Nitrogen fertilization and soil management of winter common bean crop

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Strategy of specification of management areas: rice grain yield as related to soil fertility

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Inter-relation between soybean yield and soil compaction under degraded pasture in Brazilian Savannah

As pastagens cultivadas do Cerrado brasileiro são responsáveis pela metade da produtividade da carne bovina destinada à alimentação da população, enquanto as culturas agrícolas o são pela terça parte de sua produtividade de grãos, desempenhando importante papel econômico-financeiro para o país. Dessa forma, no ano agrícola 2005/2006, na Fazenda de Ensino e Pesquisa da Faculdade de Engenharia de Ilha Solteira - FEIS/UNESP, foram estudadas a variabilidade e a dependência espacial entre atributos físicos do solo e a produtividade da soja, quando rotacionados após a pastagem degradada com Brachiaria, sobre um Latossolo Vermelho distroférrico. Também foram estudadas correlações lineares e espaciais entre esses atributos, apurando condições que proporcionassem aumento da produtividade agrícola. Para isso, na área com a referida pastagem instalou-se uma malha contendo 124 pontos amostrais, com espaçamentos de 10,0 x 10,0 e de 5,0 x 5,0 m entre eles, numa área total de 7.500 m². Dos pontos de vista linear e espacial, a elevada produtividade de grãos de soja pode ser explicada em razão do número de grãos por planta e da macroporosidade do solo. A alta variabilidade obtida na maioria dos atributos do solo denotou que a integração lavoura-pecuária é um sistema que proporciona heterogeneidade do ambiente físico do solo.

Seed size and genotype effects on maize (Zea mays L.) yield under different technology levels

Final plant population in maize crop was used as a basis to identify the technology level of a given farmer. Final population of 50,000 plants/hectare was considered as an indication of a high technology level farmer; 35,000 of a medium, and 20,000 of a low technology level farmer. These populations were artificially obtained for the hybrids HT-2X, BR-201, and BR-205 from small, medium and large seeds. The results showed the triple cross hybrid HT-2X to be the most indicated for low technology level regions, due to its lesser sensitivity to variations in seed size and also to its significant outyielding of the other two hybrids. The double cross hybrids BR-201 and BR-205 exhibited much higher sensitivity to variations in seed size so that if they have to be used in a low technology region, the most recommended procedure would be to make use of the largest possible seeds. In conclusion, genotype and seed size seem to be factors capable of compensating for plant population reductions in maize crops. The more prolific hybrids and the largess seeds are more indicated for low technology level regions.

Nitrogen management in maize cover crop rotations

Winter cover crops can affect N nutrition of the following maize crop. Although legumes have been recommend for maize rotations, in tropical areas grasses may be more interesting because they provide a longer protection of soil surface. Legumes can add N to the system and grasses can compete with maize for the available nutrient. An experiment was conducted in Botucatu, São Paulo State, Brazil, to study N dynamics in the soil surface straw-maize system as affected by N fertilization management and species included in the no-till rotation. Treatments were fallow, black oat (Avena strigosa), pearl millet (Pennisetum glaucum), white lupins (Lupinus albus), black oat fertilized with N. and pearl millet fertilized with N. Maize was grown afterwards in the same plots, receiving 0.0, 60.0 and 120.0 kg ha(-1) of N sidedressed 30 days after plant emergence. Soil, straw and maize samples were taken periodically. The highest corn yields were observed when it was cropped after pearl millet fertilized with N. Nitrogen side dressed application up to 120 kg ha(-1) was not able to avoid corn yield decrease caused by black oat. Grasses can be recommended in maize rotations in tropical areas, provided they receive nitrogen fertilizer and show no allelopathy. Due to its higher ON ratio and dry matter yield they are better than legumes, protecting the soil surface for a longer period. Pearl millet is particularly interesting because it enhances N use efficiency by the following maize crop. For a better N availability/demand synchronism, the cover crops should be desiccated right before maize planting.

Popcorn (Zea mays L. var. everta) yield and yield components as influenced by the timing of broadcast flaming

Farmers are interested in producing popcorn under organic production systems and propane flaming could be a significant component of an integrated weed management program. The objective of this study was to collect baseline information on popcorn tolerance to broadcast flaming as influenced by propane dose and crop growth stage at the time of flaming. Field experiments were conducted at the Haskell Agricultural Laboratory of the University of Nebraska, Concord, NE in 2008 and 2009 using five propane doses (0, 13, 24, 44 and 85 kg ha(-1)) applied at the 2-leaf, 5-leaf and 7-leaf growth stages. Propane was applied using a custom-built research flamer driven at a constant speed of 6.4 km h(-1). Crop response to propane dose was described by log-logistic models on the basis of visual estimates of crop injury, yield components (plants m(-2), ears plant(-1), kernels cob(-1) and 100-kernel weight) and grain yield. Popcorn response to flaming was influenced by the crop growth stage and propane dose. Based on various parameters evaluated, popcorn flamed at the 5-leaf showed the highest tolerance while the 2-leaf was the most susceptible stage. The maximum yield reductions were 45%, 9% and 16% for the 2-leaf, 5-leaf and 7-leaf stages, respectively. In addition, propane doses that resulted in a 5% yield loss were 23 kg ha(-1) for the 2-leaf and 7-leaf and 30 kg ha(-1) for the 5-leaf stage. Flaming has a potential to be used effectively in organic popcorn production if properly used. (C) 2010 Elsevier Ltd. All rights reserved.

Growth and yield analysis in different methods of beet (Cv. 'tall top early wonder') plantation

This objective of this study was to evaluate the effects of different methods of red beet seedling production and direct sowing on the development of the plant in field conditions. 'Tall Top Early Wonder' was used as the cultivar. The experimental design was a randomized blocks with 4 replications of each treatment: T1 - seedling produced in trays of 288 cells; T2 - 200 cells; T3 - 128 cells; T4 - 128 cells; T5 - direct sowing and T6 - bare-root seedling. The seedlings produced in trays and bare root seedlings were transplanted in the field 28 DAS with spacing of 0.20 x 0.10m. The mean height of plants, leaf area, leaf dry matter, petiole dry matter, shoot dry matter, root dry matter, relationship between shoot dry matter and root dry matter, absolute growth rate, relative growth rate, net assimilation rate, leaf area ratio and specific leaf area were determined. Storage root fresh matter and mean storage root diameter were determined starting from 77 DAS. Initial growth of the plants were superior for the direct sowing, resulting in smaller RGR and NAR than the other treatments. Independent of the production method, an increase of the cycle of the crop was verified. T6 had larger delay in the initial development. There was no difference for productivity. Method T1, had less expenses with respect to substrate and space in the vegetation home, without reduction in production.

Total and harvest-date yield of processing tomato cultivars

The productivity of 28 tomato cultivars was evaluated over three stages of harvest. The study was carried out during from June to December of 1999 in an open field at the experimental area of the Section of Olericulture and Aromatic Medicinal Plants, Department of Crop Production at FCAV-UNESP, Jaboticabal, SP, Brazil. The cultivars studied were H 7155, Hypeel, Andino, U 573, H 9036, IPA 6, H 9494, AG 33, Yuba, RPT 1294, AG 72, Pelmeech, Curico, Hypeel 45, RPT 1478, H 9492, H 9498, H 2710, Hitech 45, Halley, Botu 13, H 9553, U 646, NK 1570, AG 45, RPT 1095, RPT 1570, and PSX 37511. The experimental design was a randomized block design with four repetitions, with five plants per plot. Productivity was evaluated at three stages of harvest at 119, 149 and 179 days after seeding. There were no significant differences among the cultivars at the first harvest (119 days). The majority of the cultivars produced their highest yield at the second harvest; the most productive cultivars were Curicó and AG 72, which yielded 4.69 and 4.67 kg/plant, respectively, although they did not differ statistically from the cultivars Hypeel 45 (4.35 kg/plant) and H 9498 (4.16 kg/plant). Yields of the cultivars Andino and H 9494 were evenly distributed between the second and third harvests. At the third harvest, cultivar IPA 6 had the highest yield (2.9 kg/plant) and was statistically different from all other cultivars except H 9036 (2.34 kg). These two cultivars had the most delayed and concentrated maturity, making them suitable for mechanical harvesting, although at a later time. Cultivar AG 72 had the greatest total yield (5.76 kg/plant), but it was not statistically different from cultivars Hypeel 45 (5.43 kg), Curico (4.17 kg), H 9498 (4.83 kg), H 7155 (4.58 kg) and Halley (4.55 kg). All of the cultivars, with the exception of cultivars H 9036, IPA 6, Andino and H 9494 showed in the second harvest concentrated maturity, making it suitable for mechanical harvesting.

Sugar cane (Saccharum spp.) crop residue baling for energy purposes in Brazil

The sugar cane crop according to several authors can generate, besides the industrialized stalks, an amount of crop residues from the order of 15 to 30% in weight of the aerial part of the plants, depending on the field conditions. The sugar cane area in Brazil is around 5.5×106 hectares, with an amount of 400.106 tons of stalks, with stalks yield of 72 tons.ha-1 (Unica, 2005). This study took place in a sugar cane plot (Latitude 22°46'S, Longitude 47°23'W and 600m of altitude) with 3% of slope, located in São Paulo State. The sugar cane variety was SP 80-1816, in its forth cut, 11 months old and with a planted row spacing of 1.40m. By other side, several sugar mills are bringing the crop residue to their patio to produce energy with the bagasse. One way for that is the baling operation to bring the crop residue at the sugar mill. Some fundamental variables were obtained to define the best set of machines to work with in sugar cane crop residue removal in the baling system among the studied ones, some of the variables were: Soil Index (T1 = 0.83%, T2 = 0.46%, T3 = 0.65%, T4 = 0.57%); Energy Efficiency (T1 = 82.48%, T2 = 83.88%, T3 = 82.83% and T4 = 82.97%) of the system and Effective Cost for Equivalent Energy in US$.EBP-1 (T1 = 11.10, T2= 10.46, T3 = 11.47 and T4 = 10.57) of the baled trash delivered at the sugar mill.

Path analysis and expected response in indirect selection for grain yield in soybean

This study aimed to determine the best auxiliary trait for indirect selection of soybean grain yield, through path analysis and in avoidance of the adverse effects of multicollinearity and expected response. Seventy-nine F5 soybean genotypes from the cross FT-Cometa x Bossier were used. The populations were distributed on the field was the families inserted with replicated controls. Primary and secondary traits of grain yield were evaluated in four phenotypically superior plants per family. The traits number of pods, height and number of nodes were considered as the most important, showing the best combination of direct effect and genotypic correlation. The number of pods achieved the highest expected gain through the estimation method based on the selection differential. On the other hand, plant height, by the method based on selection intensity, was not a good indicator of the most productive plants.

Evaluation of yield advantage indexes in carrot-lettuce intercropping systems

The aim of this study was to estimate the effect of the association between carrot and lettuce crops in several intercropping systems through different yield advantage indexes, as well as to assess which system is better for the environmental resources management with respect to productivity and economic indicators. A 'group balanced block' experimental design was used, with four replications. Cultivars of lettuce crispleaf ('Lucy Brown', 'Tainá', 'Laurel' and 'Verônica') and looseleaf ('Babá de Verão', 'Maravilha das Quatro Estações', 'Elisa' and 'Carolina') groups were evaluated in intercropping systems with 'Alvorada' and 'Brasilia' carrot cultivars. The land equivalent ratio (LER) and yield efficiency index (YEI) were estimated, besides economic indicators such as gross (GI) and net (NI) income, modified monetary advantage (MMA), return rate (RR) and profit margin (PM). The evaluated indexes showed that carrot is the dominant and lettuce the dominated crop. Higher biological/agronomic efficiency indexes and economic indicators were observed in intercropping systems with 'Brasilia' carrot as component crop and that based on the crispleaf lettuce group.

Evaluation of different foliar fertilizers on the crop production of sugarcane

Influence of different foliar fertilizers (phosphite, micronutrients, biostimulant, phosphite + micronutrients, phosphite + biostimulant, micronutrients + biostimulant and phosphite + micronutrients + biostimulant) on yield of sugarcane was evaluated after fertilization at 30, 90 and 150 days after harvesting two-year-old sugarcane. The experiment was carried out in a commercial crop employing a randomized block design in four replicates. Higher stalk masses were observed for fertilization at 30 days after harvest, and the higher content of sucrose, total recoverable sugar and Brix degrees were observed for sugarcane fertilized after 150 days. Statistical analysis (Duncan's test) revealed no significant variation (P & 0.05) in Brix degree, sucrose content and total recoverable sugar. For total recoverable sugar x stalk weight (the main payment type for sugarcane producers), the following sequence (time treatment, fertilizer composition) 30-days, micronutrient + biostimulant; 150-days, biostimulant; and 90-days, biostimulant increased 11%, 17%, and 21% the yield of sugarcane. © 2013 Copyright Taylor and Francis Group, LLC.

Intercropping time of corn and palisadegrass or guineagrass affecting grain yield and forage production

Intercropping corn (Zea mays L.) with forages, such as palisadegrass {Urochloa brizantha (Hochst. ex A. rich.) r. D. Webster [syn. Brachiaria brizantha (Hochst. ex A. rich.) Stapf]} or guineagrass [Megathyrsus maximus (Jacq.) B. K. Simon & S. W. L. Jacobs (syn. Panicum maximum Jacq.)], provides large amounts of biomass for use as straw in no-tillage systems or as pasture. However, it is important to evaluate what time these forages have to be sown into corn systems to avoid reductions in both corn and forage production. This study, conducted for three growing seasons at Botucatu, Brazil, evaluated nutrient concentration and yield of corn as affected by time of forage intercropped as well as forage's dry matter production. our data showed that intercropping systems did not reduce leaf nutrient concentrations and grain yield of corn in relation to sole corn. The simultaneous intercropping of corn and guineagrass resulted in the lowest plant population (51, 200 plant ha-1), number of ears per plant (1.0), and, consequently, the lowest corn grain yield (9801 kg ha-1). Guineagrass seeded at the time of corn fertilizer topdressing resulted in the highest plant population (59, 400 plants ha-1), number of ears per plant (1.2), and corn grain yield (12, 077 kg ha-1). Forage production was highest when intercrop was done simultaneously. palisadegrass could be intercropped with corn both simultaneously or at topdressing fertilization stage. In contrast, it is recommended that guineagrass should only be intercropped with corn at topdressingfertilization. © Crop Science Society of America.

Sorghum grain yield, forage biomass production and revenue as affected by intercropping time

Sorghum is an excellent alternative to other grains in poor soil where corn does not develop very well, as well as in regions with warm and dry winters. Intercropping sorghum [Sorghum bicolor (L.) Moench] with forage crops, such as palisade grass [Brachiaria brizantha (Hochst. ex A. Rich) Stapf] or guinea grass (Panicum maximum Jacq.), provides large amounts of biomass for use as straw in no-tillage systems or as pasture. However, it is important to determine the appropriate time at which these forage crops have to be sown into sorghum systems to avoid reductions in both sorghum and forage production and to maximize the revenue of the cropping system. This study, conducted for three growing seasons at Botucatu in the State of São Paulo in Brazil, evaluated how nutrient concentration, yield components, sorghum grain yield, revenue, and forage crop dry matter production were affected by the timing of forage intercropping. The experimental design was a randomized complete block design. Intercropping systems were not found to cause reductions in the nutrient concentration in sorghum plants. The number of panicles per unit area of sorghum alone (133,600), intercropped sorghum and palisade grass (133,300) and intercropped sorghum and guinea grass (134,300) corresponded to sorghum grain yields of 5439, 5436 and 5566kgha-1, respectively. However, the number of panicles per unit area of intercropped sorghum and palisade grass (144,700) and intercropped sorghum and guinea grass (145,000) with topdressing of fertilizers for the sorghum resulted in the highest sorghum grain yields (6238 and 6127kgha-1 for intercropping with palisade grass and guinea grass, respectively). Forage production (8112, 10,972 and 13,193Mg ha-1 for the first, second and third cuts, respectively) was highest when sorghum and guinea grass were intercropped. The timing of intercropping is an important factor in sorghum grain yield and forage production. Palisade grass or guinea grass must be intercropped with sorghum with topdressing fertilization to achieve the highest sorghum grain yield, but this significantly reduces the forage production. Intercropping sorghum with guinea grass sown simultaneously yielded the highest revenue per ha (€ 1074.4), which was 2.4 times greater than the revenue achieved by sowing sorghum only. © 2013 Elsevier B.V.

Cover crop termination timing on rice crop production in a no-till system

Measuring shikimic acid accumulation in response to glyphosate applications can be a rapid and accurate way to quantify and predict glyphosate-induced damage to sensitive plants. The objective of this paper was to evaluate the effect of cover crop termination timing by glyphosate application on rice (Oryza sativa L.) yield in a no-till system. A factorial experiment, arranged in a split-plot design, was conducted for 2 yr. Treatments consisted of cover crops (main plots) and timed herbicide applications (subplots) to these cover crops (30, 20, 10, and 0 d before rice planting). There was a decrease in rice yield from 2866 kg ha-1 to 2322 kg ha-1 when the herbicide was applied closer to the rice planting day. Glyphosate application on cover crops increased shikimate concentrations in rice seedlings cultivated under palisade grass (Brachiaria brizantha), signal grass (B. ruziziensis), guinea grass (Panicum maximum), and weedy fallow (spontaneous vegetation) but not under millet (Pennisetum glaucum), which behaved similarly to the control (clean fallow, no glyphosate application). Glyphosate applications in the timing intervals used were associated with stress in the rice plants, and this association increased if cover crops took longer to completely dry and if higher amounts of biomass were produced. Millet, as a cover crop, allowed the highest seedling dry matter for upland rice and the highest rice yield. Our results suggest that using millet as a cover crop, with glyphosate application far from upland rice planting day (10 d or more), was the best option for upland rice under a no-tillage system. © Crop Science Society of America.