Optimizing irrigation scheduling using a drip system to enhance water use efficiency in tomato cultivation

Effect of Irrigation Frequency on Rose Flower Production and Quality

Evaluating the irrigation schedules of greenhouse tomato by simulating soil water balance under drip irrigation

Core Ideas Plant Na+ content doubled with daytime sprinkler irrigation. Plant Na+ content increased by 30% with high irrigation frequency. Irrigation frequency was not relevant for nighttime sprinkler irrigation of maize. High irrigation frequency during daytime reduced maize yield and water use efficiency. Sprinkler irrigation with solid‐set systems easily allows changing irrigation frequency. We studied, under field conditions and during 3 yr, the effects of irrigation frequency (two events per week or daily) and daytime vs. nighttime irrigation on microclimatic changes, soil matric potential, growth, yield, and water use of maize (Zea mays L.). Microclimatic changes (decrease of air temperature and vapor pressure deficit, and of canopy temperature) were slightly larger and lasted for more time after the irrigation event with low frequency irrigation. Increasing irrigation frequency during daytime resulted in a lower soil matric potential. Irrigating at nighttime resulted in higher maize height (+3%) and yield (+10%) than irrigating at daytime. The high irrigation frequency decreased maize height (−7%) and yield (−5%) compared with the low irrigation frequency when irrigation was performed at daytime but not at nighttime. The Na+ content of the plant was doubled with daytime sprinkler irrigation compared with nighttime irrigation, and was increased by 30% when the irrigation frequency was increased. Water use efficiency (WUE) was not affected by irrigation frequency when irrigating at nighttime, but it decreased with the increase of irrigation frequency when irrigation was applied during daytime. Sprinkler irrigation with solid‐set must be applied at night to obtain the maximum maize yield and WUE. Irrigation frequency is not relevant for sprinkler irrigation of maize applied at night, but high irrigation frequency should be avoided when maize is sprinkler irrigated during daytime to avoid yield and WUE decreases.

Three irrigation frequencies were applied on a soilless cucumber crop, in a greenhouse located in the coastal area of southern Cyprus. Irrigation scheduling was based on solar radiation and performed whenever accumulated solar radiation energy outside the greenhouse reached 1.3 MJ m-2 [High Irrigation Frequency (HIF)], 1.9 MJ m-2 [Medium Irrigation Frequency (MIF)] and 3.0 MJ m-2 [Low Irrigation Frequency (LIF)]. The amount of water applied was 0.192 Kg m-2, 0.288 Kg m-2 and 0.448 Kg m-2 for high, medium and low irrigation frequencies, respectively. Appropriately, the total volume of water applied was identical in each of the three cases. In order to study the effects of irrigation frequency on cucumber crops, multiple measurements were taken; the fresh and dry weight of plant organs (i.e. leaves, stem and fruit), marketable fresh yield production, and microclimate variables for a 75 day period, beginning in April and ending in June. The results revealed that the irrigation frequency did not influence the cucumber crop’s growth and production. Plants at LIF were facing water stress conditions, as estimated from leaf temperature and stem micro variation measurements. However, HIF increased the transpiration rate of the plants, resulting in less water and nutrient losses.

Sour orange (Citrus aurannum L.) seedlings were inoculated with geographic isolates of an endomycorrhizal fungus, Glomus intraradices Smith and Schneck, from a xeric (New Mexico) or mesic (Florida) climate or not inoculated as controls, and were grown for 5 months under high (soil water potential more than or equal to –0.1 MPa, irrigated once every 3 days) or low (more than or equal to –1.0 MPa, irrigated once every 12 to 15 days) irrigation frequency regimens. Similar leaf P concentrations were achieved in all plants by giving more P fertilizer to nonmycorrhizal plants than mycorrhizal plants. Plants inoculated with the xeric isolate had more arbuscules and fewer vesicles than those inoculated with the mesic isolate. Mycorrhizal fungi had little affect on plant growth under high irrigation frequency. Low irrigation frequency reduced plant growth compared with high irrigation frequency. Under low irrigation frequency, shoot and root growth increased for mycorrhizal plants; however, the magnitude of increase of shoot growth was greatest for plants inoculated with the xeric isolate. Additionally, low irrigation frequency was associated with a dramatic decrease in vesicle formation in roots inoculated with the mesic isolate. This study showed that sour orange plants especially benefited from inoculation with an isolate from a xeric climate under low irrigation frequency, independent of P nutrition.

Effects of irrigation and nitrogen fertilization on the grain yield, protein composition, protein quality, starch composition and starch pasting properties of a strong-gluten winter wheat were investigated in a high fertility field. Compared with non-irrigation treatment, grain yields under irrigation treatments were significantly increased, but the content of grain protein, monomeric protein and flour wet gluten was reduced. There were no significant differences in the above parameters between the irrigation treatments. Nitrogen application could significantly increase grain yield under low irrigation frequency (W0 and W1), while the neglected effect on yield was observed with high irrigation frequency (W2 and W3). With the increase of irrigation frequency, the glutenin content leveled off, but the changes of glutenin composition were not uniform, in which the soluble glutenin content was increased, while the insoluble glutenin content and polymerization index (the ratio of insoluble glutenin to total glutenin) were reduced. Both dough development time and stability time became shorter with the increased irrigation frequency. Nitrogen application improved the content of all grain protein fractions and grain quality, in which the increased degree in non-gluten protein (albumin and globulin) was higher than gluten protein (gliadin and glutenin), and the increased degree in soluble glutenin was found higher than that of insoluble glutenin. The interactive effects of irrigation and nitrogen on starch composition were significant. Starch content and amylopectin content was increased as irrigation frequency added in non-nitrogen treatment. Compared to non-irrigation treatment, irrigation significantly increased the starch content and the amylopectin content in nitrogen application treatment, but the starch and amylopectin content had no significant difference between irrigation treatments. Amylose content and the ratio of amylose to amylopectin were reduced while RVA indexes (peak viscosity, breakdown, final viscosity and setback) were increased as irrigation frequency was increased. Nitrogen application significantly improved the amylopectin content and decreased the amylose content in lower frequency irrigation, while the amylopectin content was decreased and the amylose content was enhanced by nitrogen application in higher frequency irrigations.

Despite increased use of irrigation to improve forage quality and quantity for grazing cattle ( Linnaeus), there is a lack of data that assess how irrigation practices influence nitrous oxide (NO) emissions from urine-affected soils. Irrigation effects on soil oxygen (O) availability, a primary controller of NO fluxes, is poorly understood. It was hypothesized that increased irrigation frequency would result in lower NO emissions by increasing soil moisture and decreasing soil O concentrations. This would favor more NO reduction to dinitrogen (N). We examined effects of high (3-d) versus low (6-d) irrigation frequency with and without bovine urine addition to pasture. Nitrous oxide fluxes were measured daily for 35 d. Soil O, temperature, and water content were continuously measured at multiple depths. Inorganic nitrogen, organic carbon, and soil pH were measured at 6-d intervals. Measurements of denitrification enzyme activity with and without acetylene inhibition were used to infer the NO/(NO + N) ratio. The NO/(NO + N) ratio was lower under high- compared with low-frequency irrigation, suggesting greater potential for NO reduction to N with more frequent irrigation. Although NO fluxes were increased by urine addition, they were not affected by irrigation frequency. Soil O decreased temporarily after urine deposition, but O dynamics did not explain NO dynamics. Relative soil gas diffusivity (/) was a better predictor of NO fluxes than O concentration. On a free-draining soil, increasing irrigation frequency while providing the same total water volume did not enhance NO emissions under ruminant urine patches in a grazed pasture.

Better understanding of the effects of irrigation frequency and dose on flower production of gerbera plants ( Gerbera jamesonii ) can lead to optimal water management and crop yield. Measurements of greenhouse microclimate and production and quality characteristics of a gerbera crop were carried out under two irrigation frequency regimens in soilless cultivation in a greenhouse located in Arta, Greece. Irrigation scheduling was based on solar radiation and performed whenever accumulated solar radiation energy outside the greenhouse reached 1650 kJ·m −2 [high irrigation frequency (HIF)] or 3300 kJ·m −2 [low irrigation frequency (LIF)]. The amount of water applied was 0.125 mm and 0.250 mm for HIF and LIF, respectively. Stem fresh weight, length and thickness, and number of harvested gerbera flowers were measured along with crop evapotranspiration, crop leaf area, and greenhouse microclimate variables. Measurements started 8 months after transplanting and lasted 90 days (May to July). Leaf area, fresh weight, harvested cut flowers, and the main quality characteristics of gerbera flowers (stem length and flower diameter) were unaffected by the irrigation frequency. In the framework of the experiment, simple formulas for calculation of leaf area index were developed. Finally, a first approach study of an alternative remote sensing irrigation control method using a reflectance index was made and the results are presented.

The optimal management of irrigation and fertilization is crucial for maximizing the yield and quality of tomatoes grown in greenhouses. To address this challenge, this study aimed to develop and implement a solar-powered Internet of Things (IoT) based drip irrigation system for tomato cultivation in plastic roof net houses. Additionally, the study evaluated the effects of water and fertilizer frequency on tomato yield and quality. The experiment was designed with 2 irrigation frequencies (1 time in a day and 1 time in 2 days) and 3 fertilizer frequencies (1 time in 2, 4, and 6 days), with 4 replicates of the tomato variety CH154. The results showed that the solar-powered IoT-based drip irrigation system was efficient, precise in water and fertilizer control, and inexpensive to install and maintain. This allows for real-time monitoring of water flow rate, flow sensor status, treatment status, and electrical parameters on the Node-Red dashboard. Irrigation frequency had a significant impact (p < 0.05) on fruit number, weight, and length per plant, with 1-day irrigation resulting in a higher yield than 2-day irrigation. No significant interaction effect was found between irrigation and fertilizer frequency on tomato yield or quality. In conclusion, the solar-powered IoT-based drip irrigation system demonstrated precise control over water and fertilizer, proving its efficiency and cost-effectiveness. Real-time monitoring capabilities and the observed impact of irrigation frequency underscore its potential for enhancing tomato cultivation in greenhouses, offering a valuable contribution to sustainable and technology-driven agricultural practices.

Abstract. Limbongan YL. 2023. Interrelationship between number of flowers, fruits, and cucumber production (Cucumis sativus) grown on a mixture of soil and chicken manure. Biodiversitas 24: 3448-3453. This study aimed to determine the effect on the relationship between the number of flowers, fruits formed and the production of cucumber (Cucumis sativus L.) in chicken manure-supplemented soil. The research was conducted from June to August 2022 in Tikala Village, Tikala Sub-district, North Toraja District, South Sulawesi, Indonesia, at an altitude of 866.9 m above sea level with climate type B (Schmidt and Ferguson) and was arranged in a randomized complete block design (RCBD). The treatment used chicken manure at five levels, namely, control, 100 g, 200 g, 300 g, and 400 g chicken manure per plant. The results showed that the application of chicken manure at different doses gave different responses to the growth and production of cucumbers. A dose of 400 g/plant is the best treatment to increase the number of flowers, number of fruits, size, and production of the fruit up to 54 days after planting, with a fruit weight of 2.69 kg per plot or 17.93-ton ha?1. The number of flowers, number of fruits, fruit diameter, and fruit length had linear responses and a significant positive correlation with the production of cucumbers.

Influences of irrigation frequency on the growth and flowering of chrysanthemum grown under restricted root volume were tested. Chrysanthemum cuttings (Chrysanthemum morifolium “Reagan White”) were grown in seedling tray which contained coconut peat in volumes of 73 and 140 cm3. Plants were irrigated with drip irrigation at irrigation frequencies of 4 (266 mL), 6 (400 mL), and 8 (533 mL) times/day to observe their growth and flowering performances. There was interaction between irrigation frequency and substrate volume on plant height of chrysanthemum. Plants grown in 140 cm3 substrates and irrigated 6 times/day produced the tallest plant of 109.25 cm. Plants irrigated 6 and 8 times/day had significantly higher level of phosphorus content in their leaves than those plants irrigated 4 times/day. The total leaf area, number of internodes, leaf length, and leaf width of chrysanthemums grown in 140 cm3 substrate were significantly higher than those grown in 73 cm3 substrate. The numbers of flowers were affected by both irrigation frequencies and substrate volumes. Chrysanthemums irrigated 8 times/day had an average of 19.56 flowers while those irrigated 4 times/day had an average of 16.63 flowers. Increasing irrigation frequency can improve the growth and flowering of chrysanthemums in small substrate volumes.

Agriculture is the most important sector that is consuming water resources. In the context of global water scarcity, how to use limited water resources to improve water use efficiency in agriculture or achieve maximum crop yield and fruit quality is of great significance for ensuring food and water security. Optimizing irrigation schedules is an effective measure to improve water use efficiency, where crop models also play an important role. However, there is little research summarizing the optimization of irrigation schedules based on crop models. This study provides a systematic review on how to optimize irrigation schedules based on crop models and simulation–optimization models. When optimizing irrigation schedules based on crop models, the selected models are usually mechanistic agro-hydrological models. Irrigation scenarios and optimization objectives are mainly focused on both crop and water aspects, such as maximizing crop yield, fruit quality, water productivity, and irrigation water productivity. Minimizing crop water consumption and total irrigation amounts serve as optimization objectives, and irrigation quantity, irrigation frequency, and irrigation interval serve as decision variables. In saline areas or low fertilizer utilization areas, the optimization objectives and decision variables also involve some indicators related to salt and nitrogen, such as the maximum desalination rate, minimum salt content, fertilizer utilization efficiency, nitrogen fertilizer productivity, nitrogen fertilizer utilization efficiency, nitrogen leaching rate, which serve as the optimization objectives, and the irrigation water salinity, or fertilization schedules serve as the decision variables. When optimizing irrigation schedules based on simulation–optimization models, the models have mainly been upgraded from water-production function to crop mechanism models. In addition, optimization algorithms have been upgraded from traditional optimization techniques to intelligent optimization algorithms. Decision-making techniques are used to make decisions on optimization results. In addition, the spatial scale for the optimization problem of irrigation schedules was developed from fields to regions, and the time scale was developed from the growth stage, beginning with months, and shortening to ten days, then to a day, and then to an hour. This study also provides a detailed introduction to widely used optimization algorithms, such as genetic algorithms, as well as decision techniques. At the same time, it is proposed that the future should focus on improving crop models and analyzing uncertainty in research on irrigation schedule optimization, which is of great significance for the precise regulation of irrigation schedules.

The effect of amount of applied water under two irrigation frequencies (once versus three times per week) on the incidence of bacterial soft rot, caused by Erwinia carotovora subsp. carotovora, and yield of broccoli was investigated in field studies conducted in 1987 and 1988. At head initiation, the amount of applied water was varied by utilizing a line source irrigation system. Incidence of soft rot was higher in the OSU breeding line 86-3 plots, followed by cv. Citation and then cv. Gem. Soft rot was not consistently affected by amount of applied water. Differences in amount of disease were apparent, however, between the separate irrigation frequency studies in 1988; disease incidence more than doubled under the high- compared with the low-frequency irrigation. Further studies on the effects of frequency and timing of sprinkler irrigation on soft rot and yield of Gem broccoli were undertaken in 1993 and 1994. Six sprinkler irrigation regimes, a factorial combination of frequency (irrigation every 2, 4, or 8 days) and timing (morning or evening), were established. Total water applied did not differ by treatment. Incidence of soft rot was negligible at the first harvest in both years. At the last harvest, the incidence of soft rot was significantly reduced, from 22 to 10% in 1993 and from 30 to 15% in 1994, by the change in frequency of irrigation from 2 to 8 days. In contrast, timing of irrigation had no effect on disease incidence. Yield of broccoli was not affected by either frequency or timing of irrigation.

Irrigation frequency is one of the most important factors in drip irrigation scheduling that affects the soil water regime, the water and fertilization use efficiency and the crop yield, although the same quantity of water is applied. Therefore, field experiments were conducted for 2 years in the summer season of 2005 and 2006 on sandy soils to investigate the effects of irrigation frequency and their interaction with nitrogen fertilization on water distribution, grain yield, yield components and water use efficiency (WUE) of two white grain maize hybrids (Zea mays L.). The experiment was conducted by using a randomized complete block split‐split plot design, with four irrigation frequencies (once every 2, 3, 4 and 5 days), two nitrogen levels (190 and 380 kg N ha−1), and two maize hybrids (three‐way cross 310 and single cross 10) as the main‐plot, split‐plot, and split‐split plot treatments respectively. The results indicate that drip irrigation frequency did affect soil water content and retained soil water, depending on soil depth. Grain yield with the application of 190 kg N ha−1 was not statistically different from that at 380 kg N ha−1 at the irrigation frequency once every 5 days. However, the application of 190 kg N ha−1 resulted in a significant yield reduction of 25 %, 18 % and 9 % in 2005 and 20 %, 13 % and 6 % in 2006 compared with 380 kg N ha−1 at the irrigation frequencies once every 2, 3 and 4 days respectively. The response function between yield components and irrigation frequency treatments was quadratic in both growing seasons except for 100‐grain weight, where the function was linear. WUE increased with increasing irrigation frequency and nitrogen levels, and reached the maximum values at once every 2 and 3 days and at 380 kg N ha−1. In order to improve the WUE and grain yield for drip‐irrigated maize in sandy soils, it is recommended that irrigation frequency should be once every 2 or 3 days at the investigated nitrogen levels of 380 kg N ha−1 regardless of maize varieties. However, further optimization with a reduced nitrogen application rate should be aimed at and will have to be investigated.

Theoretical and experimental aspects of developing irrigation scheduling strategies using continuous measurements of trunk diameter are presented. The behavior of parameters derived from trunk diameter measurements (TDM), including maximum daily trunk shrinkage (MDS), maximum daily trunk diameter (MXTD), and minimum daily trunk diameter (MNTD) is evaluated for both rapidly growing peach [Prunus persica (L.) Batsch, cv. September Snow] and mature almond [Prunus dulcis (Mill.) Webb cv. Price] trees subjected to mild deficit irrigation. Stem water potential (SWP) and MDS were highly correlated in the mature almond trees but a poor relationship was found in the rapidly growing peach trees. Conversely, daily changes in MXTD and MNTD correlated well with SWP in the fast growing trees. While there was relatively high variability ("noise") in the MDS measurements (CV 15.8%), the greater changes in the magnitude of the MDS ("signal") resulted in a significantly higher signal:noise ratio than found with the SWP measurements. In addition to soil water and trunk growth rate, MDS patterns were influenced by irrigation frequency and evaporative demand. Based on the experimental results, protocols for utilizing the trunk diameter-derived indicators for scheduling irrigations are presented for three cases: (1) mature trees under low frequency irrigation, (2) mature trees under high frequency irrigation, and (3) young trees under high frequency irrigation. The scheduling protocols provide guidelines that address both under- and over-irrigation and are predicated on the sensitivity of TDM to very mild plant water deficits. The necessity for and approaches to developing reference (baseline) and threshold values derived from TDM are emphasized. We conclude that protocols using TDM for precise irrigation scheduling hold promise as an additional tool for progressive growers who want to link irrigation management to an automated, electronic, plant-based stress indicator.