A 25-Year History of the use of Organic Soil Amendments in Oman: A review

Organic soil amendments have been used in Oman since prehistoric agriculture began and are still being used today. Recently, interest in certified organic farming, and the use of organic soil amendments to enhance soil quality has motivated more research on traditional and new diverse soil amendment products. In addition, the arid climate of Oman combined with sandy soils benefit from non-traditional soil amendments and nutrient sources, such as treated human waste and wastewater. These two are not allowed in certified organic farming but offer sustainable solutions to building soil health for non-certified crops. This review will cover studies of soil quality in Oman related to the comparison of these various amendments, including manures, composts, organic mulch materials, biochar, ash, and others. In general, most of these amendments improve the soil by adding organic carbon, increasing the water holding capacity, improving infiltration rate, and stimulating or providing habitat and food sources for diverse soil microbiological communities. Some amendments can also help crops overcome some of the stresses of agriculture in Oman, such as soil salinity, heat and drought. Most also provide macro and micronutrients for crop growth. Some anti-quality factors may be present however, such as a high carbon to nitrogen ratio in some mulches, or high heavy metal content, human pathogens, and pharmaceutical residues in treated waste or wastewater. Biochar may have a positive or negative effect on soil microbes, depending on the source material and temperature of combustion can result in byproducts that inhibit microbes. The value of soil microorganisms has been shown in organic cropping systems, and several new species have been discovered in Oman. Some of these provide possibilities for biocontrol of pathogens, and increased salt tolerance in crops like tomato. Though much valuable research has been done in Oman and the rest of the world, there is much left to be done to determine the effects of these organic amendments over the long term, and also the interactions among various amendments, soil conditions, soil microbes, and on crops grown with different irrigation methods and cropping systems

THE PROFITABILITY OF SUSTAINABLE AGRICULTURE ON A REPRESENTATIVE GRAIN FARM IN THE MID-ATLANTIC REGION, 1981-89

A long-term whole-farm analysis compared conventional and low-input farming systems. Data from a nine-year agronomic study at the Rodale Research Farm, Kutztown, Pennsylvania, were used to analyze profitability, liquidity, solvency, and risk on a representative commercial grain farm. Conventional and low-input farms participating in government programs are the most profitable scenarios, followed by conventional and low-input farms not participating in government programs. All farms increased their net worth. The low-input approach is advantageous for risk-averse farmers using a safety-first criterion.Crop Production/Industries, Environmental Economics and Policy,

Fate of legume and fertilizer nitrogen-15 in a long-term cropping systems experiment

Includes bibliographical references (pages 914-915).Relying more on biological N2 fixation has been suggested as a way to meet one of the major challenges of agricultural sustainability. A 15N study was conducted to compare the fate of applied legume and fertilizer N in a long-term cropping systems experiment. Nitrogen-15-1abeled red clover (Trifolium pratense L.) and (NH4)2SO4 ere applied microplots within the low-input and conventional cropping systems of the Farming Systems Trial at the Rodale Institute Research Center in Pennsylvania. The 15SN was applied to soil and traced into corn (Zea mays L.) in 1987 and 1988. Residual 15SN was also traced into second-year spring barley (Hordeum vulgare L.). Legume and fertilizer 15SN remaining in soil was measured and loss of N was calculated by difference. More fertilizer than legume N was recovered by crops (40 vs. 17% of input), more legume than fertilizer N was retained in soil (47 vs. 17% of input), and similar amounts of N from both sources were lost from the cropping systems (39% of input) over the 2-yr period. More fertilizer than legume N was lost during the year of application (38 vs. 18% of input), but more legume than fertilizer N was lost the year after application (17 vs. 4% of input). Residual fertilizer and legume 15SN was distributed similarly among soil fractions. Soil microbial biomass was larger in the legume-based system. A larger, but not necessarily more active, soil microbial biomass was probably responsible for the greater soil N supplying capacity in the legume-based compared with fertilizer-based system

Soil quality after eight years under high tunnels

The sustainability of soil quality under high tunnels will influence management of high tunnels currently in use and grower decisions regarding design and management of new high tunnels to be constructed. Soil quality was quantified using measures of soil pH, salinity, total carbon, and particulate organic matter (POM) carbon in a silt loam soil that had been in vegetable production under high tunnels at the research station in Olathe, KS, for eight years. Soil under high tunnels was compared with that in adjacent fields in both a conventional and an organic management system. The eight-year presence of high tunnels under the conventional management system resulted in increased soil pH and salinity but did not affect soil carbon. In the organic management system, high tunnels did not affect soil pH, increased soil salinity, and influenced soil carbon (C) pools with an increase in POM carbon. The increases in soil salinity were not enough to be detrimental to crops. These results indicate that soil quality was not adversely affected by eight years under stationary high tunnels managed with conventionally or organically produced vegetable crops

Isolation and identification of pathogenic fungi and oomycetes associated with beans and cowpea root diseases in Oman

The purpose of this study was to characterize fungal and oomycete species associated with root diseases of Phaseolus vulgaris, Vigna unguiculata, V. radiata and Vicia faba in Oman. Root samples were collected from plants suffering from weakened growth and yellowing symptoms. Fungal species were isolated on 2.5% potato dextrose agar amended with 10 mg l−1 rifampicin and 200 mg l−1 of ampicillin and identification was based on sequences of the internal transcribed spacer region of the ribosomal RNA gene (ITS rRNA), glycerol-3-phosphate dehydrogenase (GPDH), translation elongation factor-1 alpha (TEF), beta-tubulin (TUB), calmodulin (CMD), actin (ACT). Isolations yielded 204 fungal isolates belonging to nine different genera, with most isolates belonging to Alternaria and Fusarium. Molecular identification revealed that the isolates belong to 20 fungal species, the most dominant of which was Alternaria alternata. Pathogenicity tests were conducted on each plant species. The inoculations on P. vulgaris revealed that Pythium aphanidermatum induced rotting, damping-off and wilt symptoms while Fusarium equiseti induced yellowing symptoms on the leaves. Rhizoctonia solani produced lesions and root rot on Vigna unguiculata while Curvularia muehlenbeckiae and Curvularia caricae-papayae produced root lesions on the roots of V. unguiculata and V. radiata, respectively. Alternaria alternata produced brown symptoms on the tap root of Vicia faba. P. aphanidermatum resulted in a significant reduction in the fresh weight, dry weight and shoot length of Phaseolus vulgaris. The study shows that several fungal species can be found associated with the roots of beans and Vigna unguiculata in Oman and can result in varying disease symptoms. This is the first report of root lesions produced by Curvularia muehlenbeckiae on the roots of V. unguiculata and by C. caricae-papayae on V. radiata worldwide

Alternative Approaches to On-Farm Research and Technology Exchange

Decision Case Studies are Ideal for On-Farm Research R. Kent Crookston, University of Minnesota . . . . . . . . . . . . . . . . . . . . . . . . .. I Use of On-Farm Research by Farmers for Technology Development and Transfer Stewart Wuest, Baird Miller, Stephen Guy, Russ Karow, Rojer Veseth, and Donald Wysocki, Washington State U., U. of Idaho, Oregon State U. . ...... 7 Best Information for Choosing Crop Varieties Dale Hicks and Robert Stucker, University of Minnesota . . . .. …….. 13 Adaptability Analysis for Diverse Environments Peter Hildebrand and John Russell, University of Florida ………… 19 Washington State University, .................................. 29 Complementary Abilities and Objectives in On-Farm Research Derrick Exner, Iowa State University ............................. 33 Credibility of On-Farm Research in Future Information Networks Charles Francis, University of Nebraska-Lincoln ...................... 37 Recent Papers Related to On-Fann Research Participatory Research and Other Sharing of Experience Committee Report Summarized by Charles Francis, U. Nebraska - Lincoln; from W.K. Kellogg Foundation Cluster Workshop, Integrated Farming Systems, Santa Cruz, California; February 23, 1995 . . . . . . . . . . . . . . . . . . . . . . . . .. 51 On-Farm Research Emerson Nafziger, University of Illinois (Chapter 19 from 1994 book from Department of Agronomy, U. Illinois. . . . . . . . . . . . . . . . . . . . . . . . . . . .. 55 Responsive Constructivist Requirements Engineering: a Paradigm Michael Mayhew and Samuel Alessi, Iowa State Univ. and USDA/ARS, Morris, Minnesota (In Systems Engineering: A Competitive Edge in a Changing World, J. T. Whalen, D. J. Sifferman, and R. Olson, eds. Proc. 4th Ann. Int. Sym. Natl. Council on Systems Engin., Aug. 10-12, 1994. San Jose, CA) . . . . . . . . . . . . .. 61 On-Farm Research in Kansas, 1993: Summarized Results of a Farmer Opinion Survey Stay Freyenberger, Kansas St.ate University (unpublished) . . . . . . . . . . . . . . . .. 69 On-Farm Experiment Designs and Implications for Locating Research Sites Phil Rzewnicki, Richard Thompson, Gary Lesoing, Roger Elmore, Charles Francis, Anne Parkhurst, and Russell Moomaw, U. Nebraska and Practical Farmers of Iowa (Amer. J. Altern. Agric. 3:168-173. 1988) . . . . . . . . . . . . . . . . . . . . . . . . .. 81 Establishing the Proper Role for On-Farm Research William Lockeretz, Tufts University (Amer. J. Altern. Agric. 2:132-136. 1987) 87 Farmer Participation in Research and Extension: N Fertilizer Response in Crop Rotation Alan Franzleubbers and Charles Francis, University of Nebraska (J. Sustain. Agric. 2:9-30. 1991) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 93 Modified Stability Analysis of Farmer Managed, On-Farm Trials Peter Hildebrand, Univ. of Florida (Agron. J. 76:271-274. 1984) ............ 105 Farmer Initiated On-Farm Research Ron Rosmann, Practical Farmers of Iowa (Amer. J. Altern. Agric. 9:34-37. 1994) . 109 Participatory Strategies for Information Exchange Charles Francis, James King, Jerry DeWitt, James Bushnell, and Leo Lucas, Univ. of Nebraska and Iowa State Univ. (Amer. J. Altern. Agric. 5:153-160.1990) 113 Farmer Participation in Research: A Model for Adaptive Research and Education John Gerber, Univ. of Massachusetts (Amer. 1. Altern. Agric. 7:118-121. 1992) ... 121 Communicating between Farmers and Scientists: A Story about Stories Connie and Doc Hatfield, Preston and Wanda Boop, and Ray William, Oregon and Pennsylvania Farmers, and Oregon State Univ. (Amer. J. Altern. Agric. 9: 186-187. 1994). . ........................ 125 On-Farm Sustainable Agriculture Reseach: Lessons from the Past, Directions for the Future Donald Taylor, South Dakota State Univ. (J. Sustain. Agric. 1:43-86. 1990) ..... 127 Farmers\u27 Use of Validity Cues to Evaluate Reports of Field-Scale Agricultural Research Gerry Walter, Univ. of Illinois (Amer. J. Altern. Agric. 8:107-117.1993) ...... 15

Barriers and Opportunities for Sustainable Food Systems in Northeastern Kansas

Survey responses of producers and institutional buyers in northeastern Kansas (United States) were analyzed to understand barriers and opportunities for sustainable food systems in the region where their emergence has been limited. Producers and buyers identified barriers previously noted regarding mismatches of available quantities and prices. Producers’ enthusiasm to supply locally exceeded buyers’ interest to source locally. Transportation was identified as one of the major concerns by producers, and their responses to choice tasks revealed producers’ preferences to sell locally while pricing their products to secure sales revenue and to cover their logistics expenses at least partially

Barriers and Opportunities for Sustainable Food Systems in Northeastern Kansas

Survey responses of producers and institutional buyers in northeastern Kansas (United States) were analyzed to understand barriers and opportunities for sustainable food systems in the region where their emergence has been limited. Producers and buyers identified barriers previously noted regarding mismatches of available quantities and prices. Producers’ enthusiasm to supply locally exceeded buyers’ interest to source locally. Transportation was identified as one of the major concerns by producers, and their responses to choice tasks revealed producers’ preferences to sell locally while pricing their products to secure sales revenue and to cover their logistics expenses at least partially.barriers; choice tasks; farm-to-institution; survey; sustainable food systems; Great Plains

Nitrate-nitrogen sufficiency ranges in leaf petiole sap of Brassica oleracea L., pac choi grown with organic and conventional fertilizers

Greenhouse experiments were conducted to determine the response of Brassica oleracea L., pac choi to fertilizer rates and sources and to establish optimal soluble nitrogen (N) application rates and nitrate meter sufficiency ranges. Conventional soluble fertilizer was formulated from inorganic salts with a 4:1 NO[subscript 3]-N:NH[subscript 4]-N ratio. Phosphorus (P) was held at 1.72 mm and potassium (K) at 0.83 mm for all treatment levels. The organic soluble fertilizer, fish hydrolyzate (2N–1.72P–0.83K), was diluted to provide the same N levels as with conventional treatments. Both fertilizers were applied at N rates of 0, 32, 75, 150, 225, 300, and 450 mg·Lˉ¹. Seedlings were transplanted and fertilizer application began at 18 days. Plants were harvested at 7 weeks (5 weeks post-transplanting) after receiving 15 fertilizer applications during production. Samples of the most recently matured leaves were harvested weekly and analyzed for petiole sap NO[subscript 3]-N and leaf blade total N concentration. Leaf count, leaf length, and chlorophyll content were also measured weekly. Fresh and dry weights were determined on whole shoots and roots. Optimum yield was achieved at the 150-mg·Lˉ¹ fertility rate with both conventional and organic fertilizers. Field and high tunnel experiments were conducted to validate the sufficiency ranges obtained from the greenhouse studies. Sufficiency levels of NO[subscript 3]-N for pac choi petiole sap during Weeks 2 to 3 of production were 800 to 1500 mg·Lˉ¹ and then dropped to 600 to 1000 mg·Lˉ¹ during Weeks 4 through harvest for both conventional and organic fertilizers sources. Total N in leaf tissue was less responsive to fertilizer rate effects than petiole sap NO[subscript 3]-N. Chlorophyll content was not useful in evaluating pac choi N status. These guidelines will provide farmers with information for leaf petiole sap NO[subscript 3]-N to guide in-season N applications