It seems somewhat illogical to ask for agricultural "Produce during the year ending June 1." For most American crops, the harvest season is in the Fall. So the farmer would have to include any Spring harvest of 1850, and the Fall harvest of 1849. I wonder how many were actually that precise. Most, I expect, gave broad estimates.
These figures can only serve as general guidelines, of course. June-June 1849/1850 might have been an exceptionally good year, or a catastrophically bad one. So, we can't know, without annual figures, if those in the census year were in any way "typical." Up here local Assessors' Records provided similar data (though not as detailed) every year, and can act as a reasonable accounting over extended periods of time, tracing trends or abrupt changes. I am sure there were similar local, county or state agencies in S.C. that kept the same kind of records.
jno