dry the hay. Fertilization and weed control Modern hay production often relies on artificial fertilizer and herbicides. Traditionally, manure has been used on hayfields, but modern chemical fertilizers are used today as well. Hay that is to be certified as weed-free for use in wilderness areas must often be sprayed with chemical herbicides to keep unwanted weeds from the field, and sometimes even non-certified hayfields are sprayed to limit the production of noxious weeds. Organic forms of fertilization and weed control are required for hay grown for consumption by animals whose meat will ultimately be certified organic. To that end, compost and field rotation can enhance soil fertility, and regular mowing of fields in the growth phase of the hay will often reduce the prevalence of undesired weeds. In recent times, some producers have experimented with human sewage sludge to grow hay. This is not a certified organic method and no warning labels are mandated by EPA. One concern with hay grown on human sewage sludge is that the hay can take up heavy metals, which are then consumed by animals. Molybdenum poisoning is a particular concern in ruminants such as cows and goats, and there have been animal deaths. Another concern is with a herbicide known as aminopyralid, which can pass through the digestive tract in animals, making their resulting manure toxic to many plants and thus unsuitable as fertilizer for food crops. Aminopyralid and related herbicides can persist in the environment for several years. Bales Small Bales Small square bales are made in two main variations. The smaller "two tie" (two twines to hold the bale together) or larger "three-tie" (three twines to hold the bale together). They vary in size within both groups but are generally popular in different markets. The smaller two-tie bales are favored in the hobby animal market and are preferred for their convenient size. The larger, three-tie bales are favored by producers wanting to export bales because of the increase of efficiency in transportation and also by customers for a better price per ton. The two-tie small bales are the original form factor of hay bales. Balers for both types of small bales are still manufactured, as well as stackers, bundlers and accumulators for handling them. There are also some farms that still use equipment manufactured over 50 years ago to produce small bales. The small bale remains part of overall ranch lore