Guar root and shoot growth as affected by soil compaction

Guar (Cyamopsis tetragonoloba L.) is commonly grown in arid lands, because of its high drought-tolerance. However, soil compaction may be a limiting factor to its growth. This study aimed to evaluate the guar growth, according to the soil penetration resistance (0.20 MPa, 0.33 MPa, 0.50 MPa, 0.93 MPa and 1.77 MPa, in a layer with depth between 0.15 m and 0.20 m), in a Rhodic Acrudox soil. The shoot and root dry mass, root length by the Q1/2 index (mechanical soil penetration resistance in which the root growth is reduced by 50 %) and root diameter were evaluated. The impairment of the guar shoot growth begins when the penetration resistance is greater than around 1 MPa. The soil compaction alters the distribution of guar roots in the soil profile, concentrating them in the 0.15 m layer, but it does not prevent roots from penetrating this layer and developing in depth. The root diameter increases in the compacted layer. A soil penetration resistance of up to 1.77 MPa does not influence the root length density below the compacted layer, as well as the total root length density of guar. Although the guar Q1/2 index is greater than 1.58, the shoot and root dry mass are impaired

Short-term effects of crop rotations on soil chemical properties under no-tillage condition

Abstract The use of crop rotation can provide sustainability for an agricultural production system by improving soil fertility and increasing nutrient use efficiency. Short-term changes in soil chemical properties were studied for different crop rotations and management of crop residues under no-till in Santa Helena, Paraná, Brazil. The investigated crops for the crop rotation were as follows: Pearl millet (Pennisetum glaucum), grass brachiaria (Brachiaria brizantha), forage sorghum (Sorghum bicolor) and sunn hemp (Crotalaria juncea), cropped in autumn-winter as well as an additional treatment in fallow ground (spontaneous weed). The crambe (Crambe abyssinica) was cropped in the winter on all plots. The subplots were divided into either absence or presence of straw mulch mechanical management on the soil surface (Triton © ). Soil samples were collected at depths of 0-10, 10-20, and 20-40 cm after crambe harvest. Crop rotation with forage sorghum significantly increased (p ≤ 0.05) the K + exchange (0.14 cmol c dm -3 ) and organic matter (21.8 g dm -3 ) contents in the 0-10 and 20-40 cm soil layers, respectively; however, crop rotations had no effect on other soil chemical properties under no-tillage condition. Mechanical management of crop residues had no significant effect on soil chemical properties

Comportamento de híbridos de milho segunda safra quanto à incidência de podridões na Região Oeste do Paraná

The objective of this study was to evaluate the incidence and influence of stalk rot and ear in cultivation of hybrid corn second crop in west region Paraná. The experiment was conducted in randomized block design with six transgenic corn hybrids (DKB 330PRO, P4285HX, P3646HX, 30F53HX, P3340HX and P3161HX) with four replications at spacing of 0.90 m between rows and 0.20 m between plants. The characteristics evaluated were: number of healthy and symptomatic plants, number of ears healthy and symptomatic and total number of spikes. After harvest, we assessed the length of ears healthy and symptomatic, bulk grain ears healthy and symptomatic, thousand grain weight of ears healthy and symptomatic, and grain mass per spike weighted, thousand grain weight and weighted productivity. The hybrid P3646HX showed 100% of plants with stem base rot (Colletotrichum graminicola) and soft rot cob (Erwinia chrysanthemi pv. Zeae) and 100% of ears with symptoms of soft rot, followed by hybrid 30F53HX, DKB 330PRO with 34.9 and 29.1% of ears with symptoms of soft rot respectively. The hybrid DKB330PRO showed healthy spikes and patients with superior size, resulting in less interference in the grain yield. The hybrid P3340 productivity was higher, with 7952 kg ha-1 , followed by hybrid 30F53HX and DKB330PRO. A positive correlation between agronomic characteristics and grain yield.O objetivo do presente trabalho foi avaliar a incidência e a influência de podridões de colmo e de espigas no cultivo de híbridos de milho de segunda safra na Região Oeste do Paraná. O experimento foi instalado em delineamento de blocos casualizados com seis híbridos de milho transgênicos (DKB 330PRO, P4285HX, P3646HX, 30F53HX, P3340HX e P3161HX) com quatro repetições em espaçamento de 0,90 m entre linhas e 0,20 m entre plantas. As características agronômicas avaliadas foram: número de plantas sintomatológicas e saudáveis, número de espigas saudáveis e sintomatológicas e número de espigas totais. Após a colheita, foram avaliados o comprimento de espigas saudáveis e sintomatológicas, massa de grãos de espigas saudáveis e sintomatológicas, massa de mil grãos de espigas saudáveis e sintomatológicas, além da massa de grãos por espiga ponderada, massa de mil grãos ponderada e a produtividade. O híbrido P3646HX apresentou 100% das plantas com sintomas de podridão da base do colmo (Colletotrichum graminicola) e podridão mole da espiga (Erwinia chrysanthemi pv. zeae) e 100% das espigas com sintomas de podridão mole, seguido dos híbridos 30F53HX, DKB 330PRO com 34,9 e 29,1% das espigas com sintomas de podridão mole respectivamente. O híbrido DKB330PRO apresentou espigas sadias e doentes com tamanho superior, repercutindo em menor interferência no rendimento final de grãos. O híbrido P3340 apresentou produtividade superior, com 7.952 kg ha-1 , seguido dos híbridos 30F53HX e DKB330PRO. Houve correlação positiva entre características agronômicas e a produtividade de grãos

Producción, composición química y acumulación de nutrientes de residuos de cereales de invierno manejados bajo sistema de integración agricultura y pecuaria

El objetivo del estudio fue evaluar la producción, composición química y la acumulación de nutrientes de los residuos de tres diferentes cereales de invierno manejados mediante el sistema de integración agricultura y pecuaria. El estudio se llevó a cabo en el otoño invierno de 2012, en un área de la Universidade do Oeste do Paraná - Campus Marechal Cândido Rondon (Brasil), con diseño en bloques al azar en bandas, con cuatro repeticiones. Los tratamientos consistieron en tres diferentes cereales de invierno (avena IPR 126, triticale IPR 111 y trigo 111 BRS Tarumã), con tres distintos manejos: Sin pastoreo, uno pastoreo y dos pastoreos. El pastoreo se llevó a cabo hasta que se alcanzar la altura residual de 15 cm de cada forraje, utilizando vacas de raza Holstein (holandés) con un peso promedio de 663 kg. Se determinaron la producción de paja, los niveles de acumulación de C, N, P, K, Ca, Mg y la relación C:N en los residuos de cereales de invierno después de la cosecha. La producción de paja fue superior en el manejo en lo cual no se realizó el pastoreo, asociado con los cultivos de la avena y del triticale. Los diferentes cereales de invierno utilizados influenciaran en los niveles de C y K, relación C:N y cantidad de C acumulada en la zona. Los manejos afectaran en la cantidad acumulada Ca, P y N. Las otras características estudiadas no se vieron afectados. Los resultados sugieren que el manejo, así como el cultivo utilizado, interfieren directamente en la cantidad y calidad de los residuos vegetales.The aim of this study was to evaluate the production, chemical composition, as well as the accumulation of residues of three different winter cereals, managed under integration of crop and livestock. The study was conducted in the autumn/winter of 2012 in experimental area of the Universidade Estadual do Oeste do Paraná – Campus Marechal Cândido Rondon in Dystrophic Oxisol (LVdf) with a randomized block design in slot scheme, with four repetitions. The treatments consisted of three different winter cereals (oat IPR 126, triticale IPR 111 and wheat BRS Tarumã) with three different managements: no grazing, one grazing and two grazing. It was performed until achieving a residual height of 15 cm of each one of the forages, using Holstein cows with an average weight of 663 kg. It was determined the production of biomass, the content and accumulation of C, N, P, K, Ca, Mg and the relation C: N in the residues of the winter cereals after harvest. The biomass production was higher in the management which grazing was not performed, associated with oat and triticale. The different used winter cereals influenced the C and K contents, in the C: N relation and in the amount of C accumulated in the area. The managements affected the accumulated amount of Ca, P and N. The studied characteristics were not influenced. The results suggest that the management used, as well as the used crop, directly interfere in the quantity and quality of plant residues.Objetivou-se com o trabalho avaliar a produção, a composição química, bem como, o acumulo de nutrientes, dos resíduos de três diferentes cereais de inverno, manejados sob sistema de integração lavoura pecuária. O trabalho foi desenvolvido, no outono inverno de 2012, em área experimental da Universidade Estadual do Oeste do Paraná - Campus Marechal Cândido Rondon, em LATOSSOLO VERMELHO Distroférrico (LVdf), com delineamento de blocos casualizados em esquema de faixas, com quatro repetições. Os tratamentos foram constituídos de três diferentes cereais de inverno (aveia IPR 126, triticale IPR 111 e trigo BRS Tarumã), com três diferentes manejos: sem pastejo, um pastejo e dois pastejos. O pastejo foi realizado até atingir a altura residual de 15 cm de cada forrageira, utilizando-se vacas da raça holandesa com peso médio de 663 kg. Foram determinados a produção de palhada, os teores e o acumulo de C, N, P, K, Ca, Mg e a relação C:N nos resíduos dos cereais de inverno, após a colheita dos mesmos. A produção de palhada foi superior no manejo em que não foi realizado o pastejo, associado com a cultura da aveia e do triticale. Os diferentes cereais de inverno utilizados influenciaram nos teores de C e K, relação C:N e na quantidade de C acumulado na área. Os manejos afetaram na quantidade acumulada de Ca, P e N. As demais características estudadas não foram influenciadas. Os resultados sugerem que o manejo empregado, bem como a cultura utilizada, interferem diretamente na quantidade e na qualidade dos resíduos vegetais

Frações químicas e oxidáveis da matéria orgânica do solo sob diferentes sistemas de manejo, em Latossolo Vermelho

The objective of this work was to evaluate soil quality from soil organic matter (SOM) chemical and oxidizable fractions in areas with different management systems. The study was carried out in the municipality of Guaira, in the west of the state of the Paraná, Brazil, in areas with different adoption times of the no-tillage system (NT; 6, 14, and 22 years), with succession scheme of soybean (summer) and corn/wheat (winter) crops, besides areas with 12 years under NT – in the same succession scheme – plus four years of Urochloa ruziziensis intercropped with maize (M+U), and with pasture and native forest. The chemical fractions of fulvic acid (FA),humic acid (HA), and humin (HUM) were evaluated, as well as the oxidizable fractions of MOS (F1, F2, F3, and F4), total carbon (TC), and carbon storage (C) in the humic fractions. Total carbon contents increased with the increasing adoption of time of SPD, especially from NT6 to NT22. Humin fraction predominance was observed, with movement of HA and FA in the 0.0–0.4 m soil depth. The oxidizable C fractions showed equilibrium in the distribution of C contents, with higher levels in the more labile fractions, at surface. The cultivation with succession of crops contributes to the increase in labile fractions, but not to the increase of the more recalcitrant fractions of C.O objetivo deste trabalho foi avaliar a qualidade do solo a partir das frações químicas e oxidáveis da matéria orgânica (MOS) em áreas com diferentes sistemas de manejo. O trabalho foi realizado no Município de Guaíra, no Oeste do Paraná, em áreas com diferentes tempos de adoção do sistema plantio direto (SPD, 6, 14 e 22 anos), com sucessão das culturas soja (verão) e milho/trigo (inverno), além de áreas com 12 anos de SPD – no mesmo arranjo de sucessão – mais quatro anos de cultivo de braquiária (Urochloa ruziziensis) consorciada com milho (M+B) e com pastagem e mata nativa. As frações químicas de ácido fúlvico (AF), ácido húmico (AH) e humina (HUM) foram avaliadas, bem como as frações oxidáveis da MOS (F1, F2, F3 e F4), o carbono total (CT) e o estoque de carbono (C) nas frações húmicas. Os teores de CT aumentaram com o tempo de adoção do SPD, principalmente entre SPD6 e SPD22. Verificou-se predomínio da fração HUM e movimentação de AH e AF na camada de 0,0–0,4 m de profundidade. As frações oxidáveis apresentaram equilíbrio na distribuição do conteúdo de C, com maiores teores nas frações mais lábeis, em superfície. O cultivo com sucessão de culturas contribui para o aumento das frações mais lábeis, mas não para o aumento das frações mais recalcitrantes do C

Short-term green manure effects on crambe yield and oil content

Abstract Crambe (Crambe abyssinica Hochst. ex R.E. Fries) is an oilseed crop that can be cultivated in tropical conditions and used for the production of industrial oil. While crambe is believed to be a suitable crop for no-tillage systems, identification of appropriate crop species to precede it is necessary to improve its grain yield and oil content. In this study, we aimed to assess the short-term effects of crop rotation on the grain yield and oil content of a crambe crop cultivated after spring-summer cover crops. The experiment was conducted on an Rhodic Hapludox soil in Santa Helena-PR, Brazil. The experimental design consisted of randomized blocks with four replications. The plots consisted of pearl millet (Pennisetum glaucum), grass brachiaria (Brachiaria brizantha), sorghum (Sorghum bicolor), sunn hemp (Crotalaria juncea) and a fallow area (spontaneous vegetation). Grain yield, oil content, and oil yield were measured. Crambe oil content was influenced by the cover crops. The use of crotalaria as predecessor species resulted in higher oil content, but the result did not differ from that observed in the fallow area. However, grain yield and oil content were benefited by the crotalaria cover crop in the short-term. Crambe looks promising as an alternative oilseed crop for South Brazil when seeded in autumn with crotalaria cover crop in Rhodic Hapludox

Yield of maize grown in succession to green fertilization

The use of previous crops which have the capacity of supplying nitrogen to maize by symbiotic fixation or nutrient recycling is important to yield maintenance. This study aimed at evaluating the yield of maize grown in succession to green fertilization. A completely randomized blocks design was used with four replications and the following treatments: maize grown on black oat, black oat + oilseed radish, black oat + white lupin, white lupin, crambe, spontaneous vegetation (fallow ground) and spontaneous vegetation (fallow ground) + topdressing nitrogen fertilization. Concerning grain yield, significant differences were observed among treatments. The maize grown on black oat + white lupin straw reached the highest yield (10,817 kg ha-1), resulting in a higher income and differing from the one grown on black oat and crambe straw and spontaneous vegetation. The use of white lupin, black oat + white lupin and black oat + oilseed radish showed to be a viable alternative for a higher grain yield, making the topdressing nitrogen fertilization unnecessary

Deep Soil Water Content and Forage Production in a Tropical Agroforestry System

Agroforestry systems integrating tree and forage growth are important for maintaining soil health but may change the soil’s physical-hydric properties. Our goal was to investigate the impact of introducing Eucalyptus trees into a pasture on the soil water content throughout the soil profile. The study was conducted in a 6-year-old agroforestry system where two species of Eucalyptus were introduced into a palisade grass pasture. Soil moisture was sampled at 0.0 (planting row), 2.0, 4.0, and 6.0 m (midpoint between tree rows) from the Eucalyptus tree rows. A monoculture palisade grass pasture was used as a control. The soil water content down to a depth of 50 cm was lowest in the tree row and increased with distance from the trees. In the Eucalyptus row, the soil water content in the 0–50 cm layer was lower than in the monoculture pasture. Agroforestry systems decreased the water content in the superficial layers of the soil in the rainy months; in the dry season, the soil water contents in all layers were similar between the Eucalyptus inter-rows. In most seasons, the agroforest systems reduced the forage production close to the Eucalyptus tree rows, up to 2 m from the trees, likely due to the soil water content decrease. Overall, this study showed that in tropical regions with sandy soils, the grass and trees’ competition must be considered when establishing integrated agroforestry systems in order to maximize the advantages and benefits of the diversified agroecosystem