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Photosynthesis involves biological energy transduction, the transformation of light energy into chemical energy, and photosensory pigments, which play an important role in the process. Phytochrome, a photosensory pigment, regulates plant growth and development. This chapter explores research works on light-induced seed germination and the role of phytochrome to regulate plant growth and development, including seed germination. Pioneering work by Hendricks and colleagues looked at photo-reversible phytochrome responses. The use of herbicides to control weeds and the adverse affects of weeds on the environment and public health are discussed. With the persistent use of herbicides, over time weeds have developed resistance, a resurgence, and eventual replacement. The evolution of herbicide-resistant weeds and the harmful effects of herbicides lead to the development of an integrated weed-management program. Plowing presents a simple and effective method of weed control. The emergence of nighttime plowing to control weeds and its limitations are also presented.

Arable field margins are key areas for biodiversity conservation in farmed landscapes. Their connectivity and varied habitats offer huge potential but their narrow, linear nature, and the common perception of them as weed reservoirs, present major challenges. These issues were addressed through two experiments designed to identify simple and inexpensive management regimes for enhancing biodiversity while controlling weeds. The first experiment used wide field margins with contrasting grass leys managed either as hay or silage. It showed that more species-rich leys have significant advantages for wildlife, amenity, and ease of management, while retaining forage potential and being more practicable than complex wildflower seed mixtures for large-scale use. Their cost effectiveness, however, depends on the management method and species chosen, a conclusion reinforced by the second experiment. This used swards established on narrower field margins by natural regeneration or by sowing a wildflower seed mixture. Treatments included manipulating the frequency and timing of mowing. Changes in plant species richness and sward composition over thirteen years showed that short-term studies are unlikely to be a good guide to the future. Species richness and sward composition changed substantially with time and were influenced by the local flora, sward establishment methods, and subsequent management regimes. The results provide specific and practical management prescriptions, and demonstrate that effective weed control can accompany biodiversity benefits. The experiments also help to provide the ecological tools needed to tailor field margin management to achieve a wide range of outcomes that might be desirable in different circumstances.

The mostly privately held, 925,000-acre Madison Valley is located just northwest of Yellowstone National Park in southern Montana. In 1996, area ranchers concerned about rising land prices, stagnant cattle prices, predator animal and invasive plant species concerns, and pressure from environmental interests to end grazing on public lands formed the non-profit Madison Valley Ranchlands Group. By collaborating with government agencies, hunters, absentee ranch owners, and environmental groups, the organization has tackled these issues through educational workshops, range protection programs, and other multi-stakeholder dialogues and activities. Among its successes, about 36 percent of the valley’s private lands are now protected in conservation easements, Madison County has adopted a growth-policy action plan, and significant efforts are underway to control noxious invasive weeds.

The period after annexation saw rapid industry growth. HC&S’s Puʻunēnē factory was the largest and most modern in the world, and in 1908 East Maui Irrigation was formed to deliver water to the plantation. By 1912 the industry could boast 53 sugar plantations. Improvements included widespread use of large steam plows, chemical weed control, fertilizers, and steam railways. The industry led the world in the use of biological control of insect pests. The success demonstrated by hybridizing sugarcane species and identifying superior varieties dramatically increased sugar yield per acre and total sugar production. Extensive efforts were made to reforest Hawai`i’s watersheds which were damaged primarily by unrestricted cattle grazing. After World War I gasoline and diesel tractors began to replace steam plows. Irrigation ditch systems were renovated and sealed to minimize leakage, and “Maui-type” wells tapped the fresh water aquifers under the islands. Factories installed more powerful mills, more efficient systems to clarify and concentrate juice, and improved centrifuges to separate sugar crystals from molasses. By the early twentieth century Hawaii was among the most technically advanced sugar industries in the world. But Japanese labor unrest caused the HSPA to recruit Filipino immigrants, and plantations began to employ contractors for field operations.