http://www.mdpi.com/journal/agriculture Latest open access articles published in Agriculture at http://www.mdpi.com/journal/agriculture http://www.mdpi.com/2077-0472/2/2/109 Biological control of fungal plant pathogens can improve global food availability, one of the three pillars of food security, by reducing crop losses, particularly for low-income farmers. However, the interrelationships of many environmental variables can result in multiple interactions among the organisms and their environment, several of which might contribute to effective biological control. Here, we present an advanced survey of the nature and practice of biological control when it is used to control brown rot in stone fruit. Specifically, we describe the population dynamics of Penicillium frequentans and Epicoccum nigrum and their efficacy as biocontrol agents against brown rot disease under field conditions. The size of P. frequentans population after an application of a P. frequentans conidial formulation during the crop season is bigger than that of E. nigrum following the application of an E. nigrum conidial formulation. Moreover, applications of a P. frequentans conidial formulation during the crop season also caused a higher reduction in the number of Monilinia spp. conidia on the fruit surface than that found after applications of an E. nigrum formulation during the growing season. http://www.mdpi.com/2077-0472/2/2/109 Mon, 21 May 2012 00:00:00 CEST Agriculture 2012-05-21 2 2 Article 109 124 2077-0472 Use of Biofungicides for Controlling Plant Diseases to Improve Food Availability 2012-05-21 doi: 10.3390/agriculture2020109 Antonieta De Cal Inmaculada Larena Belén Guijarro Paloma Melgarejo http://www.mdpi.com/2077-0472/2/2/87 Earthworm biomass and production in savannas are limited by seasonal precipitation and the lack of organic and nutrient resources; I hypothesize that after a long-term protection of savanna from fire and agricultural activities drastic changes in the physical and chemical characteristics of the soil occur with a concomitant increase in earthworm abundance and activities. Similar changes might occur after a long-term fertilization of savannas with manure. This review article considers the earthworm communities and other soil quality indices in Trachypogon savannas of the Orinoco Basin in an organic agricultural forestal savanna (OAFS) amended with compost over forty years in Puerto Ayacucho, Venezuela, and in an Experimental Station long-term protected (PS) from fire and cattle raising from more than four decades in Central Llanos, Venezuela, comparison is made with results from similar savannas. Long-term additions of organic manure or a long protection have induced significant changes in the soil physical and chemical properties of the natural savanna (NS) soils that induce a significant increase in the density and biomass of earthworm populations. On the other hand, the protection of the savanna promotes an improvement in the physical and chemical properties of the soil, which favors an increase in the density and biomass of earthworms in the PS compared with the NS subjected to recurrent burning and grazing. The results emphasize the importance of appropriate organic matter management and the relevance of earthworms in such agroecosystems. http://www.mdpi.com/2077-0472/2/2/87 Tue, 10 Apr 2012 00:00:00 CEST Agriculture 2012-04-10 2 2 Review 87 108 2077-0472 Earthworm Populations in Savannas of the Orinoco Basin. A Review of Studies in Long-Term Agricultural-Managed and Protected Ecosystems 2012-04-10 doi: 10.3390/agriculture2020087 Danilo López-Hernández http://www.mdpi.com/2077-0472/2/1/73 Biofertilizers are becoming increasingly popular in many countries and for many crops, but very few studies on their effect on grain yield have been conducted in rice. Therefore, we evaluated three different biofertilizers (based on Azospirillum, Trichoderma, or unidentified rhizobacteria) in the Philippines during four cropping seasons between 2009 and 2011, using four different fertilizer rates (100% of the recommended rate [RR], 50% RR, 25% RR, and no fertilizer as Control). The experiments were conducted under fully irrigated conditions in a typical lowland rice environment. Significant yield increases due to biofertilizer use were observed in all experimental seasons with the exception of the 2008/09 DS. However, the effect on rice grain yield varied between biofertilizers, seasons, and fertilizer treatments. In relative terms, the seasonal yield increase across fertilizer treatments was between 5% and 18% for the best biofertilizer (Azospirillum-based), but went up to 24% in individual treatments. Absolute grain yield increases due to biofertilizer were usually below 0.5 t·ha−1, corresponding to an estimated additional N uptake of less than 7.5 kg N ha−1. The biofertilizer effect on yield did not significantly interact with the inorganic fertilizer rate used but the best effects on grain yield were achieved at low to medium fertilizer rates. Nevertheless, positive effects of the biofertilizers even occurred at grain yields up to 5 t·ha−1. However, the trends in our results seem to indicate that biofertilizers might be most helpful in rainfed environments with limited inorganic fertilizer input. However, for use in these target environments, biofertilizers need to be evaluated under conditions with abiotic stresses typical of such systems such as drought, soil acidity, or low soil fertility. http://www.mdpi.com/2077-0472/2/1/73 Wed, 14 Mar 2012 00:00:00 CET Agriculture 2012-03-14 2 1 Article 73 86 2077-0472 Evaluation of Biofertilizers in Irrigated Rice: Effects on Grain Yield at Different Fertilizer Rates 2012-03-14 doi: 10.3390/agriculture2010073 Niño Paul Meynard Banayo Pompe C. Sta. Cruz Edna A. Aguilar Rodrigo B. Badayos Stephan M. Haefele http://www.mdpi.com/2077-0472/2/1/52 Some tannins sorb to soil and reduce soluble-N. However, we know little about how they interact with organic amendments in soil. Soil (0–5 cm) from plots, which were amended annually with various carbon substances, was treated with water (control) or solutions containing tannins or related phenolic subunits. Treatments included a proanthocyanidin, catechin, tannic acid, β-1,2,3,4,6-penta-O-galloyl-D-glucose (PGG), gallic acid, and methyl gallate. We applied solutions of each of these materials to soil and measured soluble-C and -N in supernatants after application and following extraction with hot water (16 h, 80 °C). Sorption was low for non-tannin phenolics, methyl gallate, gallic acid, and catechin, and unaffected by amendment. Sorption of tannins, proanthocyanidin, tannic acid, and PGG, was higher and greater in plots amended with biosolids or manure. Extraction of soluble-N was not affected by amendment or by catechin, proanthocyanidin, or methyl gallate, but was reduced with PGG, tannic acid and gallic acid. Soil cation exchange capacity increased following treatment with PGG but decreased with gallic acid, irrespective of amendment. Tannins entering soil may thus influence soil organic matter dynamics and nutrient cycling but their impact may be influenced by the composition of soil organic matter. http://www.mdpi.com/2077-0472/2/1/52 Mon, 27 Feb 2012 00:00:00 CET Agriculture 2012-02-27 2 1 Article 52 72 2077-0472 Sorption of Tannin and Related Phenolic Compounds and Effects on Extraction of Soluble-N in Soil Amended with Several Carbon Sources 2012-02-27 doi: 10.3390/agriculture2010052 Jonathan J. Halvorson Hero T. Gollany Ann C. Kennedy Ann E. Hagerman Javier M. Gonzalez Stewart B. Wuest http://www.mdpi.com/2077-0472/2/1/38 Microbial inoculants are becoming more available as sustainable alternatives to fertilizers and other agrichemicals in broad-acre cropping. However, with the exception of legume inoculants little is understood about effective delivery and survival of the inoculum. Legume inoculants are applied to both seed and soil but seed inoculation is the most economical technique. Large quantities of pasture seed in Australia are inoculated by commercial seed coating companies, but the long-term survival of seed-applied inoculum is variable and monitoring of viability requires specialist microbiology skills and facilities. The aim of our research was to define optimum storage conditions for survival of rhizobia on legume seed and evaluate water activity as a means of monitoring shelf-life. The relationship between survival and water activity varied according to seed species, inoculum preparation, coating ingredients, initial water activity and time suggesting that storage conditions would need to be defined for each different combination. Although drying seeds after coating significantly reduced viable numbers of rhizobia, survival of rhizobia on dried commercially coated lucerne seed after 11 weeks was less variable than seeds that had not been dried. The highest numbers were maintained when seeds remained dry with water activities of between 0.47 and 0.38. The quality of inoculated seed could be improved by reducing the death rate of inoculum during preparation and providing optimum storage conditions for long-term survival. http://www.mdpi.com/2077-0472/2/1/38 Mon, 06 Feb 2012 00:00:00 CET Agriculture 2012-02-06 2 1 Article 38 51 2077-0472 Conditions Affecting Shelf-Life of Inoculated Legume Seed 2012-02-06 doi: 10.3390/agriculture2010038 Rosalind Deaker Elizabeth Hartley Greg Gemell http://www.mdpi.com/2077-0472/2/1/25 The knowledge of important parameters for honey characterization is an increasing requirement of consumers and the honey industry. In this respect, differentiation between blossom honeys and some honeydew honeys is still an unresolved task. This study includes the results of physicochemical and melissopalynological analysis of 86 honey samples from north-western Spain. The relationship between the microscopic elements in honey, such as Metschnikowia cells and fungal spores from plant pathogens, together with their physicochemical parameters were analysed. A cluster analysis was performed to differentiate blossom honey samples from honeydew samples. Metschnikowia cells and certain fungal spores were found to be good variables to enable differentiation between blossom honeys and honeydew honeys. http://www.mdpi.com/2077-0472/2/1/25 Fri, 20 Jan 2012 00:00:00 CET Agriculture 2012-01-20 2 1 Article 25 37 2077-0472 Differentiation of Blossom Honey and Honeydew Honey from Northwest Spain 2012-01-20 doi: 10.3390/agriculture2010025 Escuredo Olga Fernández-González María Seijo María Carmen http://www.mdpi.com/2077-0472/2/1/12 With increasing economic and environmental costs associated with fertilizer use, the need for low-input agroecological systems is on the rise. It is well documented that intercropping legumes can increase the supply of nutrients, through N2-fixation and P mobilization. Concurrently, the integration of trees in the agricultural landscape shows increasing evidence of nutrient inputs through efficient biogeochemical cycles. However, little is known about the effects shade has on legume-crop performance. This research aims to determine whether intercropping of the legumes soybean (Glycine max L. Merr.) and alfalfa (Medicago sativa) with wheat (Triticum turgidum durum) is beneficial for performance, particularly under shady conditions associated with tree-based intercropping. Test species were cultivated in hydroponics with a broad nutrient solution and steady state addition of N for 3 weeks. Individual plants were transferred to rhizoboxes with a 2 mm zone of soil for 16 days under (i) full sun or (ii) shade to mimic light levels at the tree-crop interface. Under monocropping, shading was found to significantly decrease wheat biomass. Intercropping wheat with alfalfa under full sun had no negative effect on growth but did increase wheat P uptake as compared to monocropped wheat. In contrast, intercropping wheat with soybean under full sun decreased wheat biomass, suggesting competition. However, under shade, this competitive effect was mitigated, as wheat exhibited similar biomass and higher N and P shoot concentration when associated with soybean as compared to monocropped wheat under lower light levels. This effect may be attributed to reduced biomass of soybean combined with higher soybean N2-fixation under shade. Legume-based intercrops may increase nutrient supply and growth but these beneficial effects will be dependent on matching species selection to light levels under tree-based intercropping. http://www.mdpi.com/2077-0472/2/1/12 Thu, 19 Jan 2012 00:00:00 CET Agriculture 2012-01-19 2 1 Article 12 24 2077-0472 Effects of Shade on Nitrogen and Phosphorus Acquisition in Cereal-Legume Intercropping Systems 2012-01-19 doi: 10.3390/agriculture2010012 Meighen Whitehead Marney E. Isaac http://www.mdpi.com/2077-0472/2/1/1 Total sulfur data of various agricultural and food items from the lab of the author, have been compiled to develop an understanding of sulfur levels and ecological cycling in Austria. As sulfur level is not an included factor among the quality criteria of soil and fertilizer composition, the database is rather small. Problems in analytical determinations of total sulfur, in particular digestions, are outlined. As a protein component, sulfur is enriched in matrices of animal origin, in particular in egg white. There is substantial excretion from animals and man via urine. Organic fertilizers (manures, composts) might contribute significantly to the sulfur budget of soils, which is important for organic farming of crops with high sulfur needs. For soils, drainage is a main route of loss of soluble sulfate, thus pot experiments may yield unrealistic sulfur budgets. http://www.mdpi.com/2077-0472/2/1/1 Thu, 12 Jan 2012 00:00:00 CET Agriculture 2012-01-12 2 1 Article 1 11 2077-0472 Levels of Sulfur as an Essential Nutrient Element in the Soil-Crop-Food System in Austria 2012-01-12 doi: 10.3390/agriculture2010001 Manfred Sager http://www.mdpi.com/2077-0472/1/1/22 This study was aimed at quantifying soybean (Glycine max) nitrogen fixation under reduced tillage (RT) and conventional tillage (CT) in a tropical Ferralsol of the sub-humid zone of western Kenya, using the isotope 15N dilution method. Crop residue (CR) management was a superimposed treatment in soybean-maize rotation and intercropping systems. This study quantified N in abscised soybean leaves. Soybean-N derived from the atmosphere (%NDfA) ranged between 41–65%; it was higher (P < 0.05) in RT (55.6%) than in CT (46.6%). Total fixed-N under ‘RT + CR’ was more than in the other treatments by at least 55% in intercropping and 34% in rotation system. Nitrogen fixed in soybean aboveground parts was 26–48 kg N ha−1 with intercropping and 53–82 kg N ha−1 with rotation. Seasonal litter fall contained about 15 kg N ha−1, with 54% NDfA. Annual nitrogen balances with soybean and maize grain removed were better in RT (−9 to −32 kg N ha−1) than in CT (−40 to −60 kg N ha−1). Application of P increased nodule weight (P < 0.05) by 3 to 16 times over the control. Soybean residues should be returned to the field after harvest to reduce soil N mining. We conclude that ‘RT + CR’ increases biological nitrogen fixation in soybean, over CT, and that phosphorus application is needed for better soybean nodulation in western Kenya. http://www.mdpi.com/2077-0472/1/1/22 Tue, 20 Dec 2011 00:00:00 CET Agriculture 2011-12-20 1 1 Article 22 37 2077-0472 Effects of Tillage and Crop Residue Application on Soybean Nitrogen Fixation in a Tropical Ferralsol 2011-12-20 doi: 10.3390/agriculture1010022 Job Kihara Christopher Martius Andre Bationo Paul L. G. Vlek http://www.mdpi.com/2077-0472/1/1/4 Significant amounts of manure are produced in the USA; however, information on the changes in ecosystem services related to soil biogeochemical cycling for agroecosystems supported with organic amendments such as manure is limited. A multi-location field study was initiated in Colorado (CO), Kansas (KS) and Kentucky (KY), USA in loam soils to evaluate the effects of manure and tillage practices on enzyme activities that are key to biogeochemical cycling such as β-glucosidase (C cycling), α-galactosidase (C cycling), β-glucosaminidase (C and N cycling) and phosphomonoesterases (P cycling). The treatments were as follows: (i) two years of beef manure applications to a fine sandy loam at different rates (control: 0, low: 34 kg N ha−1 and high: 96 kg N ha−1) and tillage practices in CO; (ii) three years of beef manure applications to a silt loam at different rates (0, low: 67 kg N ha−1 and high: 134 kg N ha−1) and tillage practices in KS and; (iii) three years of poultry and dairy manure applications to a silt loam with different tillage practices at the same rate (403 kg N ha−1) in KY. Tillage practices (none vs. conventional) had no effect on the enzyme activities. Principal Component Analyses (PCA) grouped all enzyme activities with the high beef manure application rate after the first year in CO at 0–5 cm. By the second year, the low and high beef manure rates differed in enzyme activities for the KS soil with no difference between the low rate and control in CO. Since the first year of the KY study, acid phosphatase activity was greater in the poultry treated soil compared to dairy or the control; whereas, C cycling enzyme activities were similar in soil treated with dairy or poultry manure. For all studies, PCAs for soil samples from 5–10 cm depth did not reveal treatment separation until the second year, i.e., only high application rate differed from the other treatments. Results of the study indicated significant responses in C and P cycling enzyme activities to manure applications within two years, suggesting potential benefits to soil biogeochemical cycling essential for the productivity of agroecosystems supported with organic fertilizers. http://www.mdpi.com/2077-0472/1/1/4 Fri, 09 Dec 2011 00:00:00 CET Agriculture 2011-12-09 1 1 Article 4 21 2077-0472 Multi-Location Study of Soil Enzyme Activities as Affected by Types and Rates of Manure Application and Tillage Practices 2011-12-09 doi: 10.3390/agriculture1010004 Veronica Acosta-Martinez Maysoon M. Mikha Karamat R. Sistani Phillip W. Stahlman Joseph G. Benjamin Merle F. Vigil Richie Erickson http://www.mdpi.com/2077-0472/1/1/1 Ensuring food security is an ongoing global challenge. Many forecasts point to a need to increase food production by at least 70% if we are to feed the world’s projected population of nine billion in 2050. Recent volatility in commodity prices and the general upward trend in the cost of food are indicators that global food systems are now driven by demand rather than supply. There are various reasons for this: greater demand for animal protein with economic growth in developing countries; the continuing increase in world population; competition between food and bioenergy crops for land and water; low inventories of world grain stocks; reduced investment in agricultural R&D; and unfavorable weather resulting in a succession of poor harvests around the world. Increasing production of grains, which are the foundation of the human food supply, will have to be achieved through higher crop yields without boosting inputs of land, water and energy. Meeting community expectations for environmental stewardship and sustainability, and adapting food production to increasingly variable climate, add greatly to the challenge. http://www.mdpi.com/2077-0472/1/1/1 Wed, 08 Jun 2011 00:00:00 CEST Agriculture 2011-06-08 1 1 Editorial 1 3 2077-0472 Meeting the Challenges for Agriculture 2011-06-08 doi: 10.3390/agriculture1010001 Les Copeland