actually considered a problem for olive groves’ owners and not a potential source of income. In particular, the use of a stationary chipper seemed very efficient in olive groves with a consistent amount of wooden residues to be processed and with big branches not harvestable by the most common towed pruning harvester. In addition, the stationary chipper has the advantage of avoiding the preliminary raking operation, which results in reduced costs for the farmer