Influence of two site preparation treatments on ecophysiology of planted Piceaengelmannii × glauca seedlings

1989 ◽  
Vol 19 (11) ◽  
pp. 1359-1370 ◽  
Author(s):  
John H. Bassman

The effects of mounding and soil scarification on microclimate, water relations, photosynthesis, and growth of planted Piceaengelmannii × glauca seedlings were evaluated over three growing seasons. Mounding increased soil temperatures by up to 40% at depths of 5 and 12 cm, but not at 30 cm, during periods of dry, clear weather. Scarification resulted in small increases in soil temperature only at the 5 cm depth. Soil water potential and soil water content were lower in mounds, but similar in scarified patches and controls from midsummer through fall. Transpiration, leaf conductance, and xylem pressure potentials were generally reduced by mounding and to a much lesser extent by scarification compared with controls. However, these responses were complicated by interactions with leaf to air vapor density differences and possibly by soil temperatures. Treatments had no significant effects on diurnal or light responses of photosynthesis. Mounding increased stem and needle weights during the first one-half of the growing season in the first 2 years after planting, but growth was reduced later in the season, probably as a result of increased water stress. Root growth in mounds was significantly greater than scarified patches and controls in all 3 years. Growth patterns for seedlings planted in scarified patches and control treatments were similar to each other. By the end of the third growing season after planting, seedlings in mound treatments had greater stem diameters and total seedling weight was more than double that of controls, but there was little difference in height. Seedlings in scarified patches were similar to controls in diameter and height, but had slightly greater total weights. Results suggest that the positive effects of improved soil temperatures and root growth in mound treatments were negated to a large extent by increased water stress in the first two seasons. By the third growing season, roots were beyond significant drying influence of the mound and their greater length and mass served to increase seedling biomass substantially.

1986 ◽  
Vol 66 (1) ◽  
pp. 51-58 ◽  
Author(s):  
H. W. CUTFORTH ◽  
C. F. SHAYKEWICH ◽  
C. M. CHO

Root growth between germination and emergence for the corn hybrids Pioneer 3995, Northrup King 403 and Pride 1108 was studied. Soil temperatures of 15, 19, 25 and 30.5 °C and a range of soil water contents were used. Decreases in soil temperature and water content both decreased root growth rate. Sensitivity to water content decreased with decreasing soil temperature. All three hybrids responded to soil temperature in the same way. By contrast, Pioneer 3995 was less sensitive to soil water stress than was Northrup King 403, while Pride 1108 was the most sensitive. Key words: Soil water, soil temperature, root growth (early), corn


Weed Science ◽  
1994 ◽  
Vol 42 (4) ◽  
pp. 561-567 ◽  
Author(s):  
Charles A. King ◽  
Lawrence R. Oliver

Experiments were conducted to evaluate the influence of temperature and water potential on water uptake, germination, and emergence of large crabgrass in order to predict emergence in the field. Water uptake of seed soaked in polyethylene glycol solutions of 0 to −1400 kPa underwent an initial imbibition phase followed by a lag phase and subsequent increase in water content when radicles emerged from the seed. Maximum germination at 15 C was 12% at 0 kPa and 60% at 25 C at 0 to −200 kPa osmotic potential. In the growth chamber, large crabgrass emergence from soil began 2 to 3 d after planting at 30 or 35 C and within 9 to 10 d at 15 C. Maximum emergence of 77 % occurred at 25 C and at a soil water potential of −30 kPa. Emergence percentage decreased as water potential decreased or as temperature increased or decreased. A logistic equation described emergence of large crabgrass at each combination of temperature and soil water potential at which emergence occurred, and a predictive model was developed and validated by field data. In the field, there was little or no emergence at soil temperatures below 15 C or water potentials below −50 to −60 kPa. The model predicted the time of onset of large crabgrass emergence and the time to reach maximum emergence to within 2 to 4 d of that recorded in field experiments. The model also predicted the correct number of flushes of emergence occurring in the field in three of four experiments.


1994 ◽  
Vol 21 (1) ◽  
pp. 69 ◽  
Author(s):  
JG Phillips ◽  
SJ Riha

A split-root experiment was conducted using Eucalyptus viminalis seedlings which were exposed to three watering regimes in order to investigate root growth and soil water extraction under conditions of a drying soil profile. Seedlings were grown in columns in which the soil was divided horizontally with a soft wax plate. Watering treatments were composed of (1) both upper and lower sections of the column well watered (W/W), (2) only the lower section well watered (D/W), and (3) water withheld completely from both upper and lower sections (D/D). Daily measurements included soil water potential (Ψs), column water loss and leaf elongation. Increase in above- and below-ground biomass was deter- mined from initial and final harvests after 25 days of treatment. Whole-column water loss and leaf extension were depressed as Ψs in the upper section of D/W and D/D decreased to -0.4 MPa over the first 8-10 days. However, water loss did not decrease significantly in the lower section of treatment D/W relative to the lower section of treatment W/W during this period. This indicated that water extraction by roots remaining in wet soil was not severely inhibited by the decrease in transpiration associated with the soil conditions in the upper profile. Root distribution at the end of the experiment indicated significant growth in the lower section of treatment D/W. There was evidence that hydraulic lifting of water between column sections may have occurred, as periodic increases in soil water potential of the unwatered upper section of D/W were observed.


Plant Disease ◽  
2000 ◽  
Vol 84 (8) ◽  
pp. 895-900 ◽  
Author(s):  
S. R. Kendig ◽  
J. C. Rupe ◽  
H. D. Scott

The effects of irrigation and soil water stress on Macrophomina phaseolina microsclerotial (MS) densities in the soil and roots of soybean were studied in 1988, 1989, and 1990. Soybean cvs. Davis and Lloyd received irrigation until flowering (TAR2), after flowering (IAR2), full season (FSI), or not at all (NI). Soil water matric potentials at 15- and 30-cm depths were recorded throughout the growing season and used to schedule irrigation. Soil MS densities were determined at the beginning of each season. Root MS densities were determined periodically throughout the growing season. Microsclerotia were present in the roots of irrigated as well as nonirrigated soybean within 6 weeks after planting. By vegetative growth stage V13, these densities reached relatively stable levels in the NI and FSI treatments (2.23 to 2.35 and 1.35 to 1.63 log [microsclerotia per gram of dry root], respectively) through reproductive growth stage R6. After R6, irrigation was discontinued and root densities of microsclerotia increased in all treatments. Initiation (IAR2) or termination (TAR2) of irrigation at R2 resulted in significant changes in root MS densities, with densities reaching levels intermediate between those of FSI and NI treatments. Year to year differences in root colonization reflected differences in soil moisture due to rainfall. The rate of root colonization in response to soil moisture stress decreased with plant age. Root colonization was significantly greater in Davis than Lloyd at R5 and R8. This was reflected in a trend toward higher soil densities of M. phaseolina at planting in plots planted with Davis than in plots planted with Lloyd. Although no charcoal rot symptoms in the plant were observed in this study, these results indicated that water management can limit, but not prevent, colonization of soybean by M. phaseolina, that cultivars differ in colonization, and that these differences may affect soil densities of the fungus.


HortScience ◽  
2005 ◽  
Vol 40 (3) ◽  
pp. 795-798 ◽  
Author(s):  
Dana L. Baumann ◽  
Beth Ann Workmaster ◽  
Kevin R. Kosola

Wisconsin cranberry growers report that fruit production by the cranberry cultivar `Ben Lear' (Vaccinium macrocarpon Ait.) is low in beds with poor drainage, while the cultivar `Stevens' is less sensitive to these conditions. We hypothesized that `Ben Lear' and `Stevens' would differ in their root growth and mortality response to variation in soil water potential. Rooted cuttings of each cultivar were grown in a green-house in sand-filled pots with three different soil water potentials which were regulated by a hanging water column below a fritted ceramic plate. A minirhizotron camera was used to record root growth and mortality weekly for five weeks. Root mortality was negligible (2% to 6%). Whole plant relative growth rates were greatest for both cultivars under the wettest conditions. Rooting depth was shallowest under the wettest conditions. Whole-plant relative growth rates of `Ben Lear' were higher than `Stevens' at all soil water potentials. `Stevens' plants had significantly higher root to shoot ratios and lower leaf area ratios than `Ben Lear' plants, and produced more total root length than `Ben Lear' at all soil water potentials. Shallow rooting, high leaf area ratio, and low allocation to root production by `Ben Lear' plants may lead to greater susceptibility to drought stress than `Stevens' plants in poorly drained cranberry beds.


Rangifer ◽  
1990 ◽  
Vol 10 (3) ◽  
pp. 99 ◽  
Author(s):  
Olof Eriksson ◽  
Tuomo Raunistola

During recent years, soil scarification has become a standard procedure for improving seed beds after logging. Around 57 000 ha were treated, primarily through harrowing and ploughing, in the counties of Vâsterbotten and Norbotten during 1985. The positive effects of scarification, from a forestry point of view, are improved access to plant nutrients, raised soil temperatures and reduces surface moisture. The aim of the present study was to describe long-term changes in the ground vegetation following scarification. Harrowing affects 45-55% of the plant cover while ploughing affects 65-90%. 10 years after ploughing and harrowing about 20% of the surface is still without vegetation. Real long-term effects remain in dispute. It has been claimed that ploughing, at least, may lead to irreversible changes.


2021 ◽  
Vol 25 (3) ◽  
pp. 1411-1423 ◽  
Author(s):  
Xiangyu Luan ◽  
Giulia Vico

Abstract. Crop yield is reduced by heat and water stress and even more when these conditions co-occur. Yet, compound effects of air temperature and water availability on crop heat stress are poorly quantified. Existing crop models, by relying at least partially on empirical functions, cannot account for the feedbacks of plant traits and response to heat and water stress on canopy temperature. We developed a fully mechanistic model, coupling crop energy and water balances, to determine canopy temperature as a function of plant traits, stochastic environmental conditions, and irrigation applications. While general, the model was parameterized for wheat. Canopy temperature largely followed air temperature under well-watered conditions. But, when soil water potential was more negative than −0.14 MPa, further reductions in soil water availability led to a rapid rise in canopy temperature – up to 10 ∘C warmer than air at soil water potential of −0.62 MPa. More intermittent precipitation led to higher canopy temperatures and longer periods of potentially damaging crop canopy temperatures. Irrigation applications aimed at keeping crops under well-watered conditions could reduce canopy temperature but in most cases were unable to maintain it below the threshold temperature for potential heat damage; the benefits of irrigation in terms of reduction of canopy temperature decreased as average air temperature increased. Hence, irrigation is only a partial solution to adapt to warmer and drier climates.


HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 837D-837
Author(s):  
Clinton C. Shock ◽  
Erik B.G. Feibert ◽  
Lamont D. Saunders

Six soil water potential irrigation criteria (–12.5 to –100 kPa) were examined to determine levels for maximum onion yield and quality. Soil water potential at 0.2-m depth was measured by tensiometers and granular matrix sensors (Watermark Model 20055, Irrometer Co., Riverside, Calif.). Onions are highly sensitive to small soil water deficits. The crop needs frequent irrigations to maintain small negative soil water potentials for maximum yields. In each of 3 years, yield and bulb size increased with wetter treatments. In 1994, a relatively warm year, onion yield and bulb size were maximized at –12.5 kPa. In 1993, a relatively cool year, onion marketable yield peaked at –37.5 kPa due to a significant increase in rot during storage following the wetter treatments.


Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2478 ◽  
Author(s):  
Ali Rashid Niaghi ◽  
Xinhua Jia

As an important component of the water budget, quantifying actual crop evapotranspiration (ET) will enable better planning, management, and allocation of the water resources. However, accurate ET measurement has always been a challenging task in agricultural water management. In the upper Midwest, where subsurface drainage is a common practice due to the shallow ground water depth and heavy clayey soil, ET measurement using traditional ground-based methods is more difficult. In this study, ET was measured using the eddy covariance (EC), Bowen ratio-energy balance (BREB), and soil water balance (SWB) methods during the 2018 corn growing season, and the results of the three methods were compared. To close the energy balance for the EC system, the residual method was used. For the SWB method, capillary rise was included in the ET estimation and was calculated using the measured soil water potential. The change of soil water content for ET estimation using the SWB method was calculated in four different ways, including daily average, 24:00–2:00 average, 24:00–4:00 average, and 4:00 measurement. Through the growing season, six observation periods (OPs) with no rainfall or minimal rainfall events were selected for comparisons among the three methods. The estimated latent heat flux (LE) by the EC system using the residual method showed a 29% overestimation compared to LE determined by the BREB system for the entire growing season. After excluding data taken in May and October, LE determined by the EC system was only 10% higher, indicating that the main difference between the two systems occurred during the early and late of the growing season. By considering all six OPs, a 6%–22% LE difference between the EC and the BREB systems was observed. Except during the early growing and late harvest seasons, both systems agreed well in LE estimation. The SWB method using the average soil water contents between 24:00 and 2:00 time period to calculate the daily capillary rise produced the best statistical fit when compared to the ET estimated by the BREB, with a root-mean-square error of 1.15. Therefore, measuring ET using the capillary rise from a shallow water table between 24:00 and 2:00 could improve the performance of the SWB methodology for ET measurement.


2019 ◽  
Vol 49 (11) ◽  
pp. 1441-1452
Author(s):  
Jouni Kilpeläinen ◽  
Timo Domisch ◽  
Tarja Lehto ◽  
Leena Finér ◽  
Pedro J. Aphalo ◽  
...  

Tree roots comprise a huge carbon pool. Their dynamics are driven by environmental factors and thereby affected by climate change. We studied the effects of soil temperature on root and shoot phenology and their linkages in Norway spruce (Picea abies (L.) Karst.). Saplings were grown in controlled-environment rooms for three simulated growing seasons (GS1, GS2, and GS3). Soil-temperature treatments of 9, 13, 18, and 21 °C were applied during GS2. Root growth was monitored with minirhizotrons and commenced in all treatments simultaneously. Temporal growth patterns of short and long roots were usually bimodal. Root growth was very low during the coldest treatment of GS2 but increased during GS3 as an aftereffect. During GS3, growth of short roots continued later after colder treatments than warmer treatments. Reduced sink strength of roots and increased carbohydrate accumulation into needles at 9 °C during GS2 probably enabled compensatory root growth under restored temperatures during GS3. Soil temperature did not affect shoot phenology, and root and shoot phenology varied between growing seasons; thus, the linkage of root and shoot phenology was inconsistent. In warmer soil, root longevity was shorter and turnover rate was higher than in colder soil. This can further affect soil carbon dynamics and ecosystem carbon cycling in boreal forest ecosystems.


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