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Neil S. Mattson and Marc W. van Iersel

, 2008 ). Environmental health Timing fertilizer application is also important to reduce losses to the external environment. By applying nutrients at the right time and matching supply and demand, crop nutrient uptake efficiency is high. When nutrient

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Robert L. Mikkelsen

illustration of the 4R framework for fertilizer best management practices. Selecting the right nutrient source, applied at the right rate, right time, and right place, helps to achieve crop management objectives of productivity, profitability, sustainability

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Simon A. Mng’omba and Elsa S. du Toit

parenchymatous tissues of both scions and rootstocks greatly influences the graft success ( Pina and Errea, 2005 ) and this art is likely to be low among many unskilled grafters. Time of grafting and stem diameter (thickness) of both scions and their respective

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Raymond Kruse and Ajay Nair

United States. The study also evaluated the interval between cover crop incorporation and lettuce planting to determine the right planting time. This information can help growers identify a suitable cover crop that can provide weed suppression during

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Pierre C. Robert

A better awareness of soil and crop condition variability within fields brought the notion, in the early 1980s that variable management within fields by zones rather than whole fields would increase profitability by doing the right thing at the right place in the right way. At the same time, the microcomputer became available and made possible the acquisition, processing, and use of spatial field data as well as the development of a new kind of farm machinery with computerized controllers and sensors. Precision agriculture (PA) has been considered for most common cropping systems and some specialty crops, worldwide. It is particularly well adapted to high value crops such as many horticultural crops. PA is still in infancy and its adoption varies greatly but precision agriculture is the agricultural system of the future. It offers a variety of potential benefits in profitability, productivity, sustainability, crop quality, food safety, environmental protection, on-farm quality of life, and rural economic development.

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Steven C. Wiest and Roth E. Gaussoin

The following model simulates hourly temperature fluctuations at 6 Kansas stations:
\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \[T_{h}=\frac{(T_{x}-T_{n})}{2}\left[\mathrm{exp}\left(\frac{0.693h}{DL_{M}}\right)-1\right]+T_{n};{\ }0{\leq}h{\leq}DL_{M}\] \end{document}
\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \[T_{h}=\frac{(T_{x}-T_{n})}{2}\left[1+\mathrm{sin}\frac{{\pi}(h-DL_{M})}{2(23-DL_{M})}\right]+T_{n};{\ }DL_{M}{\leq}h{\leq}23\] \end{document}
where h = time (hours after sunrise), DLM = 20.6 - 0.6 * daylength (DL), Th = temperature at time h, and TX and Tn = maximum and minimum temperature, respectively. Required inputs are daily TX and Tn and site latitude (for the calculation of DL). Whereas other models have been derived by fitting equations to chronological temperatures, this model was derived by daily fitting of hourly temperatures sorted by amplitude. Errors from this model are generally lower, and less seasonally biased, than those from other models tested.
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Steven C. Wiest and Roth E. Gaussoin

The following model simulates hourly temperature fluctuations at 6 Kansas stations:
\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \[T_{h}=\frac{(T_{x}-T_{n})}{2}\left[\mathrm{exp}\left(\frac{0.693h}{DL_{M}}\right)-1\right]+T_{n};{\ }0{\leq}h{\leq}DL_{M}\] \end{document}
\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \[T_{h}=\frac{(T_{x}-T_{n})}{2}\left[1+\mathrm{sin}\frac{{\pi}(h-DL_{M})}{2(23-DL_{M})}\right]+T_{n};{\ }DL_{M}{\leq}h{\leq}23\] \end{document}
where h = time (hours after sunrise), DLM = 20.6 - 0.6 * daylength (DL), Th = temperature at time h, and TX and Tn = maximum and minimum temperature, respectively. Required inputs are daily TX and Tn and site latitude (for the calculation of DL). Whereas other models have been derived by fitting equations to chronological temperatures, this model was derived by daily fitting of hourly temperatures sorted by amplitude. Errors from this model are generally lower, and less seasonally biased, than those from other models tested.
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Donald H. Steinegger

The Festival of Color is the annual plant and landscape open house sponsored by the Univ. of Nebraska's Horticulture Dept. The festival is the culmination of many water-centered activities that have preceded the festival throughout the year. Last year's September event drew over 10,000 people to the UNL Agricultural Research and Development Center near Mead, Neb. The festival was created to increase the urban public's awareness and motivation regarding the best landscape management practices for developing environmentally compatible landscapes and reducing urban runoff of water and pesticides. The Festival of Color is an event for all ages. By including the activities for the entire family, the festival draws a large spectrum of the urban population. The festival has grown steadily from 850 visitors in 1993 to 10,000 in 1998. The festival will continue to include demonstrations and talks on selection, installation, and management of turf; irrigation equipment and management methods; pesticide selection and pest management alternatives; fertility management alternatives; low input landscaping with native and adapted species; composting; and more. At the Sixth Annual Festival of Color: 1) 42% of new attendees learned how to implement water conserving landscape techniques (66% of the previous attendees implemented water conserving landscape practices), 2) 30% of new attendees learned how to irrigate more efficiently (63% of previous attendees used water more efficiently), and 3) 29% of new attendees learned how to fertilize more efficiently (actual positive behavior change was higher than the proposed change reported by first time attendees), 4) 98% of new attendees learned how to choose plants based on site/location “Right Plant, Right Place” (86% of previous attendees have improved their plant selection skills by putting the right plant in the right place).

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Guadalupe Osorio-Acosta and Jorge Siller-Cepeda

Cane pruning of `Superior' grapevines grown on Hermosillo valley vineyards is normally done between 5 and 10 Jan., with cyanamide application right after pruning. However, hand labor to tie the canes on the wires and rainy days occurring at that time makes it difficult to apply cyanamide right after pruning, resulting in uneven budbreak. Four-year-old `Superior' grapevines were pruned on 17 Dec. (PD1) and 27 Dec. (PD2) 1994 and 6 Jan. 1995 (PD3), and hydrogen cyanamide (5% Dormex) was applied on 7 Jan. Budbreak was evaluated on three segments of the canes. Total budbreak of vines pruned on 17 Dec. was 71%, 90%, and 80% on the first, second, and third segment of the canes, while on plants pruned on 27 Dec., the response was 39%, 50%, and 79% budbreak on the three segments of the canes, respectively. On vines pruned on 6 Jan., budbreak was 71%, 79%, and 88% on the first, second, and third segment of the canes. Response on cluster number was similar to budbreak, improving when the plants were pruned early (PD1). Number of cluster on PD1, PD2, and PD3 were 7.1, 4.5, and 4.8, respectively. Cluster distribution on PD1 among the canes were 1, 2.4, and 3.7 on the first, second, and third segments; on PD2, 0.3, 2, and 2.2; and on PD3, 0.8, 2, and 2 clusters, respectively.

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George E. Boyhan, Juan Carlos Diaz-Perez, Reid L. Torrance, Ronald H. Blackley Jr., and C. Randell Hill

The majority of Vidalia onions are produced as a transplanted crop. Seeding in high density plantings in September is followed 8 to 10 weeks later by transplanting to final spacing. This practice is labor intensive and expensive. Direct seeding would save on labor, cost, and time. Traditionally, transplanting has been done because of better winter survival, more uniform stands, and better irrigation management during seedling emergence. Beginning 5 years ago, we began evaluating direct seeding onions. Initially, seedstems (bolting) and lack of uniform stand establishment were the main problems. Sowing in September resulted in almost 100% seedstems and using a belt planter with raw seed resulted in poor singulation for uniform stand establishment. Mid-October ultimately proved to be the best time for sowing Vidalia onion seed. Earlier sowing resulted in more seedstems and later planting did not give the plants sufficient time to grow resulting in later stand loss during cold winter temperatures. Using polymer coated seed and a precision vacuum planter resulted in uniform, even stand establishment. Fertilizer requirements are almost half with direct seeded onions compared to transplanted onions with a reduction in the need for fungicides and herbicides. We have established direct seeded onions both with drip irrigation and overhead irrigation. There was concern that center-pivot irrigation would not be able to sufficiently irrigate fields during seedling establishment with the frequent hot fall days we experience. Since this work was initiated several growers have successfully produced direct seeded onions under center-pivot systems. Direct seeding Vidalia onions requires attention to detail because there is only one opportunity to get it right. Timing is also critical particularly with planting date and herbicide application.