Laércio Ricardo Sartor

Influência da luminosidade no comportamento de onze espécies forrageiras perenes de verão

Objetivou-se avaliar o comportamento de especies forrageiras (Brachiaria decumbens cv. Basilisk, Brachiaria brizantha cv. Marandu, Panicum maximum cvs. Tanzânia, Aruana e Mombaca, Hemarthria altissima cv. Florida; Paspalum notatum cv. Pensacola, Axonopus catharinensis, Cynodon sp. hibrido Tifton-85; Arachis pintoi cvs. Alqueire e Amarillo) submetidas a diferentes niveis de luminosidade produzidos por arvores de Pinus taeda (ceu aberto; 9 m entre linhas e 3 m entre arvores; e 15 m entre linhas e 3 m entre arvores). Avaliaram-se a producao de MS, a relacao lâmina foliar:colmo (L:C), o nivel de florescimento das plantas, os teores de PB e FDN e as variaveis meteorologicas e do solo, na projecao da copa e no meio da entrelinha de arvores, de cada parcela. A producao de MS foi afetada negativamente pelo sombreamento, por outro lado, o teor de PB foi maior nas parcelas sombreadas em relacao ao pleno sol. Alem da menor radiacao, a velocidade do vento e a temperatura do solo nas parcelas sombreadas foram menores naquelas a sol pleno. O teor de FDN nao diferiu significativamente entre os niveis de luminosidade, embora a relacao L:C tenha sido maior na entrelinha do 9 × 3 em relacao aquela a ceu aberto. As especies forrageiras mais produtivas e com maior potencial para utilizacao em ambiente silvipastoril foram: Axonopus catharinensis e Brachiaria brizantha cv. Marandu.

Alelopatia de acículas de Pinus taeda na germinação e no desenvolvimento de plântulas de Avena strigosa

The purpose of this study was to verify the allelopathic effect of aqueous extract from the Pinus taeda needles on the germination and development of black oat (Avena strigosa) seedlings. The work was carried out at the Plant Physiology and Biochemistry Laboratory at the Federal Technological University of Parana (UTFPR), Campus Pato Branco, using a completely randomized design with factorial distribution in three replicates, under temperature, humidity and light controlled conditions. The extract from the pine needles was composed of five percentages (0, 25, 50, 75 and 100%) from the crude extract (EB) dilution, composed of distilled water + pine needles in vegetative stage (green needles), moderately decomposed (dry needles) and in advanced decomposition (decomposed needles). The germination percentage, average speed of germination, the length of the primary roots and the length from the seedlings roots of Avena strigosa were evaluated. The stage of green needles affected the variables studied and showed linearly effect with the increasing concentration of the crude extract.

Effect of swine residue rates on corn, common bean, soybean and wheat yield

Swine residue (SR) applied as nutrient source of crops such as corn, bean, soybean and wheat, besides representing an environmental-friendly way of disposing of organic waste resulting from swine production, may significantly increase grain yields, replacing mineral fertilizer. The objective was to evaluate the effect of SR rates on corn, common bean, soybean and wheat yields from 2002 to 2007, in comparison with mineral fertilizer. The experiment was carried out at the Instituto Agronomico do Parana - IAPAR, Pato Branco, PR and consisted of increasing SR rates (0, 15, 30, 45, and 60 m3 ha-1) and one treatment with mineral fertilizer (NPK 4-30-10), using 250 kg ha-1 for bean and 300 kg ha-1 for corn, soybean and wheat. Also, in the treatment with mineral fertilizer, 60, 120 and 90 kg ha-1 N was applied as topdressing to bean, corn and wheat, respectively. There were significant increases of grain yield in all evaluated years and crops with increasing SR rates, especially in the grass species under study. Also, with increasing SR rates applied every six months, K, P, Ca and Mg were accumulated in the soil and the pH increased. The application of 60 m³ ha-1 SR increased yields and exceeded the yield obtained with the recommended mineral fertilizer, indicating this amount as adequate for these crops.

Efeitos de diferentes intensidades de pastejo em pastagem nativa melhorada sobre o desempenho animal

A grazing trial was carried out to evaluate the effect of two forage masses on the animal yield from natural pasture over-sown with exotic legumes species (white clover - Trifolium repens, red clover - Trifolium pratense and birdsfoottrifoil - Lotus corniculatus). The grazing method consisted of a variable continuous stocking rate over the period from July 2003 to April 2004. The experimental treatments were two forage masses: low forage mass (LFM) (1,021 kg of DM/ha) and high forage mass (HFM) (1,751 kg of DM/ha). Pasture and animal evaluations were accomplished nearly at 30 days intervals. Heavy treatment ´ experimental period interaction was observed for the stocking rate that showed an average of 690 and 437 kg of DM/ha to LFM and HFM respectively. Forage mass affected the animal average daily gain estimates of 480 and 262 g/animal/day for HFM and LFM, respectively, but had no effect on animal body weight yield per unit of land area estimates of 231 and 207 kg/ha for the LFM and HFM, respectively. These results point out that the improved natural pasture management must be accomplished under herbage mass valus near to 1,700 DM/ha, because it maintain good weight gain rate.

Desempenho de forrageiras hibernais sob distintos níveis de luminosidade

Possible effects of brightness restriction, obtained by different Pinnus taeda tree densities, on the production and quality of black oat (Avena strigosa Schreb) cv. Common, white oat (Avena sativa L.) cv. FAPA 2, annual ryegrass (Lolium multiflorum L.) cv. Common, hairy vetch (Vicia villosa), wheat (Triticum aestivum L.) cv. dual purpose BRS Taruma were studied. It was evaluated three brightness levels: 1 - full sunlight with no trees; 2 - 30% of radiation restriction, using 15 × 3 m spacing between trees (222 trees/ha), and; 3 - 60% of radiation restriction, using 9 × 3 m between trees (370 trees/ha). It was performed evaluations of forage production, chemical composition and structural component of plants, water potential of the plants, soil moisture, microclimate variables and production of needles. The experimental design was completely randomized blocks, in split-plots and three replicates. Ryegrass was the most productive species at all brightness levels, although hairy vetch showed the lowest reduction on production under shading. There was higher water potential in the plants and higher soil moisture under shading, however, forage production was significantly reduced in the most intense shading (81%). Chemical composition and structural components of all studied forage species are also affected by brightness restriction increase.

Nitrogen fertilizer use efficiency, recovery and leaching of an alexandergrass pasture

Nitrogen usually determines the productive potential of forage crops, although it is highly unstable in the environment. Studies on recovery rates and use efficiency are important for more reliable fertilizer recommendations to reduce costs and avoid environmental pollution. The purpose of this study was to evaluate N use efficiency and recovery rate of Alexandergrass pasture (Brachiaria - Syn. Urochloa plantaginea) as well as N-NO3- and N-NH4+ soil concentrations using different levels of N fertilization under two grazing intensities. The experiment was arranged in a randomized block design in a factorial scheme with three replications. Treatments consisted of three N rates (0, 200 and 400 kg ha-1 N) and two grazing intensities termed low mass (LM; forage mass of 2,000 kg ha-1 of DM) and high mass (HM; forage mass of 3,600 kg ha-1 of DM) under continuous stocking and variable stocking rates. Results of N fertilization with 200 kg ha-1 were better than with 400 kg ha-1 N. There was a significant effect of N rates on soil N-NO3-concentration with higher levels in the first layer of the soil profile in the treatment with 400 kg ha-1 N. Grazing intensity also affected soil N-NO3- concentration, by increasing the levels under the higher stocking rate (lower forage mass).

Dynamic of a papuã pasture under two grazing intensities and two nitrogen levels

This work aimed to evaluate the effects of grazing intensities and nitrogen fertilization levels on the dynamics of a Brachiaria plantaginea pasture. The experiment was laid out as a random block design, in a 3 × 2 factorial scheme, composed of three nitrogen levels (0, 200 and 400 kg/ha nitrogen in urea form) and two grazing intensities termed low mass (LM; forage mass of 1500 kg of DM/ha) and high mass (HM; forage mass of 3000 kg of DM/ha) in a continuously stocked swards with two replications. Animals used were half-blood Boer goats averaging five months old and 21 kg body weight (BW) for adjustment of the target forage mass. Real forage mass, average height of the plants and animal stocking rates were of 2,567 and 3,862 kg DM/ha; 23.6 and 31.2 cm and 2,804 and 2,089 kg BW/ha respectively for low and high mass. Accumulation rate was of 100, 147 and 132 kg DM/ha/day and total production 13,659; 19,834 and 17,820 kg DM/ha, respectively to the 0, 200 and 400 kg N/ha. There were no differences on pasture yield among grazing intensities suggesting that higher stocking rates can be used. The level of 200 kg N/ha promotes the best response on papua grass pastures. Papua grass shows high yield, good production distribution during the plant cycle and excellent nutritional value.

Produção animal e de grãos de trigo duplo propósito em diferentes períodos de pastejo

The objective of this work was to evaluate the influence of different grazing periods on beef animal production and on wheat forage and grain yield. The experiment was carried out in Pato Branco, PR, Brazil. Six grazing periods were evaluated (0, 21, 42, 63, 84, and 105 days) on dual-purpose wheat cultivar BRS Taruma. Puruna steers, with average live weight of 162 kg and ten months of age, were kept under continuous grazing using a variable stocking rate, in order to maintain the established sward height of 25 cm. Greater increases in total animal gain (TAG) occurred with longer grazing periods. However, there was little increase after 63 days (490 kg ha-1), and TAG decreased from 552 to 448 kg ha-1 between 84 and 105 days. Grain yield decreased from 2,830 to 610 kg ha-1 when the grazing period increased from 0 to 105 days, but there was little change after 63 days (750 kg ha-1). Cultivar BRS Taruma shows excellent animal production potential, and the decision on how long wheat pastures should be grazed must be based on relative prices of grain and livestock.

Nitrogen Efficiency and Nutrient Absorption by a Sorghum-Oats Forage Succession

Balance between nutrient uptake by the crop and the amount of applied fertilizer is desired in a production system, and this measurement can predict the nutrient use efficiency. The present study aimed to evaluate nitrogen- (N-) use and recovery efficiency and extraction of N, phosphorus (P), and potassium (K) by sorghum (Sorghum bicolor) and black oat (Avena strigosa) forages under nitrogen fertilization in three consecutive crop cultivation. The experiment was carried out at Federal Technological University of Parana (UTFPR), Dois Vizinhos, Parana, Brazil, in Rhodic Hapludox soil. Treatments included 0, 37.5, 75, 150, 225, 300, and 375 kg N ha−1 applied to sorghum in the summer seasons of 2010/2011 and 2011/2012, intercalated by, respectively, 0, 40, 80, 120, 160, 200, and 240 kg N ha−1 applied to black oat in the winter/2011. Forage production, N, P, and K extraction, and N recovery efficiency were determined through samplings during the crop cycle. The highest sorghum forage production and N and K extraction were under 230 to 300 kg N ha−1, which was around 190 kg N ha−1 for black oat. The values of N recovery, efficiency, and N-use physiological efficiency were higher under lower N rates for both crops. Based on this, about 150 kg N ha−1 is recommended to obtain good sorghum forage production with higher N efficiency levels, which is about 120 kg N ha−1 for black oat.