KANSAS CITY — U.S. Department of Agriculture weekly crop condition ratings edged upward for corn and spring wheat but edged downward for soybeans while winter wheat harvest progressed slowly and was mostly behind the average pace.

Corn in the 18 major states was rated 76% good to excellent as of June 15, up one percentage point from a week earlier but well above 64% at the same time last year, the U.S.D.A. said in its weekly Crop Progress report. This year’s crop was rated 20% fair (21% a week earlier and 28% last year) and 4% poor to very poor (4% a week earlier and 8% last year).

Corn emergence in the 18 states was at 97%, ahead of 91% a year ago and about even with 96% as the 2009-13 average for the date.

Spring wheat in the six major states was rated 72% good to excellent, compared with 71% a week earlier and 68% at the same time last year, the U.S.D.A. said. The crop was rated 24% fair (25% the prior week and 27% last year) and 4% poor to very poor (4% a week earlier and 5% last year).

The spring wheat crop was 91% emerged as of June 15, well ahead of 82% a year ago and about even with 90% as the 2009-13 average for the date.

Winter wheat in the 18 major states was 16% harvested as of June 15, up from 9% a week earlier, ahead of 10% at the same time last year but behind 20% as the five-year average for the date. In major hard winter states, harvest was 47% completed in Oklahoma (27% a year ago and 56% average), 40% in Texas (47% last year and 49% average) and 2% in Kansas (none last year and 19% average. In major soft wheat states the crop was 16% harvested in Arkansas (32% last year and 67% average) and 33% in North Carolina (15% last year and 50% average).

Winter wheat condition ratings were unchanged from a week earlier at 30% good to excellent, 26% fair and 44% poor to very poor, with very low ratings in the southern Plains hard winter states pulling the overall average down. The winter wheat crop was 92% headed in the 18 states, ahead of 88% last year and 90% as the five-year average.