Water depths and nitrogen rates on sugarcane growth and dry biomass accumulation

Irrigation and soil fertilization management are essential agricultural practices that improve the growth and development of sugarcane plants and, consequently, increase their production capacity, which is important for sugar and alcohol productions. In this context, the objective of this work was to evaluate the effect of water depths and nitrogen rates on the growth and dry biomass accumulation of sugarcane plants. The treatments consisted in four water depths (1,498; 1,614; 1,739; and 1,854 mm), five nitrogen rates (0; 20; 40; 80; and 120 kg ha-1) and five evaluation times. The experiment was conducted in a randomized block design with a split-split-plot arrangement and four replications, including the factors water depths, nitrogen rates, and days after planting. The dry biomasses of the plant pointer, leaves and culms, culm diameter, plant height, and number of plants were analyzed. The application of nitrogen increased the sugarcane biomass, mainly the pointer (with leaves) and dry culm biomass, and the number of plants. The highest dry culm biomass accumulation and dry leaf biomass were found at the end of the crop cycle for the treatment with the application of nitrogen rates of 80 and 120 kg ha-1. The increases in water depths applied increased the number of plants per linear meter, but the culm and dry leaf biomass did not happen.

Mobility of Pratylenchus coffeae in segmented soil columns submitted to water flows and plant stimuli / Mobilidade de Pratylenchus coffeae no solo em colunas segmentadas submetidas a fluxos de água e estímulos vegetais

The root-lesion nematode Pratylenchus spp. causes a high-severity disease, promoting high economic losses in various crops of agricultural importance. The nematode control is difficult, especially after introduction into the area. Studies on the migration of this parasite in the soil are scarce. However, understanding nematode behavior in the soil is fundamental to increase the efficiency of management practices, especially in irrigated agriculture. This study aimed to evaluate the influence of water flow and plant stimulus on Pratylenchus coffeae mobility in segmented soil columns. The columns were segmented into 11 rings of 1 cm long filled with washed sand, one of the ends exposed to a bait, and submitted to flows of 0, 3, 7 cm3/min of water. Baits for nematode attraction and repelling consisted of sectioned tubers of yam (Dioscorea cayennensis) and cut leaves of neem (Azadirachta indica), respectively, and the absence of baits as the control. Nematodes were injected into the central segment of the column, and migration and presence in water leaching were determined five days after soil infestation. Mobility of P. coffeae varied with water flow and bait type. In the absence of water flow, nematodes migrated in the opposite direction to the neem baits, but migration was well distributed in the presence of yam baits, with specimens present in all column segments. The nematode had significantly higher resistance to water flow of 3 cm3/min in the presence of yam baits. No nematodes were found in the water leached at flows of 3 and 7 cm3/min in the absence of bait. (AU)

O nematoide das lesões radiculares Pratylenchus spp. causa doença de alta severidade promovendo elevadas perdas econômicas em inúmeras culturas de importância agrícola. O controle é difícil, principalmente depois de sua introdução na área. Estudos sobre a migração desse parasito no solo são escassos. No entanto, entender o comportamento do nematoide no solo é fundamental para aumentar a eficiência das práticas de manejo, especialmente em agricultura irrigada. O objetivo do estudo foi avaliar a influência do fluxo de água e do estímulo vegetal na mobilidade de Pratylenchus coffeae em colunas de solo. As colunas foram segmentadas em 11 anéis de 1 cm de comprimento, preenchidas com areia lavada, tendo uma das extremidades exposta à isca e submetida a fluxos de 0, 3, 7 cm3/min de água. As iscas para atração e afastamento do nematoide consistiram de túberas seccionadas de inhame (Dioscorea cayennensis) e folhas picotadas de nim (Azadirachta indica), respectivamente, e a ausência de iscas como testemunha. Os nematoides foram injetados no segmento central da coluna e a migração e lixiviação determinadas cinco dias após infestação do solo. A mobilidade de P. coffeae variou com fluxo de água e tipo de isca. Na ausência de fluxo de água os nematoides migraram em sentido contrário às iscas de nim, mas a migração foi bem distribuída na presença de iscas de inhame, com espécimes presentes em todos os segmentos da coluna. Quando aplicado fluxo de 3 cm3/min de água, P.coffeae ofereceu significativamente maior resistência ao fluxo na presença de iscas de inhame. Os nematoides não foram lixiviados nos fluxos de 3 e 7 cm3/min de água na ausência de isca.(AU)

Mobility of Pratylenchus coffeae in segmented soil columns submitted to water flows and plant stimuli / Mobilidade de Pratylenchus coffeae no solo em colunas segmentadas submetidas a fluxos de água e estímulos vegetais

The root-lesion nematode Pratylenchus spp. causes a high-severity disease, promoting high economic losses in various crops of agricultural importance. The nematode control is difficult, especially after introduction into the area. Studies on the migration of this parasite in the soil are scarce. However, understanding nematode behavior in the soil is fundamental to increase the efficiency of management practices, especially in irrigated agriculture. This study aimed to evaluate the influence of water flow and plant stimulus on Pratylenchus coffeae mobility in segmented soil columns. The columns were segmented into 11 rings of 1 cm long filled with washed sand, one of the ends exposed to a bait, and submitted to flows of 0, 3, 7 cm3/min of water. Baits for nematode attraction and repelling consisted of sectioned tubers of yam (Dioscorea cayennensis) and cut leaves of neem (Azadirachta indica), respectively, and the absence of baits as the control. Nematodes were injected into the central segment of the column, and migration and presence in water leaching were determined five days after soil infestation. Mobility of P. coffeae varied with water flow and bait type. In the absence of water flow, nematodes migrated in the opposite direction to the neem baits, but migration was well distributed in the presence of yam baits, with specimens present in all column segments. The nematode had significantly higher resistance to water flow of 3 cm3/min in the presence of yam baits. No nematodes were found in the water leached at flows of 3 and 7 cm3/min in the absence of bait.

O nematoide das lesões radiculares Pratylenchus spp. causa doença de alta severidade promovendo elevadas perdas econômicas em inúmeras culturas de importância agrícola. O controle é difícil, principalmente depois de sua introdução na área. Estudos sobre a migração desse parasito no solo são escassos. No entanto, entender o comportamento do nematoide no solo é fundamental para aumentar a eficiência das práticas de manejo, especialmente em agricultura irrigada. O objetivo do estudo foi avaliar a influência do fluxo de água e do estímulo vegetal na mobilidade de Pratylenchus coffeae em colunas de solo. As colunas foram segmentadas em 11 anéis de 1 cm de comprimento, preenchidas com areia lavada, tendo uma das extremidades exposta à isca e submetida a fluxos de 0, 3, 7 cm3/min de água. As iscas para atração e afastamento do nematoide consistiram de túberas seccionadas de inhame (Dioscorea cayennensis) e folhas picotadas de nim (Azadirachta indica), respectivamente, e a ausência de iscas como testemunha. Os nematoides foram injetados no segmento central da coluna e a migração e lixiviação determinadas cinco dias após infestação do solo. A mobilidade de P. coffeae variou com fluxo de água e tipo de isca. Na ausência de fluxo de água os nematoides migraram em sentido contrário às iscas de nim, mas a migração foi bem distribuída na presença de iscas de inhame, com espécimes presentes em todos os segmentos da coluna. Quando aplicado fluxo de 3 cm3/min de água, P.coffeae ofereceu significativamente maior resistência ao fluxo na presença de iscas de inhame. Os nematoides não foram lixiviados nos fluxos de 3 e 7 cm3/min de água na ausência de isca.

Relationship between soil organic matter and nematodes in sugarcane fields / Relações entre a matéria orgânica e os nematoides em área cultivada com cana-de-açúcar

Sugarcane plays an important socio-economic role in northeastern Brazil. However, the low yield in this region is associated with several factors (e.g. frequent occurrence of plant-parasitic nematodes). In order to observe the influence of soil organic matter on the nematodes, this study aimed to characterize the spatial nematode distribution in a sugarcane field. The study was carried out in Goiana - Pernambuco State (Brazil), fifty days after sugarcane cutting (10 days after vinasse application). The sampling scheme consisted of a regular 60 × 50-m grid, 10 m spaced, through 0 to 0.2 m depth. Spatial distribution was evaluated by semivariograms fit and performed by ordinary kriging interpolation for mapping. Exponential and spherical models promoted the best fit to semivariograms, resulting in ranges from 16 to 19 m. There was a strong negative correlation between soil organic matter and plant-parasitic nematode population density. Free-living nematodes had a similar distribution pattern as soil organic matter content. These results indicated that soil organic matter had important effects on spatial distribution of both plant-parasitic and free-living nematodes.(AU)

A cana-de-açúcar desempenha importante papel socioeconômico para o Nordeste Brasileiro. Por outro lado, a baixa produtividade nesta região está associada a diversos fatores, dentre estes, a relevante presença de nematoides fitoparasitas. A fim de verificar a influência da matéria orgânica sobre os nematoides, o objetivo deste estudo foi caracterizar a distribuição espacial da matéria orgânica e da nematofauna em área cultivada com cana-de-açúcar fertirrigada com vinhaça. O estudo foi realizado no município de Goiana, Zona da Mata Norte de Pernambuco, 50 dias após corte da cana (10 dias após aplicação da vinhaça). Utilizou-se um sistema de amostragem em malha regular de 60 × 50 m, com espaçamento de 10 m, na profundidade de 0-0,2 m. A distribuição espacial foi avaliada por meio de ajustes de semivariogramas e realizada interpolação por krigagem ordinária para mapeamento. O modelo esférico e o exponencial proporcionaram melhor ajuste aos semivariogramas, com alcances de 16 a 19 m. A matéria orgânica correlacionou-se negativamente com a população dos nematoides fitoparasitas. O mapeamento permitiu observar padrões de distribuição espacial similares entre as comunidades de nematoides de vida livre e a matéria orgânica. Esses resultados indicam que a matéria orgânica tem um papel importante na distribuição espacial dos nematoides fitoparasitas e de vida livre.(AU)

Relationship between soil organic matter and nematodes in sugarcane fields / Relações entre a matéria orgânica e os nematoides em área cultivada com cana-de-açúcar

Sugarcane plays an important socio-economic role in northeastern Brazil. However, the low yield in this region is associated with several factors (e.g. frequent occurrence of plant-parasitic nematodes). In order to observe the influence of soil organic matter on the nematodes, this study aimed to characterize the spatial nematode distribution in a sugarcane field. The study was carried out in Goiana - Pernambuco State (Brazil), fifty days after sugarcane cutting (10 days after vinasse application). The sampling scheme consisted of a regular 60 × 50-m grid, 10 m spaced, through 0 to 0.2 m depth. Spatial distribution was evaluated by semivariograms fit and performed by ordinary kriging interpolation for mapping. Exponential and spherical models promoted the best fit to semivariograms, resulting in ranges from 16 to 19 m. There was a strong negative correlation between soil organic matter and plant-parasitic nematode population density. Free-living nematodes had a similar distribution pattern as soil organic matter content. These results indicated that soil organic matter had important effects on spatial distribution of both plant-parasitic and free-living nematodes.

A cana-de-açúcar desempenha importante papel socioeconômico para o Nordeste Brasileiro. Por outro lado, a baixa produtividade nesta região está associada a diversos fatores, dentre estes, a relevante presença de nematoides fitoparasitas. A fim de verificar a influência da matéria orgânica sobre os nematoides, o objetivo deste estudo foi caracterizar a distribuição espacial da matéria orgânica e da nematofauna em área cultivada com cana-de-açúcar fertirrigada com vinhaça. O estudo foi realizado no município de Goiana, Zona da Mata Norte de Pernambuco, 50 dias após corte da cana (10 dias após aplicação da vinhaça). Utilizou-se um sistema de amostragem em malha regular de 60 × 50 m, com espaçamento de 10 m, na profundidade de 0-0,2 m. A distribuição espacial foi avaliada por meio de ajustes de semivariogramas e realizada interpolação por krigagem ordinária para mapeamento. O modelo esférico e o exponencial proporcionaram melhor ajuste aos semivariogramas, com alcances de 16 a 19 m. A matéria orgânica correlacionou-se negativamente com a população dos nematoides fitoparasitas. O mapeamento permitiu observar padrões de distribuição espacial similares entre as comunidades de nematoides de vida livre e a matéria orgânica. Esses resultados indicam que a matéria orgânica tem um papel importante na distribuição espacial dos nematoides fitoparasitas e de vida livre.

Spatial Dependence of Physical Attributes and Mechanical Properties of Ultisol in a Sugarcane Field.

This study investigates the effect of conventional tillage and application of the monoculture of sugar cane on soil health. Variables like density, moisture, texture, consistency limits, and preconsolidation stress were taken as indicators of soil quality. The measurements were made at a 120 × 120 m field cropped with sugar cane under conventional tillage. The objective of this work was to characterize the soil and to study the spatial dependence of the physical and mechanical attributes. Then, undisturbed soil samples were collected to measure bulk density, moisture content and preconsolidation stress and disturbed soil samples for classification of soil texture, and consistency limits. The soil texture indicated that soil can be characterized as sandy clay soil and a sandy clay loam soil, and the consistency limits indicated that the soil presents an inorganic low plasticity clay. The preconsolidation tests tillage in soil moisture content around 19% should be avoided or should be chosen a management of soil with lighter vehicles in this moisture content, to avoid risk of compaction. Using geostatistical techniques mapping was possible to identify areas of greatest conservation soil and greater disturbance of the ground.

Chemical attributes of soil fertilized with cassava mill wastewater and cultivated with sunflower.

The use of waste arising from agroindustrial activities, such as cassava wastewater, has been steadily implemented in order to reduce environmental pollution and nutrient utilization. The aim of this study is that the changes in chemical properties of dystrophic red-yellow latosol (oxisol) were evaluated at different sampling times after reuse of cassava wastewater as an alternative to mineral fertilizer in the cultivation of sunflower, hybrid Helio 250. The experiment was conducted at the Experimental Station of the Agricultural Research Company of Pernambuco (IPA), located in Vitória de Santo Antão. The experimental design was randomized blocks with 6 × 5 subplots; six doses of cassava wastewater (0; 8.5; 17.0; 34.0; 68.0; and 136 m(3) ha(-1)); and five sampling times (21, 42, 63, 84, and 105 days after applying the cassava wastewater), with four replications. Concentrations of available phosphorus and exchangeable potassium, calcium, magnesium and sodium, pH, and electrical conductivity of the soil saturation extract were evaluated. Results indicate that cassava wastewater is an efficient provider of nutrients to the soil and thus to the plants, making it an alternative to mineral fertilizers.