Zero Grade

Why Zero Grade?

Zero Grade is the name we give to the process of making a rice field completely flat.

No ground is naturally perfectly level. This causes a problem in rice farming because you must keep rice fields flooded throughout the growing season. With any slope at all in the field, all of your water will run to one end, causing the high end of the field to be totally dry.

The way that most farmers deal with this is by putting small contour levees throughout the field at specified intervals to hold back the water. This breaks the field up into many smaller 'fields' with not as much slope. Using this method, you can flood each individual levee. At the high end of the smaller 'fields' the water may be only 2 inches deep while at the lower end it is 4 inches deep. While this is still not the best scenario, it is possible to maintain a flood on the field.

While the above method does work, it is labor intensive. The smaller levees have the propensity to burst in seasonal downpours. If this occurs, the levee must be patched with a shovel. Also, this method requires a small gate to be placed in between each levee to hold and manipulate the water depth in each smaller 'field'. These must be checked quite often. All in all, this method is just a lot of work.

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In the late 1970's, Leroy Isbell was convinced their must be a better way. His solution? Just move the hill to the hole and make the field perfectly flat - like a table. In theory this sounds simple, but how do you know how much dirt to take from the hill and put in the hole so that the field is precisely level? The answer? A laser. Lasers were already in use for surveying fields to see where to place the levees, and people were also using them to level their fields on a slope.

By now you may be asking how do you use a laser to level a field in such a way? Well, the laser used to do this is one that spins at a very high rate of speed. This laser is mounted on a tripod in the center of the field. The implements used to move the dirt are fitted with sensors that read the level of the laser. If you drive into a hill and the whole implement raises up out of the laser beam, the receiver triggers the implements hydraulics to lower the implement so that the receiver is back in the line of the laser. When this happens it causes the implement to dig into the ground and cut part of the hill until the dirt bucket is filled to capacity. The driver then drives down to the low end of the field. This causes the laser receiver to fall below the line of the laser. When this happens the sensor informs the operator to dump the contents of the implement. After many hours of monotonous work, you have a perfectly level field, with no slope or 'grade.'

During this process some of the dirt cut from the hill is used to build a perimeter levee around the entire field, this levee is large enough to drive a truck on and is used to access the field. A perimeter ditch is also dug for drainage.

When you are through you have a field perfectly suited to grow rice. Open a gate and raise the water level in the field, open another one and drain it. No more shovels.

Because of this unique way of farming, Isbell Farms has been featured in many magazines and newspapers and has received industry awards.