High Frequency Irrigation Research Articles

Irrigation Management, Fruit Quality, and Storage Life of Apple

Abstract ‘Delicious’ and ‘Golden Delicious’ apples (Malus domestica Borkh.) on seedling rootstock were grown with trickle and sprinkler irrigation, both operated at high frequency of irrigation (daily). Trees with trickle irrigation developed lower leaf water potentials and produced less vegetative growth than trees with sprinkler irrigation, but fruit and productivity were similar. Apples from the trickle-irrigated trees had less water content and higher soluble solids than those from sprinkler-irrigated trees. Titratable acidity tended to be lower and both red color in ‘Delicious’ and yellow color in ‘Golden Delicious’ tended to be higher in fruit from trickle-irrigated trees than from sprinkled trees; firmness at harvest was similar regardless of irrigation procedure. Storage life was not influenced consistently by irrigation. Where differences did occur, the fruit from trickle-irrigated trees was softer after storage. Changes in fruit quality similar to those observed in trickle-irrigated trees were produced by imposing, through high frequency deficit irrigation with sprinklers, similar moisture deficits on apple trees, as measured by leaf water potential.

Soil Sensor Control of High-Frequency Irrigation Systems

HIGH-FREQUENCY irrigation can be controlled accurately by an electronic feedback soil moisture sensor installed in the root zone of row crops. A validating experiment conducted with processing tomatoes in a fine sandy loam soil indicates that this control method can be used successfully to improve crop yield and quality, and provide precise automatic control of trickle irrigation systems.

Leaf Water Potentials for Management of High Frequency Irrigation on Apples

ABSTRACT LEAF water potentials {yjj offer a reliable means to evaluate the water status of apple trees if the values are adjusted to compensate for diurnal and daily changes associated with weather changes. A strong linear relationship suitable for field use has been found to predict \p^ from a known atmospheric vapor density gradient (Ap^J where stomatal conductance is high for both nondeficit and deficit irrigated trees. The slopes of linear equations for trees grown under nondeficit and deficit irrigation regimes differ significantly which indicates that conventional predawn measurements of nj^ Site not adequate for establishing the plant water status of apples. This relationship appears to be independent of the type of irrigation system.

Effects of Soil Water Content on Pendimethalin Dissipation

AbstractLaboratory and field studies were conducted to evaluate pendimethalin [N‐(1‐ethylpropyl)‐3,4‐dimethyl‐2,6‐dinitroaniline] dissipation over time in a Crowley silt loam (Typic Albaqualfs). In the laboratory, dissipation rates approximately followed pseudo first‐order kinetics over a 56‐d period, except in air‐dried soil that had no significant loss of pendimethalin detected after 56 d. Half‐lives for 30 kPa, continuous flood, and alternately flooded and dried treatments averaged 59, 63, and 30 d, respectively, under laboratory conditions. Application rates of 0.5, 1.0, and 2.0 µg/g of soil did not have a significant influence on the half‐lives. The ratio of pendimethalin residues in laboratory systems detected by a root bioassay with grain sorghum [Sorghum bicolor (L.) Moench.] to those detected with gas‐liquid chromatography (GLC) declined by 17% from 0 to 56 d after treatment. Dissipation in the field in each of 2 y was studied with lowland rice (Oryza sativa L.) (flush irrigated then flooded 2–3 weeks after application), upland rice (flush irrigated throughout the season), and soybean [Glycine max (L.) Merr.] (furrow irrigated as needed) management systems. Soil water content had a strong influence on the amount of pendimethalin that dissipated, especially for about the first 2 weeks after herbicide application. Half‐lives in the field were much shorter during the initial 2 weeks than after 2 weeks, with >50% of the applied herbicide having disappeared in 1 week for all treatments except in soybeans the first year. Soil persistence of pendimethalin was greater under soybean culture (soil‐incorporated herbicide, low irrigation frequency) than under rice culture (surface‐applied herbicide, high irrigation frequency, and/or flooded conditions).

Simulation of Water and Chloride Transport in Field Lysimeters

AbstractIn a lysimeter study in the field with soil samples of a Fluvisol the transport of chloride was monitored under high frequency irrigation. The results of this investigation were used for verification of two computer models of different complexity. One was a transient state water and solute movement model the other a simplified steady state model.It was demonstrated that both models predicted nearly equally well the chloride concentrations in the drainage water. For many practical situations, the simple model may be all that is needed to predict the downward movement of solutes in field soils.

Effect of irrigation frequency and nitrogen on groundnut yield and nutrient uptake

Field experiments were conducted during 1979 and 1980 summer seasons on sandy loam soils of low moisture retentive capacity to study the effect of high frequency irrigation at different levels of N on groundnut yield and nutrient uptake (NPK).

Intensive Forage Production in Northern Mexico. I. Responses Of Italian Ryegrass to Nitrogen and Irrigation

SUMMARYThe response of Italian ryegrass (IRG) to nitrogen fertilization, irrigation frequency and harvest interval indicated that management of nitrogen and water is the determinant of productivity under semi-arid northern Mexican conditions. Where water is non-limiting the effects of harvest interval can be eliminated. A soil moisture balance model indicated the inadvisability of seeding IRG in sandy soils if water is a scarce resource because of the high frequency of irrigation that would be required. The seeding (September) and late production (April) periods were identified as critical in regard to irrigation need and limiting in terms of the area that it would be possible to seed.

A field test of a conceptual computer simulation model for predicting water and salt distribution

The unsaturated flow and unsaturated chemistry submodels of a conceptual computer simulation model, developed at the United States Bureau of Reclamation to predict water and salt behaviour in soils, were tested under field conditions. The comparison of results was done with data obtained from an irrigation trial with alfalfa over a period of four years. The model simulated the actual physical and chemical processes taking place in the soil to a fair degree of accuracy. The predicted moisture contents compared reasonably well with ob served data, especially in the soil layers between 480 and 1200 mm (Figs. 1 and 2, Tables 3 and 4). The simulation of moisture distribution was more accurate for plots receiving a high irrigation frequency than for plots given a low irrigation frequency. On a depth-weighted-mean scale, the predicted salt concentration of the soil layers shallower than 1200 mm was within 11% of the observed data. However when the salt content of the soil layers between 1200 and 1920 mm was taken into account, the percentage error increased to about 40% (Table 6). The results indicate that this simulation model can be extremely useful in predicting the long and short term effect of irrigation water on the root zone of a soil. Field data are however at all times needed to calibrate the unsaturated flow model for specific soil types.

Frequency and depth of irrigation for groundnut

Studies on frequency and depth of irrigation for groundnut ( Arachis hypogaea) for two summer seasons at Tirupati campus of Andhra Pradesh Agricultural University, India showed that, keeping the total quantity of applied irrigation water almost the same, high frequency irrigation gave the highest yield. For each irrigation frequency, highest yields were obtained when the depth of water applied was equal to that lost in evapotranspiration. Low irrigation frequency and low depth of irrigation resulted in lower yields. Increase in yield with increase in frequency and depth of water was due to optimum available moisture and nutrients in the root zone throughout the crop period. The results from the trial indicated that on sandy loam soils of poor water retentive capacity, high yields can be obtained with frequent irrigations with the depth of water applied equal to that lost in evapotranspiration.

The effect of nitrogen fertilizer and irrigation frequency on a semi-dwarf wheat in south-east Australia. 2. Water use

The semi-dwarf wheat WW15 was grown under four irrigation frequencies and two nitrogen rates in the Murrumbidgee Irrigation Area of south-eastern Australia. The irrigation treatments, which were scheduled using pan evaporation and rainfall, ranged from natural rainfall alone to seven flood irrigations. Water use was determined using the water balance equation, and measurements or irrigation water applied, rainfall, change in soil-stored moisture, and surface drainage. The water-use figures were high in comparison with values obtained overseas, ranging from 408 mm with no irrigation to 818 mm at the highest irrigation frequency. Despite the high water use, water-use efficiency was comparable with that for semi-dwarf wheat in other parts of the world, with a mean value of 10.4 kg grain ha-1 mm-1. Nitrogen fertilizer had little effect on plant growth and no effect on crop water use.

Fertilizer Management with Drip Irrigation in an Oxisol1

AbstractOxisols are the dominant soils of the continental shields in the tropics under permanently moist and alternately wet and dry climates. Oxisols have a low cation exchange capacity, high permeability, but low available waterholding capacity. Some have a low pH, which can cause Al3* toxicity to many crops. Together with erratic rainfall patterns, special management methods of soil‐water and plant nutrients for Oxisols are yet to be carefully studied. The relatively recent development of combined high frequency irrigation and fertilizer techniques, “drip fertilization,” may be one of the solutions for intensive production of food crops on Oxisols.A drip irrigation system using porous plastic tubing was designed for a field experiment to study the feasibility and operational techniques of drip irrigation and fertilization management in a highly weathered, acid Oxisol (Coto clay). Green pepper (Capsicum annuum L.), ‘Blanco del Pais’ was the test crop. A randomized, completeblock design was chosen to compare different fertilization techniques. In addition to the check plot, the three other treatments were: fertigation (drip irrigation and drip application of N and K, banded P); drip irrigation with banded N, P, and K; and drip irrigation with broadcast N, P, and K. All treatments, except the control plot, received a total amount of fertilizer equal to 56.8 g of 10‐10‐10 commercially available fertilizer per plant and all treatments were uniformly drip irrigated according to pan evaporation data.Different moisture profiles during the wet (June‐November) and dry (December‐May) seasons were observed. Nutrient movement profiles suggested that the distribution of fertilizer under drip irrigation depended on the method of fertilizer placement. Root development patterns indicated that more than half of the root system (dry weight) was developed in the 5 to 15 cm layer. More fibrous roots were developed toward the porous drip tubing which supplied moisture and nutrients. Yield were significantly different among all treatments during the dry season and the fertigation, broadcast, and control during the wet season. Yields from broadcast fertilizer treatments were 15.8% lower than from fertigation, and 12.3% lower than from banded fertilizer. The results of this research indicates drip fertigation can be a promising alternative to currently used water‐nutrient management methods for Oxisols in the wet‐dry tropics.

Water and salt transport, water uptake, and leaf water potentials during regular and suspended high frequency irrigation of citrus

High frequency irrigation of citrus was interrupted for up to 2 months to study the dynamics of salt and water transport in soil, water uptake distributions and leaf water potentials. Irrigation water was applied to less than half the surface area per tree. Water content profiles and chloride distributions indicated that of the water uptake below the irrigated area, about 80% took place above 0.60-m depth, and that considerable water was taken up from outside the irrigated area. The water for the latter was supplied by lateral flow, as evidenced by the hydraulic gradients, the relative extent of the lateral flow in summer and winter, and the fact that at 0.90-m depth water contents were uniform. In summer, the citrus showed signs of stress after about 4 weeks of suspended irrigation. At that time leaf water potentials did not recover any longer during the night. This study indicates that high frequency irrigation of citrus is not too vulnerable to temporary system breakdown and that deficit-irrigation could be practiced.

High‐frequency Irrigation for Water Nutrient Management in Humid Regions

AbstractA water‐nutrient management method was designed to prevent plant‐water and nutrient stresses while maximizing the available soil water storage to accommodate rainfall. This method minimized the need for the soil as a storage reservoir for water and nutrients by frequently irrigating a portion of the root zone with small amounts of water and nutrients. The optimal range of soil matric potential, based on soil oxygen diffusion rate, soil strength, water desorption characteristics, and unsaturated hydraulic conductivity was used to determine high‐frequency irrigation criteria for sweet corn (Zea mays L.). Trickle‐irrigated plots yielded 12 and 14% more corn than did the furrow‐ and sprinkler‐irrigated plots. When fertilizers were broadcast and banded, soil NO3‐N profiles measured near the end of the growing season showed that, compared to furrow and sprinkler irrigation, trickle irrigation reduced NO3‐N losses from the root zone.Optimal ear yield was produced with high‐frequency trickle irrigation when the soil matric potential at the 15‐cm soil depth was controlled at about −0.2 bar and plants were fertilized with 168 kg/ha each of N and K. Ear yield for this treatment was 66% higher than that for nonirrigated corn fertilized at the same rate. Soil NO3‐N did not accumulate in the profile with depth and time in plots fertilized at the 168‐kg/ha rate, but did accumulate in plots fertilized with 336 kg/ha. Generally, plots trickle‐irrigated with fertilizer solution had a higher soil NO3‐N content on the row than 50 cm from the row.The results of this research indicate that water use efficiency, N‐use efficiency, and N leaching can be controlled in sandy soils when N and K are applied with high‐frequency trickle irrigation systems and N and K rates are adjusted to maintain an optimal N‐level in corn plants.

Prospects for High-Frequency Irrigation

Prospects for High-Frequency Irrigation

Optimization of Water Use Efficiency under High Frequency Irrigation — I. Evapotranspiration and Yield Relationship

Optimization of Water Use Efficiency under High Frequency Irrigation — I. Evapotranspiration and Yield Relationship

Optimization of Water Use Efficiency under High Frequency Irrigation — II. System Simulation and Dynamic Programming

Optimization of Water Use Efficiency under High Frequency Irrigation — II. System Simulation and Dynamic Programming

Time‐Dependent Linearized Infiltration. I. Point Sources

AbstractWater flow from a point source is analyzed using a linearized form of the moisture flow equation. Time‐dependence is assumed with the results simplifying to those of previous investigators for steady‐state conditions. Discrete time‐distributed inputs such as might occur for trickle or high frequency irrigation is amenable to the solution. Numerical simulations include (i) the advance of a wetting front during infiltration, (ii) moisture variation resulting from a cyclic input as during irrigation, and (iii) the matric flux potential field for a two‐source problem.

Principles of Managing High Frequency Irrigation

AbstractThe consequences of increasing irrigation frequency are explored, taking into consideration the laws governing water flow in soil. As frequency increases, the waterholding capacity of the soil becomes less important because water is supplied as the plants require it. Soil water content, and therefore matric potential, are continuously high and only slightly dependent upon deep percolation rate. This makes the need for deep percolation to leach salts the only valid criterion for applying more water than the plants transpire. The need to apply extra water to those crops that require high soil water content is eliminated. Controlling the deep percolation rate rather than the soil water status requires measurements of flux rather than water potential as inputs for managing the quantity of water to be applied.

Impacto de los sólidos suspendidos totales sobre la obstrucción en emisores de riego localizado de alta frecuencia

Este estudio a escala piloto evaluó el impacto de los sólidos suspendidos totales, SST, sobre la obstrucción en emisores de riego localizado de alta frecuencia, RLAF, empleando como tratamiento para mejorar la calidad de agua un filtro de grava de flujo ascendente con mantas sintéticas (FGAC Manta). El efluente de dicho tratamiento alimentó cuatro tipos de sistemas RLAF: Lyn, Autocompensado, Microjet y Cinta de riego, para evaluar la incidencia del aporte de los SST sobre cada uno de ellos. Para ello se evaluó el riesgo de obturación, el coeficiente de uniformidad (Cu), la concentración de sólidos depositados en las paredes de los conductos y el tamaño de partícula que ingresó a los RLAF. Los resultados mostraron que cuanto mayor fue la concentración de SST, menor fue el tiempo de riego alcanzado por las tecnologías RLAF. La relación de los SST aportados a los RLAF con el tamaño de partícula que ingresó a los conductos y emisores presentó partículas hasta de 129 micras, que contribuyen a la obturación de los emisores. El régimen laminar contribuye a la deposición de sólidos en los conductos de los emisores de las tecnologías RLAF afectando el Cu.

A technique for conducting pot experiments with saline water

A technique based on the principles of leaching accumulated salts and removing excess water by applying suction through a porous plate has been suggested for conducting pot experiments with saline irrigation water. This technique is suitable for greenhouse experiments on a large scale because of its relative simplicity and accuracy. The container design incorporates a number of simple improvements and provides greater accuracy without complicating the experimental procedure. The technique was tested by conducting two experiments with corn. Large fluctuations in salt concentration within the soil could be prevented only with a high irrigation frequency.