# Precision Farming in Hilly Areas: The Use of Network RTK in GNSS Technology
## 4 Discussion  
Despite an increasing awareness in hilly situations [30; 36], techniques for precision farming are essentially used in flat areas. One of the major problems of precision agriculture concerns the difficulty of properly monitoring and managing hilly areas due to the high probability of error and loss of important information during detection operations [23; 31; 32]. This trouble can become critical if precision agriculture is applied to the Italian context. The latter presents a very varied territory, in which there is a strong presence of hills. Moreover, Italy has a fragmented rural landscape [20], which may complicate territorial analysis operations. Few studies have focused and compared GPS and GNSS technologies, demonstrating their validity in hilly areas [37].  
In this paper, attempts have been made to minimize possible errors derived from GNSS technology. Devices as GNSS technology permit land mapping, optimizing machining operations in which rural vehicles can repeat (or exclude) a path already done. The innovative element of GNSS technology is the opportunity of putting rural machines and the farm management in communication. This interaction allows a timely technical analysis that points out the degree of improvement, further agronomic practices that need to be implemented, or a unique business database containing all the surface areas cultivated and the activities carried out on them. All the collected data can be processed through a Geographic Information System program (GIS), allowing rural processes and suitable agro-technological assessments [34]. GIS and remote sensing are layer-based systems, giving their users the flexibility to superimpose different levels of reality and find the best model for more accurate agricultural practice. An interpolated map describing the soil type, slope, and aspect in hilly areas can simulate the yield of crops with various variety groups and other agricultural inputs. With specific devices (RTK bridge), it is possible to overcome any signal deficiencies. Finally, in rugged hilly terrain areas, using the satellite navigation system can safeguard operators' safety from potential risk concerning the overturning of agricultural vehicles.  
The present work gives new insights for research activities in hilly environments. In fact, with simple field trials at the stage of weeding, significant results have been achieved, without requiring statistical comparison. Achieving the main purpose, a homogeneous environment was chosen for the selected farms, where only one seasonal crop was present (wheat). Future research development may deal with heterogeneous environments having different crop areas and more than one crop season cycle.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Parameters Signed** & **Manual Guide** & **Assisted Guide** & **Automatic Guide** \\ \hline Time spent (min) & 7:04 & 6:50 & \(-3.30\%\) & 6:38 & \(-6.13\%\) \\ Product used (l) & 355 & 304 & \(-14.37\%\) & 301 & \(-15.21\%\) \\ Surface area (ha) & 1.25 & 1.25 & - & 1.25 & - \\ Distance travelled (km) & 1.10 & 1.10 & - & 1.10 & - \\ \hline \hline \end{tabular}
\end{table}
Table 2: Comparison of the parameters found in the three types of soil processing.