If you are looking for ways to earn extra income from a small amount of land or a small farm then I would recommend you investigate how camping and glamping - agritourism - can fit with your particular business model.
Particularly, it is wise to investigate how starting a glamping business (a new and rapidly growing tourism trend), bed and breakfast or other tourism income models can help you.
This uses the assets you already have (e.g. land/acreage) and requires minimal investment to gain a return. For example, in the UK the National Farmers Union (NFU) reported that farms that had diversified into some kind of tourism activity had managed to boost their income by £21,000 (c $34,500) per year. I have since interviewed farmers who have set up glamping businesses and they have agreed with the estimate given by the NFU.
This innovative farming practice of diversifying land to increase income streams, resulting in a more profitable acreage, has been introduced across the world. Farms are a partifularly successful at introducing tourism into their business models because of the agri-entertainment factors, i.e. tourists enjoying their vacations being part of the working farm environment - often a significant leap away from their regular daily lives and something their kids really enjoy.
Starting a glamping business, or other similar tourism idea, is certainly worth considering if you want to increase the profitability, diversity and strength of an existing farm business, particularly if it is a small one. There's a lot more information available (including figures outlining what you could earn) if you want to investigate this option further and if it's right for your land / farm, via 'Inspired Camping' using this link to the business inspiration section... http://www.inspiredcamping.com/category/business-tips/
Alternatively there's a detailed course available here if you're sure it's the right option for you http://www.inspiredcourses.com/glamping
Hope it helps and good luck!