scholarly journals Effects of annual precipitation pattern variation and different cultivation modes on the growth of Amaranthus retroflexus and Glycine max

2018 ◽  
Vol 26 (11) ◽  
pp. 1158-1167
Author(s):  
Baiwen Jiang ◽  
◽  
Jing Li ◽  
Rui Chen ◽  
Ping Lu ◽  
...  
2021 ◽  
Author(s):  
Shakti Suryavanshi ◽  
Nitin Joshi ◽  
Hardeep Kumar Maurya ◽  
Divya Gupta ◽  
Keshav Kumar Sharma

Abstract This study examines the pattern and trend of seasonal and annual precipitation along with extreme precipitation events in a data scare, south Asian country, Afghanistan. Seven extreme precipitation indices were considered based upon intensity, duration and frequency of precipitation events. The study revealed that precipitation pattern of Afghanistan is unevenly distributed at seasonal and yearly scales. Southern and Southwestern provinces remain significantly dry whereas, the Northern and Northeastern provinces receive comparatively higher precipitation. Spring and winter seasons bring about 80% of yearly precipitation in Afghanistan. However, a notable declining precipitation trend was observed in these two seasons. An increasing trend in precipitation was observed for the summer and autumn seasons, however; these seasons are the lean periods for precipitation. A declining annual precipitation trend was also revealed in many provinces of Afghanistan. Analysis of extreme precipitation indices reveals a general drier condition in Afghanistan. Large spatial variability was found in precipitation indices. In many provinces of Afghanistan, a significantly declining trends were observed in intensity-based (Rx1-day, RX5-day, SDII and R95p) and frequency-based (R10) precipitation indices. The duration-based precipitation indices (CDD and CWD) also infer a general drier climatic condition in Afghanistan. This study will assist the agriculture and allied sectors to take well-planned adaptive measures in dealing with the changing patterns of precipitation, and additionally, facilitating future studies for Afghanistan.


2017 ◽  
Author(s):  
Yiben Cheng ◽  
Hongbin Zhan ◽  
Wenbin Yang ◽  
Hongzhong Dang ◽  
Wei Li

Abstract. Deep soil recharge (DSR) (at depth more than 200 cm) is an important part of water circulation in arid and semi-arid regions. Quantitative monitoring of DSR is of great importance to assess water resources and study water balance in arid and semi-arid regions. Simple estimates of recharge based on fixed fractions of annual precipitation are misleading because they do not reflect the plant and soil factors controlling recharge. This study used a typical bare land on the Eastern margin of Mu Us Sandy Land of China an example to illustrate a new lysimeter method of measuring DSR underneath bare sand land in arid and semi-arid regions. Positioning monitoring was done on precipitation and DSR measurement underneath mobile sand dunes from 2013 to 2015 in the study area. Results showed that use of a constant recharge coefficient for estimating DSR in bare sand land in arid and semi-arid regions is questionable and could lead to considerable errors. It appeared that DSR in those regions was influenced by precipitation pattern, and was closely correlated with spontaneous heavy precipitation (defined for an event with more than 10 mm precipitation) other than the average precipitation strength. This study showed that as much as 42 % of precipitation in a single heavy precipitation event can be transformed into DSR. During the observation period, the maximum annual DSR could make up to 24.33 % of the annual precipitation. This study provided a reliable method of estimating DSR in sandy area of arid and semi-arid regions, which is valuable for managing groundwater resources and ecological restoration in those regions.


Weed Science ◽  
1970 ◽  
Vol 18 (1) ◽  
pp. 137-139 ◽  
Author(s):  
C. S. James ◽  
G. N. Prendeville ◽  
G. F. Warren ◽  
M. M. Schreiber

Interactions between carbamate and growth regulator herbicides were antagonistic both in whole plants and in plant segments. When combinations of isopropylm-chlorocarbanilate (chlorpropham) and (2,4-dichlorophenoxy)acetic acid (2,4-D) were applied to the foliage of either redroot pigweed (Amaranthus retroflexusL.) or pale smartweed (Polygonum lapathifoliumL.), the severe twisting effects of 2,4-D were greatly reduced. This interaction did not involve differential movement or metabolism of either herbicide. The induced elongation of soybean hypocotyl sections by the three growth regulators 2,4-D, 3,6-dichloro-o-anisic acid (dicamba), and 4-amino-3,5,6-trichloropicolinic acid (picloram) was inhibited in the presence of either chlorpropham orS-ethyl dipropylthiocarbamate (EPTC). Similarly, curvature tests using soybean (Glycine max(L.) Merr.) hypocotyl sections showed the curvature induced by the growth regulators to be almost completely eliminated by the presence of the carbamates.


Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2092 ◽  
Author(s):  
Sharma ◽  
Ojha

Analysis of Spatio-temporal changes in precipitation (Pre) on the land surface of the earth was the focus of this study. Thiel-Sen median slopes and Modified Mann-Kendall (MMK) test were utilized to draw inferences. Majority of the regions were identified to show an increasing trend of annual precipitation except some of the low to mid-latitude regions in Northern hemisphere. The trends of wet-day frequency (Wet) were found in agreement with precipitation for most of the regions, but the inverse relationship was found for the subtropical regions of Northern hemisphere. These changes were examined for the world climate types based on Koppen-Gieger climate classes. Also, it was tried to find the probability distribution, which best describes the annual precipitation pattern in different climate types of the world among 21 commonly assumed probability distributions.


2019 ◽  
Vol 11 (24) ◽  
pp. 2977 ◽  
Author(s):  
Hongwei Zeng ◽  
Bingfang Wu ◽  
Ning Zhang ◽  
Fuyou Tian ◽  
Elijah Phiri ◽  
...  

Precipitation plays an important role in the food production of Southern Africa. Understanding the spatial and temporal variations of precipitation is helpful for improving agricultural management and flood and drought risk assessment. However, a comprehensive precipitation pattern analysis is challenging in sparsely gauged and underdeveloped regions. To solve this problem, Version 7 Tropical Rainfall Measuring Mission (TRMM) precipitation products and Google Earth Engine (GEE) were adopted in this study for the analysis of spatiotemporal patterns of precipitation in the Zambezi River Basin. The Kendall’s correlation and sen’s Slop reducers in GEE were used to examine precipitation trends and magnitude, respectively, at annual, seasonal and monthly scales from 1998 to 2017. The results reveal that 10% of the Zambezi River basin showed a significant decreasing trend of annual precipitation, while only 1% showed a significant increasing trend. The rainy-season precipitation appeared to have a dominant impact on the annual precipitation pattern. The rainy-season precipitation was found to have larger spatial, temporal and magnitude variation than the dry-season precipitation. In terms of monthly precipitation, June to September during the dry season were dominated by a significant decreasing trend. However, areas presenting a significant decreasing trend were rare (<12% of study area) and scattered during the rainy-season months (November to April of the subsequent year). Spatially, the highest and lowest rainfall regions were shifted by year, with extreme precipitation events (highest and lowest rainfall) occurring preferentially over the northwest side rather than the northeast area of the Zambezi River Basin. A “dry gets dryer, wet gets wetter” (DGDWGW) pattern was also observed over the study area, and a suggestion on agriculture management according to precipitation patterns is provided in this study for the region. This is the first study to use long-term remote sensing data and GEE for precipitation analysis at various temporal scales in the Zambezi River Basin. The methodology proposed in this study is helpful for the spatiotemporal analysis of precipitation in developing countries with scarce gauge stations, limited analytic skills and insufficient computation resources. The approaches of this study can also be operationally applied to the analysis of other climate variables, such as temperature and solar radiation.


Weed Science ◽  
1985 ◽  
Vol 33 (5) ◽  
pp. 669-672 ◽  
Author(s):  
Janet L. Shurtleff ◽  
Harold D. Coble

The influence of relative planting date on the growth of common cocklebur (Xanthium pensylvanicumWallr. ♯ XANST), common ragweed (Ambrosia artemesiifoliaL. ♯ AMBEL), sicklepod (Cassia obtusifoliaL. ♯ CASOB), and redroot pigweed (Amaranthus retroflexusL. ♯ AMARE) grown in competition with soybean [Glycine max(L.) Merr. ‘Bragg’] was studied in the greenhouse. Increases in dry matter and height were slower for the five weed species than for soybean throughout the period of the study. The root: shoot ratio of soybean was the highest of any plant in the study, while common ragweed, common cocklebur, common lambsquarters, and sicklepod were intermediate, and redroot pigweed was the lowest. Soybean dry weight was always reduced when grown in competition with a weed. Soybean dry-matter production was reduced most when weeds were planted 2 weeks before soybean, especially with common cocklebur and common lambsquarters. Weed dry-matter content was severely reduced when the weed seed were planted simultaneously with or following soybean. Soybean height was usually reduced by competition with the weeds. The height of common ragweed was increased, however, when planted simultaneously with soybean. Common lambsquarters, redroot pigweed, and common ragweed heights were increased when planted 2 weeks prior to soybean.


Weed Science ◽  
1979 ◽  
Vol 27 (6) ◽  
pp. 665-674 ◽  
Author(s):  
P. L. Orwick ◽  
M. M. Schreiber

Redroot pigweed (Amaranthus retroflexusL.) and robust foxtail [Setaria viridis(L.) Beauv. var.robusta-albaSchreiber (RWF) orSetaria viridisvar.robusta-purpureaSchreiber (RPF)] were investigated regarding their ability to interfere with soybean [Glycine max(L.) Merr. ‘Amsoy 71′] at different weed densities and soybean row spacing throughout two growing seasons. Final weed densities for each species tended to reach a common value because of intraspecific interference regardless of the initial density. With cultivation, a narrow soybean row spacing (38 cm) resulted in less weed growth than did a wide row spacing (76 cm) but with no cultivation, the trend was reversed. Soybeans provided less interference to foxtail than to pigweed during both growing seasons. Interference from foxtail adversely affected soybean yield components and soybean seed yield more than did pigweed interference. Water-stress conditions in 1976 increased the intensity of weed interference and reduced soybean seed yield more severely than in 1975 when moisture was adequate throughout the growing season.


Weed Science ◽  
1970 ◽  
Vol 18 (3) ◽  
pp. 357-359 ◽  
Author(s):  
Jerry D. Doll ◽  
Donald Penner ◽  
William F. Meggitt

In the presence of relatively high but non-toxic levels of phosphate, the suppression of corn (Zea mays L.) or squash (Cucurbita maxima Duchesne) seedling growth in the dark by 3-amino-2,5-dichlorobenzoic acid (amiben) or 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine) was enhanced. This effect was not due to increased uptake of either herbicide in the presence of the phosphate by roots of corn, squash, soybeans (Glycine max (L.) Merr.), or redroot pigweed (Amaranthus retroflexus L.). A proportional decrease in herbicide uptake with increasing herbicide concentration was most evident for amiben and atrazine uptake by the roots of soybean plants grown in the light.


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