The effect of defoliation on the persistence of Atriplex vesicaria

1971 ◽  
Vol 22 (2) ◽  
pp. 239 ◽  
Author(s):  
JH Leigh ◽  
WE Mulham
Keyword(s):  
Soil Moisture ◽  
Potential Growth ◽  
Merino Sheep ◽  
Perennial Shrub ◽  
Soil Moisture Status

To determine the response of the perennial shrub Atriplex vesicaria Hew. ex Benth. (bladder saltbush) to grazing, bushes were grazed by Merino sheep to two levels of defoliation, severe and complete. Ungrazed bushes were used as controls. Separate groups of plots were defoliated in October and February and two levels of soil moisture were imposed. Results showed that the more heavily the bushes were grazed the less likely they were to regenerate. Completely defoliated bushes did not regrow, irrespective of soil moisture status or season. It is hypothesized that the inability of A, vesicaria to persist after complete or severe grazing is due to the removal, by grazing, of potential growth sites which apparently occur only along the young stems.

Distribution of soil moisture content and its effect on the potential growth of the over-story species in North-East Chalkidiki

2001 ◽  
Vol 66 ◽  
Author(s):  
M. Aslanidou ◽  
P. Smiris
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Soil Depth ◽  
Moisture Distribution ◽  
Taxus Baccata ◽  
Mixed Stands ◽  
Potential Growth ◽  
North East ◽  
Soil Moisture Distribution

This  study deals with the soil moisture distribution and its effect on the  potential growth and    adaptation of the over-story species in north-east Chalkidiki. These  species are: Quercus    dalechampii Ten, Quercus  conferta Kit, Quercus  pubescens Willd, Castanea  sativa Mill, Fagus    moesiaca Maly-Domin and also Taxus baccata L. in mixed stands  with Fagus moesiaca.    Samples of soil, 1-2 kg per 20cm depth, were taken and the moisture content  of each sample    was measured in order to determine soil moisture distribution and its  contribution to the growth    of the forest species. The most important results are: i) available water  is influenced by the soil    depth. During the summer, at a soil depth of 10 cm a significant  restriction was observed. ii) the    large duration of the dry period in the deep soil layers has less adverse  effect on stands growth than in the case of the soil surface layers, due to the fact that the root system mainly spreads out    at a soil depth of 40 cm iii) in the beginning of the growing season, the  soil moisture content is    greater than 30 % at a soil depth of 60 cm, in beech and mixed beech-yew  stands, is 10-15 % in    the Q. pubescens  stands and it's more than 30 % at a soil depth of 60 cm in Q. dalechampii    stands.

scholarly journals Root Response to Soil Water Status via Interaction of Crop Genotype and Environment

Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 708
Author(s):  
Phanthasin Khanthavong ◽  
Shin Yabuta ◽  
Hidetoshi Asai ◽  
Md. Amzad Hossain ◽  
Isao Akagi ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Root Distribution ◽  
Water Status ◽  
Soil Layer ◽  
Shoot Biomass ◽  
Soil Conditions ◽  
Crop Adaptation ◽  
Soil Moisture Status ◽  
Root Distributions

Flooding and drought are major causes of reductions in crop productivity. Root distribution indicates crop adaptation to water stress. Therefore, we aimed to identify crop roots response based on root distribution under various soil conditions. The root distribution of four crops—maize, millet, sorghum, and rice—was evaluated under continuous soil waterlogging (CSW), moderate soil moisture (MSM), and gradual soil drying (GSD) conditions. Roots extended largely to the shallow soil layer in CSW and grew longer to the deeper soil layer in GSD in maize and sorghum. GSD tended to promote the root and shoot biomass across soil moisture status regardless of the crop species. The change of specific root density in rice and millet was small compared with maize and sorghum between different soil moisture statuses. Crop response in shoot and root biomass to various soil moisture status was highest in maize and lowest in rice among the tested crops as per the regression coefficient. Thus, we describe different root distributions associated with crop plasticity, which signify root spread changes, depending on soil water conditions in different crop genotypes as well as root distributions that vary depending on crop adaptation from anaerobic to aerobic conditions.

scholarly journals A COMPARISON OF TWO METHODS FOR DETERMINING THE EVAPOTRANSPIRATION AND DRAINAGE COMPONENTS OF THE SOIL WATER BALANCE

1987 ◽  
Vol 67 (1) ◽  
pp. 43-54 ◽  
Author(s):  
C. P. MAULÉ ◽  
D. S. CHANASYK
Keyword(s):  
Soil Moisture ◽  
Water Balance ◽  
Gradient Method ◽  
Field Capacity ◽  
The Other ◽  
Soil Water Balance ◽  
Moisture Loss ◽  
Moisture Extraction ◽  
Soil Moisture Status ◽  
Capacity Method

Two simple techniques for separating soil moisture loss into drainage and evapotranspiration for cropped conditions were compared. The study was conducted during May through September 1983 at Ellerslie, Alberta. One technique, the field capacity method, utilized soil tension at − 4 kPa to demarcate the cessation of drainage; the other technique, the gradient method, utilized changes in soil moisture status relative to fallow conditions, to mark the onset of moisture extraction by roots. Both methods estimated similar amounts of drainage and evapotranspiration for the barley plots. Application and thus proper evaluation of these two methods were limited as more than 83% of the total drainage occurred during a 3-wk period in which only the Penman method for estimating evapotranspiration could be used. Key words: Water balance, drainage, evapotranspiration, field capacity method, gradient method

Drip irrigation affects N2O emission differently depending on soil moisture status in an intensive vegetable production system

2021 ◽  
Author(s):  
Xiuchun Xu ◽  
Di Wu ◽  
Wei Zhang ◽  
Bang Ni ◽  
Xuan Yang ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Drip Irrigation ◽  
Production System ◽  
Nitrate Content ◽  
Site Preference ◽  
Vegetable Production ◽  
Flood Irrigation ◽  
Tomato Production ◽  
Production Region ◽  
Soil Moisture Status

<p>Plastic-shed vegetable production system is becoming the main type of vegetable production in China, while excessive irrigation and fertilization input lead to significant N loss by leaching, runoff, and gaseous N. The current study established a field experiment to investigate the effects of drip irrigation and optimized fertilization on vegetable yield, water and fertilizer efficiencies and N<sub>2</sub>O emission in a typical intensive plastic-shed tomato production region of China. The treatments include CK (no fertilization, flood irrigation), FFP (farmers’ conventional fertilization, flood irrigation), OPT1 (80% of FFP fertilization, flood irrigation), OPT2 (80% of FFP fertilization, drip irrigation). N<sub>2</sub>O isotopocule deltas, including δ<sup>15</sup>N<sup>bulk</sup>, δ<sup>18</sup>O and SP (the <sup>15</sup>N site preference in N<sub>2</sub>O), have been used to investigate microbial pathways of N<sub>2</sub>O production under different treatments. Our results showed: i) optimized fertilization and drip irrigation significantly improved the fertilizer and water use efficiency without reducing tomato yield, ii) compared with flood irrigation, drip irrigation decreased soil WFPS and soil ammonium content, but increased soil nitrate content. When soil moisture was higher than 60%WFPS, drip irrigation led to a decrease of N<sub>2</sub>O emission with lower N<sub>2</sub>O SP signature observed than that of food irrigation, suggesting a reduction of denitrification derived N<sub>2</sub>O. In contrast, drip irrigation significantly increased N<sub>2</sub>O emission and N<sub>2</sub>O SP value when soil moisture status was lower than 55% WFPS, which may be due to the enhanced nitrification or fungal denitrification derived N<sub>2</sub>O.</p>

Effect of Stand Density on Water Use of Mulga (Acacia aneura F.muell.) Woodlands in South-Western Queensland

1976 ◽  
Vol 24 (2) ◽  
pp. 177 ◽  
Author(s):  
AJ Pressland
Keyword(s):  
Soil Moisture ◽  
Water Use ◽  
Stand Density ◽  
Tree Density ◽  
Pan Evaporation ◽  
Permanent Wilting Point ◽  
The Mean ◽  
Acacia Aneura ◽  
Soil Moisture Status ◽  
Wilting Point

The important Australian fodder tree mulga (Acacia aneura F. Muell.) was thinned to densities ranging between 0 and 4000 trees ha-1 near Charleville, Queensland. Water use by the ensuing communities was studied from December 1971 to October 1973. Evapotranspiration over this 22 month period increased with tree density from 814 mm for the totally cleared plots to 852 and 891 mm for those plots supporting 4000 and 640 trees ha-1 respectively. Regression analysis was used to relate soil moisture to time since rain; it was established that the soil had dried to its permanent wilting point within 60 days of rain sufficient to recharge the soil to a depth of 135 cm. The mean apparent maximum evapotranspiration of the mulga communities was 4.7 mm day-1. The ratios of evapotranspiration to pan evaporation (Et/Eo) were influenced by both soil moisture status and tree density. Et/Eo ratios ranged between 0.55 and 0.07 in the summer of 1972, and between 1.05 and 0.05 the following summer. In the winters of 1972 and 1973 Et/Eo ratios ranged between 0.92 and 0.04, and 1.33 and 0.09 respectively. The significance of the results to production and management of mulga lands in south-western Queensland is discussed.

Dark Island heath (Ninety-mile Plain, South Australia). V. The water relationships in heath vegetation and pastures on the Makin sand

1957 ◽  
Vol 5 (2) ◽  
pp. 151 ◽  
Author(s):  
RL Specht
Keyword(s):  
Soil Moisture ◽  
Balance Sheet ◽  
South Australia ◽  
Field Capacity ◽  
Severe Drought ◽  
Soil Moisture Storage ◽  
Drought Conditions ◽  
Moisture Storage ◽  
Medicago Sativa L ◽  
Soil Moisture Status

Heath vegetation shows a major flush of growth during the mediterraneantype summer season, a time when calculations of the soil moisture storage by the techniques of Thornthwaite (1948) or Prescott, Collins, and Shirpurkar (1952) indicate that severe drought conditions should oocur. Monthly observations on the moisture status of the Makin sand under heath vegetation and, for comparison, under various pastures are therefore recorded. The problems of obtaining an accurate water balance-sheet for such a heterogeneous vegetation as the heath are discussed. Difficulties in the use of the various techniques for measuring soil moisture in sand, which has a low pF of 1.85 at field capacity, are enumerated. The following relationships were found between the evapotranspiration index (Itr = Etr / Ew0.75) and the available water (W). These data were calculated for 6 ft of sand. (i) Heath vegetation (10–14 years old) log (2.4–Itr) = 0.420–0.0383 W (ii) Heath vegetation (burnt) log (2.4–Itr) = 0.461–0.0380 W (iii) Oenothera odorata Jacq. pasture log (2.4–Itr) = 0.395–0.0269 W (iv) Medicago sativa L. pasture log (2.4–Itr) = 0.390–0.0270 W (v) Ehrharta calycina Sm. pasture log (2.4–Itr) = 0.400–0.0339 W From these equations the mean monthly quantities of rainfall which may be stored in 6 ft of sand under the various treatments described were calculated. Drought conditions are shown to occur in December and January, but are relieved in the later months of summer. Even if the stored moisture below 8 ft is considered, the soil moisture status would be expected to be just sufficient to maintain the vegetation in a "dormant" state, and yet the major growth of the heath vegetation occurs at this time. The calculated mean annual values of Itr range from 0.53 to 0.60 for these perennial communities. Close approximations to the actual soil moisture status can be obtained by substituting these values for K in Prescott's formula for potential evaporation, i.e. Etr = K x Ew0.75. Supplementary data on transpiration, growth, and the root systems of the pastures are also included.

scholarly journals Early-Stage Phenotyping of Root Traits Provides Insights into the Drought Tolerance Level of Soybean Cultivars

Agronomy ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 188
Author(s):  
Elana Dayoub ◽  
Jay Ram Lamichhane ◽  
Céline Schoving ◽  
Philippe Debaeke ◽  
Pierre Maury
Keyword(s):  
Soil Moisture ◽  
Water Stress ◽  
Early Stage ◽  
Canopy Cover ◽  
Early Growth ◽  
Growth Difference ◽  
Controlled Conditions ◽  
Significant Difference ◽  
Soil Moisture Status ◽  
Root And Shoot Traits

Soybean (Glycine max (L.) Merr.) may contribute to the agro-ecological transition of cropping systems in Europe, but its productivity is severely affected by summer drought. New drought-avoidance cropping strategies, such as early sowing, require cultivars with high early plant growth under suboptimal conditions. This study aims at phenotyping early-stage root and shoot traits of 10 cultivars commonly grown in Europe. Cultivars were grown in minirhizotrons under two soil moisture status in controlled conditions. Root and shoot traits were evaluated at 10 days after sowing. Field early growth of two cultivars was also analyzed under early and conventional sowing dates. A significant intraspecific variability (p < 0.05) was found for most investigated shoot and root morpho-physiological traits regardless of the soil moisture status under controlled conditions. However, no significant difference among cultivars (p > 0.05) was found in terms of root architectural traits that were mainly affected by water stress. Total root length was positively correlated with shoot length and shoot dry matter (p < 0.05). Under field conditions, the differences between cultivars were expressed by the canopy cover at emergence, which determines the subsequent canopy cover dynamics. The significant early growth difference among cultivars was not related to the maturity group. Cultivars characterized by high root depth and length, high root density and narrow root angle could be considered as good candidates to cope with water stress via better soil exploration. New agronomic strategies mobilizing the diversity of cultivars could thus be tested to improve soybean water use efficiency in response to climate change.

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