I am continuing to write about drought because dealing with drought and its effects is going to be important to a lot of people for some time to come. Though at times it seems as if it never will, droughts eventually end. Depending on how an area has been managed during drought, recovery can be rapid and complete or it can require years of good management to get back to pre-drought levels. Part of the damage is due to the loss of high quality forage species to over grazing but the most serious and long lasting harm comes through damage to the ecological processes: water cycle, nutrient cycles, energy flow and biological succession. It hurts to lose favored forage species but these plants can and do re-produce themselves if conditions are right. If conditions are not right, the high quality forage plants, which require good growing conditions, will be replaced with plants able to thrive under the poor conditions. Critical to limiting damage both ecological and financial is removing animals from land that can no longer support them before the ecological processes are severely damaged. Even if animals are being fed all they can eat, they will roam continuously picking each new leaf before it can become functional and through a combination of grazing and hoof action destroy the ground cover that is so critical to the health of the ecological processes. When the ground cover is lost several things, all bad, happen: the water cycle becomes ineffective due to increased run off and higher evaporation rates, the nutrient cycle slows due to soil erosion and loss of soil life, and energy flow into the system slows due to the loss of effective leaf area. These conditions combine to dramatically deteriorate growing conditions and when this happens, biological succession recedes. The plague of weeds that follows the first rains after a long dry spell is the result of this loss of quality in the long term growing conditions. Good forage plants cannot tolerate for long the poor growing conditions so nature replaces them with something that can grow and reproduce under the existing conditions. The weeds are not the problem; the problem is the loss of good long term growing conditions. Perhaps, I hammer on this point too hard and too often but one of the questions that I get most frequently is “What do you do about ragweed – or bitter weed or snake weed or wooly croton?” It is hard to remain objective when your pasture is smothered with a rank growth of weeds but the correct question is, “What did I do to get in this condition?”
Most of the ranges and pastures in the U.S. are weedy – if we define weedy as having a large percentage of quality forage plants replaced by lower seral (able to thrive in poor growing conditions) plants. These low seral plants, both forbs and grasses, share certain characteristics that cause them to be poor forage but also that allow them to proliferate under harsh growing conditions. By and large these plants are short lived – annuals or short lived perennials – that are able to establish and complete their life cycle in a short time period. They devote a large percentage of their energy budget to reproduction; they produce more seed than higher seral plants so that the species can persist even if only a small percentage of the seeds manage to become plants. Many of these plants are cool season plants that can germinate and complete most of their life in the normally better moisture conditions of winter and early spring. There are large areas (like the whole of California) where warm season perennial forage plants have been all but replaced by cool season annuals. This has not happened because we have “invasive species” or “super weeds”; it has happened because by our management we have created long term growing conditions that favor the low seral plants over the more productive forage species. If we accept this concept, then the question becomes not how do we kill weeds but rather how do we change long term growing conditions. We change long term growing conditions for the better by improving the health of the water cycle and of the nutrient cycles and by increasing the amount of energy flow through the system; when this is done – it takes time – weeds cease to be a problem. There is more information on how this can be accomplished in my book How to Not Go Broke Ranching.