Effect Of Soil Matric Potential Research Articles

Synergistic and antagonistic interactions of soil water potential and osmotic potential linked to nitrogen fertilization on spinach traits and water use efficiency

Few studies have attempted to investigate the combined effects of soil matric potential (Ψm) and osmotic potential (Ψs) on plant production and water use efficiency (WUE). The purpose of this study is to evaluate the synergistic and antagonistic effects of Ψm and Ψs associated with nitrogen (N) fertilization on spinach (Spinacia oleracea L.) growth traits and WUE. Five levels of salinity (1, 4, 7, 9, 11 dS m−1), three levels of water use amounts including deficit-irrigation (W–), full-irrigation (W0) and over-irrigation (W+), and four levels of N application rates (0, 50, 75, and 100% of N requirement) were applied. A new parameter namely "WUEθ" is suggested based on soil water content (θ). Results showed that water deficit combined with high saline irrigation water caused the most reduction in the plant biomass, leaf area index (LAI) and evapotranspiration (ET). The acquired plant yield coefficient (Ky) of 1.003 indicates that the spinach is a moderately salt-sensitive vegetable. The highest WUE was observed under deficit-irrigation and intermediate salinity conditions, which was attributed to an adaptation mechanism in the plant. However, WUEθ (R2 > 0.98) was a better predictor of the plant yield than WUE (R2 > 0.48). Nitrogen use efficiency (NUE) decreased with increasing salinity and water deficiency. Also, Ψm and Ψs had a synergistic interaction on yield and ET, while their effect on WUE and WUEθ was antagonistic. Salinity greater than drought reduced yield, while both had equal reducing effects on ET. Furthermore, WUE and WUEθ were more influenced by Ψm than Ψs. Research Highlights The new parameter WUEθ is a better predictor of the spinach plant yield than WUE. WUE and WUEθ are more influenced by water potential (Ψm) than osmotic potential (Ψs). Synergistic interaction of Ψm and Ψs on yield and ET, but antagonistic effect on WUE and WUEθ. Salinity greater than drought reduces yield, while both have equal reducing effects on ET. Ψm shows negative effects on yield and ET, but positive effects on WUE and WUEθ.

Understanding soil water effects on nitrogen release from controlled‐release fertilizers

AbstractControlled‐release fertilizers (CRFs) have the potential to deliver crop production and environmental benefits through better control of applied nitrogen (N) in cropping systems. Whereas N release from CRFs can be impacted by several factors, there has been a widely held view that soil water has little effect on N release from polymer‐coated CRFs. Past research has often studied the soil water effect as a function of soil water content. This limits the transferability of results. In this study we measured N release from a polymer‐coated urea (PCU) and a polymer‐sulfur–coated urea (PSCU) using undisturbed soil cores at set matric potentials. Soil matric potential had a significant effect on N release from PCU. Release at −1,000 kPa was delayed by up to 30 d compared with −10 kPa. Optical stereo microscopy clarified that this was linked to differences in the rate of water absorption. Theoretical considerations demonstrate that these relatively large differences could not be explained by the effect of soil matric potential on vapor flow. It is possible that soil matric potential interacted with the properties of the coating to change its permeability or the involvement of liquid flow. The effect of soil water on N release from PSCU was less clear. The magnitude of the soil water effect is, therefore, product‐specific and dependent on coating properties. The soil matric potential provided a consistent description of release patterns between soils with contrasting soil water retention characteristics. Soil water effects should hence be studied as a function of soil matric potential.

Soil salinity and matric potential interaction on water use, water use efficiency and yield response factor of bean and wheat

We studied the effects of soil matric potential and salinity on the water use (WU), water use efficiency (WUE) and yield response factor (Ky), for wheat (Triticum aestivum cv. Mahdavi) and bean (Phaseoulus vulgaris cv. COS16) in sandy loam and clay loam soils under greenhouse conditions. Results showed that aeration porosity is the predominant factor controlling WU, WUE, Ky and shoot biomass (Bs) at high soil water potentials. As matric potential was decreased, soil aeration improved, with Bs, WU and Ky reaching maximum value at −6 to −10 kPa, under all salinities. Wheat WUE remained almost unchanged by reduction of matric potential under low salinities (EC ≤ 8 dSm−1), but increased under higher salinities (EC ≥ 8 dSm−1), as did bean WUE at all salinities, as matric potential decreased to −33 kPa. Wheat WUE exceeds that of bean in both sandy loam and clay loam soils. WUE of both plants increased with higher shoot/root ratio and a high correlation coefficient exists between them. Results showed that salinity decreases all parameters, particularly at high potentials (h = −2 kPa), and amplifies the effects of waterlogging. Further, we observed a strong relationship between transpiration (T) and root respiration (Rr) for all experiments.

Effect of Soil Matric Potential on Urea Hydrolysis

Soil water availability affects NH3 loss from surface applied urea, partly due to its influence on urea hydrolysis rates. However, the quantitative effects of soil water on hydrolysis rates are not well understood. Our objective was to quantify how soil matric potential affects urea hydrolysis rates across a wide range of soil matric potentials. Urea hydrolysis rates were measured based on disappearance of urea at various soil water potentials in soils limed to a pH of 8.2 to eliminate confounding by soil pH. Urea‐N was applied on a soil mass basis (1200 μg urea‐N g−1 soil, 0.2–2.4 mol urea L−1) in Exp. I and at a constant urea‐N soil solution concentration of 40,000 μg urea‐N g−1 soil solution (1.43 mol urea L−1) in Exp. II. Differences in relative rates of urea hydrolysis between both experiments suggested that in Exp. I there was a confounding effect of urea‐N solution concentration on the response of urea hydrolysis to soil matric potential. In Exp. I, relative rates of hydrolysis changed little at intermediate soil matric potentials between −0.1 and −1.0 MPa because urea‐N concentration in solution increased as matric potential decreased. In Exp. II, relative rates were greatest at the highest matric potentials (>−0.24 MPa) and decreased more rapidly as matric potential decreased, approaching zero at a matric potential of approximately −10 MPa. These results also suggest that research to describe urea hydrolysis rates as affected by soil water content should be based on urea‐N concentrations in soil solution and not urea‐N concentrations on a soil mass basis.

Effect of soil matric potential on wolfberry (Lycium barbarbum L.) yield, evapotranspiration and water use efficiency under drip irrigation

The experiment was undertaken in order to investigate the effect of soil matric potential (SMP) on wolfberry yield, evapotranspiration (ET), water use efficiency (WUE) and the implications for soil water management under drip irrigation in the Yinchuan Plain arid region of Northwest China. The experiment consisted of five treatments, which maintained SMP at a depth of 0.2 m immediately under a drip emitter releasing water at -10 (S1), -20 (S2), -30 (S3), -40 (S4) and -50 kPa (S5), respectively, after wolfberry had been planted. The results showed that during the growing season, the target SMP value of the five different treatments was maintained within the experimental design range and the irrigation volume and ET declined as the target SMP value decreased. The temporal and spatial soil water content (SWC) changes observed in the soil profile suggested that the S1 and S2 treatments could meet the crop water absorption demand because the soil moisture was over 15 % and soil water was in excess of crop needs. However, the soil water content for S3, S4 and S5 was less than 15 %, which produced visible water stress in the crop. Statistical analysis for the change values in the electrical conductivity of the saturated soil-paste extract (ECe) showed the significant differences between the different SMP treatments in the middle layer (40 – 80 cm) and the plots S2 (-20 kPa) had the better effect of the soil salinity leached. The highest yield was achieved in the S2 plots and the lowest fresh to dry weight ratio was found in the S3 plots, which also produced the highest quality seed. WUE was in the order S3 > S5 > S2 > S4 > S1. Based on a comprehensive analysis that included irrigation volume, ET value, crop yield and WUE, it is recommended that the SMP threshold should be controlled in the range from -20 to -30 kPa, which was the most favorable drip irrigation schedule for increasing yields and irrigation efficiency. The study should provide information that could be used in other regions suffering from drought and water scarcity. Key words: Deep percolation, irrigation volume, soil salinity, soil water content (SWC), vacuum tensiometers.

Effects of soil matric potential on potato growth under drip irrigation in the North China Plain

This research examines the affect of five soil matric potential (SMP) treatments [F1 (−15 kPa), F2 (−25 kPa), F3 (−35 kPa), F4 (−45 kPa), F5 (−55 kPa)] under drip irrigation conditions conducted in the North China Plain. The temporal and spatial SMP changes observed in the soil profile along with changes in potato root growth suggest that tensiometers placed immediately beneath the emitter (at 20 cm) can be effectively used in scheduling the drip irrigation regimen. Although rain affected soil water distribution during the growing season, the affects of SMP on potato growth were very clear. Crop evapotranspiration was highest for F2, decreasing thereafter to F1, F3, F4, and F5. Other potato growth properties such as crop height, leaf and stem water content, tuber bulk rate and grade, as well as WUE (water use efficiency) and I WUE (irrigation water use efficiency) suggest that an SMP of −25 kPa was the most favorable setting for potato production, while −15 kPa was too high and −45 kPa lead to severe water stress.

Effect of soil matric potential on tomato yield and water use under drip irrigation condition

Field experiment was carried out to investigate the effect of soil matric potential (SMP) on tomato yield, evapotranspiration (ET), water use efficiency (WUE) and irrigation water use efficiency (IWUE) under drip irrigation condition in North China Plain. The experiment included five treatments, which controlled SMP at 0.2 m depth immediately under drip emitter higher than −10 (S1), −20 (S2), −30 (S3), −40 (S4) and −50 kPa (S5), respectively, after tomato plant establishment. The results showed that different SMP affected irrigation amount and tomato ET. Irrigation amount decreased from 185 mm (S1) to 83.6 mm (S5) in 2004, and from 165 mm (S1) to 109 mm (S5) in 2005, respectively. The ET decreased from 270 mm (S1) to 202 mm (S5) in both years. However, it was found that SMP did not affect the tomato yield significantly, for the range of SMP investigated. Both WUE and IWUE increased as SMP decreased. The maximum WUE (253 and 217 kg/ha mm) and IWUE (620 and 406 kg/ha mm) were for S5 in 2 years, whereas the minimum WUE (178 and 155 kg/ha mm) and IWUE 261 and 259 kg/ha mm) were for S1 in 2004 and 2005. Based on the above results, therefore, it is recommended that if the tomatoes are well irrigated (SMP is higher than −20 kPa) during establishment, controlling SMP higher than −50 kPa at 0.2 m depth immediately under drip emitter can be used as an indicator for drip irrigation scheduling during following period of tomato growth in North China Plain.

Sclerotial formation and strand growth of Phymatotrichopsis omnivora in minirhizotrons planted with cotton at different soil water potentials

In situ strand growth and sclerotium formation of Phymatotrichopsis omnivora were observed in minirhizotrons using a microvideo camera. Strand growth was greater in soils subject to decreasing levels of soil matric potential (high water stress) compared with a continuously wet treatment. Intermediate levels of water stress (−0.5 to −0.9 MPa) resulted in less strand growth than either the dry or wet treatments. In all treatments strand growth increased to a maximum within 10 days of inoculum placement in soil but then declined to approach an apparent steady‐state value. The effects of soil matric potential on sclerotium formation were apparent when barley seeds were sown in the experimental units 3 weeks after the experiment had begun, permitting differential water cycling patterns to be obtained. Sclerotia were recovered in larger numbers from experimental units in which high water potentials (> −0.2 MPa) occurred 2 weeks prior to and following the death of host plants.

Effect of soil matric potential on sharp eyespot in germinating wheat following seed treatment

AbstractThe influence of soil matric potential on sharp eyespot was examined in wheat seedlings following seed treatment with the fungicide cyproconazole. Emergence of wheat was tested at matric potentials between 0 and –850 hPa in non‐infested soil and in soil infested with Rhizoctonia cerealis. Optimal shoot emergence was at –50 and –20 hPa in non‐infested and infested soil, respectively. Disease severity was strongly affected by soil matric potential. It continuously increased as matric potential decreased from –5 to –200 hPa. In contrast, optimum growth conditions for the pathogen was at matric potentials between –50 and –200 hPa. With decreasing matric potential the drought stress for the plant seems to increase its predisposition to the pathogen. Seed treatment with cyproconazole reduced sharp eyespot although disease severity increased with decreasing soil matric potential.

Survival of bacterial and fungal populations following chloroform-fumigation: Effects of soil matric potential and bulk density

Survival of bacterial and fungal populations following chloroform-fumigation: Effects of soil matric potential and bulk density

Effects of soil matric potential and bulk density on the growth of Fusarium oxysporum f. sp. raphani

The effects of soil dry bulk density and matric potential on the growth of the pathogenic fungus Fusarium oxysporum f. sp. raphani PEG-4 (PEG-4) in the absence or presence of selected soil microorganisms were investigated. These ‘challenging’ organisms included F. oxysporum f. sp. cucumerinum, a soil fungus Trichoderma viride and a Gram-positive bacterium Pimelobacter sp. The degree of growth of PEG-4 in sterile soils previously colonised by, or simultaneously inoculated with, the soil microorganisms was determined. Soil extracts were also used to test for the effects of a mixed pupulation of soil microorganisms on the interactions. Soil bulk density, ranging from 1.1 to 1.5 Mg m −3 and matric potential (− 1000 to −1 kPa) significantly affected the PEG-4 propagule numbers: PEG-4 appeared to form fewer propagules in more compacted soil or soil at lower matric potential (i.e. drier soil). The potential for the prior colonisers to explore the soil and inhibit the growth of PEG-4 is discussed in relation to the soil structure and associated moisture conditions.

A Two-dimensional, Dynamic Model for Root Growth Distribution of Potted Plants

A two-dimensional mathematical model was developed to describe the time course of root growth and its spatial distribution for container-grown plants, using chrysanthemum [Dendranthema ×grandiflorum (Ramat.) Kitamura] as the model system. Potential root growth was considered as consisting of several concurrent processes, including branching, extension, and death. Branching rate was assumed to be related sigmoidally to existing root weight density. Root growth extension rate was assumed to be proportional to the existing root weight density above some threshold root weight density in adjacent cells. The senescence rate of root weight density was assumed to be proportional to existing root mass. The effects of soil matric potential and temperature on root growth were quantified with an exponential function and the modified Arrhenius equation, respectively. The actual root growth rate was limited by the amount of carbohydrate supplied by the canopy to roots. Parameters in the model were estimated by fitting the model to experimental data using nonlinear regression. Required inputs into the model included initial root dry weight density distribution, soil temperature, and soil water potential data. Being a submodel of the whole-plant growth model, the supply of carbohydrates from canopy to roots was required; the total root weight incremental rate was used to represent this factor. Rather than linking to a complex whole-plant C balance model, the total root weight growth over time was described by a logistic equation. The model was validated by comparing the predicted results with independently measured data. The model described root growth dynamics and its spatial distribution well. A sensitivity analysis of modeled root weight density to the estimated parameters indicated that the model was more sensitive to carbohydrate supply parameters than to root growth distribution parameters.

Texas Panicum (Panicum texanum) Growth as Affected by Irrigation Management and Planting Date

The effect of soil matric potential from −0.02 to <–1.5 MPa on Texas panicum growth in drainage lysimeters covered by an automatic rainfall shelter was measured in 1984, 1985, and 1986. Rate of tiller production was faster for plants established in April than June in 1984 and 1985, but not 1986. In 1985 and 1986, dry weight was greater, but total seed production was less for plants established in April than June. Irrigation when the soil matric potential was −0.02, −0.075, or −1.5 MPa did not affect rate of tiller production in 1984. Irrigation when the soil matric potential was −1.5 MPa decreased dry weight of plants but increased seed number per panicle compared to irrigation when the soil matric potential was −0.02 MPa in 1985 and 1986. Plants grown in lysimeters irrigated at soil matric potential <–1.5 MPa in 1985 and 1986 did not wilt at 8:00 a.m.; therefore, they were not watered after establishment. These nonirrigated plants averaged 0.9 and 0.4 kg dry weight and produced 92 200 and 16 100 seeds in 1985 and 1986, respectively.

Effect of soil matric potential and nitrogen on growth, yield, nutrient uptake and water use of banana

The influence of irrigating at different soil matric potentials (−25, −45, −65 and −85 kPa at 15 cm depth) under different levels of nitrogen (100, 200 and 300 g/plant) on growth, yield, nutrient uptake and water use of banana (“Robusta”) were investigated at the Indian Institute of Horticultural Research, Bangalore. The most frequent irrigation at a soil matric potential of −25 kPa resulted in maximums of growth, dry matter and yield, although data were not significantly different from those for irrigation at −45 kPa. Infrequent irrigations at −65 and −85 kPa delayed flowering and had a significantly adverse effect on growth and yield. Nutrient uptake declined with decreasing frequency of irrigation except in the case of K and mostly followed the changes in dry matter. Banana irrigated at −45 kPa used 1601 mm of water in 485 days. Increasing nitrogen fertilization improved growth, yield, nutrient uptake and water use, although no difference between application rates of 200 and 300 g/plant was found.

Effect of soil matric potential, method of irrigation and nitrogen fertilization on yield, quality, nutrient uptake and water use of radish (Raphanus sativus L.)

Field experiments carried out at the Indian Institute of Horticultural Research, Bangalore during 1983 and 1984 on radish indicated that frequent irrigations when soil matric potential reached −20 kPa at 18 cm depth resulted in maximum root yield, lower NO3-N content in roots, higher N, P, K, Ca and WUE of radish.

Effect of Soil Matric Potential on Phytophthora Root Rot of Alfalfa

Effect of Soil Matric Potential on Phytophthora Root Rot of Alfalfa

Effect of Soil Matric Potential on the Formation and Indirect Germination of Sporangia ofPhytophthora parasitica, P. capsici,andP. cryptogea

Effect of Soil Matric Potential on the Formation and Indirect Germination of Sporangia of<i>Phytophthora parasitica, P. capsici,</i>and<i>P. cryptogea</i>

Effect of Soil Matric Potential on the Formation and Indirect Germination of Sporangia ofPhytophthora parasitica, P. capsici,andP. cryptogea

Effect of Soil Matric Potential on the Formation and Indirect Germination of Sporangia of<i>Phytophthora parasitica, P. capsici,</i>and<i>P. cryptogea</i>

Growth and Water Relations of Wheat Plants with Roots Split Between Soil and Nutrient Solution1

AbstractSoil matric potential controls plant growth. Yet it is difficult to determine the effect of soil matric potential, by itself, on plant water relationships and growth. One way to isolate matric potential is to split roots between soil and nutrient solution because the soil has a matric potential while the nutrient solution has a matric potential of zero. Therefore, in this study, leaf water potential, stomatal resistance, rate of water use, leaf area, plant height, and root length of winter wheat (Triticum aestivum L. em. Thell. cv. Osage), grown with and without wind, and with roots split between soil:soil, soil: nutrient solution (soln), and soln:soln were measured to determine the effect of soil matric potential on wheat water relationships and growth. During the first 16 days of the 38‐day experiment, the soil (Kirkland silt loam, Udertic Paleustoll) was well‐watered. Water was withheld from all soil treatments after the 16th day. Plants were grown with and without wind, and with and without soil drought, because, in the Great Plains, wind and drought, or a combination of the two, are the main causes of crop loss.Leaf water potential and stomatal resistance of plants with roots in soi1:soln were usually between those of plants with roots in soil:soin and soln:soln. Plants with all roots in nutrient solution had the highest leaf water potential and lowest stomatal resistance. Plants with all roots in well‐watered soil lost 2.5 times less water, but grew as well as plants with all roots in solution. Plants with roots split between solution and well‐watered soil lost the same total amount of water as plants with all roots in solution. But the plants with roots in soil:soln lost 7 and 11 times more water from the solution side than from the soil side of the split root containers for the wind and no‐wind treatments, respectively. Nonstressed plants (no wind, no drought) with roots split between soi1:soln were taller and had a larger leaf area than plants with roots all in soil or all in solution. The results showed that growth of wheat was increased if part of its root system was in media with zero matric potential (nutrient solution) and part in soil.

Effect of soil matric potential on leaf water potential, diffusive resistance, growth and development ofGmelina arborea L. seedlings

Gmelina arborea L. seedling growth and diurnal stomatal opening (as measured by stomatal resistance) were studied at soil matric potential 0, -0.1 and -0.72 × 10−5 Pa. Leaf area, leaf number, plant height and dry weights of the vegetative parts were significantly reduced as soil matric potential decreased from 0 to -0.72 × 10−5 Pa. The growth responses followed the same trend as net assimilation rate and relative growth rate. The highest moisture stress induced leaf senescence and leaf fall. Leaf water potential decreased from - 2 × 10−5 Pa to - 20 × 10−5 Pa with increasing soil moisture stress. Results indicate that the diurnal stomatal opening is controlled by photon flux density when this species is grown at soil matrio potential 0 Pa. However, with decreasing soil matrio potential (- 0.10 and -0.72 × 10−5 Pa) the internal plant water deficit appears to oontrol the stomatal opening.