In this study, yield and water productivity response of rice to various irrigation levels applied with subsurface and surface drip systems in 2019 and 2020 in the Mediterranean Region of Turkey was evaluated in comparison with conventional flooding (CF). The treatments consisted of two irrigation methods namely surface drip (DI) and subsurface drip systems (SDI), three irrigation levels designated as plant pan coefficients (I1.00: Evaporation from Class A pan (Ep) × 1.00; I1.25: Ep × 1.25 and I1.50: Ep × 1.50) and CF as control. The effects of drip systems and coefficients on yield and yield components were statistically significant (P < 0.01). DI produced higher yield than SDI. CF produced significantly greater yield than both DI and SDI systems. With two drip systems, average water savings of 60.5% in I1.00, 54.5% in I1.25 and 49% in I1.50 were achieved as compared to CF. However, yield reductions of 15% in I1.50, 20% in I1.25, 29% in I1.00 were observed for DI; corresponding values for SDI were 20, 28 and 44%, respectively. Drip irrigation in aerobic rice production system had almost twice the water productivity based on total irrigation water applied (WPI) or total water input (irrigation + rainfall) (WPI+P) compared with CF. During the study years, the highest WPI and WPI+P values were found in DI-I1.00 (0.81–0.73 kg/m3) and (0.85 and 0.74 kg/m3), respectively. In conclusion, DI-I1.50 treatment is recommended for sustainable aerobic rice production since DI-I1.50 resulted in water saving of 49% but yield decrease of 15% as compared to CF.

Drip irrigation is installed under polyethylene mulch to supply irrigation and nutrients to vegetables grown in plasticulture. This irrigation system also provides an alternative method for application of herbicides into the plant bed for control of yellow and purple nutsedge. Greenhouse and field studies were conducted to determine bell pepper tolerance to halosulfuron, imazosulfuron, and trifloxysulfuron applied POST (over the top of pepper in greenhouse study, POST-directed in the field study) or soil applied (applied by hand with water in greenhouse study or through drip irrigation in the field study). In greenhouse studies, pepper injury from halosulfuron, imazosulfuron, and trifloxysulfuron applied POST was similar at 14 and 21 d after treatment (DAT; 21 to 35% and 54 to 60%, respectively). Halosulfuron, imazosulfuron, and trifloxysulfuron soil applied in greenhouse studies caused 6 to 8% and 13 to 20% injury to pepper at 14 and 21 DAT, respectively. Pepper injury in greenhouse studies increased as rate of halosulfuron, imazosulfuron, and trifloxysulfuron increased regardless of application method (soil or POST applied). Dry pepper weight at 28 DAT followed an inverse linear response to increasing rates of halosulfuron, imazosulfuron, and trifloxysulfuron. In field studies, bell pepper height among herbicide treatments ranged from 32 to 37 cm at 14 DAT and was not different from the nontreated check (36 cm). Number one grade (7.8 to 14.7 MT ha−1) and fancy grade (2.1 to 2.8 MT ha−1) pepper fruit yield was not different in herbicide-treated pepper compared with yield of pepper in the nontreated check (10.0 to 26.6 MT ha−1, respectively). Based on these studies, pepper has excellent crop tolerance to halosulfuron, imazosulfuron, and trifloxysulfuron applied through drip irrigation or POST-directed but is not tolerant to POST applications.

Volunteer corn (Zea mays L.) is a competitive weed in corn-based cropping systems. Scientific literature does not exist about the water use of volunteer corn grown in different crops and irrigation systems. The objectives of this study were to characterize the growth and evapotranspiration (ETa) of volunteer corn in corn, soybean [Glycine max (L). Merr.], and sorghum [Sorghum bicolor (L.) Moench] under center-pivot irrigation (CPI) and subsurface drip irrigation (SDI) systems. Field experiments were conducted in south-central Nebraska in 2021 and 2022. Soil moisture sensors were installed at depths of 0 to 0.30, 0.30 to 0.60, and 0.60 to 0.90 m to track soil water balance and quantify seasonal total ETa. Corn was the most competitive, as volunteer corn had the lowest biomass, leaf area, and plant height compared with the fallow. Soybean was the least competitive with volunteer corn, as the plant height, biomass, and leaf area of volunteer corn in soybean were similar to fallow at 15, 30, 45, and 60 d after transplanting (DATr). Averaged across crop treatments, irrigation type did not affect volunteer corn growth at 15 to 45 DATr. Soil water depletion and ETa were similar across crop treatments with and without volunteer corn, as water was not a limiting factor in this study. The ETa of volunteer corn was the highest in soybean (623 mm), followed by sorghum (622 mm), and corn (617 mm) under CPI. The SDI had higher irrigation efficiency, because without affecting crop yield, it had 3%, 6%, and 8% lower ETa in soybean (605 mm), sorghum (585 mm), and corn (571 mm), respectively. Although soil water use did not differ with volunteer corn infestation, a soybean yield loss of 27% was observed, which suggests that volunteer corn may not compete for moisture under fully irrigated conditions; however, it can impact the crop yield potential due to competition for factors other than soil moisture.

This study evaluated the yield and water productiivty response of quinoa to regulated deficit irrigation (RDI), partial root-zone drying (PRD) and conventional deficit irrigation (DI) and full irrigation (FI) using surface (SD) and subsurface drip (SSD) systems in 2016 and 2017 in the eastern Mediterranean region of Turkey. The treatments consisted of RDI, PRD50, DI50, DI75 and FI. A rainfed treatment (RF) was also included in the study. The experimental design was split plots with four replications. DI75 and DI50 received 75 and 50% of FI, respectively. PRD50 received 50% of FI, but from alternative laterals. RDI received 50% of FI during vegetative stage until flowering, and then received 100% of water requirement. The results showed that quinoa under SD used slightly more water than SSD due to reduced surface evaporation. RDI resulted in water saving of 23 and 21% for SD and SSD, respectively, compared to FI; and RDI produced statistically similar grain yields to FI. DI75 treatment resulted in water savings of 16% for both drip methods in the first year and 10 and 25% for SD and SSD systems, respectively, in the second year. PRD50 produced greater yield than DI50 eventhough they received the same amount of irrigation water. RF and PRD50 treatments resulted in significantly greater water productivity (WP) values than other treatments. There was no significant difference between SD and SSD regarding the grain and dry matter yields and WP values. Thus, RDI and DI75 appear to be good alternatives to FI for sustainable quinoa production in the Mediterranean region.

Palmer amaranth (Amaranthus palmeri S. Watson) is a major biotic constraint in agronomic cropping systems in the United States. While crop–weed competition models offer a beneficial tool for understanding and predicting crop yield losses, within these models, certain weed biological characteristics and their responses to the environment are unknown. This limits understanding of weed growth in competition with crops under different irrigation methods and how competition for soil moisture affects crop growth parameters. This research measured the effect of center-pivot irrigation (CPI) and subsurface drip irrigation (SDI) on the actual evapotranspiration (ETa) of A. palmeri grown in maize (Zea mays L.), soybean [Glycine max (L.) Merr.], and fallow subplots. Twelve A. palmeri plants were alternately transplanted 1 m apart in the middle two rows of maize, soybean, and fallow subplots under CPI and SDI in 2019 and 2020 in south-central Nebraska. Maize, soybean, and fallow subplots without A. palmeri were included for comparison. Soil-moisture sensors were installed at 0-0.30, 0.30-0.60, and 0.60-0.90-m soil depths next to or between three A. palmeri and crop plants in each subplot. Soil-moisture data were recorded hourly from the time of A. palmeri transplanting to crop harvest. The results indicate differences in A. palmeri ETa between time of season (early, mid-, and late season) and crop type across 2019 and 2020. Although irrigation type did not affect subplot data, the presence of A. palmeri had an impact on subplot ETa across both years, which can be attributed to the variable relationship between volumetric soil water content (VWC) and ETa throughout the growing season due to advancing phenological stages and management practices. This study provides important and first-established baseline data and information about A. palmeri evapotranspiration and its relation to morphological features for future use in mechanistic crop–weed competition models.

Understanding the water use of drought-tolerant crops of the drought-prone Mediterranean regions is important for sustainable agriculture. The aim of this study was to evaluate the yield and yield responses of amaranth (Amaranthus hybridus L.) to different irrigation strategies conducted in 2019 and 2020 under Mediterranean climatic conditions using surface drip (SD) and subsurface drip (SSD) systems. Strategies investigated were: regulated deficit irrigation (RDI), conventional deficit irrigation (DI25, DI50, DI75), full irrigation (FI) and rainfed treatment. The highest grain yield was observed in FI treatments; RDI treatments produced 5% lower grain yield than the FI treatments, although the RDI treatments resulted in water savings of 23 and 21% for SD and SSD systems, respectively. DI treatments resulted in lower leaf water potential (LWP) and higher crop water-stress index (CWSI) compared to FI in both systems values. The results showed that optimum irrigation conditions to obtain the highest amaranth grain yields were associated with an LWP of −1.0 MPa and an average CWSI of about 0.25. The FI treatments under SSD systems had the highest grain production, followed by FI under SD and RDI under both the drip systems. Under SD and SSD systems, RDI saved 23 and 21% water, respectively, and produced a yield statistically comparable to that of FI. The SSD methods generated higher net income than SD. From these results it can be concluded that both RDI and DI75 could be a good alternative to FI under the conditions of water scarcity in the Mediterranean region.

A comparison has been made of drip and conventional check basin methods of irrigation, using onions and ladies finger as test crops. Significant increases in yield and water use efficiency in drip irrigated over conventionally irrigated plots resulted from increased availability of soil moisture at low tensions and reduced surface evaporation losses. Reduced soil strength in drip irrigated plots was also a factor resulting in increased yield of onions.

We consider the critical Weber number (Wec≡ρV20D/σ) at which the transition from dripping to jetting occurs when a Newtonian liquid of density ρ and surface tension σ is injected with a velocity V0 through a tube of diameter D downward into stagnant air, under gravity g. We extend Taylor's (1959) model for the recession speed of a free edge, and obtain in the inviscid limit an exact solution which includes gravity and inertia effects. This solution provides a criterion for the transition which is shown to occur at a critical Weber number

formula here

where Bo and Boo are the Bond numbers (Bo≡[ρgD2/(2σ)]1/2), respectively based on the inside and outside diameter of the tube, and K is a constant equal to 0.37 for the case of water injected in air. This critical Weber number is shown to be in good agreement with existing experimental values as well as with new measurements performed over a wide range of Bond numbers.

The problem considered is the determination of the mass of the drops which break away when a viscous liquid drips slowly out of a narrow vertical tube. A simple one-dimensional theory of the unsteady extension of a viscous thread under its own weight is given, which holds when viscosity, capillarity and gravity are important but inertia is negligible. A comparison with experiment is given. There are several systematic errors, the most important of which are associated with detailed behaviour at the pipe exit where die-swell and wetting are difficult to assess. With due allowance for these errors, agreement is fairly good.

On the day that dividends are paid, we find a significant positive mean abnormal return that is completely reversed over the following days. This dividend pay date effect has strengthened since the 1970s and is consistent with the temporary price pressure hypothesis. The pay date effect is concentrated among stocks with dividend reinvestment plans (DRIPs) and is larger for stocks with a higher dividend yield, greater DRIP participation, and greater limits to arbitrage. Over time, profits from a trading strategy that exploits this behavior are positively related to the dividend yield and spread and negatively associated with aggregate liquidity.

We give a hydrodynamical explanation for the chaotic behaviour of a dripping faucet using the results of the stability analysis of a static pendant drop and a proper orthogonal decomposition (POD) of the complete dynamics. We find that the only relevant modes are the two classical normal forms associated with a saddle–node–Andronov bifurcation and a Shilnikov homoclinic bifurcation. This allows us to construct a hierarchy of reduced-order models including maps and ordinary differential equations which are able to qualitatively explain prior experiments and numerical simulations of the governing partial differential equations and provide an explanation for the complexity in dripping. We also provide a new mechanical analogue for the dripping faucet and a simple rationale for the transition from dripping to jetting modes in the flow from a faucet.

Vineyards worldwide are subjected to spatial variability, which can be exhibited in both low and high yield areas. We developed a variable rate drip irrigation (VRDI) concept to reduce such variability. The VRDI system divides the vineyard into 30×30-meter irrigation zones, enabling individual irrigation of each zone according to normalized difference vegetation index (NDVI) maps. The first VDRI system was installed in on a 1.2-hectare vineyard Syrah red grape in Israel. With the VRDI system, the yield, leaf area index (LAI), canopy size, water potential, and primary juice chemical analysis results were very uniformed in comparison to previous years without the system.

The following article is based on the Symposium X presentation given by David A. Weitz (Harvard University) on April 11, 2007, at the Materials Research Society Spring Meeting in San Francisco. The article describes how simple microfluidic devices can be used to control fluid flow and produce a variety of new materials. Based on the concepts of coaxial flow and hydrodynamically focused flow, used alone or in various combinations, the devices can produce precisely controlled double emulsions (droplets within droplets) and even triple emulsions (double emulsions suspended in a third droplet). These structures, which can be created in a single microfluidic device, have various applications such as encapsulants for drugs, cosmetics, or food additives.

The transition to dripping in the gravity-driven flow of a liquid film under an inclined plate is investigated at zero Reynolds number. Computations are carried out on a periodic domain assuming either a fixed fluid volume or a fixed flow rate for a hierarchy of models: two lubrication models with either linearised curvature or full curvature (the LCM and FCM, respectively), and the full equations of Stokes flow. Of particular interest is the breakdown of travelling-wave solutions as the plate inclination angle is increased. For any fixed volume, the LCM reaches the horizontal state where it attains a cosine-shaped profile. For sufficiently small volume, the FCM and Stokes solutions attain a weak Young–Laplace equilibrium profile, the approach to which is described by an asymptotic analysis generalising that of Kalliadasis & Chang (J. Fluid Mech., vol. 261, 1994, pp. 135–168) for the LCM. For large volumes, the bifurcation curves for the FCM and Stokes model have a turning point so that the fully inverted state is never reached. For fixed flow rate, the LCM blows up at a critical angle that is well predicted by asymptotic analysis. The bifurcation curve for the FCM either has a turning point or else reaches a point at which the surface profile has an infinite slope singularity, indicating the onset of multi-valuedness. The latter is confirmed by the Stokes model, which can be continued to obtain overturning surface profiles. Overall, the thin-film models either provide an accurate prediction for dripping onset or else supply an upper bound on the critical inclination angle.

Field studies were conducted in 2009 at Clinton, NC and 2014 at Pontotoc, MS to determine the influence of simulated glyphosate drip on sweetpotato yield and quality. Treatments consisted of three glyphosate solution (140 g ae L–1) drip volumes (0.16, 0.32 and 0.48 ml) by four application timings [(4 wk after transplanting (WAP); 6 WAP; 8 WAP; and 4 WAP followed by (fb) 6 WAP fb 8 WAP]. A non-treated check was included for comparison. Visual sweetpotato injury consisted of chlorosis at the shoot tips approximately 1 wk after treatment fb necrosis and stunting. At 6 WAP and 8 WAP, sweetpotato injury following glyphosate applied 4 WAP was 71 and 65%, respectively. Injury from glyphosate applied 4 WAP fb 6 WAP was 78%. Injury from glyphosate applied 6 WAP was 26% at 8 WAP. In 2009, jumbo, no. 1, canner, and marketable yield of the non-treated check were two to three times greater than glyphosate treatments (0.16, 0.32, 0.48 ml). Likewise, yield of the non-treated check was substantially greater than those treated with 0.16 to 0.48 ml glyphosate solution in 2014. In 2009 and 2014, sweetpotato yield of all grades increased as glyphosate application timing was delayed. In 2009, no. 1 yield from glyphosate 8 WAP (8,210 kg ha–1) was similar to the non-treated check. In 2009, there were no cracked storage roots in the non-treated check. However, sweetpotatoes receiving 0.16 to 0.48 ml glyphosate solution displayed 8 to 17%, 11 to 18%, 5 to 13%, and 11 to 16% cracking (by weight) in jumbo, no. 1, canner, and marketable storage roots, respectively. Compared to the non-treated check, glyphosate applied 4 WAP, 6 WAP, or 4 WAP fb 6 WAP fb 8 WAP had a greater percentage of cracked marketable sweetpotato storage roots.

To determine simazine movement and dissipation in a drip-irrigated Vitis vinifera vineyard under two irrigation schedules [ grower standard (GS) and current evaporation/transpiration (CET)], field experiments were conducted in a Hanford fine sandy loam, a soil type prone to leaching. In experiment 1, simazine was surface-applied in a 1.7-m swath down the vine row, and chloride was applied as a tracer. Total recovery of simazine was < 1.0% under the irrigation emitters 51 and 57 d after simazine application in 1997 and 1999, respectively. Simazine was not detected in the soil profile from 0 to 150 cm deep, 1.0 m from the emitters. A chloride tracer moved to a soil depth of 90 cm but not deeper. In experiment 2, simazine moved 75 cm under the emitters in 7 d but did not move deeper into the soil. Under the emitter, 28% of applied simazine was found 0 to 45 cm deep and 3% was > 45 cm deep. In experiment 3, which was conducted in the absence of irrigation, total recovery of simazine was 30% when sheltered from rain and 8% when exposed to rain. Rapid dissipation and proper irrigation management were key factors preventing deep percolation of simazine in these studies.