I just planted my yard this fall. New house construction. I planted 1.25 -1.50 acres with 600 lbs of fescue. Fertilized it, applied calcium, and strawed it all. Grass did really well even though a downpour 7 days later did wash some gulleys here and there and washed away some of my seed. Most of the grass is very thick and dark green, but my problem is some areas of it is kind of a pale yellow. There seems to be no rhyme or reason why the areas that are yellow should be. I first thought that maybe those were the wet areas where water might be standing after a rain, but I might have a yellow patch on a high spot of the yard making that not seem like the cause. Can anyone tell me what this is caused by and what should I do to correct it? Attached is a photo of one area of the yard that shows what I am trying to explain. Any help much appreciated.