The establishment of a permanent stand of grass is very dependent on its root mat, which in turn is dependent on the amount of plant food available. The greater the growth of the grass above the ground, the greater the growth of the root mat below the ground will be and, therefore, the better the erosion control characteristics. Another advantage to having a good root mat is that the grass will be much healthier and heartier, which enables it to withstand severe weather like heat, drought, and cold and helps prevent displacement of soil. It is also essential for establishing a long-term stand of grass that requires less maintenance.
1665-2 MATERIALS
The analysis of the fertilizer must be in the ratio shown in the Special Provisions. For example, 8-8-8 has a ratio of 1-1-1 and so does 10-10-10. So, one could be used for the other if the rate is adjusted. Likewise, 5-10-10 has a ratio of 1-2-2, so 10-20-20 could be used at the adjusted rate. However, 5-10-10 or any other fertilizer that does not have a 1-1-1 ratio cannot be used if the required analysis is 8-8-8.
1665-3 APPLICATION
The timing of fertilizer application is very important because if it is applied at the wrong time, it can burn and kill the grass. For example, if fertilizer is applied when the grass is very young and tender, it will burn it and possibly damage the small roots. The same thing could happen if applied in a drought when the grass is stressed. Likewise, if the fertilizer is applied when the grass is supposed to be dormant, it will either do nothing and be wasted, or it could activate the growth at the wrong time of the year and thus damage the grass. On the other hand, if the grass is not fertilized, the growth will not happen. When to apply the fertilizer is dependent on several factors, such as amount of rain, type of soil, time of year, temperature, soil temperature, time since the last fertilizer was applied, etc. If in doubt, contact the Roadside Environmental Field Operations Engineer.
The type or analysis of the fertilizer is also very important because the grass needs different elements at different times. This is described in the Special Provisions.
1665-4 MEASUREMENT AND PAYMENT
Fertilizer with different analysis ratios can be used
only if the ratio is the same as that which is called for in the contract. However, the rate will have to be adjusted to assure that the proper amount of each element is placed. The following example helps to illustrate this concept.
The contract calls for 1000 lbs/ac of 8-8-8 fertilizer topdressing. The Contractor wants to use 10-10-10 fertilizer topdressing. Should he be allowed to use it, how much must he use, and what quantity should he be compensated for?
It can be used because the ratio of each element is the same. 10-10-10 can be used because it has a ratio of 1-1-1 just as the 8-8-8 does.
When 1000 lbs/ac of 8-8-8 is placed 80 lbs. of each element is used (1000 lbs. x 0.08 = 80 lbs.). To place the same number of pounds of each element using 10-10-10 you would only need to put down 800 lbs./ac. For example: ? x 0.10 = 80 lbs.
Therefore 80 lbs/0.10 = 800 lbs. 800lbs/ac of 10-10-10 equals 1000lbs/ac of 8-8-8.
Since the same number of pounds
of each element is incorporated into the work, the Contractor should be paid a comparable quantity. Therefore, the Contractor would be paid the 800 pounds of
10-10-10 fertilizer as if the Contractor had put down
1000 pounds of
8-8-8. This should be so noted in the pay record book.
In the example used above, the
800 pounds of
10-10-10 will be paid for as if it were
1000 pounds of 8-8-8.
ADDITIONAL RESOURCES
