The effects of biochar and nitrogen application on yields of upland rice and cowpea and on soil fertility were determined in a greenhouse in Macaíba, RN, Brazil. The trial consisted of the succession of two crops in a completely randomized design and a factorial scheme, with four replicates. Initially, four doses of biochar and four doses of nitrogen were tested for cultivation of rice. Subsequently, four doses of biochar and two doses of nitrogen were tested in half of the pots maintained for planting cowpea. Soil was sampled after rice harvest for half of the pots and at end of the trial for the remaining pots. We evaluated the following parameters: mass of hundred grains of rice, dry shoot mass, panicle number, number of filled spikelets and of empty spikelets, and grain production. Determinations for cowpea were: pod number per pot, grain number per pod, and grain production per pot. Measured soil parameters were: pH, contents of organic carbon, P, K, Ca, Mg, Na, cation exchange capacity, and exchangeable sodium percentage. Biochar addition did not influence yield components of upland rice and cowpea, but resulted in increased soil N retention, which influenced rice dry shoot mass, spikelets sterility, panicle number, and grain mass. Biochar also promoted increased soil pH, potassium content, and exchangeable sodium percentage and decreased calcium and magnesium concentrations.

This study aimed to define areas suitable, and the irrigation water requirement for, cultivation of Tanzania guineagrass in the state of Ceará, Brazil. Tanzania guineagrass yield was estimated by a mathematical model, which considers the crop actual evapotranspiration, resulting from the crop climatological water balance. The water requirement throughout the year was estimated for soils with a water holding capacity of 20 (shallow soils), 40 (sandy soils), 60 (soils with medium texture) and 100 mm (clay soils). The relative frequency of occurrence of monthly productions greater than 2,750 kg DM ha-1 month-1 was obtained for different areas in Ceará, representative of most of the state's economic mesoregions. Tanzania guineagrass annual yields in the state of Ceará were between 20,000-30,000 kg DM ha-1 year-1. During the rainy season, the productive potential varies with the economic mesoregion, which presents different climatic conditions. The state of Ceará is only suitable for the rainfed production of Tanzania guineagrass for 4 months each year, predominantly from February to May, while weather conditions do not favor the development of this grass in the remaining months.

This paper aimed to assess tomato grafting on different solanaceous species through two grafting methods. Scions were cut from cultivar Santa Cruz Kada seedlings. A fully randomized experimental design was carried out with treatments in a 9 x 2 factorial scheme. As rootstocks, four accessions of mini - tomatoes (0224 - 53, RVTC 57, RVTC 20 and 6889 - 50 - Solanum lycopersicum L); two species of wild tomato ( Solanum habrochaites var hirsutum ‘PI - 127826’ and Solanum pennellii ‘LA716’); other two tomato species [ Solanum, cocona ( Solanum sessiliflorum ) and physalis ( Physalis peruviana )] and a control with cultivar Santa Cruz Kada (auto - graft) rootstocks were used. In addition, two grafting methods were evaluated full cleft and approach graft. Fifteen days after grafting, plants were assessed for graft - take percentage; root length; plant height; leaf number; foliar area; root, stem and leaf dry matter; and ratio between shoot and root dry matter. Based on the results, we may state rootstock and grafting interaction had effect on both graft - take rate and plant development. Overall, the studied plants should be recommended as rootstock, except for 6889 - 50 mini - tomato ( S. lycopersicum L.) and S. pennellii . Full cleft grafting was most suitable for cocona and physalis, while the approach method showed better results for the mini - tomato accessions 0224 - 53, RVTC 57 and RVTC 20, as well as for S. habrochaites .

The selectivity of five insecticides, regularly used in peach farming, was assessed for larvae of the predator Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae) by means of bioassay in semi-field conditions. The bioassay was based on the counting of captured larvae after release in peach trees treated with the insecticides (% of active ingredient in spray liquid): deltamethrin (0.001), fenthion (0.050), phosmet (0.100), lufenuron (0.005) and malathion (0.200). Bait-cards with eggs of Anagasta kuehniella (Zeller) (Lepidoptera: Pyralidae) were used to capture larvae from treated plants; five of them were fixed in plant canopy and five others left on the soil around stem. A protective barrier made up of galvanized steel sheet was used for each plant to avoid loss of larvae. The number of larvae feeding on the bait-cards was measured for four days. According to the number of captured larvae, each insecticide effect was estimated and classified into toxicity categories as stated by the International Organization for Biological and Integratec Control of Noxious Animals and Plants (IOBC). Based on observations, the insect growth regulator lufenuron was harmless, while the neurotoxins deltamethrin and malathion were slightly harmful; and lastly, fenthion and phosmet were moderately harmful to C. externa larvae in semi-field conditions. Thus, lufenuron should be recommended for integrated pest management, since it would preserve this predator species in peach orchards.

Cacao (Theobroma cacao L.) is an important fruit in the Brazilian economy, which is mainly cultivated in the southern State of Bahia. The optimal stage for harvesting is a major factor for fruit quality and the knowledge on its growth curves can help, especially in identifying the ideal maturation stage for harvesting. Nonlinear regression models have been widely used for description of growth curves. However, several studies in this subject do not consider the residual analysis, the existence of a possible dependence between longitudinal observations, or the sample variance heterogeneity, compromising the modeling quality. The objective of this work was to compare the fit of nonlinear regression models, considering residual analysis and assumption violations, in the description of the cacao (clone Sial-105) fruit growth. The data evaluated were extracted from Brito and Silva (1983), who conducted the experiment in the Cacao Research Center, Ilheus, State of Bahia. The variables fruit length, diameter and volume as a function of fruit age were studied. The use of weighting and incorporation of residual dependencies was efficient, since the modeling became more consistent, improving the model fit. Considering the first-order autoregressive structure, when needed, leads to significant reduction in the residual standard deviation, making the estimates more reliable. The Logistic model was the most efficient for the description of the cacao fruit growth.

Fruit thinning is the removal of fruitlets in heavy fruit set situations and aims to increase salable fruit sizes, avoid branch breakdown, reduce harvesting costs, and promote a balance between the vegetative and reproductive growth of plants. Furthermore, this procedure may improve coloring, increase soluble solids, and maintain plant vigor. This study aimed to evaluate the effects of fruit thinning in five varieties of lychee (Bengal, American, Mauritius, Sweet Cliff, and WB4), in the conditions of Jaboticabal - São Paulo state (Brazil). The experimental design was a completely randomized design (CRD) with five treatments and seven replications of three plants each. Treatments consisted of fruit thinning intensities characterized by the number of fruit left on terminal branch panicles, being T1: 3 fruits/branch; T2: 6 fruits /branch; T3: 9 fruit/ branch; T4: 12 fruits/branch; T5: no thinning (control plot). Evaluations were made through a colorimetric assay on ripe fruits, besides a physical and chemical analysis for each variety. The treatments affected the response of varieties on each studied variable. The variety “Mauritius” showed interesting physical and chemical characteristics for the consumer market.

Early blight (caused by Alternaria tomatophila ) is a major disease of tomato with no resistant cultivars. Thus, it is necessary to identify sources of resistance and productive genotypes for the development of new cultivars. Therefore, this study aimed to evaluate the productive potential of cherry tomato genotypes grown in the summer / fall, the severity of early blight on leaves and the incidence of disease in fruits. The treatments consisted of Carolina tomato genotypes, Cereja Vermelho, CH 152 and CLN1561A. The experimental design consisted of randomized blocks with six replications, and the experimental plot had 16 plants. The following characteristics were evaluated: area under the disease progress curve (AUDPC), average number of microinjuries on the fruits (MF), average number of fruits per bunch (NFC), average number of bunches per plant (NCP), average number of fruits per plant (NFP), average yield, number of fruits with incidence of early blight per plant (NFI) and the severity of early blight in leaves (%). The cherry tomato genotype CH152 showed tolerance to early blight with a smaller area under the disease progress curve, lower severity and fruits with incidence of A. tomatophila were not observed in this genotype. The CH152 had the highest number of fruits per bunch, greater number of bunches per plant, higher number of fruits per plant and higher productivity. This line has great potential of being integrated into breeding programs.

Cowpea has great socioeconomic importance in the northeastern part of Pará state. However, in order to provide suitable irrigation management during the dry period this region requires solid information regarding water demand by regional crops. This research aims to determine the water demand, the crop coefficient (Kc) and the uncoupling factor during the different development stages of cowpea in the northeast of Pará. The crop evapotranspiration (ETc) was measured by drainage lysimeters. This information was coupled to the reference evapotranspiration (ETo) to obtain the crop coefficients, which were used to adjust the model function of accumulated degree-days and the leaf area index (LAI). The uncoupling factor was estimated to indicate the factors that control evapotranspiration. The ETc values reached a cumulative total of 267.73 mm ± 10.21 mm during the cowpea cycle. The average value of the uncoupling factor was 0.66. This indicates that the cowpea crop does not fully uncouple from the atmosphere underneath the climatic conditions in northeast Pará. The cowpea Kc values presented averages of 0.8, 1.4 and 0.8 in the vegetative phase, reproductive phase and final stage, respectively. The Gaussian model showed an excellent fit for the estimation of Kc values based on accumulated degree days and the LAI. These amounts differ from others found in the literature. Therefore, it reinforces the necessity for an assessment of crop coefficients under local conditions and for the employment of more precise methods.

Water deficit at certain cotton growth stages can cause severe damage to crop development, affecting physiological processes and reducing reproductive structures, with consequent yield losses. The objective of this study was to evaluate the response of cotton cultivars under water deficit applied at different stages of the crop cycle. We compared the number of bolls per meter, cotton yield, and water use efficiency for eight different cotton cultivars under a water deficit of 15 days. We selected the following growth stages: Emergence (EM), First Square (FS), First Flower (FL), Peak Bloom (PB), and First Open Boll (FOB). The control treatment was irrigated with 100% ETc. The experiment was conducted in Apodi, RN State of Brazil, semiarid region, using a sprinkler irrigation system. The number of bolls per meter, cotton yield, and water use efficiency were influenced by the interaction of cultivars x deficit periods. Lowest values were observed for water suppression in the FL and PB stages. When the water deficit was imposed in the initial stages of growth (EM to FS) or after the FOB stage, the cotton yield reduction was not significant. At the same stage and water deficit, the behavior of the different cultivars was similar. Producers are urged to take this information into account when developing irrigation schemes for cotton crops, thereby avoiding water deficits during the most critical periods of the crop cycle.

Information on the recovering of areas of gravel extraction of the Caatinga biome are scarce. Thus, the objective of this work was to assess the soil fauna as bioindicator of soil quality, evaluating areas with addition of topsoil (WAT) and control areas (CWT) without the addition of topsoil used for forest plantations, which were implemented for recovering gravel extraction areas. A native forest of the Caatinga biome (NFC) was taken as a reference. Ten traps with three replicates were installed in each area, which were evaluated in a randomized block design in split - plot arrangement at the end of the rainy season of different years, 0, 1, 3 and 6 years after the experiment implementation. A total of 45,740 specimens were captured. These specimens were from 36 taxonomic groups. The Acari, Diptera, Entomobryomorpha, Formicidae, Poduromorpha and Symphypleona were the predominant groups in all areas (WAT, CWT and NFC). Nine groups (25% of the total) had restricted occurrence. The fauna richness and diversity were higher in the NFC, followed by the WAT and CWT. The uniformity and total abundance of the soil fauna community showed no defined patterns. The abundance of most groups was inhibited in the treatments evaluated, compared with NFC, however, this adverse effect was more significant in CWT compared with WAT. The CWT and WAT had high similarity and both had very low similarity with NFC. The ecological complexity of soil fauna community was higher in NFC. The soil fauna was efficient as a bioindicator of soil quality, which was higher in WAT, compared with CWT.