Re: white vinegar vs round up
25 yrs back, I used to spray about 5 x 20 litre containers of Roundup per 6 months at half strength on a large sub tropical orchard here in NZ. If timing it right, I used to spray twice a year (before grasses/weeds flowered) and use only drip irrigation. 3 times per yr if I was slow getting to it. If knocking down fresh pasture, I'd increase strength to 75%.
I found calibration of the tractor spraying system well worth the effort. Over spraying gets so costly and also is not good environmentally.
Now I'm off the orchard and practice organic methods for virtually every thing around the yards I care for. What BanjoBob (2 above) wrote, 'is dead on the nail' in any land based farming or care because we are only here on our little patches of dirt for such a short time. It absolutely horrifies me to read about those who practice salting of the soils. I learnt the problems that drip irrigation has on the soils when orcharding, especially when over watering.
If wanting to kill grasses/weeds, like one chap wanted around a vehicle stored for a long period of time, I'd suggest laying down black plastic or old woolen carpet down then. (or a goat) When black polythene plastic is used, & the soil is wanted to be used for growing again, its simple and VERY cost effective. Newspaper is ok & certainly works wonderfully but generally I find it rots down pretty quick and unless a mulch is placed on top, such as pine bark chips which is commonly used here in NZ. Another product used is sea shells (usually crushed) or a layer or small (>half inch) peebles.
Up my drive way, I've taken to hot water for areas where paving stones and concrete is and a push hoe for broader spaces of gravel & peebles.