Welcome lumacurve!
I have been detecting for quite a few years now and one of my favorite places to hunt is the fields here in Pennsylvania. They have very little trash to impede your searches and produce great quality items! It has been my experience that the plow will constantly bring new items closer to the surface! Because the turning of soil and of the depth that the plow cultivates to, you can hit a field over and over again, only to find more items. One year things could reside at a depth that was just beyond the limits of your coil or only inducing a faint response that you can easily miss. Those same items could also be sitting on edge another year, making them next to impossible to get a reading off of but for a single angle, only to be shifted the following year and easily found the next time the field is searched! My best advice to you is to watch your fields! Farmers tend to utilize crop rotation and also allow fields to rest to maximise crop output and minimize soil erosion, so fields are not necessarily plowed every year. They also do not always use the same cultivation methods every single time for a given field. If you find a field that produces well, watch it the following years to see how the field is utilized and revisit it when warranted, you may find yourself pleasantly surprised! Another reason to watch is that farmers here in Pa have begun to utilize a "No Till" method where they don't cut deep furrows into the soil, which factors greatly into when and if I revisit a field! Fields will always surprise you if you have the patients and determination to hunt such large areas effectively! My very first hunt was in a field next to where I worked at the time. The shop was about a 1/2 mile back a dirt road and smack dab in the middle of fields on all sides. The building was no more than 20 years old, so I really didn't think much about finding anything, but I always had time to kill after work because of waiting for my shared ride home. I had just gotten my detector that weekend and thought that Monday I'd take it to work for my first hunt to try it out and get a feel for how it worked and to play around with the pre-programed programs on it. I swept around the building finding only junk and extremely hard digging because the area had "Modified" stone laid down and compacted around the building to stabilize the soil, which is akin to digging in concrete. After about 30 mins of work and with blisters already forming on the palm of my digging hand, I thought I'd give the farm field a shot. After stepping off the driveway and swinging my detector not more than 20 ft I got a strong reading that said it was a quarter. I bent down and took out my trusty digging tool using it to sweep away the loose detritus, clearing the area to begin digging. When scraping the surface it hit something with a resounding "TINK", causing it fly a short distance away! I immediately thought, "Cool my very first coin"! I picked it up thinking "Awesome a quarter to boot", but as I rubbed it between my fingers to clean off the loose dried dirt from its face I saw to my astonishment the words "ONE CENT"! Becoming more excited by the second, I immediately returned to the shop and washed off the coin only to discover that what I had initially thought to be a quarter, was in fact a 1853 large cent!!! My very first coin, on my very first hunt! The next week I also managed to pull a 1841 seated dime and a 1800 button as well from the same field! So don't be discouraged, fields tend to give up their riches slowly and only to those with patients and determination to look, but the reward is there for the taking!