Custo de produção e indicadores de rentabilidade da cultura do milho safrinha

The objective of this study was to evaluate the production cost and profitability of the second season corn crop in the Medio Paranapanema region, São Paulo State Brazil, under two technological levels (middle and high technology), crop 2008/2009, and compare the results with the 2006/2007 agricultural year. Effective and total operational cost as well as five profitability indicators were used. It was concluded that the high technology production cost for corn crop (direct seedling, sowing during the recommended period, use of simple hybrid seed, application of side-dressing fertilization, and treatment of seeds with different insecticides) was superior to the middle technology production cost (direct seedling, sowing after the recommended time, use of double hybrid seed, and no side-dressing fertilization). However, the average cost was inferior (US$ 8.5), due to a higher yield (4 t). The high technology corn crop was profitable (gross income and profitability index of 14% and 12%, respectively). For the middle technology crop, profitability indexes pointed out that the cropping system needs to be reevaluated by technicians and research institutions, regarding the adequate technical recommendations. Profitability indexes decreased considerably in both cropping systems. It was verified that, in relation to the 2006/2007 harvest period, the total operational cost increased for both technologies, mainly because of the increase of supplies prices.

Socio-economic vulnerability to natural disasters in Mexico: rural poor, trade and public response

Includes bibliography

Variabilidade espacial do estado nutricional do cafeeiro canephora visando o manejo localizado

Mapping the plant nutritional condition allows viewing different regions in a cropping area, providing the producers with different criteria to use foliar and soil fertilization. The aim of this study was to evaluate the spatial variability of the nutritional condition of canephora coffee (Coffea canephora Pierre ex Froehner) regarding the site specific management of foliar and soil fertilization. In a one hectare area 60 georeferenced points were sampled at irregular intervals. There were five plants in each sampled point; two pairs of leaves were removed from the lateral branches (3 rd and 4 th pairs from extremity to the basis) in the cardinal points of each plant, counting up 40 leaves per point. The foliar samples were chemically analyzed for the following nutrients: N, P, K, Ca, Mg, S, B, Cu and Zn. The same pattern of spatial dependence was presented with adjustment for K and B. Except for N and P, which presented random distribution, the other nutrients presented mild to severe spatial dependence justifying the geostatistical data analysis for making maps for differential and located, foliar and soil fertilizer application in coffee crop.

Utilização de componentes principais para analisar o comportamento do cafeeiro a pleno sol e sombreado

The aim of this work is to describe the behavior of coffee (Coffea arabica L.) grown for nine years under organic management systems in full sun and shaded by banana trees (Musa sp.) and Erythrina verna Vell., in Valença, RJ. We performed a joint evaluation of vegetative characteristics, nutritional content and yield, with the aid of a principal component analysis. Twelve treatments were arranged in a randomized block design with four replications in a split plot. The plots evaluated farming systems in full sun and shade, and the subplots consisted of the following varieties of coffee: Tupi IAC 1669-33, MG 6851, IAC 3282 Icatu, Catucaí 2SL, Obatã IAC 1669-20; lineage IAC IAC 144. After five years we assessed the following variables, height, stem and canopy diameter, leaf area, number of branches, number of nodes per branch, number of leaves present, the distance between nodes, the percentage of green,ripe and dried fruit, number of dead plants, number of plants with death of the apical bud, coffee yield, and foliar concentrations of N, P, K, Ca and Mg. A multivariate analysis efficiently discriminates the variables in full sun and shaded cropping systems. Shading increases the percentage of green fruit, leaf area, height, diameter, distance between nodes, number of leaves on the branches, number of branches and leaf N content, but does not reduce the level of productivity when the shade is adequate.

Improving the affinity of tomato grafted on Solanum torvum using an intermediate rootstock

Most of the interspecific rootstocks (Lycopersicum esculentum × L. hirsutum) used in grafted Spanish tomato crops are resistant to Meloidogyne nematodes, but the 'Mi' resistance gene does not work well at high soil temperatures. Ralstonia solanacearum is a bacterial disease usual in tropical areas, but recently identified with low incidence in several European countries. This disease could be controlled by grafting tomato on Solanum torvum, which is also resistant to Meloidogyne. However, S. torvum and tomato have low grafting affinity, which could be improved using an intermediate rootstock. Some cultivars of eggplant have a relatively good affinity with tomato and complete affinity with S. torvum. In this study we compared two tomato cultivars (one resistant to Verticillium dalihae, Fusarium oxysporum v. lycopersici race 2 and Meloidogyne spp., and one non-resistant) grafted onto 'Beaufort' (Lycopersicum esculentum × L. hirsutum), 'Torvum Vigor' (Solanum torvum) and also with an intermediate grafting of eggplant ('Cristal') between tomato and S. torvum, with nongrafted plants as controls. This arrangement was carried out in two cropping cycles (winter-spring and summer-autumn). In both cycles, plants grafted onto S. torvum, both single or double grafted, yielded less than those grafted onto 'Beaufort' or nongrafted plants. In the spring cycle, no differences were found between single and double-grafted plants using S. torvum rootstocks, but in the autumn cycle double grafted plants had higher yields than the single grafted plants. The severity of nematode infections, in terms of reducing yields, and/or hypothetical infections of Ralstonia, will determine the utility of this technique in tomato production.

Taxa de semeadura de Brachiaria brizantha consorciada com milho na incidência de plantas daninhas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Carbono orgânico e carbono residual do solo em sistema de plantio direto, submetido a diferentes manejos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Air-assistance in spray booms which have different spray volumes and nozzle types for chemically controlling spodoptera frugiperda on corn

The study aimed to evaluate the performance of air assistance in spray booms using different types of nozzles and spray volumes. We took into account spray deposits, fall armyworm control and crop corn performance in a narrow row cropping system. The experiment was carried out at the experimental area of Sao Paulo State University, Botucatu/SP, Brazil, during the 2008/2009 agricultural season, in randomized blocks with a factorial scheme (2×2+1) and four replications. Two spray nozzles (flat fan nozzle and hollow cone nozzle) were tested, combined with two air assistance levels in the spray boom (with and without air assistance) and a treatment control. In the experimental spraying, Spinosad insecticide was sprayed in amounts of 48 g active substance (a.s.)/ha. The air assistance in the spray boom increased the spray deposits in the V 4 growth stage of the corn plants. Moreover, the application of this technology showed higher efficiency on fall armyworm control, reaching a 100% level 15 days after spraying, in the V 10 growth stage of the plants. The hollow cone nozzle increased the spray deposit level on the corn plants compared with the flat fan nozzle, at growth stage V 4. However, the flat fan nozzle, combined with air assistance technology, was more effective for controlling fall armyworm in the same growth stage (V 4), although the hollow cone nozzle increased the deposit levels on the plants. All the technologies tested in the study promoted a reduction of plant damage from fall armyworm attack. Corn productivity is directly related to the control efficiency of fall armyworm.

Effects of spray nozzles and spray volume on spodoptera frugiperda management and narrow row corn performance

The high demand of pesticides in the production systems makes the application technology one of the main alternatives to optimize the products efficiency. In this context, the study aimed to evaluate the effects of spray nozzles and spray volumes on spraying deposits, armyworm control and crop corn performance in narrow row sowing system. The experiment was carried out at experimental area of Sao Paulo State University, Campus of Botucatu/SP, Brazil, during the 2009/2010 agricultural season, in randomized blocks with factorial scheme (2x2+1) and four replications. It was tested two flat fan spray nozzles (with and without air induction) combined with two spray volumes (100 and 200 L ha-1) plus a control treatment. There was no influence of spray nozzles (without air induction) in the spray deposits levels on plants. However, the flat fan nozzle with air induction was more effective on fall armyworm, with 100% of control against 47.84% from other at 15 days after spraying. The increase in the spray volume promoted high spray deposits (415.4 and 388.6 μL g-1 dry mass for flat fan nozzle with and without air induction, respectively at V10 growth stage) and consequently, the highest spray volume (200 L-1) was more efficient in the fall armyworm suppression, with 100% of control. All the technologies tested showed lower plant injury from fall armyworm. The insecticide sprayed with different technologies did not affect the parameters of plant height and leaf area index. The corn productivity was directly related with control efficiency of fall armyworm. © 2012 Academic Journals Inc.

Influência de diferentes sistemas de cultivo nos atributos físicos e no carbono orgânico do solo

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

Unidade amostral para determinação de massa média de frutos em lichieira em sistema orgânico e convencional

The experimental unit of measurement is a suitable technique to estimate the average character in evaluation, and experimentation should be well understood and executed, because the precision characterizes the quality of the inferences of the results. This research aimed to analyze the possibility to obtaining the quantity of fruit required for sampling of lychee plants, to determining the average mass of the fruits, with less sampling error. One hundred fruits were collected, in a hectare, in two cropping systems, conventional and organic, being one fruit per plant. From the data of fruit mass was used the Excel® to calculate the average fruit mass and number of fruits samples needed to represent the area of the producer. The results show that to achieve a sampling error of 10% for determining the average mass of fruit, 400 fruits should be collected for organic system and 370 for the conventional, while for 20% sampling error, it is necessary to collect 250 fruits per hectare in organic system and 220 in the conventional.

Performance of cultivars of crisp mini-lettuce with respect to ground cover and spacing, in three planting times

The planting of lettuce in greenhouses, as well as covering beds with a polyethylene sheet, is a viable technology, promoting improvements in microclimatic conditions of the environment. In view of the little information on mini-lettuce, the aim of this work was to evaluate the performance of three cultivars of crisp minilettuce ('Green Frizzly', 'Red Frizzly no. 1' and 'Red Frizzly no. 2') with and without ground cover, under different spacings (20 × 15 cm and 20 × 20 cm), in three planting times (1: November 16, 2004; 2: December 17, 2004; and 3: January 20, 2005). The study was conducted in a greenhouse at UNESP-FCAV, Jaboticabal-SP. The experiments were carried out using a randomized block design, following a 3 × 2 × 2 factorial scheme with 12 treatments and three repetitions. The characteristics evaluated were plant height (cm), head diameter (cm), fresh weight (g) and number of leaves per plant. Planting time 3 was shown to be favorable for all the characteristics analyzed. 'Red Frizzly no. 2' was found to be the most suited to planting time 1, and for planting times 2 and 3, this cultivar did not differ from 'Red Frizzly no. 1'. The factor ground cover was not found to affect the characteristics evaluated, and therefore, cultivation without ground cover is recommended. The spacing 20 × 15 cm was shown to be favorable, resulting in cultivation with the highest populations, thereby increasing productivity. Based on the results obtained and for the conditions in which the experiment was conducted, it can be concluded that: planting time 3 (January 20, 2005) was the most favorable; the cultivars 'Red Frizzly no. 2' and 'Red Frizzly no. 1' are adapted to all the planting times; and cultivation without ground cover using a spacing of 20 × 15 cm was the most suitable.

Rhizoctonia solani GA-3PT es el principal patógeno asociado con el chancro del tallo y la sarna negra de la papa en Colombia

Stem canker and black scurf diseases of potatoes are caused by the basidiomycetous fungus Tanatephorus cucumeris (ana-morphic species complex Rhizoctonia solani). Tese diseases have worldwide distribution wherever potato is grown but their etiology varies depending on the predominance of distinct R. solani anastomosis groups (AGs) in a particular area. Within the species complex, several AGs have been associated with stem canker or black scurf diseases, including AG-1, AG-2-1, AG-2-2, AG-3, AG-4, AG-5 and AG-9. Tis article reports on the most comprehensive population-based study, providing evidence on the distribution of R. solani AGs in Colombian potato fields. A total of 433 isolates were sampled from the main potato cropping areas in Colombia from 2005 to 2009. Isolates were assigned to AGs by conventional PCR assays using specific primers for AG-3, sequencing of the ITS-rDNA and hyphal interactions. Most of the isolates evaluated were assigned to AG-3PT (88.45%), and a few to AG-2-1 (2.54%). Te remaining isolates were binucleate Rhizoctonia (AG-A, E, and I). Pathogenicity tests on the stems and roots of different plant species, including the potato, showed that AG-3PT affects the stems of solanaceous plants. In other plant species, damage was severe in the roots, but not the stems. AG-2-1 caused stem canker of Solanum tuberosum cv. Capiro and in R. raphanistrum and B. campestris subsp. Rapa plantlets and root rot in other plants. Te results of our study indicated that R. solani AG-3PT was the principal pathogen associated with potato stem canker and black scurf diseases of potatoes in Colombia.

Reação de cultivares de cana-de-açúcar à broca do colmo

The objective of this study was to evaluate the reaction of ten sugarcane cultivars to Diatraea saccharalis under field conditions, using a randomized block design with treatments in factorial 2x10 with six replications. The first factor was represented by two levels of infestation (infested and not infested) by borer and the second one, by the ten sugarcane varieties (IAC87-3396, IAC91-1099, IACSP93-3046, IACSP94-2101, IACSP94-2094, IACSP94-4004, IACSP95-5000, IACSP96-3060, IACSP96-2042 and SP91-1115). The experiment was evaluated in two crop cycles: plant crop and first ratoon. All cultivars were attacked by the borer, being IACSP94-4004, IACSP96-2042 and SP91-1115 the most damaged cultivars with the highest infestation index. During the plant crop, plots infested by the borer presented higher fiber content than the ones not infested. During the first ratoon, non infested plants produced 10% less and presented lower purity and higher content of reducing sugars than the non-infested plants.

Upland rice growth and mineral nutrition as affected by cultivars and sulfur availability

A better understanding of the differential growth of upland rice (Oryza sativa L.) cultivars with increasing soil S availability could help improve rice yield under upland conditions. The objective of this study was to evaluate root and shoot growth and nutrition of upland traditional and modern rice cultivars as affected by S availability. The experimental design was completely randomized in a 3 (rates of S) × 3 (cultivars) factorial with four replications. Low availability of S in the soil reduces root and shoot development and the efficiency of N, P, and S uptake, as well as the concentration and content of these nutrients in rice cultivars. At 0 mg dm-3 of S, rice cultivars prioritize root growth over shoots, and the traditional cultivar does so with greater intensity. Our results suggested that more development of traditional cultivars under low S availability facilitates its adaptation in soils under this condition. On the other hand, the intermediate and modern cultivars are more responsive to S fertilization. Moreover, S fertilization allows significant increases in upland rice growth and must be considered in cropping systems aiming for high yields. © Soil Science Society of America.