Effects of plant density on alfalfa (Medicago sativa L.) seed yield in western Heilongjiang areas.

Alfalfa (Medicago sativa L.) is known as the "king of forages". The aim of the current study is to determine the optimum planting density as the key cultivation technique for high yield of alfalfa seed. Alfalfa variety (Longmu 801) was planted in experimental fields from 2014 to 2017. In the planting density test, the row spacing was 65, 80, and 95 cm, and the plant spacing was 30, 45, 60, 75, and 90 cm. The seed yield and yield components in the row spacing and plant spacing tests were measured. On the basis of 3 years average of the experimental data, the highest seed yield of 225.49 kg ha-1 was obtained with row spacing vs plant spacing of 65 and 60 cm, respectively. Correlation analysis showed a significant positive correlation between the racemes per stem, pods per raceme, pods per stem, seeds per pod, and the seed yield. These results suggested that Longmu 801 should be cultivated with 65 cm row spacing and 60 cm plant spacing to maximize seed yields in western Heilongjiang areas.

Effect of blended fertilizer rates and planting density on yield and yield components of Irish potato (Solanum tuberosum L.) at Gombora condition, Hadiya zone, Southern Ethiopia.

Potato is an important food and cash crop and it has high yielding potential in many parts of Ethiopia; however the yield of the crop is often constrained due to low and imbalanced rates of inorganic fertilizers and inappropriate spacing. The field experiment was conducted to determine the effect of five rates of blended fertilizer (0, 100, 150, 200, and 250) kg NPS ha-1 and intra-row planting spacing of 20 cm, 30 cm and 40 cm and laid out by randomized complete block design with three replication in a factorial arrangement. The analysis of variance revealed that, marketable tuber yield, total tuber yield, stem number per hill, total fresh mass, underground fresh and dry mass were significantly (P < 0.05) influenced by the interaction of Nitrogen, Phosphorous and Sulfur (NPS blended fertilizer) and intra-row spacing. The highest plant height (96.60 cm), highest marketable tuber yield (34.29 tha-1), highest total tuber yield (38.36 t ha-1) and highest total fresh biomass (1274.2 g plant-1) were recorded from NPS rate of 250 kg NPS ha-1 and intra-row spacing of 20 cm while the lowest recorded from control treatment in wider intra-row spacing (40 cm). Therefore, the application of 250 kg NPS ha-1 with the intra-row spacing of 20 cm can give an optimum tuber yield and it could be recommended for the production of potato in the study area.

Influence of management practices on water-related grain yield determinants.

Adequate management of N supply, plant density, row spacing, and soil cover has proved useful for increasing grain yields and/or grain yield stability of rainfed crops over the years. We review the impact of these management practices on grain yield water-related determinants: seasonal crop evapotranspiration (ET) and water use efficiency for grain production per unit of evapotranspired water during the growing season (WUEG,ET,s). We highlight a large number of conflicting results for the impact of management on ET and expose the complexity of the ET response to environmental factors. We analyse the influence of management practices on WUEG,ET,s in terms of the three main processes controlling it: (i) the proportion of transpiration in ET (T/ET), (ii) transpiration efficiency for shoot biomass production (TEB), and (iii) the harvest index. We directly relate the impact of management practices on T/ET to their effect on crop light interception and provide evidence that management practices significantly influence TEB. To optimize WUEG,ET,s, management practices should favor soil water availability during critical periods for seed set, thereby improving the harvest index. The need to improve the performance of existing crop growth models for the prediction of water-related grain yield determinants under different management practices is also discussed.

Optimal planting pattern of cotton is regulated by irrigation amount under mulch drip irrigation.

Objective: It is of great importance to explore agronomic management measures for water conservation and cotton yield in arid areas. Methods: A four-year field experiment was conducted to evaluate cotton yield and soil water consumption under four row spacing configurations (high/low density with 66+10 cm wide, narrow row spacing, RS66+10H and RS66+10L; high/low density with 76 cm equal row spacing, RS76H and RS76L) and two irrigation amounts (CI:conventional drip irrigation; LI:limited drip irrigation) during the growing seasons in Shihezi, Xinjiang. Results: A quadratic relationship was observed between the maximum LAI (LAImax) and seed yield. Canopy apparent transpiration rate(CAT), daily water consumption intensity (DWCI) and crop evapotranspiration (ETC) were positively and linearly correlated with LAI. The seed yields, lint yields, and ETC under CI were 6.6-18.3%,7.1-20.8% and 22.9-32.6%higher than those observed under LI, respectively. The RS66+10H under CI had the highest seed and lint yields. RS76L had an optimum LAImax range, which ensured a higher canopy apparent photosynthesis and daily dry matter accumulation and reached the same yield level as RS66+10H; however, soil water consumption in RS76L was reduced ETC by 51-60 mm at a depth of 20-60 cm at a radius of 19-38 cm from the cotton row,and water use efficiency increased by 5.6-8.3%compared to RS66+10H under CI. Conclusion: A 5.0

Density and row spacing of short-season cotton suitable for machine picking in the cotton region of Yellow River Basin.

To determine the suitable planting density and row spacing of short-season cotton suitable for machine picking in the Yellow River Basin of China, we conducted a two-year field experiment in Dezhou during 2018-2019. The experiment followed a split-plot design, with planting density (82500 plants·hm-2 and 112500 plants·hm-2) as the main plots and row spacing (equal row spacing of 76 cm, wide-narrow row spacing of 66 cm+10 cm, equal row spacing of 60 cm) as the subplots. We examined the effects of planting density and row spacing on growth and development, canopy structure, seed cotton yield and fiber quality of short-season cotton. The results showed that plant height and LAI under high density treatment were significantly greater than those under low density treatment. The transmittance of the bottom layer was significantly lower than under low density treatment. Plant height under 76 cm equal row spacing was significantly higher than that under 60 cm equal row spacing, while that under wide-narrow row spacing (66 cm +10 cm) was significantly smaller than that under 60 cm equal row spacing in peak bolling stage. The effects of row spacing on LAI varied between the two years, densities, and growth stages. On the whole, the LAI under the wide-narrow row spacing (66 cm+10 cm) was higher, with the curve declining gently after the peak, and it was higher than that in the two cases of equal row spacing in the harvest time. The change in transmittance of the bottom layer presented the opposite trend. Density, row spacing, and their interaction had significant effects on seed cotton yield and its components. In both years, seed cotton yield was the highest (3832 kg·hm-2 in 2018, 3235 kg·hm-2 in 2019) under wide-narrow row spacing (66 cm+10 cm), and it was more stable at high densities. Fiber quality was less affected by density and row spacing. To sum up, the optimal density and row spacing of short-season cotton were as follows: density with 112500 plants·hm-2 and wide-narrow row spacing (66 cm+10 cm).

Optimizing plant spatial competition can change phytohormone content and promote tillering, thereby improving wheat yield.

As an important type of interplant competition, line-spacing shrinkage and row-spacing expansion (LSRE) can increase the number of tillers and improve resource utilization efficiency in wheat. Wheat tillering is closely related to various phytohormones. However, it is unclear whether LSRE regulates phytohormones and their relationship to tillering and wheat yield. This study evaluated tillering characteristics, phytohormone content in tiller nodes at the pre-winter stage, and grain yield factors for the winter wheat variety Malan1. We used a two-factor randomized block trial design with two sowing spacings of 15 cm (15RS, conventional treatment) and 7.5 cm (7.5RS, LSRE treatment) at the same density and three sowing-date groups (SD1, SD2, and SD3). LSRE significantly promoted wheat tillering and biomass at the pre-winter stage (average increases of 14.5% and 20.9% in the three sowing-date groups, respectively) and shortened the accumulated temperature required for a single tiller. Changes in the levels of phytohormones, including decreased gibberellin and indole acetic acid and increased zeatin riboside and strigolactones, were determined by high-performance liquid chromatography and were shown to be responsible for the tillering process under LSRE treatment in winter wheat. LSRE treatment can improve crop yield by increasing the number of spikes per unit area and grain weight. Our results clarified the changes in tillering and phytohormones content of winter wheat under LSRE treatment and their correlation with grain yield. This study also provides insights into the physiological mechanisms of alleviating inter-plant competition to improve crop yield.

Contribution of Fertilizer, Density and Row Spacing Practices for Maize Yield and Efficiency Enhancement in Northeast China.

The research aimed to assess the contribution of fertilizer, density, and row spacing in integrated cultivation measures and identify their regulation mechanism on canopy architecture and factors in biomass accumulation in spring maize. Zhengdan 958 was used as the experimental material, and the optimum mode (OM) was identified based on a preliminary experiment, including the optimal fertilizer management, suitable plant density and wide-narrow row spacing, and dramatic yield performance (11,445.16 kg ha-1 in 2017). Then, the effects of these practices on maize canopy structure performance were analyzed using the omission factors design experiment in optimum mode (OM). Treatments were set as follows: without fertilization (OM-F), without density (OM-D), and without wide-narrow plant spacing (OM-S). The results showed that the contribution of fertilization was maximum (23.85%), the second was intensive planting (16.05%), which promoted nitrogen accumulation and transport in leaves and stems via increased leaf area index and dry matter accumulation around the anthesis simultaneously, elevating the radiation utilization efficiency of the canopy and allowing a higher grain weight to be obtained. Wide-narrow row spacing yield contribution is minimum among the measures (8.649%), which could regulate the leaf and radiation transmittance in the middle and bottom layer of the canopy, while increasing the nitrogen accumulation of leaves and stalks in the silking stage, then significantly enhance the nitrogen transport and the matter accumulation of maize after anthesis. Our results showed that fertilizer management and density were the essential practices for integrated cultivation mode for northeast China. Moreover, wide-narrow row planting was advocated if permitted, which could elevate the utilization efficiency of radiation to 1%, and the yield of more than 11,000 kg ha-1 was obtained in Northeast China.

Allometric Characteristics of Rice Seedlings under Different Transplanted Hills and Row Spacing: Impacts on Nitrogen Use Efficiency and Yield.

The number of seedlings per hill and the configuration of plant row spacing are important management measures to improve rice yield. In the present study, we evaluated the impact of various seedlings per hill (1, 3, 6, and 9 seedlings hill-1) under four different rice verities (two conventional rice, two hybrid rice) on allometric characteristics, nitrogen use efficiency (NUE) and yield in 2020 at early and late season. Results showed that compared with nine seedlings per hill (wide row spacing), the number of effective panicles, yield, grain biomass allocation, grain-to-leaf ratio, grain nitrogen accumulation, nitrogen dry matter production efficiency (NDMPE), N harvest index (NHI) of 1 seedling per hill increased by 21.8%, 10.91%, 10.5%, 32.25%, 17.03%, 9.67%, 6.5%, respectively. With the increase of seedlings per hill and the expansion of row spacing, stem biomass (SB) and reproductive biomass (RB) increased with the increase of above-ground biomass, mainly showing the relationship of isometric growth. Leaf biomass (LB) increased with above-ground biomass, mainly showing the relationship of allometric growth. The results suggested that under the same basic seedlings, transplanting 1 seedling per hill and dense planting was the most beneficial to improve rice yield.

Exogenous application of bio-stimulant and growth retardant improved the productivity of cotton cultivars under different planting arrangement / A aplicação exógena de bioestimulante e regulador de crescimento na melhoria da produtividade de cultivares de algodão sob diferentes configurações de plantio

Optimum planting arrangement is an important attribute for efficient utilization of available resources and to obtain high yield of cotton. Application of plant growth promoter and retardant on cotton in improved planting density are the innovative techniques in the establishment of more productive cotton crop. Therefore, we planned a field study to assess the role of bio-stimulant and growth retardant in the resource utilization efficiency of cotton cultivars planted under variable row spacing at Agronomic Research Area Bahauddin Zakariya University and Usmania Agricultural Farm Shujabad during Kharif 2012. Experimental treatments consisted of cotton genotypes viz. CIM-573 and CIM-598, cultivated under conventional (75 cm), medium (50 cm) and ultra-narrow row spacing (25 cm) with foliar spray of bio-stimulant (moringa leaf extract) and growth retardant (mepiquate chloride), either sole or in combination, keeping distilled water as a control. Exogenously applied MLE alone and MLE + MC significantly enhanced the number of squares, flowers and green bolls per plant leading to higher cotton seed and lint yield of CIM 598 cultivar cultivated under conventional row spacing. While application of MC alone and MLE + MC produced maximum micronaire value, fiber strength and fiber uniformity ratio of CIM 573 cultivar cultivated under conventional row spacing. The results suggested that application of MLE is a possible approach to enhance the cotton productivity and the use of MC to enhance the fiber quality attributes under conventional row spacing.

A configuração ideal de plantio é um atributo importante para a utilização eficiente dos recursos disponíveis e para obter alto rendimento de algodão. A aplicação de promotores de crescimento de plantas e reguladores de crescimento no algodão em uma densidade de plantio adequada são técnicas inovadoras na obtenção de safras de algodão mais produtivas. Portanto, foi planejado um estudo de campo para avaliar o papel de um bioestimulante e um regulador de crescimento na eficiência da utilização de recursos de cultivares de algodão plantadas com espaçamento variável entre linhas na Área de Pesquisa Agronômica Universidade Bahauddin Zakariya e Usmania Agricultural Farm Shujabad durante Kharif 2012. Os tratamentos experimentais consistiram em genótipos de algodão viz. CIM-573 e CIM-598, cultivadas sob espaçamento convencional (75 cm), médio (50 cm) e ultraestreito (25 cm) e pulverização foliar de bioestimulante (extrato de folha de moringa) e regulador de crescimento (cloreto de mepiquato)), sozinho ou combinado, mantendo a água destilada como controle. O MLE aplicado exogenamente sozinho e o MLE + MC aumentaram significativamente o número de quadrados, flores e cápsulas verdes por planta, levando a um maior rendimento de sementes e fibra de algodão da cultivar CIM 598 cultivada sob espaçamento convencional entre fileiras. Enquanto a aplicação de MC sozinho e MLE + MC produziu valor máximo de micronaire, resistência da fibra e razão de uniformidade da fibra da cultivar CIM 573 cultivada sob espaçamento convencional entre linhas. Os resultados sugeriram que a aplicação do MLE é uma abordagem possível para aumentar a produtividade do algodão e o uso de MC para aprimorar os atributos de qualidade da fibra no espaçamento convencional entre linhas.

Exogenous application of bio-stimulant and growth retardant improved the productivity of cotton cultivars under different planting arrangement / A aplicação exógena de bioestimulante e regulador de crescimento na melhoria da produtividade de cultivares de algodão sob diferentes configurações de plantio

Optimum planting arrangement is an important attribute for efficient utilization of available resources and to obtain high yield of cotton. Application of plant growth promoter and retardant on cotton in improved planting density are the innovative techniques in the establishment of more productive cotton crop. Therefore, we planned a field study to assess the role of bio-stimulant and growth retardant in the resource utilization efficiency of cotton cultivars planted under variable row spacing at Agronomic Research Area Bahauddin Zakariya University and Usmania Agricultural Farm Shujabad during Kharif 2012. Experimental treatments consisted of cotton genotypes viz. CIM-573 and CIM-598, cultivated under conventional (75 cm), medium (50 cm) and ultra-narrow row spacing (25 cm) with foliar spray of bio-stimulant (moringa leaf extract) and growth retardant (mepiquate chloride), either sole or in combination, keeping distilled water as a control. Exogenously applied MLE alone and MLE + MC significantly enhanced the number of squares, flowers and green bolls per plant leading to higher cotton seed and lint yield of CIM 598 cultivar cultivated under conventional row spacing. While application of MC alone and MLE + MC produced maximum micronaire value, fiber strength and fiber uniformity ratio of CIM 573 cultivar cultivated under conventional row spacing. The results suggested that application of MLE is a possible approach to enhance the cotton productivity and the use of MC to enhance the fiber quality attributes under conventional row spacing.

A configuração ideal de plantio é um atributo importante para a utilização eficiente dos recursos disponíveis e para obter alto rendimento de algodão. A aplicação de promotores de crescimento de plantas e reguladores de crescimento no algodão em uma densidade de plantio adequada são técnicas inovadoras na obtenção de safras de algodão mais produtivas. Portanto, foi planejado um estudo de campo para avaliar o papel de um bioestimulante e um regulador de crescimento na eficiência da utilização de recursos de cultivares de algodão plantadas com espaçamento variável entre linhas na Área de Pesquisa Agronômica Universidade Bahauddin Zakariya e Usmania Agricultural Farm Shujabad durante Kharif 2012. Os tratamentos experimentais consistiram em genótipos de algodão viz. CIM-573 e CIM-598, cultivadas sob espaçamento convencional (75 cm), médio (50 cm) e ultraestreito (25 cm) e pulverização foliar de bioestimulante (extrato de folha de moringa) e regulador de crescimento (cloreto de mepiquato)), sozinho ou combinado, mantendo a água destilada como controle. O MLE aplicado exogenamente sozinho e o MLE + MC aumentaram significativamente o número de quadrados, flores e cápsulas verdes por planta, levando a um maior rendimento de sementes e fibra de algodão da cultivar CIM 598 cultivada sob espaçamento convencional entre fileiras. Enquanto a aplicação de MC sozinho e MLE + MC produziu valor máximo de micronaire, resistência da fibra e razão de uniformidade da fibra da cultivar CIM 573 cultivada sob espaçamento convencional entre linhas. Os resultados sugeriram que a aplicação do MLE é uma abordagem possível para aumentar a produtividade do algodão e o uso de MC para aprimorar os atributos de qualidade da fibra no espaçamento convencional entre linhas.

Exogenous application of bio-stimulant and growth retardant improved the productivity of cotton cultivars under different planting arrangement

Abstract Optimum planting arrangement is an important attribute for efficient utilization of available resources and to obtain high yield of cotton. Application of plant growth promoter and retardant on cotton in improved planting density are the innovative techniques in the establishment of more productive cotton crop. Therefore, we planned a field study to assess the role of bio-stimulant and growth retardant in the resource utilization efficiency of cotton cultivars planted under variable row spacing at Agronomic Research Area Bahauddin Zakariya University and Usmania Agricultural Farm Shujabad during Kharif 2012. Experimental treatments consisted of cotton genotypes viz. CIM-573 and CIM-598, cultivated under conventional (75 cm), medium (50 cm) and ultra-narrow row spacing (25 cm) with foliar spray of bio-stimulant (moringa leaf extract) and growth retardant (mepiquate chloride), either sole or in combination, keeping distilled water as a control. Exogenously applied MLE alone and MLE + MC significantly enhanced the number of squares, flowers and green bolls per plant leading to higher cotton seed and lint yield of CIM 598 cultivar cultivated under conventional row spacing. While application of MC alone and MLE + MC produced maximum micronaire value, fiber strength and fiber uniformity ratio of CIM 573 cultivar cultivated under conventional row spacing. The results suggested that application of MLE is a possible approach to enhance the cotton productivity and the use of MC to enhance the fiber quality attributes under conventional row spacing.

Resumo A configuração ideal de plantio é um atributo importante para a utilização eficiente dos recursos disponíveis e para obter alto rendimento de algodão. A aplicação de promotores de crescimento de plantas e reguladores de crescimento no algodão em uma densidade de plantio adequada são técnicas inovadoras na obtenção de safras de algodão mais produtivas. Portanto, foi planejado um estudo de campo para avaliar o papel de um bioestimulante e um regulador de crescimento na eficiência da utilização de recursos de cultivares de algodão plantadas com espaçamento variável entre linhas na Área de Pesquisa Agronômica Universidade Bahauddin Zakariya e Usmania Agricultural Farm Shujabad durante Kharif 2012. Os tratamentos experimentais consistiram em genótipos de algodão viz. CIM-573 e CIM-598, cultivadas sob espaçamento convencional (75 cm), médio (50 cm) e ultraestreito (25 cm) e pulverização foliar de bioestimulante (extrato de folha de moringa) e regulador de crescimento (cloreto de mepiquato)), sozinho ou combinado, mantendo a água destilada como controle. O MLE aplicado exogenamente sozinho e o MLE + MC aumentaram significativamente o número de quadrados, flores e cápsulas verdes por planta, levando a um maior rendimento de sementes e fibra de algodão da cultivar CIM 598 cultivada sob espaçamento convencional entre fileiras. Enquanto a aplicação de MC sozinho e MLE + MC produziu valor máximo de micronaire, resistência da fibra e razão de uniformidade da fibra da cultivar CIM 573 cultivada sob espaçamento convencional entre linhas. Os resultados sugeriram que a aplicação do MLE é uma abordagem possível para aumentar a produtividade do algodão e o uso de MC para aprimorar os atributos de qualidade da fibra no espaçamento convencional entre linhas.

[Effects of row spacing and sowing rate on vertical distribution of photosynthetically active radiation, biomass, and grain yield in winter wheat canopy.] / è¡Œè·å’Œæ’­ç§é‡å¯¹å†¬å°éº¦å† å±‚å ‰åˆæœ‰æ•ˆè¾å°„åž‚ç›´åˆ†å¸ƒã€ç”Ÿç‰©é‡å’Œç±½ç²’äº§é‡çš„å½±å“.

To clarify the effects of row spacing and sowing rate on the vertical distribution of canopy PAR, biomass, and grain yield in winter wheat, a field experiment was conducted without increa-sing water and fertilizer input. There were two row spacing modes, R1 (equal spacing, 20 cm+20 cm) and R2(wide and narrow row spacing, 12 cm+12 cm+12 cm+24 cm), and three sowing rates, D1 (low, 120 kg·hm-2), D2 (medium, 157.5 kg·hm-2), D3 (high, 195 kg·hm-2). The canopy photosynthetically active radiation (PAR) interception and utilization rate in different heights, population photosynthetic capacity, biomass, and grain yield were measured during the main growth stages of winter wheat. The results showed that both total PAR interception and upper layer PAR interception of winter wheat canopy under R1 treatment were significantly higher than those in R2 treatment, but those of the middle layer and lower layer were higher in R2 than in R1, and with significant difference in the middle layer. From flowering to maturity, the photosynthetic potential (LAD), population photosynthetic rate (CAP), PAR conversion rate, and utilization rate in R2 were all significantly higher than those in R1 under the same sowing rate, with the highest value under R2D2 treatment. With the increasing sowing rate, the population biomass (BA) and leaf biomass (BL) at different layers increased, but the individual biomass (BP) showed an opposite trend. Under the same sowing rate, BA, BL and BP in R2 were higher than that in R1 after the flowering stage. Among them, BA and BP had significant difference in row spacing treatments at the maturity stage, with significant difference between the two row spacing treatments being observed in BL of the middle and lower layers under D2 and D3 sowing rates. The spike number, grain number per spike, 1000-kernel weight, and grain yield of winter wheat among different treatments were the highest in R2D3, R2D1, R2D1, and R2D2, respectively. The 1000-kernel weight, grain number per spike and grain yield in R2 treatment were significantly higher than R1. In summary, the PAR interception in the middle and lower layers of winter wheat canopy was improved by changing row spacing, with positive consequence on the photosynthetic capacity of individual plant and population, PAR utilization and transformation efficiency, which finally increased biomass and grain yield. Therefore, optimizing the field structure and shaping the ideal population photosynthetic structure should pay more attention during the high-yield cultivation of winter wheat. Making full use of light resources per unit land area and excavating the photosynthetic production potential of crops were also critical to achieve high yield and efficiency. In this experiment, the population photosynthetic capacity, photosynthetic effective radiation utilization rate, and yield were the highest under the treatment of R2D2.

Evaluation of common bean varieties (Phaseolus vulgaris L.) to different row-spacing in Jimma, South Western Ethiopia.

This study evaluated the effect of row spacing on growth, yield and yield components of common bean varieties at Jimma. The objectives of the study were (i) to evaluate the best performed common bean variety (ii) to determine the optimum row spacing for different common bean varieties under the test environment. The experiment was laid out in randomized complete block design (RCBD) in factorial arrangement with three replications. A combination of three common bean Varieties (Nasir, Goberesha and Local Asendabo) and row spacing at four levels (30, 40, 50, 60cm) were used as experimental treatments. Leaf number was significantly varied between the varieties; whereas row spacing significantly influence leaf area index. The main effect of row spacing and the interaction effect did not show significant influence on both. Hundred seed weight and number of seed per pod were varied between the varieties and row spacing. Hundred seed weight was increased with row spacing. Pod number per plant, nodule number per plant, grain yield and harvest index was significantly affected row spacing, variety and their interactions. Grain yields increased with plant population assuming a parabolic curve to the plant density of both determinate varieties at 40cm row spacing. The highest yield for variety-Nasir and variety-Goberesha were observed at40 cm row spacing; whereas the highest yield for the local variety was recorded at 50 cm row spacing.

Row spacing, cultivar and fungicide application affect the incidence of soybean stem blight / Espaçamento entre linhas, cultivares e aplicação de fungicida afetam a incidência da seca da haste em soja

Brazil is a major soybean production country and cultivate yearly more than 36 million hectares. Several factors have been reported reducing soybean production and occurrence of diseases is one of the most important. Some diseases such as the pod and stem blight (Diaporthe phaseolorum var. sojae) can limit soybean yield by shortening plant cycle and reducing seed quality. Field experiments were conducted aiming to evaluate the effect of row spacing, soybean cultivar and fungicide application on the incidence of pod and stem blight on soybean. The trial was carried out twice, with planting date at 11/15/2012 and 12/15/2012, in Planaltina-DF, Brazil. Treatments were arranged in a split-split plot scheme obeying the randomized block design. The factors evaluated were row spacing (42, 60 and 75 cm), soybean cultivars ("Syn1180RR" and "Syn1080RR") and spray or not the fungicide Boscalid (500 g a.i./ha) at R1 and R3 soybean growth stages. Disease incidence was assessed on stems at the harvest time and on seeds after harvest and yield was estimated. Results obtained show that broader row spacing increased disease incidence on stems and seed, cultivar "Syn1180RR" was more susceptible than "Syn1080RR" and fungicide application reduced disease incidence. Pod and stem blight significantly reduced soybean yield.

O Brasil é um dos principais países produtores de soja e cultiva anualmente mais de 36 milhões de hectares. Diversos fatores têm sido relatados reduzindo a produção de soja e a ocorrência de doenças está entre os mais importantes. Algumas doenças como a seca da haste e da vagem (Diaporthe phaseolorum var. sojae) podem reduzir a produtividade pelo encurtamento do ciclo e redução na qualidade da semente. Experimentos de campo foram conduzidos com o objetivo de avaliar o efeito do espaçamento entre linhas, cultivares e aplicação de fungicida sobre a incidência da seca da haste e da vagem na soja. O experimento foi conduzido duas vezes, com semeadura da soja em 15/11/2012 e 15/12/2012, em Planaltina-DF, Brasil. Os tratamentos seguiram o esquema de parcelas sub-sub-divididas no delineamento de blocos ao acaso. Os fatores avaliados foram espaçamento entre linhas (42, 60 e 75 cm), cultivares de soja ("Syn1180RR" e "Syn1080RR") e aplicação ou não do fungicida Boscalida nos estádios R1 e R3 da soja. A incidência da doença em hastes e sementes e a produtividade da soja foram mensurados. Os resultados obtidos mostram que espaçamentos mais amplos favorecem maior incidência da doença em hastes e sementes, a cultivar "Syn1180RR" é mais suscetível do que a "Syn1080RR" e a aplicação de fungicida reduz a incidência da doença. A seca da haste e da vagem reduz significativamente a produtividade da soja

Comportamento ingestivo de novilhas de corte em pastagem de sorgo forrageiro implantada com diferentes arranjos populacionais / Ingestive behavior of heifers in sorghum implanted with different population arrangements

O objetivo do presente estudo foi avaliar os efeitos da implantação de pastagem de sorgo forrageiro com diferentes arranjos populacionais no comportamento animal e na estrutura do pasto e de suas relações. Os tratamentos foram a combinação de dois espaçamentos entrelinhas e duas densidades de sementes ha-1, sendo 22 ou 44cm entrelinhas e 12 ou 24kg de sementes ha-1. Foram utilizadas 36 novilhas, com idade e peso corporal inicial de 15 meses e 262kg, respectivamente. Os tratamentos E44D24 e E22D12 apresentaram maior tempo de pastejo (469,33 e 467,78 minutos, respectivamente). Os animais do tratamento E44D24 apresentaram menor taxa de bocado (23,99 bocados minuto-1) em relação ao tratamento E22D24 (32,45 bocados minuto-1). Os animais do tratamento E44D12 apresentaram maior número de estações alimentares minuto-1 (9,21) e maior taxa de deslocamento (11,76 passos minuto-1). O espaçamento entrelinhas de plantio de 22cm aumenta o número de bocados estação-1. O aumento na densidade de sementes (24kg ha-1) e a utilização de maiores espaçamentos entrelinhas de plantio aumentam a densidade de folhas nos estratos inferior (0-30cm) e superior (acima de 60cm) do pasto. Os tratamentos E44D12 e E22D24 apresentaram maiores quantidades de colmos no estrato superior do pasto.(AU)

The objective of the study was to evaluate the effects of sorghum pasture implantation with different population arrangements in animal behavior and pasture structure and their relationships. The treatments were the combination of two row lines and two seeds per hectare densities, 22 or 44cm between rows and 12 or 24kg ha -1 of seed. 36 heifers at 15 months of age and 262kg body weight were used. The E44D24 and E22D12 treatments showed higher time of grazing (469.33 and 467.78 minutes, respectively). The animals in E44D24 treatment had lower bit rate (23.99 bites minute -1 ) compared to treatment with E22D24, a higher bit rate (32.45 bits min -1 ). The animals in E44D12 treatment presented the largest number of stations minute -1 (9.21) and higher displacement rate (11.76 steps min -1 ). The row spacing of 22cm increases the number of bits station -1 . The increase in seed density and the use of larger planting row spacing's increase the leaf density of the lower (0-30cm) and higher stratum (above 60cm) of pasture. The E44D12 and E22D24 treatment have higher amounts of stems in the upper stratum of the pasture.(AU)

Architectural Response of Wheat Cultivars to Row Spacing Reveals Altered Perception of Plant Density.

Achieving novel improvements in crop management may require changing interrow distance in cultivated fields. Such changes would benefit from a better understanding of plant responses to the spatial heterogeneity in their environment. Our work investigates the architectural plasticity of wheat plants in response to increasing row spacing and evaluates the hypothesis of a foraging behavior in response to neighboring plants. A field experiment was conducted with five commercial winter wheat cultivars possessing unique architectures, grown under narrow (NI, 17.5 cm) or wide interrows (WI, 35 cm) at the same population density (170 seeds/m2). We characterized the development (leaf emergence, tillering), the morphology (dimension of organs, leaf area index), and the geometry (ground cover, leaf angle, organ spreading, and orientation). All cultivars showed a lower number of emerged tillers in WI compared to NI, which was later partly compensated by lower tiller mortality. Besides, the upper leaf blades were larger in WI. Finally the leaf area index at flowering showed little difference between WI and NI treatments. The rate of leaf emergence and the final leaf number were higher in WI compared to NI, except for one cultivar. Around the start of stem elongation, pseudo-stems were more erect in WI, while around the time of flowering, stems were more inclined and leaves were more planophile. Cultivars differed in their degrees of responses, with one appearing to prospect more specifically within the interrow space in WI treatment. Altogether, our results suggest that altering interrow distance leads to changes in the perceived extent of competition by plants, with responses first mimicking the effect of a higher plant density and later the effect of a lower plant density. Only one cultivar showed responses that suggested a perception of the heterogeneity of the environment. These findings improve our understanding of plant responses to spatial heterogeneity and provide novel information to simulate light capture in plant 3D models, depending on cultivar behavior.

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Using two peanut varieties Shanhua108 (early-maturing variety) and 780-15 (late maturing variety), a field experiment was conducted to investigate the influences of row-spacing of wheat (25 cm, 30 cm, 40 cm+20 cm) and two peanut cropping patterns (intercropped peanut with wheat, summer-sowing peanut) on yield components, photosynthetic characteristics, antioxidant system, and dry matter accumulation and transportation. The results showed that wide spacing form of wheat and wide-narrow row planting pattern increased the pod yield, kernel yield, leaf area index, total dry matter accumulation and photosynthetic capacity, as well as SOD, POD and CAT activities, but decreased the MDA content. There are no obvious differences of wheat yield between the two row-spacing. Intercropping system increased peanut yield compared with summer-sowing peanut, which were much higher for wide-narrow row planting pattern than row spacing of 25 cm or 30 cm. The wide-narrow row planting pattern increased the pod yield and kernel yield by 6.3%, 13.3% and 7.7%, 16.5% for Shanhua108 and 780-15 than those of row spacing of 30 cm, respectively. Wide-narrow row planting could enlarge photosynthetic area, improve the net photosynthetic rate, and increase total dry matter accumulation. Meanwhile, it could alleviate the contradictionbetween the plant individual and group, delay the senescence, and increase peanut yield.

Variáveis morfogênicas e estruturais de sorgo forrageiro implantado com diferentes arranjos populacionais sob pastoreio contínuo / Morphogenetic and structural variables of sorghum implanted with different population arrangements under continuous grazing

O objetivo do estudo foi avaliar os efeitos da utilização de diferentes arranjos populacionais na implantação de sorgo forrageiro nas características morfogênicas e estruturais do pasto. Os tratamentos foram 22 ou 44cm entrelinhas e 12 ou 24kg de sementes ha-1. O método de pastoreio foi contínuo. Foram utilizadas 36 novilhas, com idade e peso corporal médios de 15 meses de 262kg. As variáveis morfogênicas não foram influenciadas significativamente (P>0,05) pelos arranjos populacionais e pelos períodos de avaliação, sendo obtidos taxa de alongamento e senescência foliar de 1,43 e 1,11cm dia-1afilho-1, respectivamente, taxa de aparecimento foliar e intervalo de surgimento de folhas de 0,28 folhas dia-1afilho-1 e 3,81 dias, filocrono e duração de vida foliar de 72,99 e 351,68 graus dia, nessa ordem. As características estruturais do pasto foram influenciadas pelos períodos de avaliação. Do primeiro para o terceiro período de avaliação, foi verificada uma redução de 65,53% no número de folhas em alongamento e de 47,79% no número de folhas vivas.(AU)

The objective of the study was to evaluate the effects of using different population arrangements in the implementation of sorghum in the morphogenetic and structural characteristics of the pasture. The treatments were 22 or 44cm between rows and 12 or 24kg ha-1 of seed. The grazing method was continuous. The sample consisted of 36 heifers with an average age of 15 months and average body weight of 262kg. Morphogenic variables were not significantly influenced (P>0.05) by population arrangements and evaluation periods, elongation rate and leaf senescence of 1.43 and 1.11cm afilho-1 day-1 being obtained, respectively, and leaf appearance rate of leaf appearance leaves the range of 0.28 day-1 and 1afilho 3.81 days, phyllochron and leaf duration of life of 72.99 and 351.68 degree day, in that order. The structural characteristics of the pasture were influenced by evaluation periods. From the first to the third evaluation period, a reduction of 65.53% in the number of leaves in stretching and 47.79% in the number of living leaves was verified.(AU)

Can Row Spacing Influence Arthropod Communities in Soybean? Implications for Early and Late Planting.

Row spacing in agricultural systems can influence crop yield as well as pest and predator abundances. Soybean (Glycine max L. Merrill) growers in Maryland typically plant in narrow (∼19 cm), medium (∼38 cm), or wide (∼76 cm)-spaced rows, and there is a general lack of information on how these row-spacing schemes influence arthropod abundance and soybean yields. A study was conducted during two growing seasons to determine the effect of soybean row spacing and planting date (early and late) on soybean arthropods and yield. Despite a great deal of variation in arthropod responses to row spacing, and interactions between row spacing and study year, leaf-feeding herbivores were generally more abundant in narrow-spaced soybeans. All arthropod functional groups were more abundant, and yield was greater in early-planted soybeans relative to late-planted soybeans. Potential causes and implications of these finding are discussed.

Incidence and severity of white mold for soybean under different cultural practices and local meteorological conditions / Incidência e severidade de mofo-branco em soja sob diferentes práticas culturais e condições meteorológicas locais

The Sclerotinia sclerotiorum (Lib.) de Bary fungus is a necrotrophic and polyphagous pathogen with soybean crop as one of its most important hosts. However in order to occur epidemics caused by such a pathogen it is necessary that the climatic conditions, mainly air temperature and relative humidity be favorable to the occurrence and development of the disease. The current research aimed to assess the incidence and severity of S. sclerotiorum in soybean plants grown in Arapoti, PR, Brazil, as a function of different plant populations, row spacing, and microclimate. The experiment was conducted in a naturally infested area. The experimental design adopted was a randomized block in a factorial combination with 4 row spacing (0.35, 0.45, 0.60, 0.75 m) and 4 plant populations (150, 200, 250; 300 thousand plants per hectare), totaling 16 treatments and 4 replications. Throughout the current study we performed 4 assessments of incidence and severity. Local climatic conditions were favorable for the incidence and severity of the pathogen. Mean air temperature, rainfall, relative humidity and leaf wetness duration, monitored during all experimental period, favored the development of the pathogen in the experimental field. Yield and 100 seed weight did not show fluctuations as a function of variations on the incidence and severity of white mold in soybean crop fields. Nevertheless, crop yield was higher under a reduced spacing, whereas the 100 seed weight showed the highest values under the lowest plant population treatment.

O fungo Sclerotinia sclerotiorum (Lib.) de Bary é um patógeno necrotrófico, polífago que tem a planta da soja como um dos seus principais hospedeiros. Porém, para que ocorram epidemias em decorrência desse patógeno é necessário que as condições climáticas, principalmente de umidade e temperatura do ar, sejam favoráveis para a ocorrência e o desenvolvimento da doença. O presente trabalho teve como objetivo avaliar a incidência e severidade de S. sclerotiorum em plantas de soja cultivadas em Arapoti, PR, Brasil, em função de diferentes densidades populacionais, espaçamentos entrelinhas e microclima. O experimento foi conduzido em área naturalmente infestada. O delineamento experimental adotado foi o de blocos casualizados em esquema fatorial, combinando 4 espaçamentos entrelinhas (0,35; 0,45; 0,60; 0,75 metros) e 4 densidades populacionais (150, 200, 250, 300 mil plantas ha-1), totalizando 16 tratamentos e 4 repetições. Ao longo do experimento foram efetuadas 4 avaliações de incidência e severidade. A temperatura média do ar, precipitação, umidade relativa do ar e a duração do molhamento foliar, monitoradas durante todo o período experimental, foram favoráveis para o desenvolvimento do patógeno na área experimental. A produção e a massa de 1000 grãos não apresentaram oscilações em função das variações nos níveis de incidência e severidade de mofo-branco na cultura da soja cultivada na condição climática estudada. Contudo, a produtividade da cultura foi maior nos tratamentos com espaçamentos reduzidos. Já a massa de 1000 grãos apresentou maiores valores em tratamentos com reduzida densidade populacional.