Most dogs who have a penchant for digging up your "BACK 40" do it for some of the same reasons they are destructive indoors.
I. REASONS FOR DIGGING.
A. Cooling Off. Many dogs (especially "cold weather" dogs) will dig in order to search for cool earth to lay in and lower their body temperature.
B. Breed. Some breeds were bred to be extremely motivated by digging, and will have a tendency to dig more than others, but, ultimately any dog can develop a digging problem. Many members of the sporting group, hound and terrier groups are popular diggers.
C. Nervous Energy/Lack of Exercise. Dogs that tend to be more high strung will often dig out of frustration or boredom. All dogs need PLENTY OF EXERCISE. The less exercise they get, the more likely they are to dig.
D. Burying objects. Some dogs will bury a bone or favorite toy. This is very natural and instinctive, especially in pregnant bitches. What she is doing is creating a food reserve in the event her food supply for her young should become scarce.
E. Scent. Some dogs dig because they smell an animal, fertilizer or a bone, under the ground and dig out of curiosity. Many hunting dogs will do this.
F. Freedom. Some dogs, when put behind a fence or gate, will dig in an attempt to free themselves of this barrier or to get to a highly stimulating object or animal. Most dogs left outside all day due to either indoor destruction or because the owner feels they "need the fresh air" become great escape artists. You should solve your indoor problem first, rather than put your dog outside when he really doesn't want to be alone in the first place.
G. Boredom. Digging will surely excite the dog who has nothing to do all day when left outdoors.
II. SOLUTIONS.
A. The Digging Pit. Since your dog loves to dig, give him one spot in your yard where he is allowed to dig. Give it a name like "Digging Pit". Once you have chosen the spot, keep it stocked with bones, food treats, balls, and toys. Watch him closely and be sure to praise him when he is digging in "his" pit. Tell him to "DIG" so he can find his reward. You must also carefully and consistently supervise him when you are attempting to introduce the pit so you can immediately redirect his inappropriate digging to the appropriate spot. If he starts digging in the flower beds, quickly tell him NO! and take him to his spot and tell him to "DIG".
B. Exercise. Remember to always give your dog as many opportunities as you can manage to burn off any excess energy. This will rid your dog of a lot of tension and he will surely be less inclined to think his job is to dig up your "BACK 40"!
C. Supervision. A dog should never be left alone outdoors to get some fresh air or exercise. Since dogs are pack animals, they prefer to be in the company of the rest of the pack. If the pack is not home, they prefer to be in the area where the pack usually rests (bedroom, den, kitchen, etc.) Leaving the dog outside unattended will only encourage him to find his own fun. Digging can be very rewarding to the dog and at the same time frustrating to you. All outdoor activities should be supervised and constructive.
CONCLUSION
Always remember, your dog is not spiteful and trying to make you angry. His destruction, whether it be outdoors or indoors, is only as a result of lack of constructive stimulation and too early freedom. He is just being a dog who has not learned our "human rules". If you are clear about your rules and supervise him at all times, he will quickly learn what behaviors are
acceptable to you, his leader, companion and friend.