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Maize producers transitioning to an organic cropping system must grow crops organically without price premiums for 36 months before certification. We evaluated conventional and organic maize with recommended and high seeding and N rates in New York to identify the best organic management practices during the transition. Conventional versus organic maize management differences included a treated (fungicide/insecticide) Genetically Modified (GM) hybrid versus a non-treated non-GM isoline; side-dressed synthetic N versus pre-plow composted manure; and Glyphosate versus mechanical weed control, respectively. Organic versus conventional maize yielded 32% lower as the entry crop (no previous green manure crop). GrainN%and weed densities explained 72% of yield variability. Organic and conventional maize, following wheat/red clover in the second year, yielded similarly. Organic maize with high inputs following wheat/red clover and conventional maize with high inputs following soybean in the third year yielded the highest. Grain N% and maize densities explained 54% of yield variability. Grain crop producers in the Northeast USA who do not have on-farm manure and forage equipment should plant maize after wheat/red clover with additional N (~56 kg N/ha) at higher seeding rates (~7%) during the transition to insure adequate N status and to offset maize density reductions from mechanical weed control. [ABSTRACT FROM AUTHOR]

Organic soybean hectares will increase in the Northeast United States of America (USA) because of demand by the expanding organic dairy industry. We evaluated organic and conventional soybean with recommended and high inputs (high seeding rate + organic seed treatment in organic system) from 2015 to 2018 in New York, USA to determine if high input management could reduce the yield penalty in organic soybean. Organic compared with conventional soybean yielded similarly in 2015 and 2016 but ≈ 11% lower in 2017 and 2018. Organic compared with conventional soybean had similar early and harvest plant densities in 2017 but lower early and harvest plant densities in 2018 when both densities correlated with yield (r = 0.33 and 0.36, respectively). Weed densities in organic soybean were low (2 in all years). Nevertheless, organic compared with conventional soybean in 3 of 4 years had greater weed densities, which had significant negative correlations with yield in 2015 (r = −0.36), 2017 (r = −0.53) and 2018 (r = −0.36). Organic compared with conventional soybean mostly had fewer pods/plant and greater seed weight but yield components showed no consistent correlations with yield. Organic soybean had similar weed densities and yield with recommended and high input management in all years indicating that growers should probably plant organic soybean at recommended seeding rates (370,500 seeds/ha) during the first 4 years of organic production under similar environmental conditions of this study.

Organic wheat production has increased significantly because of increased demand by consumers. We used the same variety to evaluate organic (seed treatment) and conventional wheat (no seed treatment) under no-till conditions in 2016 and 2018 with recommended (296 kernels/m2 and 80 kg N/ha) and high inputs (420 kernels/m2 and 56 + 56 kg N/ha) to identify the best organic management practices. Organic compared with conventional wheat with recommended inputs had ~13% lower yields in 2016 but ~7.5% higher yields with high inputs in 2018. Organic wheat emerged 1 to 1.5 days earlier, had 10 to 38% higher plant establishment rates, and had similar weed densities (2) to high input conventional wheat, which received a fall herbicide. Organic compared with conventional wheat had lower grain N% (0.3 to 0.45% in 2016 and 0.17 to 0.27% in 2018). Organic compared with conventional wheat had mostly higher spike densities, especially with high inputs (~60 more spikes/m2 in 2016 and ~130 more in 2018), probably because of better plant establishment, but mostly lower kernels/spike and kernel weight. Organic compared with conventional wheat had comparable yields, probably because of its competitiveness with weeds. We recommend that growers use recommended seeding and N rates on organic wheat because high seeding rates did not improve weed control, and high N rates were not economical.

Euphorbia dentata es una maleza anual, de ciclo primavero - estival que está presente en el 85% del área agrícola del partido de Azul, Pcia Buenos Aires Argentina, con densidades que oscilan entre 20 a 200 plantas m-2. Estudios en campo fueron conducidos durante dos años para determinar la relación de competencia entre soja y E. dentata a través de la evaluación del efecto de distintas densidades de la maleza sobre los componentes del rendimiento del cultivo y su biomasa. El peso seco y rendimiento de soja mostraron una respuesta dependiente de la densidad y de la biomasa de la maleza, siendo reducidos al 80% por la interferencia a partir de la densidad de 20 plantas m-2. En el rango de densidades estudiadas se observó una respuesta lineal que fue ajustada a una ecuación de regresión que indica que la producción de semillas de soja decrece 6,73 kg ha-1 por el incremento de cada planta m-2 de E. dentata. De los componentes del rendimiento del cultivo, el número de vainas por planta fue el más severamente afectado por la competencia obteniéndose reducciones del 40% respecto del tratamiento sin maleza. Altos niveles de correlación fueron observados entre el rendimiento de soja, el número de vainas por planta y el peso de 1.000 semillas (98 y 85% respectivamente).Euphorbia dentata is a spring-summer annual weed first detected in Azul Co., Buenos Aires Province, Argentina., in 1983, in an isolated soybean crop spot crops. It is now found as a weed in 85 % of the cropland, with densities ranging from 20 to 200 plants m-2. Two year- field studies were conducted to determine the competition relationship between soybean and E. dentata. The effect of different weed densities was evaluated on yield parameters and biomass. Both soybean dry weight and yield gave a significant response to weed density and biomass, resulting in a reduction of 80% due to interference starting at a density of 20 plants m². It was determined that E. dentata has a strong influence on soybean yield showing a linear response at the range of the studied densities, fitted to a regression equation indicating that seed production decreases 6,73 kg ha-1 for each plant m-2 increase of E. dentata. From the crop yield components, the number of pods per plant was more severely affected by competition reducing yield in 40%, when compared to the unweeded treatment. The number of grains per pod and weight of 1000 seeds were significantly affected at high densities of E. dentata (55 plants m-2). High correlation levels were found between soybean seed yield, number of pods per plant and weight of 1000 seeds (98 and 85 % respectively).

Conservation cropping systems are being developed for cotton (Gossypiumspp.) traditionally grown on raised beds with several soil-disturbing tillage passes in the San Joaquin Valley (SJV) of California, USA. Overhead (OH) irrigation and subsurface drip irrigation (SSDI) systems are water-conserving techniques being tested with reduced tillage in the SJV. However, crop growth, yield, microclimate, and pest population dynamics in these systems have not been documented. A field study was conducted in 2011 and 2012 at Five Points, Calif., to evaluate the difference between the two irrigation systems. Cotton cv. Phytogen 725 RF was no-till planted into wheat residue. In both years, the soil surfaces in the OH plots were 1° to 2°C cooler and 5% to 15% wetter than the SSDI plots. These differences had no effect on crop growth, development, yield, or quality, but weed densities and biomass were lower in the SSDI than in the OH in both years. However, the SSDI plots had more spider mites (Tetranychussp.) than the OH plots in 2011. The study showed that cotton could be successfully grown with conservation tillage, high residue systems, with either OH or SSDI systems in the SJV. [ABSTRACT FROM AUTHOR]

Organic soybean hectares will increase in the Northeast United States of America (USA) because of demand by the expanding organic dairy industry. We evaluated organic and conventional soybean with recommended and high inputs (high seeding rate + organic seed treatment in organic system) from 2015 to 2018 in New York, USA to determine if high input management could reduce the yield penalty in organic soybean. Organic compared with conventional soybean yielded similarly in 2015 and 2016 but ≈ 11% lower in 2017 and 2018. Organic compared with conventional soybean had similar early and harvest plant densities in 2017 but lower early and harvest plant densities in 2018 when both densities correlated with yield (r = 0.33 and 0.36, respectively). Weed densities in organic soybean were low (<0.77 weeds/m2 in all years). Nevertheless, organic compared with conventional soybean in 3 of 4 years had greater weed densities, which had significant negative correlations with yield in 2015 (r = −0.36), 2017 (r = −0.53) and 2018 (r = −0.36). Organic compared with conventional soybean mostly had fewer pods/plant and greater seed weight but yield components showed no consistent correlations with yield. Organic soybean had similar weed densities and yield with recommended and high input management in all years indicating that growers should probably plant organic soybean at recommended seeding rates (370,500 seeds/ha) during the first 4 years of organic production under similar environmental conditions of this study. [ABSTRACT FROM AUTHOR]

Organic wheat production has increased significantly because of increased demand by consumers. We used the same variety to evaluate organic (seed treatment) and conventional wheat (no seed treatment) under no-till conditions in 2016 and 2018 with recommended (296 kernels/m2 and 80 kg N/ha) and high inputs (420 kernels/m2 and 56 + 56 kg N/ha) to identify the best organic management practices. Organic compared with conventional wheat with recommended inputs had ~13% lower yields in 2016 but ~7.5% higher yields with high inputs in 2018. Organic wheat emerged 1 to 1.5 days earlier, had 10 to 38% higher plant establishment rates, and had similar weed densities (<0.25 weeds/m2) to high input conventional wheat, which received a fall herbicide. Organic compared with conventional wheat had lower grain N% (0.3 to 0.45% in 2016 and 0.17 to 0.27% in 2018). Organic compared with conventional wheat had mostly higher spike densities, especially with high inputs (~60 more spikes/m2 in 2016 and ~130 more in 2018), probably because of better plant establishment, but mostly lower kernels/spike and kernel weight. Organic compared with conventional wheat had comparable yields, probably because of its competitiveness with weeds. We recommend that growers use recommended seeding and N rates on organic wheat because high seeding rates did not improve weed control, and high N rates were not economical. [ABSTRACT FROM AUTHOR]