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Plastic mulches have been extensively used in tomato fields around the world; its use has been growing in Brazil, especially in semi-arid regions. However, whether plastic mulches are beneficial to tomato grown in the Brazilian semi-arid and should replace other traditionally used practices is little known. Two on-farm experiments were carried out aiming at assessing the yield response of 'Trucker' hybrid tomato to plastic mulching in interaction with other practices, viz, irrigation, earthing up, and plant population. The first experiment consisted of a randomized block design with six treatments arranged in a 3 x 2 factorial and replicated four times: three crop practices (earthing up, plastic mulching and bare soil) combined with two plant populations (12,500 and 10,416 plants ha-1). The second experiment was a randomized complete block design with four replications, in a splitplot arrangement. Irrigation levels (305, 440, 495, 610 and 725 mm cycle-1) were assigned to plots, and mulching and earthing up to subplots. Fruit diameter, fruit weight and crop yield were evaluated. Plastic mulching had no effect on crop yields and water-use efficiency at both experiments. Overall, the results suggest planting 'Trucker' tomato at 12,500 plants ha-1, 580-630 mm cycle-1 of irrigation, and without plastic mulching. [ABSTRACT FROM AUTHOR]

Copyright of Revista Brasileira de Agricultura Irrigada - RBAI is the property of Revista Brasileira de Agricultura Irrigada - RBAI and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Caatinga is the property of Revista Caatinga and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Agricultural Research in the Tropics / Pesquisa Agropecuária Tropical is the property of Pesquisa Agropecuaria Tropical and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aim of this study was to evaluate the agronomic performance of corn hybrids in three densities. The experimental design was randomized block in factorial 2x3 with four replications. No interaction between cultivars and density for any of the characters. Significant differences among hybrids, except for the number of rows of grain. The hybrid 2B707 showed greater height, ear length, number of kernels per row, ear weight and grain yield. The 2B710 hybrid overcomes 2B707 in ear diameter and grain weight. It was found that increasing the density a significant decrease in spike length, number of kernels per row and average ear weight. Also there was a decrease, but not significantly, with increasing density, the number of rows and weight of 100 grains. The ideal population was 55,000 plants where the yield was higher. [ABSTRACT FROM AUTHOR]

Maize does not have an effective mechanism to compensate empty spaces in the field. Therefore, tillering hybrids may be more efficient to use environmental resources, especially under low plant populations. This reserach was carried out aiming to evaluate the agronomic performance of maize hybrids grown at two plant densities, with and without tiller's presence. The experiment was set in Lages, SC, Brazil, during the 2005/ 2006 and 2006/2007 growing seasons. Three hybrids were tested: AS 1560, Penta and P30F53. Each hybrid was evaluated at the densities of 4 and 7pl m-2, keeping tillers until harvest or removing them when the crop had nine expanded leaves. The percentage of plants with tillers at four growth stages, grain yield and yield components were assessed. Hybrids P30F53 and AS 1560 produced more tillers than Penta at the density of 4pl m-2. Tillers destiny did not affect grain yield during the first growing season. In 2006/2007 tiller maintenance promoted higher grain yield than tiller removal for all hybrids at the lower plant density. The results of this work showed that tiller removal does not enhance maize agronomic performance. Furthermore, they demonstrated that tiller maintenance may increase grain yield when maize is grown under low plant densities. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Journal of Biology is the property of Instituto Internacional de Ecologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Despite being an important commodity, < 2% of the cotton cultivated area in Brazil is considered to be "low-input". A major reason for this relatively small area is infestation by boll weevils (BWs), Anthonomus grandis grandis Boheman, which are usually controlled using conventional synthetic-based insecticides. Cotton grown in low-input systems of Brazil lack an integrated pest management strategy. We hypothesized that the alteration in row spacing would act as a preventive cultural practice driving BW infestation down while improving lint production and fiber quality, thus justifying its adoption. We assessed the effects of three row spacings: 0.5 m (narrow), 0.75 m (conventional), and 1.0 m (wide) on boll weevil infestation levels, during two seasons in areas without the adoption of any control against BW. In both seasons, plants were surveyed for 23 successive weeks and shed structures were collected for 17-21 weeks. BW-infested and non-infested reproductive structures, number of BW, and yield parameters were assessed. Shed structures were kept for 21 days to assess BW emergence. The narrow row spacing was the least effective, and the conventional and wide spacings delayed boll weevil control interventions and resulted in fewer boll weevil-injured reproductive structures early in the season, and produced lower numbers of adult boll weevils without altering the quantity and improving the quality of lint and the financial returns obtained from a better quality lint. This is the first study to demonstrate the effect of row spacing on boll weevil infestations and inflicted injury in low-input systems. The results can also be applied to conventional cotton production systems. [Display omitted] • Boll weevil management can benefit from cultural control practices such as row spacing. • Row spacing of 0.5 m increases reproductive structures infestation and abcision. • 0.75 m and 1.0 m row spacings help on boll weevil management without altering yield. • Wider row spacings (0.75 m and 1 m) produced better quality lint. • Wider row spacings (0.75 m and 1 m) should be preferred over narrow row spacings (0.5 m). [ABSTRACT FROM AUTHOR]