Everardo Chartuni Mantovani

Produção e qualidade do tomate produzido em substrato, no campo e em ambiente protegido

The tomato (hybrid Carmen) fruit yield and quality in the FITO system were evaluated, using plastic bags containing organic compost + sand + nutrients, in the field and under unheated greenhouse conditions. Seven treatments were evaluated: 1) FITO, under unheated greenhouse, using perforated plastic bags, with 9 dm3 substratum per plant, containing 25% of organic compost and 75% of sand, all the macro and micronutrientes being added through trickle irrigation; 2) FITO A, similar to the previous treatment, except that only sand was used as substratum; 3) FITO 1, similar to FITO, except that the N and K were applied through trickle irrigation and the other nutrients were directly mixed in the substratum; 4) check plot in unheated greenhouse in which plants were directly transplanted in the soil; 5) FITO C, similar to FITO, except that the plants were cultivated under field condition; 6) check plot in unheated greenhouse in which plants were transplanted to the soil N and K being applied through trickle irrigation; 7) check plot with plants directly transplanted in the soil under field conditions. The experiment was conducted in randomized blocks design with four repetitions. There was no significant effect of treatments on N, Zn and Mn contents in leaf; in big and small sized fruits; in total fruit yield and fruit quality (pH, acidity, total soluble solids and vitamin C). Significant differences were found among treatments for leaf dry weight, medium, commercial and non-commercial production of fruits per day after transplantation (PCD). Significant differences were observed for P, K, Ca, Mg, S, Fe and Cu contents in leaves. The highest commercial, weighted and PCD yields, 104.79 t ha-1, 94,71 t ha-1 and 0.851 t ha-1 day-1, respectively, were obtained with the FITO system. However these values did not differ from those observed in the check plot using soil in the unheated greenhouse. FITO system can substitute the cultivation in the soil, either in the field or in unheated greenhouse.

Recovery of drippers clogged by use of water high in iron content

A study was carried out (Reciclean) to evaluate the efficiency of using the phosphoric acid, sodium hypochlorite, a commercial product and mechanical impact for cleaning the drippers in which the clogging was due to the presence of high iron content in water. The experiment was set up in the Vista Alegre Farm, located in Jaboticatubas County - Minas Gerais State. A drip irrigation system was adopted for the accomplishment of the tests. Eight treatments were tested, of which, seven with application of chemical products and one with mechanical impact. In accomplishing the chemical treatments, the phosphoric acid was used at pH 2 and 3, sodium hypochlorite at 100, 50 and 25 mg L-1 chlorine and Reciclean at 50 and 25 mg L-1. According to the results, the following conclusions were drawn: the treatment using the phosphoric acid at pH 2 provided the best results, when evaluating the improvement of uniformity in the irrigation system, since it showed the highest increase in the values of uniformity coefficients (CUD and CUC); however, it is an expensive treatment. The treatment with 25 mg L-1 chlorine presented the best benefit/cost relation, since it showed to be the cheapest besides being the second best in improving the uniformity of the irrigation system. The mechanical impact is a good alternative to recover the drip irrigation systems, principally under organic farming.

Avaliação do manejo de irrigação no Perímetro Irrigado de Pirapora, MG

The objective this paper was to evaluate the water management in the Pirapora Irrigation District in the State of Minas Gerais during 1999 to 2000. The irrigation demands of crops were simulated using the soil water balance for the entire district. The water volumes obtained in the simulations were monthly integrated and compared with the water volumes measured in the field by hydrometers. According to the results it may be concluded that, excessive water application occurred in the district, except for the months of January 1999, January, February, March and April 2000, when the crops were sub-irrigated. Thus, it is necessary to implant an irrigation scheduling program to optimize the water use.

Viabilidade de inserção dos efeitos da uniformidade de irrigação em modelos de crescimento de culturas

A study was designed to evaluate the effects of uniformity of sprinkler irrigation in maize and dry bean crops. For maize crop, the treatments consisted of five depths of water applied in two application uniformities: one high (CUC> 82%) and the other low (CUC<67%). For dry beans, the treatments consisted of four Christiansen application uniformity coefficients (CUC - 94.1, 85.6, 65.6 and 57.9%). A regression equation was adjusted for maize grain yield versus water application depth for high uniformity irrigation treatments, whereas for treatments with low irrigation uniformity in maize crop and for all treatments in dry beans the regression equations observed had very low values of R2. These data indicate that, it is impossible to introduce irrigation uniformity effects in crop growth simulation models

Avaliação da eficiência do uso da energia elétrica no Perímetro Irrigado de Pirapora, MG

The efficiency of electrical energy use was evaluated in the Pirapora Irrigation District, during the years of 1999 and 2000. The irrigation demand was simulated based on the soil water balance, considering an optimum irrigation management. The annual average energy consumption index for the irrigation district was determined using the water irrigation volume applied and the energy consumption in the pumping plants. With the simulated water volumes and the mean annual energy consumption index, the energy consumption was simulated for the condition of an ideal irrigation management. The simulated energy consumption was compared with the real one. According to the results it may be concluded that due to excessive water application the energy consumption was high. Thus, a good irrigation management program is needed to optimize the use of water and electrical energy in the Pirapora Irrigation District.

Influência da cobertura de resíduos de culturas nas fases da evaporação direta da água do solo

The effects of surface mulches from corn and wheat crop residues on the direct soil water evaporation stages were analyzed for two soils of different textural classes. The treatments consisted of three rates of crop residues, 0, 50 and 100% of the dry matter and three water evaporative demands. The bare soil water evaporation presented distinct behavior for the three tested water evaporative demands. For the water evaporative demand of nearly 3 mm d-1, the treatment with bare soil stayed in the first stage of evaporation rate, at least for the period of 21 days of the experiment. The concept U established by Ritchie (1972) to define the end of the first water evaporation stage, was not observed for the water evaporative demands of 5.2 and 3.0 mm d-1. For these demands, the soil stayed in the first evaporation stage during the data collection period of 21 days. For the residual rate of 100% of dry matter and for the corn and wheat cultivations, the evaporative demand had a modest influence in reducing the soil water evaporation, which on average varied 28% of the evaporation occurred in the treatment with bare soil, having significant difference among the residual rates, but did not occur differences between the two soil classes, for the water depth evaporated in 21 days.

Simulação da produtividade do milho pelo modelo CERES-Maize em função da lâmina e da uniformidade de aplicação de água

This study was carried out to compare the data simulated by CERES-Maize model, which is included into the package DSSAT 3.5, to the data obtained from an experiment set up in the field for evaluating the influence of the depth and uniformity of water application by a conventional sprinkler irrigation system on the yield of maize crop. The treatments consisted of five water depths applied with two uniformities, that is, a high (>80%) and a low one (<70%). The CERES-Maize model showed a high performance, when simulating the productivity, leaf area index, and dry matter for most of the treatments. The model underestimated the crop productivity in those treatments where a high water deficit occurred. For the treatments receiving a water depth higher than that known to be appropriate, the values simulated by the model were slightly higher than the experimental ones.

Análise da sensibilidade dos componentes da equação de Hargreaves - Samani para a região de Bebedouro - SP

The estimation of reference evapotranspiration (ETo) subsidizes the calculations of water consumption in irrigated agriculture. The use of simpler methodologies are common however should be carefully studied. The present study evaluated the sensitivity of the Hargreaves -Samani equation compared to the standard Penman-Monteith -FAO to estimate ETo for the climatic conditions of the Bebedouro-SP region, simulating the effects of increasing and decreasing 5 % in the temperatures, resulting in ten different scenarios (PM -Penman-Montheit -FAO; S0 -original Hargreaves Samani; S1 to S8 -modified Hargreaves Samani). The obtained results of sensitivity, linear regression, accuracy and concordance index, were compared. We concluded that the Hargreaves -Samani equation overestimates the monthly values of the ETo in 13% compared to the standard method. A variation of 5% in maximum and minimum temperatures resulted in errors of up to 1 mm day-1 (monthly average) and this increase is more expressive in maximum temperature.

Tarifa binômia para o custo de água pressurizada em perímetros irrigados

In irrigation districts, the variable cost tariff have being depended only on the amount of water consumed, and not in the energy and the demand for electric power to supply the water pressure and flow rate recommended by the irrigation system. This way of charge the irrigation water is nonsense, since the less efficient participants subsidized the more efficient ones. Thus, this work proposes that the water tariffs not only consider the amount of water consumed in the month, but also the pressure, since the hydraulic power demand is a function of the product of flow rate times the pressure. The study compared the water cost for participants that consume the same amount monthly for the present situation and the proposed methodology. It was verified, also, the effect of isolated irrigations or simultaneous ones and their implications on the water costs. The results showed that the implementation water tariff that charges the volume of water may reduce the costs for the participants at low pressures up to 66%. On the other hand, high pressure participants may have their water bill increased up to 133%. The simultaneity on the water use also influences its cost due to electrical power demand variation.

Estimate of the crop coefficient for Eucalyptus cultivated under irrigation during initial growth

The expansion in areas planted with eucalyptus crops has raised concern about the effects these may have on water resources and existing correlations between water use and crop productivity, which calls for better understanding of water requirements by plant species. The objective of this study was to determine the water requirements of an irrigated eucalyptus crop, having the estimated dual crop coefficient (dual Kc) as a reference. Mean values found for estimated crop coefficients were 0.57, 0.13 and 0.70 for Ke, Kcb and Kc respectively during initial growth stage, and 0.01, 0.81 and 0.82 for Ke, Kcb and Kc respectively during the mid-season stage. The methodology used in this study is not intended to replace field measurements for development of Kc curves. However, it provides a consistent method to evaluate values measured while providing means for estimating variations in values of Kc according to change in the soil fraction covered by vegetation.