Irrigation with domestic treated sewage and nitrogen fertilizing in sunflower cultivation

The objective of this study was to evaluate the productive performance of sunflower plants irrigated with different levels of domestic treated sewage and groundwater well with different doses of nitrogen. It was used randomized blocks design in split-split plots with four replications. In the plots, we evaluated the effect of two types of irrigation water, in the subplots we evaluated the five irrigation levels expressed as 25, 50, 75, 100 and 125% of the Class A pan Evaporation (CAE), and in the sub subplots, we evaluated the effect of four different doses of nitrogen (25, 50, 75 and 100 kg ha-1). The irrigation of sunflower with domestic sewage produced greater yield potential of grain and oil. The use of water from treated wastewater can replace up to 50 kg N ha-1 without affecting productivity. It is recommended for the commercial production of sunflower the use of treated sewage water with irrigation depth relative to 100% of CAE (296.64 mm) and nitrogen of 25 kg ha-1.

Growth and plant mass of radish fertirrigated with different doses nitrogen

ABSTRACT The objective of the present study was to evaluate the effect of nitrogen doses applied via fertigation and associated with different types of crop establishment fertilization on growth and biomass of radish. The experiment was conducted in a greenhouse of the Academic Unit of Agricultural Engineering, Federal University of Campina Grande, from April to May 2014. Treatments consisted of five doses of nitrogen fertilizer applied by fertigation (0, 0.7, 1.4, 2.1 and 2.8g per pot) and three types of crop establishment fertilization (humus 2:2; NPK and control), arranged in a 5 x 3 factor design with four repetitions. The 15 treatments were arranged in 60 plots. The nitrogen source used in the study was urea, divided in three applications: the first application was carried out eight days after transplanting, the second, on day 15, and the third, on day 22. The crop establishment fertilization significantly influenced the growth variables and plant mass of the radish on day 35 after transplanting. The highest values of the variables (number of leaves, plant height, bulb diameter, leaf area, fresh mass of the aerial part, dry mass of the aerial part and root/aerial part were observed in the treatment with humus on day 35 after transplanting. The dose of 2.8g nitrogen per pot corresponding to 6.22g of urea per plant provided the highest yield for the variable number of leafs, leaf area and root length on day 35 after transplanting.

Water Balance Components in Covered and Uncovered Soil Growing Irrigated Muskmelon

ABSTRACT Knowledge of the terms (or processes) of the soil water balance equation or simply the components of the soil water balance over the cycle of an agricultural crop is essential for soil and water management. Thus, the aim of this study was to analyze these components in a Cambissolo Háplico (Haplocambids) growing muskmelon (Cucumis melo L.) under drip irrigation, with covered and uncovered soil, in the municipality of Baraúna, State of Rio Grande do Norte, Brazil (05º 04’ 48” S, 37º 37’ 00” W). Muskmelon, variety AF-646, was cultivated in a flat experimental area (20 × 50 m). The crop was spaced at 2.00 m between rows and 0.35 m between plants, in a total of ten 50-m-long plant rows. At points corresponding to ⅓ and ⅔ of each plant row, four tensiometers (at a distance of 0.1 m from each other) were set up at the depths of 0.1, 0.2, 0.3, and 0.4 m, adjacent to the irrigation line (0.1 m from the plant row), between two selected plants. Five random plant rows were mulched using dry leaves of banana (Musa sp.) along the drip line, forming a 0.5-m-wide strip, which covered an area of 25 m2 per of plant row with covered soil. In the other five rows, there was no covering. Thus, the experiment consisted of two treatments, with 10 replicates, in four phenological stages: initial (7-22 DAS - days after sowing), growing (22-40 DAS), fruiting (40-58 DAS) and maturation (58-70 DAS). Rainfall was measured with a rain gauge and water storage was estimated by the trapezoidal method, based on tensiometer readings and soil water retention curves. For soil water flux densities at 0.3 m, the tensiometers at the depths of 0.2, 0.3, and 0.4 m were considered; the tensiometer at 0.3 m was used to estimate soil water content from the soil water retention curve at this depth, and the other two to calculate the total potential gradient. Flux densities were calculated through use of the Darcy-Buckingham equation, with hydraulic conductivity determined by the instantaneous profile method. Crop actual evapotranspiration was calculated as the unknown of the soil water balance equation. The soil water balance method is effective in estimating the actual evapotranspiration of irrigated muskmelon; there was no significant effect of soil coverage on capillary rise, internal drainage, crop actual evapotranspiration, and muskmelon yield compared with the uncovered soil; the transport of water caused by evaporation in the uncovered soil was controlled by the break in capillarity at the soil-atmosphere interface, which caused similar water dynamics for both management practices applied.

Quince 'CPP': new dwarf rootstock for pear trees on organic and high density planting

In Brazil, pear production presents the same incipient situation over the last 15 years, due mostly to low production technology. In this context, this study aimed to evaluate the development, growth and production of the pear tree cultivars Cascatense, Tenra and Hosui grafted on 'CPP' quince rootstock, using 'FT' pear as interstem. This trial was carried out in Guarapuava, State of Paraná, Southern region of Brazil, by five productive cycles. The pear trees were planted in September of 2004, spaced at 1.0 x 4.0 m (2,500 trees ha-1), trained to the modified central leader, on a Four-wire trellis, with drip irrigation and cultivated under organic production system. The following variables were evaluated: sprouting, anthesis, yield, fruit weight, soluble solids content, titratable acidity, pulp firmness, canopy area per plant and per hectare and trunk diameter. The pear tree cv. Tenra was outstanding most of the years for fruit yield, and, consequently, showed the highest accumulated yield over the period (51.6 t ha-1), followed by the cultivars Cascatense (39.7 t ha-1) and Hosui (18.7 t ha-1). All pear cultivars presented suitable physical-chemical characteristics for commercial purposes, with minimal average soluble solids content of 11% at harvest. The maximum canopy area per hectare was attained for cv. Cascatense (3063.2 m²), that was considered insufficient for a high yield. These results suggest the needs for studies with higher density planting and other training systems, searching optimize canopy volume. One of the most limiting factors in the organic pear orchard was the incidence of pear dieback caused by Botriosphaeria dothidea, severe more often in pear trees cv. Hosui.

New hosts of Oidiopsis haplophylli in the solanaceae family in Brazil

A powdery mildew disease was observed on leaves of Solanum gilo, S. melongena, S. tuberosum S. chacoense, Nicotiana rustica and N. tabacum in Brasília (Federal District), Brazil. Symptoms were mainly characterized by adaxial yellow areas in the leaves corresponding to white fungal colonies on the abaxial surface. Profuse sporulation was often observed. Light microscopy of the fungal colonies revealed the presence of conidiophores emerging through stomata with some having two or three branches. Ellipsoidal, subhyaline conidia were predominantly born singly and terminally on the conidiophore. All morphometrical characteristics agreed with those of Oidiopsis haplophylli (Syn. O. sicula). The teleomorph (Leveillula taurica) was not observed. Inoculation tests indicated that O. haplophylli isolates obtained from S. gilo, S. melongena, S. tuberosum, S. chacoense, Nicotiana rustica and N. tabacum were also pathogenic to sweet pepper (Capsicum annuum) and tomato (Lycopersicon esculentum). This is apparently the first report of these Solanaceae species as hosts of O. haplophylli in Brazil. This disease may become important in these crops, especially in greenhouses, and in hot and dry areas where drip irrigation is employed.

Biomass allocation and water use efficiency in fertigated sweet pepper

The use of productivity information and efficiency of water use is important for the economic analysis of production and irrigation management, and also helps the economy of water use, which is essential to plant life. The objective of this study was to evaluate the biomass allocation, the water use efficiency and water content in fruits of sweet pepper cropped under the influence of irrigation blades and potassium doses. The statistic design was a completely randomized factorial scheme (5 x 2) and four replications, with five irrigation blades (80; 90; 100; 110 and 120% of crop evapotranspiration) and two levels of potassium (80 and 120 kg K2O ha-1 ), applied according to phenological phase, through a system of drip irrigation with self-compensated drippers, installed in a battery of 40 drainage lysimeters cultivated with sweet pepper (Maximos F1), at Federal Rural University of Pernambuco (UFRPE), Recife, state of Pernambuco, Brazil. The dry biomass production of sweet pepper was influenced by fertigation regimes; when it was set the lowest dose, estimates of the efficiency of water use and moisture in the fruit occurred with the use of irrigation depth of 97 and 95% of ETc, respectively.

Coffea arabica (cv Catuaí) production and bean size under different population arrangements and soil water availability

The purpose of this research was to evaluate the effect of drip irrigation under different population arrangements on the phytometric features, coffee productivity and bean size classification according to sieve retention. The experiment with Coffea arabica L. cv Catuaí was carried out in Mococa, São Paulo, Brazil. The experimental design was a 6 x 2 factorial scheme in randomized blocks, with four replications. The six densities of plantation were E1 (1.60 x 0.50 m); E2 (1.60 x 0.75 m); E3 (1.60 x 1.00 m); E4 (3.20 x 0.50 m); E5 (3.20 x 0.75 m) and E6 (3.20 x 1.00 m), which were divided according to the availability of water (irrigated - I - or non-irrigated - NI - groups). Data were submitted to analysis of variance and averages compared by Tukey test at 1 and 5% of probability. Descriptive analysis of coffee beans according to sieve classification was performed. Irrigation promoted an increase in plant height, crown diameter and production of processed coffee when compared with the NI group. Interaction between population arrangement and irrigation was observed, with an increase in production and crown diameter as the spacing was decreased. Therefore, irrigation provided significant increase in coffee bean size.

Sweet grape mini tomato grown in culture substrates and effluent with nutrient complementation

The objective of this study was to evaluate production of Sweet Grape mini tomato (Lycopersicum esculentum Mill.) using culture substrates and nutrient solution sewage effluent, applied by drip irrigation (fertigation). The experiment was conducted at the University of Goiás State (UEG-UnUCET), from June to November 2011 in Anápolis-GO, Brazil. The experimental design was a 2 x 3 factorial arrangement in a randomized complete block design with four repetitions. The plots were made by combining two nutrient solutions, effluent supplemented with mineral fertilizers (EcS); conventional nutrient solution (SnC); in addition three cultivation substrates: 60% of fine sand washed + 40% substrate composed by 20% coconut fiber plus 80% pine bark (S1); 20% coconut fiber and 80% pine bark (S2) and natural coconut fiber (S3). Sewage effluent were determined nitrate, calcium, potassium, manganese, total phosphate, total iron, magnesium, chloride, sulphate, boron, zinc and molybdenum. We evaluated average mass and average number of fruits per bunch, total fruit and total yield per plant. Statistical difference absence among tested solutions indicates sewage effluent can be used as an alternative source of nutrients in growing mini tomatoes in hydroponics.

Modelling head loss along emitting pipes using dimensional analysis

Local head losses must be considered in estimating properly the maximum length of drip irrigation laterals. The aim of this work was to develop a model based on dimensional analysis for calculating head loss along laterals accounting for in-line drippers. Several measurements were performed with 12 models of emitters to obtain the experimental data required for developing and assessing the model. Based on the Camargo & Sentelhas coefficient, the model presented an excellent result in terms of precision and accuracy on estimating head loss. The deviation between estimated and observed values of head loss increased according to the head loss and the maximum deviation reached 0.17 m. The maximum relative error was 33.75% and only 15% of the data set presented relative errors higher than 20%. Neglecting local head losses incurred a higher than estimated maximum lateral length of 19.48% for pressure-compensating drippers and 16.48% for non pressure-compensating drippers.

Backpressure effects on the flow-pressure relation of driplines

ABSTRACT For drip irrigation design and management, it is necessary to know the relation between flow and pressure acting on emitters. In the case of subsurface drip irrigation, the backpressure phenomenon may change the hydraulic characteristics of emitters. Thus, this study aimed at determining such relationship between flow and pressure of different driplines in surface and subsurface conditions; aiming to find possible differences in hydraulic behavior. We tested four emitter types; two pressure compensating (D5000 and Hydro PCND) and two non-pressure compensating (TalDrip and Jardiline). Emitter flow rates were attained in atmospheric conditions and submerged in water, in which submergence levels represented backpressure. Assays were performed using inlet pressures of 80, 100, 120, and 150 kPa for the Hydro PCND dripline and 25, 50, 100, and 150 kPa for the other ones; the backpressures were of 0.49, 1.47, 2.45, 4.41 and 6.37 kPa with four replications. The emitters had their proportionality constants and discharge exponents changed in submerged applications, representing backpressure effect. Non-pressure compensating emitters had their discharge exponent decreased, while in pressure compensating ones, it was increased. Backpressure reduced emitter flow rates at all evaluated pressures.

Potato plant growth and macronutrient uptake as affected by soil tillage and irrigation systems

The objective of this study was to evaluate potato plant growth and macronutrient uptake, as affected by soil tillage methods, in sprinkle and drip irrigated experiments. Eight treatments were set: T1, no tillage, except for furrowing before planting; T2, one subsoiling (SS); T3, twice rotary hoeing (RH); T4, one disc plowing (DP) + twice disc harrow leveling (DL); T5, 1DP + 2DL + 1RH; T6, 1DP + 2DL + 2RH; T7, 1SS + T6; T8, one moldboard plowing (MP) + 2DL. Treatments were arranged in a randomized block design with four replications. In both irrigation systems, plants presented higher emergence velocity index (EVI), when the soil was not tillaged, and the EVI was inversely related to the maximum tuber dry mass production. In both experiments, a functional direct relationship was found between the leaf area index and maximum tuber dry mass yield. The growth of plant organs (tuber, leaf, stem and root) and the macronutrient (N, P, K, Ca and Mg) contents in potato plant responded positively to a deeper soil revolving caused by plowing, especially with moldboard plow.

Obstruction of drippers as a result of application of moisturized whitewash in irrigation water

Plug dynamics of non compensate drip tubes were evaluated, by the precipitation of moisturized whitewash [Ca(OH)2], which is used in the fertigation for the bulb pH control of the trademarks Azud, Amanco, Naandan, Netafim, Petroisa, Queen Gil, with flow rate varying between 0.4 to 3.0 L h-1 usually used in the country. For this matter, increasing doses of Ca(OH)² were applied in the irrigation water, from 0.01 g L-1 to 1.84 g L-1. The flow rate of each drip tube was measured in intervals of time initially of 7 days, later of 15 days of system operation, totaling a time of 100 days of operation, corresponding to nine applications or 432 hours. The coefficient of variation (CV), and relative rate flow (Qr) were evaluated. The results pointed differences among the evaluated emitter regarding the occurrence of the clogging, and the models G2 and G5 presented the smallest levels of flow rate variation comparing to the models G6, G7 and G9.

Effect of trickle irrigation on root development of the wet bulb and 'pera' orange tree yield in the state of São Paulo, Brazil

The aim of this study was to evaluate the effect of different microirrigation designs on root system distribution in wet bulb region, orange orchard yield and quality of orange fruits. The experiment was installed as random blocks with five treatments and four replicates in an orchard of 'Pêra' orange trees grafted on 'Cleopatra' mandarin rootstock. The treatments consisted of: one drip line (T1), two drip lines (T2), four drip lines (T3) per planting row, microsprinkler irrigation (T4) and without irrigation (T5). Irrigation treatments favored yield and ºBrix. The treatment with a single drip line (T1) showed the greatest quantity of roots in relation to the treatments T2 and T3.

Evapotranspiration and crop coefficient of drip irrigated watermelon in Piaui coastline, Brazil

The knowledge of the evapotranspiration (ETc) and crop coefficient (Kc) is fundamental to plan and to manage the irrigation of any crop. The aim of this study was to determine the daily and hourly evapotranspiration of drip irrigated watermelon (Citrullus Lanatus, var. Crimson Sweet) and crop coefficient (Kc) in each crop development phase. The experiment was carried out in an experimental area of 1.27 ha of Embrapa Mid-North, localized in Parnaíba (02°54'S, 41°47'W and 46 m above of sea), State of Piauí, Brazil, from September to November, 2006. Electronic weighing lysimeters of 1.5 m x 1.5 m wide and long and 1.0 m deep were used to obtain the evapotranspiration. The plants were drip irrigated with a lateral row per plant row and drippers spaced 0.5 m from each other. The reference evapotranspiration (ETo) was estimated using the Penman-Monteith equation from the climatic data obtained by electronic sensors. The total evapotranspiration during the watermelon crop cycle cultivated in the state of Piauí was 233.87 mm, with mean values of 3.7 mm day-1, minimum of 1.18 and maximum of 8.14 mm day-1. The Kc of the drip irrigated watermelon was 0.18 in the initial stage of crop growth; 0.18 to 1.3, in crop development stage; 1.3 in the intermediate stage and 0.43 in the final stage.

Root system distribution of sugarcane irrigated with domestic sewage effluent aplication by subsurface drip system

Irrigation with domestic sewage effluent (DSE) has been recommended by subsurface dripping, as it can obtain a high rate of irrigation efficiency and faster use of salts in comparison with other irrigation methods. The study aimed at evaluating the area, the length and the effective depth of the root system of sugarcane irrigated with DSE by subsurface drip system and with different irrigation rates at depths of 0.00-0.20, 0.20-0.40, 0.40-0.60 and 0.60-0.80m. The experiment was carried out in the municipality of Piracicaba, in the state of São Paulo (SP), Brazil, in a sugarcane area irrigated with DSE in a completely randomized blocks set up in furrows, with three replications and four treatments, which are: one area without irrigation (AWI) and three irrigated areas meeting 50% (T50%), 100% (T100%) and 200% (T200%) of the crop's water need between each round of irrigation. T100% and T200% provided smaller areas and lengths of roots in the two deepest layers, as compared to AWI and T50%, which stimulated the development of deeper roots due to the water stress. TWI, T100% and T200% presented 80% of the roots up to a depth of 0.40m and T50% treatment presented 76.43% of roots total.