Kay found that Hardinggrass tolerates fire, making it a good candidate for erosion control. However, the California Invasive Plant Council has listed Hardinggrass as an invasive, non-native plant that threatens wildlands. In the 1960s, summer-dormant orchard grass did well in many test plots around the state and became part of perennial grass seeding recommendations. Several other grasses, including smilograss, tall wheatgrass , and mission veldtgrass , were also recommended. Recent releases of summer-dormant tall fescue varieties are currently showing promise as a companion with summer-dormant orchard grass. Except for poor rainfall years, weed management prior to sowing perennial grasses is the greatest factor for successful establishment. Annual grass competition during establishment of perennial grasses can cause complete failures of perennial grass seedings.Native grasses, especially California needlegrass , were tested along with the introduced perennial grasses and are included in the recommendations by Love et al. . Restoration of native grasses has been a recurring objective of range managers on California’s annual rangelands since the 1940s. The goal of restoring grasslands and woodland understories to some presettlement condition has proven to be unrealistic, because not only is there uncertainty about the historical composition and extent of California native grasslands, but restoration failure is common. Rangeland and restoration scientists have tried to restore native grasses but have not found dependable native grass restoration practices for use on land that is steep, rocky, hydroponic rack system or highly eroded. Competition from naturalized annual grasses and forbs remains a major barrier to native grass restoration. Season-long heavy grazing has also resulted in poor stand survival.

Proper grazing of perennial grass stands is discussed in the eighth publication of this series, “Grazing Management.” On arable land, native grasses can be grown for seed and pasture following standard crop production practices. Scientists continue to seek practices to control the annuals and promote native perennials.Annual rangeland soils without legumes are nitrogen deficient . To increase winter forage and total production, nitrogen must be added by a legume or nitrogen fertilization. Phosphorus and sulfur deficiencies are also widespread. In some areas, molybdenum deficiencies are quite common. Deficiencies of potassium, boron, and lime occur on acid soils but are not widespread. Usually these latter deficiencies become evident only after adequate amounts of phosphorus and sulfur have been applied on legume pastures. In the 1950s and 60s, the effects of nitrogen, phosphorus, and sulfur on forage production were estimated on several annual rangeland soil series using greenhouse pot studies as well as field plots . These studies showed that most soil series responded to phosphorus and/or sulfur as well as nitrogen.For about 15 years in the 1950s and 60s, University of California at Davis researchers studied the effect of nitrogen fertilization on range forage production and animal productivity on 28 ranches in 20 counties . When analyzed together, fertilizer effects the first year increased carrying capacity from 38 head days per acre to 92 head days per acre and livestock gains from 60 pounds per acre to 170 pounds per acre. Greater first year benefits were observed where nitrogen plus sulfur or nitrogen plus phosphorus were required than where only nitrogen was needed. Second-year carryover effects measured at 13 locations were much greater where nitrogen was applied with either sulfur or phosphorus than from nitrogen alone .

Table 6 is a comparison of the 1957 costs and returns, reported by Martin and Berry in 1970, with projected costs and returns in 2012. In 2012, fertilizer costs for nitrogen, depending on the formulation, were 2 to 5 times higher than in 1957 and stocker cattle prices were 5 to 6 times higher. In the mid-1980s, nitrogen was again shown to be beneficial in a large-scale study of the effects of fertilization and legumes on beef production at the UC Sierra Foothill Research and Extension Center, northeast of Marysville, California . In this study, nitrogen was applied at 40 and 80 pounds/ acre with and without phosphorus and sulfur. Phosphorus and sulfur were applied at two rates with and without nitrogen, phosphorus at 30 and 60 pounds/acre, and sulfur at 33 and 66 pounds/acre. This study showed that animal weight gains were greater with nitrogen than without and that the greatest gains resulted from application of nitrogen, phosphorus, and sulfur. This study also showed that dry matter digestibility was increased. One of the most important benefits of nitrogen fertilization is that it can substantially increase production during the winter and early spring . This early feed is extremely valuable because it replaces expensive hay or other energy supplements for livestock. For ranchers dependent on annual rangeland for winter and spring feed, the onset of the green season is awaited with great urgency each year. Nitrogen fertilizer can increase winter forage production before the spring flush of growth and effectively replace 2 to 6 weeks of supplemental feeding during the winter. Nitrogen fertilization will also increase spring feed, but this is usually not a forage-short season for the range livestock producer in California.Knowledge of range sites and their forage productivity and response to fertilization is critical in making the decision to fertilize annual rangeland. Productive sites should receive priority for fertilization. Range forage response to fertilization varies with prevailing weather patterns .

During a favorable weather year, above-average forage productivity is further increased by application of nitrogen . Likewise, low productivity during an unfavorable year can be increased by fertilization but not to the levels expected under favorable weather conditions . However, the percentage increase may be greater than in a wet year. To properly assess the response to fertilization on a given range site, the site’s forage productivity and fertilizer response during a favorable, average, and unfavorable weather year should be estimated to allow the decision maker to better assess fertilization benefits and risks over the range of weather patterns characteristic of California’s Mediterranean climate. A favorable year in terms of forage production can result from fall rains coinciding with warm fall temperatures or from extended warm, wet spring weather. An unfavorable year results when the fall rainy season is delayed or when cold fall temperatures occur earlier than normal. Most years are intermediate to these favorable and unfavorable extremes . Table 7 and fig. 12 illustrate the estimated annual forage production for a favorable, average, and unfavorable year on a range site of average productivity in the California annual rangeland. Included are expected and possible productivity improvements based on numerous fertilizer trials. Tables 8 and 9 show the combined results of 54 grazing trials designed to evaluate the effects of nitrogen fertilization over a 15-year period in 20 counties . Factors other than prevailing weather contribute to the inherent productivity of the range site. Those sites that have inherently low productivities may respond to range improvement, but the response may not be great enough to pay for the cost of improvement. Range fertilization frequently produces a 1½-to-2-fold increase in dry matter production. A site normally averaging 1,500 pounds of dry matter per acre will yield an additional 1,500 pounds from nitrogen fertilization and there is a reasonable chance that this improvement is economically feasible. If the average productivity is only 500 pounds per acre, cannabis vertical grow system then the economic feasibility of a 2-fold increase, or 500 additional pounds of forage per acre, is less likely. Range economists often advise ranchers to improve those range sites with the highest potential first. This is good advice except where the lower-potentialsite improvement has strategic value or an exception is known through past research or experiences. Additional benefit from nitrogen fertilization may be achieved by using nitrogen application as a method of manipulating livestock utilization of the range. Although it is not widely practiced, it has been shown that use of underutilized range forage can be increased by applying nitrogen and other fertilizers to that forage . Once the livestock find this area of application, they seek it out and use it to a greater extent than before it was fertilized. Similarly, it has been shown that the application of nitrogen to weed infestations can increase their utilization. If the utilization of medusahead and immature summer annuals such as yellow starthistle and tarweed is increased and grazing is properly timed, it can reduce flowering and seed set of these weeds.Ammonium sulfate , ammonium phosphate sulfate , and urea are most frequently applied on annual rangeland.

Ammonium sulfate is frequently used because sulfur deficiencies are widespread on annual rangeland, and it is less expensive than 16-20-0 containing both sulfur and phosphorus. Where sulfur and/or phosphorus are deficient, application of these nutrients should be considered. When the soil contains adequate levels of phosphorus and sulfur, urea may be used. Nitrate nitrogen tends to leach too rapidly, and it is often lost early in the first year before it can be utilized by the forage plants. Although urea is an inexpensive nitrogen source, volatility losses can reduce its effectiveness if soil pH is greater than 7 and if applied too early in the fall when soil temperatures are still high. To avoid volatilization, rainfall in excess of ¼ inch is necessary for urea soil incorporation, and greater than ½ inch is desired. A worst-case scenario is an early fall rain of less than ¼ inch that breaks down the prills but does not carry the urea into the soil. Chicken manure and other manures can be satisfactory sources of nitrogen where transportation and spreading costs do not prohibit their use. Manures are longer-lasting nitrogen sources because the nitrogen is released slowly as the organic matter decomposes. Soil and tissue testing can help to answer the question of what nutrients to apply in addition to nitrogen. Commercial agricultural testing laboratories can conduct needed soil and plant tissue tests at very low costs.In the 12-to-30-inch rainfall zone, nitrogen is generally applied in the fall to lengthen the green feed period by increasing winter growth. The amount and distribution of rainfall, as well as temperature, are principal factors governing the timing of application. Nitrogen is not profitable in central and southern California, where annual rainfall is less than 12 inches annually, because reduced soil moisture restricts plant growth and response to fertilizers. Research at the Hopland Field Station, where nitrogen was applied monthly from September through January in a 36-inch rainfall zone, showed that the earlier nitrogen was applied in the fall, the greater the winter forage growth . Total forage as measured at the end of the growing season was not affected by the time of application unless the application was made after February. Nitrogen is generally not recommended where rainfall is greater than 30 inches, since leaching losses are high. Denitrification can contribute to nitrogen losses, especially on poorly drained soils that are saturated for extended periods. Winter temperatures averaging much below 50ºF severely limit responses to nitrogen fertilization. Daily mean temperatures below this limit are common in northern California and Oregon during the months of December, January, and February. Therefore, nitrogen should be applied before the first autumn rains when mean temperatures are 50ºF or more. Lack of response in cold weather is mainly a simple restriction of plant growth, but nitrogen-fertilized grass often is less damaged by frost and appears to recover faster than nitrogen-deficient grass. Nitrogen should not be applied to ground covered in snow, as much of the snow may be lost to evaporation along with the applied fertilizer.Generally, a good forage response is gained from applying between 40 and 80 pounds/acre of nitrogen. To apply 80 pounds of nitrogen would require application of approximately 400 pounds of ammonium sulfate or 160 pounds of urea. The variation in recommendations between counties is a reflection of year and range site differences, especially annual variation in amount and distribution of precipitation. How much nitrogen to apply has been a continuing question and the subject of numerous fertilizer trials. Rates of nitrogen up to 200 pounds/acre have been applied and forage or animal yield measured. Production functions for nitrogen fertilization follow the law of diminishing returns. Therefore, beyond a certain level, each additional increment of fertilizer will give less production than the previous increment. On California annual rangelands, this point is commonly in the range of 40 and 80 pounds/ acre, and it will vary within this range due to seasonal and yearly variations in weather.