Letter: Inefficient fertilization polluting the Bay
Delegate Morgan makes many excellent points in the article "Restoring the Bay makes environmental and economic sense" published in the Sept. 22 issue of the Gazette-Journal. But he, like most politicians, fails to place the blame for Bay pollution squarely where it belongs, on inefficient agricultural fertilization.
Half the nitrogen and phosphorus pollution of Chesapeake Bay is due to agricultural fertilization, a fact known with certainty for decades and most recently documented in Virginia’s TMDL document submitted to EPA. Half of agricultural pollution comes from about 90 percent of farm acreage fertilized with conventional chemical fertilizers, which are only about 65 percent efficient. If 150 pounds of nitrogen are applied per acre, about 100 pounds of nitrogen are removed in the grain. The remaining 50 pounds of nitrogen constitutes pollution from runoff, infiltration to groundwater or volatilization to the atmosphere.
We must phase in controlled- (timed- or slow-) release fertilizers so that more of the nutrients end up in the crop, not in the environment. The other half of agricultural pollution comes from animal waste (poultry litter, sewage sludge and manure) applied to less than 10 percent of farm acreage. No "fertilizer" causes more nitrogen pollution than sewage sludge, and the 12 million pounds of nitrogen pollution it causes annually is similar to the annual nitrogen pollution caused by all the septic systems in Virginia. Citizens who might face expensive upgrades of their septic systems need to understand that simple fact. No "fertilizer" causes more phosphorus pollution than poultry litter.
We have made great progress in reducing pollution from wastewater treatment plants, at great expense. If we stay on track, nutrient discharge from wastewater treatment plants, which now contribute less than half as much pollution as agriculture, will closely approach the "Limit of Technology" by EPA’s 2025 deadline. Agriculture has not kept pace with the level of pollution reduction from wastewater plants. Many of the "sop up the pollution" strategies such as cover crops and riparian buffers are not very efficient. Anyone who has studied pollution knows the only solution is to stop polluting. Once the pollutant is released to the environment it is difficult, perhaps impossible, and certainly expensive, to clean it up. So agriculture must change the way fertilization is accomplished. The land application of animal waste must be banned, the waste used as biofuel and the phosphorus (a diminishing finite resource) recovered. Chemical fertilizers must be replaced with controlled-release products. Unless the largest source of Bay pollution, agriculture, is meaningfully addressed, Bay water quality cannot possibly improve significantly.
Dr. Lynton S. Land, emeritus professor
Geological Sciences, University of Texas Austin