SPREAD OF TOADFLAX IN SASKATCHEWAN

1963 ◽  
Vol 43 (2) ◽  
pp. 214-221 ◽  
Author(s):  
R. T. Coupland ◽  
S. Zilke ◽  
G. W. Selleck
Keyword(s):  
Soil Moisture ◽  
Good Control ◽  
Weather Conditions ◽  
Survey Sampling ◽  
Linaria Vulgaris ◽  
Precise Data ◽  
Perennial Weeds ◽  
Farm Survey ◽  
Line Transects

During 1949–57, surveys and resurveys were conducted throughout one-third of the settled area of Saskatchewan for the purpose of ascertaining the abundance of several species of introduced persistent perennial weeds and to evaluate their rates of increase. The methods used included an extensive farm-to-farm survey, sampling quarter-sections along transects in heavily infested areas, and resurveys of the same land at intervals. Detailed studies along line transects in various habitats were used during 1954–61 to obtain more precise data concerning increases and decreases in extent of infestations. These studies indicated that, within the area surveyed, 142,702 acres were infested with toadflax (Linaria vulgaris Mill.) in 4,993 quarter-sections. The increase in abundance of the weed was particularly great from 1949 to 1954, while after that date uncultivated infestations spread much less rapidly and cultivated ones were kept under fairly good control. The data indicate that the weed probably responds to weather conditions in such a way as to be favored relative to grasses by deficiency of soil moisture in the upper levels of the soil.

scholarly journals Examination of the physical state of the soil under conventional and reduced tillage systems

2013 ◽  
pp. 183-186
Author(s):  
Géza Tuba
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Compaction ◽  
Soil Layer ◽  
Weather Conditions ◽  
Penetration Resistance ◽  
Conventional Tillage ◽  
Reduced Tillage ◽  
Deep Soil ◽  
Tillage Systems

he effect of reduced and conventional tillage systems on soil compaction and moisture content in two years with extreme weather conditions is introduced in this paper. The investigations were carried out in a long-term soil cultivation experiment set on a heavy textured meadow chernozem soil at the Karcag Research Institute. In 2010 the amount of precipitation during the vegetation period of winter wheat was 623.3 mm, 2.2 times higher than the 50-year average, while in 2011 this value was 188.7 mm giving only 65% of the average. The examinations were made after harvest on stubbles on 4 test plots in 5 replications in the case of each tillage system. Soil compaction was characterised by penetration resistance values, while the actual soil moisture contents were determined by gravimetry. The values of penetration resistance and soil moisture content of the cultivated soil layer were better in the case of reduced tillage under extreme precipitation conditions. It could be established that regular application of deep soil loosening is essential due to the formation of the unfavourable compact soil layer under 30 cm. Conventional tillage resulted in enhanced compaction under the depth of ploughing, the penetration resistance can reach the value of 4 MPa under wet, while even 8 MPa under dry soil status.

scholarly journals Spatial variability and its scale dependency of observed and modeled soil moisture under different climate conditions

2012 ◽  
Vol 9 (9) ◽  
pp. 10245-10276 ◽  
Author(s):  
B. Li ◽  
M. Rodell
Keyword(s):  
Soil Moisture ◽  
Spatial Variability ◽  
Warm Season ◽  
Weather Conditions ◽  
Data Sets ◽  
Scale Dependency ◽  
Convex Shape ◽  
Climate Conditions ◽  
Spatial Moments

Abstract. Past studies on soil moisture spatial variability have been mainly conducted in catchment scales where soil moisture is often sampled over a short time period. Because of limited climate and weather conditions, the observed soil moisture often exhibited smaller dynamic ranges which prevented the complete revelation of soil moisture spatial variability as a function of mean soil moisture. In this study, spatial statistics (mean, spatial variability and skewness) of in situ soil moisture measurements (from a continuously monitored network across the US), modeled and satellite retrieved soil moisture obtained in a warm season (198 days) were examined at large extent scales (>100 km) over three different climate regions. The investigation on in situ measurements revealed that their spatial moments strongly depend on climates, with distinct mean, spatial variability and skewness observed in each climate zone. In addition, an upward convex shape, which was revealed in several smaller scale studies, was observed for the relationship between spatial variability of in situ soil moisture and its spatial mean across dry, intermediate, and wet climates. These climate specific features were vaguely or partially observable in modeled and satellite retrieved soil moisture estimates, which is attributed to the fact that these two data sets do not have climate specific and seasonal sensitive mean soil moisture values, in addition to lack of dynamic ranges. From the point measurements to satellite retrievals, soil moisture spatial variability decreased in each climate region. The three data sources all followed the power law in the scale dependency of spatial variability, with coarser resolution data showing stronger scale dependency than finer ones. The main findings from this study are: (1) the statistical distribution of soil moisture depends on spatial mean soil moisture values and thus need to be derived locally within any given area; (2) the boundedness of soil moisture plays a pivoting role in the dependency of soil moisture spatial variability/skewness on its mean (and thus climate conditions); (3) the scale dependency of soil moisture spatial variability changes with climate conditions.

Can climate models capture the high amplitudes circumglobal waves and their surface imprints?  

2021 ◽  
Author(s):  
Fei Luo ◽  
Kai Kornhuber ◽  
Frank Selten ◽  
Dim Coumou
Keyword(s):  
Soil Moisture ◽  
Climate Models ◽  
Phase Locking ◽  
Weather Conditions ◽  
Reanalysis Data ◽  
Circulation Types ◽  
Temperature And Precipitation ◽  
Wave Patterns ◽  
Precipitation Anomalies ◽  
June July

<p>Pronounced circumglobal waves can trigger and maintain persistent summer weather conditions by remaining in their preferred phase-locked positions for several weeks in a row. This phenomenon, especially important for wave numbers 5 and 7, has been observed in recent years, but it is unclear whether climate models can reproduce circulation types and their surface imprints.</p><p>Here we assess three climate models (EC-Earth3, CESM1.2, and MIROC5)  for their representation of amplified circumglobal waves and associated surface imprints in summer (June, July and August) over 1979-2016. ERA5 reanalysis data is used as reference to assess the models’ performance. We run a series of modeling experiments to understand the source of biases in the climate models: free interactive atmosphere and soil moisture runs (AISI), atmospheric nudged runs (AFSI), soil moisture prescribed runs (AISF), and both atmosphere and soil moisture nudged experiments (AFSF).</p><p>We show that all models reasonably well reproduce the climatological wave spectra. Further, both wave 5 and wave 7 are found to exhibit phase-locking behaviors across all models, resulting in similar wave patterns across the hemisphere as compared to reanalysis. The surface imprints are observed in the models as well, but depending on the model, the results vary in strength. We also found the biases in surface temperature and precipitation anomalies mainly come from the atmospheric circulation in the models as these biases reduced considerably from AISI runs to AFSI and AFSF runs where upper atmosphere levels were nudged. Nudging soil moisture also minimizes some biases in the models but not as obvious as nudging the atmosphere. </p><div> <div> <div> </div> </div> </div>

EFFECTS OF BORON AND CALCIUM SPRAYS AND OF MULCH ON CRACKING OF ITALIAN PRUNE

1973 ◽  
Vol 53 (4) ◽  
pp. 827-831 ◽  
Author(s):  
R. A. CLINE ◽  
G. TEHRANI
Keyword(s):  
Soil Moisture ◽  
Fruit Development ◽  
Calcium Concentration ◽  
Foliar Application ◽  
Leaf Tissue ◽  
Weather Conditions ◽  
Prunus Domestica ◽  
Foliar Sprays ◽  
Wide Range ◽  
Fruit Surface

Cracking, a disorder of the fruit of Prunus domestica L., cult Italian (Fellenberg) (Italian prune), occurs on any part of the fruit surface and over a wide range of stage of fruit development. Several treatments were examined to reduce the extent of this disorder in five commercial orchards in the Niagara Peninsula of Ontario. Foliar application of calcium reduced the severity of cracking in several orchards. Cracking was related to the calcium concentration in the fruit but not in the leaf tissue. A mulch applied to conserve soil moisture, or foliar sprays of boron, or both, were unsuccessful in preventing this disorder. The severity of cracking varied from orchard to orchard and year to year and was not related to weather conditions.

scholarly journals Agrocompanion: A Smart Farming Approach Based on Iot and Machine Learning

2020 ◽  
Vol 9 (12) ◽  
pp. 254-262
Keyword(s):  
Machine Learning ◽  
Soil Moisture ◽  
Random Forest ◽  
Weather Conditions ◽  
The Internet ◽  
Machine Learning Model ◽  
Smart Farming ◽  
Water Tanks ◽  
And Control ◽  
The Internet Of Things

Agriculture is one of the cardinal sectors of the Indian Economy. The proposed system offers a methodology to efficiently monitor and control various attributes that affect crop growth and production. The system also uses machine learning along with the Internet of Things (IoT) to predict the crop yield. Various weather conditions such as temperature, humidity, and soil moisture are monitored in real-time using IoT sensors. IoT is also used to regulate the water level in the water tanks, which helps in reducing the wastage of water resources. A machine learning model is developed to predict the yield of the crop based on parameters taken from these sensors. The model uses Random Forest Regressor and gives an accuracy of 87.5%. Such a system provides a simple and efficient way to maintain and monitor the health of the crop.

scholarly journals Effect of weather variability on growth and yield of wheat crop under semi-arid region of India

2021 ◽  
Vol 22 (2) ◽  
pp. 124-131
Author(s):  
ANANTA VASHISTH ◽  
AVINASH GOYAL ◽  
P. KRISHANAN
Keyword(s):  
Soil Moisture ◽  
Soil Temperature ◽  
Grain Yield ◽  
Water Content ◽  
Relative Water Content ◽  
Significant Positive Correlation ◽  
Weather Conditions ◽  
Grain Filling ◽  
Phenological Stages ◽  
Relative Water

For generating different weather conditions during various phenological stages, experiments were conducted on two varieties of wheat (HD-2967 and HD-3086) sown on three different dates at the research farm of IARI, New Delhi during rabi 2015-16 and 2016-17. Soil temperature, soil moisture, leaf area index, biomass, chlorophyll content, radiation interceptions were measured during different crop growth stages. Number of days taken for each phenological stage was observed and thermal time for different phenological stages were calculated. Results showed that first sown crop had higher value of crop growth parameters and yield as compared to second and third sown crop.HD-3086 had higher value of LAI, biomass and yield than HD-2967. Grain yield had significant positive correlation with growing degree days during grain filling stage. Soil temperature measured at 2.21 PMat 5, 10, 15, 20 cm depth had 1-5°C lower value than the air temperature. Soil moisture measured at 0-15, 15-30, 30-45 and 45-60 cm depths had slightly higher soil moisture for HD-3086 as compared to corresponding value in HD-2967 during emergence, flowering and grain filling stages. Percentage relative water content in HD-2967 was found to be higher in first sown crop followed by second and third sown crop. However, in HD-3086, percentage relative water content was found to be higher in first sown crop followed by third and second sown crop. Grain yield had significant positive correlation with relative water content during different phenological stages. HD-3086hadhigherradiation use efficiency as compared to HD-2967 in all weather conditions.

scholarly journals Assimilation of vegetation optical depth retrievals from passive microwave radiometry

2020 ◽  
Vol 24 (7) ◽  
pp. 3431-3450
Author(s):  
Sujay V. Kumar ◽  
Thomas R. Holmes ◽  
Rajat Bindlish ◽  
Richard de Jeu ◽  
Christa Peters-Lidard
Keyword(s):  
Soil Moisture ◽  
Optical Depth ◽  
Optical Sensors ◽  
Land Surface ◽  
Surface Soil ◽  
Land Surface Model ◽  
Weather Conditions ◽  
Passive Microwave ◽  
Surface Model ◽  
Surface Soil Moisture

Abstract. Vegetation optical depth (VOD) retrievals from passive microwave sensors provide analog estimates of above-ground canopy biomass. This study presents the development and analysis of assimilating VOD retrievals from X-, C-, and L-band passive microwave instruments within the Noah-MP land surface model over the Continental U.S. The results from this study demonstrate that the assimilation of VOD retrievals have a significant beneficial impact on the simulation of evapotranspiration and GPP, particularly over the agricultural areas of the U.S. The improvements in the water and carbon fluxes from the assimilation of VOD from X- and C-band sensors are found to be comparable to those obtained from the assimilation of vegetation indices from optical sensors. The study also quantifies the relative and joint impacts of assimilating surface soil moisture and VOD from the Soil Moisture Active Passive (SMAP) mission. The utility of soil moisture assimilation for improving evapotranspiration (ET) is more significant over water-limited regions, whereas VOD DA is more impactful over areas where soil moisture is not the primary controlling factor on ET. The results also indicate that the information on moisture and vegetation states from SMAP can be simultaneously exploited through the joint assimilation of surface soil moisture and VOD. Since passive microwave-based VOD retrievals are available in nearly all weather conditions, their use within data assimilation systems offers the ability to extend and improve the utility obtained from the use of optical/infrared-based vegetation retrievals.

Temporal fluctuations in soil water repellency following wildfire in chaparral steeplands, southern California

2005 ◽  
Vol 14 (4) ◽  
pp. 439 ◽  
Author(s):  
K. R. Hubbert ◽  
V. Oriol
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Water Repellency ◽  
Weather Conditions ◽  
Antecedent Rainfall ◽  
Soil Water Repellency ◽  
Soil Wetness ◽  
Moisture Conditions ◽  
East West ◽  
Seasonal Weather

Soil water repellency is particularly common in unburned chaparral, and its degree and duration can be influenced by seasonal weather conditions. Water repellency tends to increase in dry soils, while it decreases or vanishes following precipitation or extended periods of soil moisture. The 15 426 ha Williams Fire provided an opportunity to investigate post-fire fluctuations in water repellency over a 1-year period. Soil water repellency was measured at the surface, and at 2-cm and 4-cm depths along six east–west-positioned transects located within the chaparral-dominated San Dimas Experimental Forest. During the winter and spring, seasonal variation in the degree of surface water repellency appeared to be inversely proportional to antecedent rainfall and soil moisture conditions. Precipitation through December reduced the proportion of surface ‘moderate or higher repellency’ from 49 to 4% as soil wetness increased to 12%. Throughout the summer, soil wetness remained below 2%; however, surface soils remained ‘wettable’, with the proportion of surface ‘moderate or higher repellency’ never returning to the early post-fire amount of 47%. Interestingly, at the 4-cm depth, the proportion of ‘moderate or higher repellency’ remained at levels >25% throughout the summer dry season.

Weather factors affecting the development of maize from sowing to flowering

1972 ◽  
Vol 78 (2) ◽  
pp. 325-331 ◽  
Author(s):  
M. N. Hough
Keyword(s):  
Soil Moisture ◽  
Correlation Analysis ◽  
Linear Correlation ◽  
Weather Conditions ◽  
Weather Data ◽  
Weather Factors ◽  
Mean Values ◽  
Rate Of Development ◽  
Linear Correlation Analysis ◽  
The Mean

SUMMARYThe phenological development from sowing to flowering of the eaxly maize hybrid INRA 200 is related to the weather conditions. Plot trial data from Wytham, near Oxford, England, and weather information from that and nearby sites formed the basic data.The mean rate of development per day from sowing to emergence is related by linear correlation analysis to the mean values of soil temperature at 5 cm depth and soil moisture deficit. A range of temperature thresholds for emergence development exist, which depend upon the soil moisture, and which differ from the true physiological threshold.Between omergence and flowering the mean rate of development per day is related by linear correlation analysis to mean air temperature, solar radiation and potential transpiration estimated from weather data. All correlations are significant, but the parameters which combine radiation and temperature are statistically better.

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