scholarly journals Root and shoot responses of upland New Rice for Africa varieties to fluctuating soil moisture conditions as affected by different levels of nitrogen fertilization

2020 ◽  
Vol 206 (3) ◽  
pp. 322-337
Author(s):  
Daniel Makori Menge ◽  
Mana Kano‐Nakata ◽  
Akira Yamauchi ◽  
Roel Rodriguez Suralta ◽  
Daigo Makihara
Weed Science ◽  
2007 ◽  
Vol 55 (5) ◽  
pp. 399-405 ◽  
Author(s):  
Clifford H. Koger ◽  
Darrin M. Dodds ◽  
Daniel B. Reynolds

Bispyribac is registered for postemergence control of broadleaf, sedge, and grass weeds in rice. Bispyribac inhibits the acetolactate synthase enzyme in sensitive plants. Herbicides in this class of chemistry require a spray adjuvant to achieve optimal efficacy, often achieve different levels of weed control according to the spray adjuvant used, and typically have rainfast periods of at least 6 to 8 h. Efficacy and rainfastness of bispyribac can be affected by spray adjuvant and the addition of urea ammonium nitrate (UAN). Greenhouse experiments were conducted to investigate the effect of spray adjuvant type, addition of UAN, and soil moisture on bispyribac efficacy on barnyardgrass. Control of barnyardgrass was improved when UAN was added to bispyribac at 0.4 or 0.8 g ha−1plus an organosilicone-based nonionic surfactant (OSL/NIS) or methylated seed oil/organosilicone (MSO/OSL) spray adjuvant. The type of adjuvant added to the spray solution affected bispyribac efficacy on barnyardgrass. The addition of UAN decreased the rainfast period from 8 h (registered rainfast period) to 1 or 4 h (99 to 100% control) when either the OSL/NIS or MSO/OSL adjuvant was applied with bispyribac, respectively. Applying UAN and OSL/NIS or MSO/OSL adjuvant with bispyribac enhanced efficacy and reduced the time period required between bispyribac application and washoff during a rainfall event. Increasing soil moisture conditions resulted in greater efficacy from bispyribac when applied with and without UAN.


1963 ◽  
Vol 43 (2) ◽  
pp. 219-228 ◽  
Author(s):  
F. W. Sosulski ◽  
E. A. Paul ◽  
W. L. Hutcheon

The protein content of Thatcher wheat grown in the growth chamber was increased by reduced water supply, nitrogen fertilization, and higher air temperatures. Soil moisture conditions had a greater influence on protein content at higher temperatures, while the largest responses to nitrogen fertilization were obtained at the medium moisture level. Changes in sedimentation value and mixing time were associated with protein content except for plants grown at 62°F. Apparently the low temperature had an adverse effect on gluten quality.The relative distribution of 9 amino acids was significantly correlated with changes in grain protein content. Only 6 amino acids gave similar high correlations with flour protein content and sedimentation value. These differences are explained on the basis of changes in the morphology of the wheat grain and the proportion of flour proteins.


HortScience ◽  
1997 ◽  
Vol 32 (4) ◽  
pp. 599E-600
Author(s):  
Regina P. Bracy ◽  
Richard L. Parish

Improved stand establishment of direct-seeded crops has usually involved seed treatment and/or seed covers. Planters have been evaluated for seed/plant spacing uniformity, singulation, furrow openers, and presswheel design; however, effects of presswheels and seed coverers on plant establishment have not been widely investigated. Five experiments were conducted in a fine sandy loam soil to determine effect of presswheels and seed coverers on emergence of direct-seeded cabbage and mustard. Seed were planted with Stanhay 870 seeder equipped with one of four presswheels and seed coverers. Presswheels included smooth, mesh, concave split, and flat split types. Seed coverers included standard drag, light drag, paired knives, and no coverer. Soil moisture at planting ranged from 8% to 19% in the top 5 cm of bed. Differences in plant counts taken 2 weeks after planting were minimal with any presswheel or seed coverer. Visual observation indicated the seed furrow was more completely closed with the knife coverer in high soil moisture conditions. All tests received at least 14 mm of precipitation within 6 days from planting, which may account for lack of differences in plant emergence.


2020 ◽  
Vol 3 (1) ◽  
pp. 58
Author(s):  
Rachele Venanzi ◽  
Loredana Barbona ◽  
Francesco Latterini ◽  
Rodolfo Picchio

The aim of this work was to assess the possible impacts on the forest soil and stand due to silvicultural treatment and forest operations in a beech high forest. Even aged beech forests (Fagus sylvatica L.) in the Municipality of Cappadocia (L’Aquila) and in the Municipality of Vallepietra (Roma) were analyzed. The analysis of the soil and stand were performed in order to assess the effects attributable to applied silviculture and forest logging. Two different logging methodologies (in particular for the extraction) were applied: mules were used in the areas with greater slopes and with obstacles, while for the areas with better accessibility, mechanical means were used, in this case tractors. In detail, the main objective was to assess the disturbance on the ground and on the stand, generated by the two different levels of mechanization. In addition, it was also interesting to understand the possible effect on the soil and specifically on the partial uncovering where part of the tree canopy was removed. Only through an accurate cross-analysis of the studied parameters and indices could the anthropogenic impacts on the soil and stand due to forest operations be highlighted according to the different logging methodologies applied. The main results showed that the disturbances caused to the soil and stand were essentially caused in the bunching and extraction operations. The importance of avoiding or limiting the continuous passage of vehicles and animals on forest soil clearly emerges, especially in conditions of high soil moisture. It is also important to use correct technologies that are adequate for the specific environmental characteristics and the work plan. Finally, it can be said that there was no difference in the disturbance caused by the two logging methods when compared. Substantial differences in terms of improvement can be defined when comparing the findings of this study with other research studies. This can be done by applying a different type of mechanization with a different logging system.


Author(s):  
Yaolin Liu ◽  
Qinghu Jiang ◽  
Tiezhu Shi ◽  
Teng Fei ◽  
Junjie Wang ◽  
...  

2021 ◽  
Author(s):  
Nunziarita Palazzolo ◽  
David J. Peres ◽  
Enrico Creaco ◽  
Antonino Cancelliere

<p>Landslide triggering thresholds provide the rainfall conditions that are likely to trigger landslides, therefore their derivation is key for prediction purposes. Different variables can be considered for the identification of thresholds, which commonly are in the form of a power-law relationship linking rainfall event duration and intensity or cumulated event rainfall. The assessment of such rainfall thresholds generally neglects initial soil moisture conditions at each rainfall event, which are indeed a predisposing factor that can be crucial for the proper definition of the triggering scenario. Thus, more studies are needed to understand whether and the extent to which the integration of the initial soil moisture conditions with rainfall thresholds could improve the conventional precipitation-based approach. Although soil moisture data availability has hindered such type of studies, yet now this information is increasingly becoming available at the large scale, for instance as an output of meteorological reanalysis initiatives. In particular, in this study, we focus on the use of the ERA5-Land reanalysis soil moisture dataset. Climate reanalysis combines past observations with models in order to generate consistent time series and the ERA5-Land data actually provides the volume of water in soil layer at different depths and at global scale. Era5-Land project is, indeed, a global dataset at 9 km horizontal resolution in which atmospheric data are at an hourly scale from 1981 to present. Volumetric soil water data are available at four depths ranging from the surface level to 289 cm, namely 0-7 cm, 7-28 cm, 28-100 cm, and 100-289 cm. After collecting the rainfall and soil moisture data at the desired spatio-temporal resolution, together with the target data discriminating landslide and no-landslide events, we develop automatic triggering/non-triggering classifiers and test their performances via confusion matrix statistics. In particular, we compare the performances associated with the following set of precursors: a) event rainfall duration and depth (traditional approach), b) initial soil moisture at several soil depths, and c) event rainfall duration and depth and initial soil moisture at different depths. The approach is applied to the Oltrepò Pavese region (northern Italy), for which the historical observed landslides have been provided by the IFFI project (Italian landslides inventory). Results show that soil moisture may allow an improvement in the performances of the classifier, but that the quality of the landslide inventory is crucial.</p>


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