It shows that bunchgrasses develop slowly during the spring, followed by a period of rapid growth and then a tapering off of growth in early summer. The period of slow development in the spring may cover several weeks, depending on the weather. Because the temperature of the soil is too cold for root activity at this time, the food for plant growth comes from that which the plant has stored in the roots during the previous summer and fall. As the air and soil become warmer, more nutrients are absorbed from the soil and transported to the leaves where, in conjunction with the photosynthesis from sunlight, they are made into food for plant growth. As the leaf growth accelerates, the ability of the plant to produce more food increases and plant growth increases rapidly.
Rapid growth continues until the plant begins to form seed stalks.
It then tapers off, partially because of the increasing demand of seed stalks, flowers, and seed for food. At the same time, the onset of hot, dry weather also effects the rate of growth. Then growth slows down and the growth curve flattens out. At the same time that top growth of the plant begins its rapid rise, the grass also begins to store up reserve plant food in the roots and crowns for the next year's use. But during the period of rapid growth and seed production, the storage of plant food slows down as all of the plant's resources go into production of seed stalks, flowers and seeds.