Yes, new gates and some nice improvements to the farmland in that area. It would take some research to see if there is some kind of easement or right of way through that area that allows public access to Martinez Canyon.
The new gates might be related to theft (copper from pumps and crops).
It does look like that gates are on the boundary between private land and public land administered by BLM, but I could be reading the map wrong and you'd have to be a surveyor to know for sure. A lot of the land between the farmland and the National Monument in that area is administered by BLM. In addition a big chunk of the private holdings of undeveloped desert land that are in that area where sold for conservation in the last few years.
Maybe BLM will be able to clarify the access situation.
Map (some changes have taken place since this map was drawn):
http://www.cvmshcp.org/Plan%20Documents ... s/d2-1.pdf