The Professional's Guide to Sustainable Landscaping
Resources to help you:
- Use water conservatively
- Build and maintain soil health
- Eliminate non-storm run-off to storm drains
- Use plants appropriate for their space, use, and climate
- Minimize green waste to the landfill
- Provide food and shelter for beneficial wildlife
- Minimize chemical fertilizers and pesticides in the environment through INTEGRATED PEST MANAGEMENT
GREEN GARDENER TRAINING
Course for professional maintenance gardeners
Next course begins February 2020. FIND OUT MORE by clicking HERE.
Click for a list of San Joaquin County Qualified Green Gardeners for download
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Questions about water and fertilizer use efficiency are major economic and environmental issues for California agriculture. Excess nitrate is an important concern for San Joaquin Valley communities that depend on groundwater for drinking. Vegetable crops such as carrots, onions and potatoes typically require high amounts of nitrogen fertilizer and frequent irrigation, usually by sprinkler. Although sprinkler lateral spacings vary from 30 to 50 feet, no season-long field study had determined the impact of these different spacings on efficiency of water and nitrogen use.
Ornamental plant producers that want to increase trade with Central and South America face many challenges, including the need to develop pest risk assessments (PRAs) for their products. PRAs can be rather complicated, and the PRA process involves numerous reviews by the USDA Animal Plant Health Inspection Service (APHIS). Additionally, PRAs are sometimes deemed unacceptable by the receiving country, due to the high level of expertise in pest management required to meet the requirements of the document. The PRA can thus present a hurdle, delaying trade and, hence, potential profitability for aspiring growers and exporters. Part of the UCCE mission is to assist California growers with sustainability and profitability, and we are also the experts when it comes to pest management and pest risk. The following case set useful precedents for trade in ornamental plants with Guatemala.
For many years, we have worked with local agricultural producers to develop sound management practices to alleviate water quality and other environmental problems. Many of the legal requirements faced by the growers are a result of the concern of homeowners and other non-farming groups. Ironically, in many situations, the environmental impact of a large housing development can be equal to or greater than the impact of the farming operation. However, many residents do not understand the collective impact of their home and garden pest control and fertilization activities on the environment. In addition, most of these homeowner activities are generally unregulated.
Diminishing water resources, climate changes brought about by global warming, and drought conditions in many arid and semi-arid regions of the world are making it increasingly difficult to grow viable crops. Rainfall in California has been below normal in recent years, raising concerns that the state may be experiencing another of its periodic droughts. And in the sub-Saharan area of Africa where many regions depend on rain-fed agricultural production, rain can be extremely scarce and the rainy season short. On top of this, there will be enormous needs for increased food production over the next 50 years. Current projections are that the global human population will increase from approximately 6 billion currently to between 8 and 12 billion around 2050.
The California drought from 2012 to 2015 included historic dryness and warmth. This drought generated widespread water stress in trees across California and instigated a massive wave of tree mortality in the Sierra Nevada. U.S. Forest Service aerial surveys detected over 127 million newly dead trees due to the drought and other disturbance agents such as bark beetles. This unprecedented tree die-off is transforming California at the stand-to-landscape level and reveals the vulnerability of large portions of California’s forests to novel conditions.
Since the enactment of the Healthy Schools Act (HSA) in 2001, both UC Cooperative Extension (UCCE) and the California Department of Pesticide Regulation (DPR) have been working with school districts in California to provide information about integrated pest management (IPM). The strategies employed in an IPM program include modifying horticultural practices, such as changing mowing heights and managing irrigation appropriately. These practices can reduce the amount of pesticides used on school grounds to help schools to meet the standards of the HSA and provide a safe and healthy environment for students, teachers and staff. DPR has coordinated numerous workshops for school districts covering general landscape and building IPM topics. However, attendees requested more detailed training about turf IPM since they manage turf areas like playgrounds and sports fields. UCCE has extensive experience in this area and was called upon to help schools implement this policy.
Trees and shrubs help clean the air. They absorb carbon dioxide, release oxygen and provide surfaces for the deposition of airborne particles and unhealthful gases such as ozone. Also, water evaporating from tree leaves cools the air and shade from trees cuts energy consumption, reducing the need for air-polluting energy generation. However, there is another side to the story. Some trees and shrubs emit high rates of certain volatile organic compounds (VOC), which react with nitrogen oxides (NOx) and sunlight to form ozone, a ground-level pollutant. Other plants emit very little VOC.
Recent droughts and expanding urban populations place increasing pressure on California’s water supplies. In residential areas, outdoor water use, primarily for landscapes, comprises 50 percent or more of total water use. It is commonplace to see excess water gushing down storm drains from poorly aimed sprinklers, broken sprinkler heads, and a larger volume of water applied than the soil can absorb. The runoff water can carry pesticides, fertilizers and other waste into waterways, causing a detrimental effect on the health of the aquatic life in rivers, lakes and bays.
The eucalyptus snout beetle, Gonipterus scutellatus, was discovered defoliating eucalyptus trees in Ventura County in March 1994. This insect has been introduced accidentally into several eucalyptus-growing regions around the world from Australia and has caused extensive damage wherever it has become established. Female beetles deposit hard brown egg capsules on shoots and young leaves. Both adults and larvae consume young and tender leaves, buds, and shoots. Extensive feeding completely defoliates trees and kills branches, while intermediate levels of defoliation retard growth and affect tree shape.
The year 2004 was a crossroads for Ventura County agriculture. Stricter water quality regulations promised over the past decade were finally being implemented. Regulatory agencies were mandating changes that would greatly impact agriculture, especially the intensely managed nursery industry. There was much concern that the new regulations would drive Ventura County nurseries out of business or into other areas where regulations were not as restrictive. Another concern was that substantial capital would be required to comply with these regulations, especially for those nurseries where the best solution would be the construction of recycling and water capture systems.
Imparting an exotic and dramatic theme, palms are emblematic of California landscapes. Indeed, there is a revival of interest in palms as specimens and accents or to add height, dimension, and architectural interest for homes, businesses, parks and other public areas. Because of their unique root and trunk structure, large specimen palms can be transplanted with a relatively small root ball, creating an instant, mature landscape. The standard industry practice when transplanting palms is to use builder's or washed plaster sand as the backfill medium in order to enhance stability and anchorage, drainage and survival, but the practice had not been scientifically validated.
Applying nitrogen and phosphorus with irrigation water is a common practice in the Imperial Valley. If the fertilizers are applied incorrectly, the nutrients end up in the drains rather than in the crop. Nitrogen and phosphorus are the two main nutrients that cause eutrophic conditions (high algal biomass and low dissolved oxygen concentrations that cause massive fish kills) in the Salton Sea. Current and proposed federal water quality standards for California require growers to improve the quality of drainage waters. To achieve both federal and state water quality objectives, growers will have to reduce the amount of phosphorus that reaches the drains and the Salton Sea.
Water is a limited natural resource for most of the arid and semi-arid regions of the United States. Despite this, rapid population growth and development are occurring in these areas, especially California. Many municipal water providers are faced with the need to reduce demand for freshwater supplies while protecting against drought and cutting down on wastewater discharges into sensitive bays and estuaries. Agencies encourage the use of reclaimed or recycled water from wastewater treatment facilities for appropriate non-potable uses, including urban landscape irrigation. In 2000, 19.5 percent of recycled water in California was used for landscape irrigation, saving enough fresh water to supply 300,000 homes. An important caveat to the use of reclaimed water for landscape irrigation is that after most of the water treatment processes, sodium chloride is the most detrimental chemical compound remaining in the recycled water. Little information is available on the tolerance of common landscape plant species to the levels of salts found in reclaimed waters. This basic information is needed by landscape managers to ensure the maintenance of healthy landscapes, given the reality of increased use of reclaimed water for irrigation.
California's landscape horticulture industry is constantly growing due to population growth, housing expansion and refurbishing of older urban areas. This industry growth requires an almost constant input of new plant material to address a variety of horticultural needs and tastes. Historically, many landscapes were planted with species requiring large amounts of water, fertilizers, and pesticides to remain attractive and healthy. One significant result of this practice has been increasing levels of chemicals in urban water run-off to watersheds, leading to negative impacts on the health of the aquatic ecosystems. In addition to this, widespread use of inappropriate plants in a summer-dry climate can contribute to a shortage of water in areas supplied by seasonal snow-melt. For these reasons, the nursery and landscape industry is in constant need of a supply of new, beautiful, drought-tolerant and disease-resistant plants.
Lygus bugs are a key economic pest of many crops in California, including field crops, vegetables, nuts and fruits. There are 43 species of Lygus bugs in the world, 34 of which are known to exist in North America. Three species are reportedly found in the central San Joaquin Valley of California: Lygus hesperus, Lygus elisus, and Lygus lineolaris. To date, there has been no simple method to distinguish among these three species. Pest management strategies must begin with correct identification.
Farmers are facing increasing regulation of pesticides, in part the result of environmental concerns about pesticides in water supplies and health effects on farmworkers.
The Colorado River is the only source of irrigation and drinking water in the Imperial Valley and the main source in Mexicali, Mexico. As much as 4.5 million acre-feet of Colorado River water is used every year to irrigate more than 500,000 acres in the Imperial Valley and in the Mexicali Valley, Mexico. Growers in Southern California are under continuous pressure to conserve water and transfer some of the agricultural water to urban regions of the state. The current water transfer agreement between the Imperial Irrigation District and the San Diego County Water Authority calls for transfer of up to 200,000 acre-feet annually of Imperial Valley-Colorado River water. Increased irrigation efficiency using CIMIS-based irrigation scheduling techniques and other water conservation practices is needed to supply the water demand in Southern California and northern Baja California.