Chemicals

Chemicals causes grass to turn yellow and die in regular and irregular patches. The yellow areas do not get bigger and they appear after two to five days of fertilization or a chemical has been spilled on the lawn. When large amounts of pesticides, fertilizers, gasoline, and hydrated lime are applied improperly or accidentally spilled on the grass, it will cause the blades to dry out and die.

http://www.ipm.ucdavis.edu/TOOLS/TURF/PESTS/abiofert.html

http://www.improve-your-garden-soil.com/fertilizer-burn.html

Salts

The salts in water, soil, and dog urine causes discoloration and even death to lawns and plants. Salt damage happen along the seashore, in places where there is low rain fall, poor drainage, and areas where salt is use to melt snow and ice. Too much salt in the soil causes the water to accumulate in the leaf tips and edges where it kills the tissues. The salt also interferes with how much water the plant gets. The dog urine has nitrogen that sometimes causes the grass to grow rapidly that cause a dark green and vigorously growing ring.

Here are some sites that have more info. http://web1.msue.msu.edu/imp/mods1/00000089.html

http://www.hilltopanimalhospital.com/urine%20lawn%20burn.htm

Introduction

Fertilizer burn is the injury of the roots or crown of the plant. The part of the plant or the leaves turn a brown color the plant may die. The tissues do not burn but decrease of water causes the plant to slowly die. Sometimes it is cause by fertilizing to much or the concentration being too strong. But sometimes it is cause by watering to much or not watering enough