Effect of weather on organic cropping systems in Kenya

Rainfall is the single most important factor affecting yield and biomass accumulation by crops as well as residue decomposition in the tropics. The ability to capture this resource in organic systems calls for appropriate techniques. Kenya experiences bimodal type of rainfall with two rainfall peaks; the long (730 mm) and the short (376 mm) rains. Rainfall fluctuations in both seasons are becoming more common in the recent years with a likelihood of crop failure in one out of five years. The question addressed was how to utilize the short rains for food and biomass production. Lablab (Dolichos lablab), a N-fixing legume was sown in the short rains and the seeds harvested. The effect of lablab biomass incorporation on organic maize and potatoes planted in the long rains was evaluated in comparison with farmyard manure application. The 3-year trial showed that dry matter biomass (1.95 t/ha) and grain yield (0.5 t/ha) of lablab was a factor of the amount of rainfall. The amount of lablab biomass applied was proportional to maize grain and potato tuber yields. Similarly, amount of yield and biomass in the long rains was species specific and were a factor of both rainfall amounts and distribution

Response of Root Properties to Tripartite Symbiosis between Lucerne (Medicago sativa L.), Rhizobia and Mycorrhiza Under Dry Organic Farming Conditions

It is generally considered that root turnover is a major contributor to organic matter and mineral nutrient cycles in organic managed agroecosystems. Approach: This study designed to investigate whether microbial activity could affect on root properties of lucerne in an organically managed field under dry weather conditions. The trial was laid out as a factorial experiment in the fields of the University of Natural Resources and Applied Life Sciences, Vienna-Austria at Raasdorf in 2007. The experimental factors of Sinorhizobium meliloti and arbuscular mycorrhiza (AM) including Glomus etunicatum, G. intraradices and G. claroideum and irrigation levels were tested. Results: Results showed that increasing water deficit affected root dry weigh, specific root mass and root length significantly at 1% level and co-inoculation of rhizobium and mycorrhiza with irrigation could increase all root parameters. Data’s of variance analysis for mycorrhizal colonization showed that main effect of using mycorrhiza had significant effects on root parameters at 5% and 1% probability level in first and second harvest, respectively. Results of mean comparisons by Duncan’s multiple range test showed that mycorrhizal colonization was higher in the inoculated treatments by rhizobium , mycorrhiza and irrigated plots in both harvests. Double interaction of mycorrhiza and irrigation was higher in both harvests (37.05% and 65.73%, respectively). Conclusion: Hence, it can be suggested that the tripartite symbiosis of S. meliloti, AM and lucerne can improve the performance of lucerne in organic farming and under dry conditions. Such traits could be incorporated into breeding programs to improve drought tolerance especially in organic fields

Genetic diversity and distance among Iranian and European alfalfa (Medicago sativa L.) genotypes

Alfalfa is the best known fodder crop with high ability of biological nitrogen fixation and drought tolerance in dry, Pannonian region of east Austria. Different morphological and physiological characteristics of 18 alfalfa genotypes from different geographical origins, 8 Iranian ecotypes and 10 European cultivars were evaluated under irrigated and rainfed conditions during 2006-08 cropping seasons. The objectives of this study were to measure genetic distance and divergence among genotypes and to classify them based on morphological and physiological characters. Cluster analysis differentiated Iranian ecotypes and European cultivars from each other under irrigated condition, and when data averaged across two environments (irrigated and rainfed). However, under rainfed conditions small changes occurred in grouping of genotypes due mainly to differential responses of the genotypes to rainfed condition. Considerable genetic distance observed between Iranian and European genotypes. Different crossing programs are recommended between Iranian and European genotypes to develop new alfalfa cultivars

Einfluss von Stoppelhobel als Alternative zum Grubber auf Beikrautentwicklung und Dinkelertrag

Der modifizierte Schälpflug oder "Stoppelhobel" schützt den Boden durch seine flach wendende Arbeitsweise, unterdrückt Beikräuter durch das ganzflächige Unterschneiden des Bodens, reduziert den Energieverbrauch und ermöglicht höhere Arbeitsgeschwindigkeiten. Im Jahr 2016/17 wurde auf einem Biobauernhof im Waldviertel im nördlichen Niederösterreich ein Praxis-Feldversuch durchgeführt. Zwei Bodenbearbeitungsverfahren vor dem Dinkelanbau - Var. A: 3x Stoppelhobel, Var. B: 2x Grubber / 1x Stoppelhobel - wurden hinsichtlich Bodeneigenschaften, Beikrautdruck und Ertragsmerkmalen untersucht. Es wurden keine signifikanten Unterschiede zwischen dem Dinkel-Kornertrag (Var. A 17,2 dt TM ha-1 / Var. B 18,3 dt TM ha-1), den pflanzenverfügbaren Nährstoffen im Boden, Humusgehalt und der Beikrautdichte festgestellt. Die Versuchsergebnisse bestätigten den Stoppelhobel als Alternative zum Grubber, da die gleichen Ergebnisse mit einer geringeren Arbeitstiefe erzielt werden konnten

Suitability of drought tolerance indices for selecting alfalfa (Medicago sativa L.) genotypes under organic farming in Austria

In eastern Austria, alfalfa is usually grown as a rainfed crop in crop rotations in organic farming systems, where year-to-year rainfall fluctuations cause different levels of drought stress. To identify the suitability of different alfalfa genotypes and drought tolerance indices, 18 contrasting alfalfa genotypes were evaluated under irrigated and rainfed conditions at the research station of the University of Natural Resources and Life Sciences (BOKU), Vienna, Austria, during 2006-08. The first study year (2006) was considered as the establishment year. Five drought tolerance selection indices were estimated based on shoot dry matter, total biomass yield and biological nitrogen fixation (BNF) data. The correlation between irrigated and rainfed performances increased (from r=-0.17 to 0.56) with decreasing stress intensity from the first to the second year. Genotypes Sitel, Plato ZS, Vlasta and NS-Banat were the best genotypes based on their performance under both conditions. Drought tolerance selection indices TOL and SSI showed high correlations (r = 0.32 to 0.81) only with rainfed performance, and SSI was the index that best identified genotypes with high yield potential under rainfed conditions. Indices STI and GMP were the ones that best identified genotypes with high performance under both conditions

Modellberechnungen für treibhausgasrelevante Emissionen und Senken in landwirtschaftlichen Betrieben Ost-Österreichs

Landwirtschaftliche Nutzungssysteme sind in unterschiedlicher Weise an der Emission und Speicherung von klimarelevanten Gasen (CO2, CH4 und N2O) beteiligt. Die wesentlichen Projektziel sind die Bereitstellung von Daten- und Berechnungsgrundlagen für eine umfassende Darstellung von Profilen treibhausgasrelevanter Emissionen und Senken landwirtschaftlicher Betriebe in den acht Hauptproduktionsgebieten Österreichs. In jeder Region werden die beiden vorherrschenden Betriebstypen mit dem Programm REPRO modelliert, da es die Analyse der C-, N- und Energieflüsse im System Boden-Pflanze-Tier-Umwelt kombiniert. Als Beispiel werden die Ergebnisse des Hauptproduktionsgebietes "Nordöstliches Flach- und Hügelland" im Anschluss präsentiert

Biological nitrogen fixation and growth parameters correlations of alfalfa (Medicago sativa L.) genotypes under organically managed fields with limited irrigation

To identify the effective characters and their relative importance in improvement of BNF, two separate field experiments were conducted under irrigated and rain-fed organic managements of dry, Pannonian region of east Austria. The experiments were laid out in an α-lattice design with two replications and 18 genotypes (eight Iranian ecotypes and ten European cultivars). Plant height was positively and significantly correlated with leaf area index (LAI) and shoot dry matter (DM) under both conditions. Positive correlations were found between biological nitrogen fixation (BNF) and shoot DM (r = 0.61** and 0.87**, irrigated and rain-fed management, respectively). Regarding correlation coefficients, high yielding genotypes had taller plants and denser stands, especially under rain-fed condition. In path analysis, all direct effects of BNF components were positive in both conditions, while some of the indirect effects were negative. These can be regarded in selection models to avoid undesirable negative effects. Plant height and LAI can be considered as primary selection criteria for improving shoot DM, while crop re-growth and plant height, with antonymous effects, were more important for improving root dry matter

AGTEC-Org Agronomy Handbook of Methods

A common handbook was conceived in the CORE Organic AGTEC-Org project in order to give some elements of field trial monitoring

Nitrogen fixation and yield of lucerne (Medicago sativa L.), as affected by co-inoculation with Sinorhizobium meliloti and arbuscular mycorrhiza under dry organic farming conditions

This study evaluated the effects of co-inoculation with Sinorhizobium meliloti and arbuscular mycorrhizal fungi on the growth, yield and biological nitrogen fixation (BNF) of lucerne (Medicago sativa L.) under organic farming and dry weather conditions. The trial was laid out as a factorial experiment in the fields of the University of Natural Resources and Applied Life Sciences, Vienna-Austria at Raasdorf in 2007. The experimental factors of S. meliloti and arbuscular mycorrhiza (AM) including Glomus etunicatum, G. intraradices and G. claroideum and irrigation levels were tested. Co-inoculation of lucerne with S. meliloti and AM increased shoot dry weight as well as BNF at the first and second harvest but for BNF it was not significant. Irrigation resulted in the enhanced growth of some growth parameters. Microbial activities in this organically managed field were high enough for establishing an effective symbiosis with lucerne without any necessity for inoculation. Hence, it can be suggested that the tripartite symbiosis of S. meliloti, AM and lucerne can improve the performance of lucerne in organic farming and under dry conditions

Effect of Different Fertilizing Systems on Seed Yield and Phosphorus Uptake in Annual Medics under Dryland Farming Conditions

The effect of different fertilizing systems on the seed yield and phosphorus uptake in annual medic (Medicago scutellata cv. Robinson) was examined at two locations under dry farming conditions in Kermanshah province, Iran, in 2009. Experiments were conducted based on a randomized complete block design with three replications; the treatments consisted of control (no fertilizer), chemical fertilizer, biological fertilizer and different combinations of chemical and biological fertilizing systems. The results showed that application of different fertilizing systems had a highly significant effect on the number of pods per plant. The highest values were obtained in the treatment using the urea chemical fertilizer + phosphorus-solubilizing bacteria + mycorrhiza. The highest soil seed bank was recorded in the nitrogen-fixing bacteria + phosphorus-solubilizing bacteria treatment; it increased the number of seeds by approximately 50 percent compared to the control (only 134 pod containing seeds). The highest pod yield was obtained after applying nitrogen-fixing bacteria + mycorrhiza (445 kg/ha), the lowest yield in the control treatment (266 kg/ha). In general, under the conditions of this experiment, the seed yield of annual medic var. Robinson receiving nitrogen-fixing + phosphorus-solubilizing bacteria out-yielded other fertilizing treatments. This indicates a synergistic interaction between these groups of bacteria that increases seed yield, the soil seed bank as well as the seed phosphorus uptake of this plant species under dry farming conditions