scholarly journals Agroecological evaluation of interrelationships of soil properties in time and space

2021 ◽  
pp. 163-175
Author(s):  
V. I. Savich ◽  
V. V. Gukalov ◽  
A. E. Sorokin ◽  
M. D. Konakh

This paper assesses the relationship between the physico-chemical and agro-chemical properties of sod-podzolic soils in the Moscow region and ordinary heavy-loamy chernozems in the Krasnodar region within the catenas and down the soil profile. Soil properties changed significantly through seasonal dynamics. From the end of April to the middle of June in the soil solution of sod-podzolic soils, the value of Eh varied from 534 to 759 mv, the ratio of NO3/NH4 – from 0.2 to 15.4; the content of water-soluble manganese – from 4.0 to 10.1. At the same time, there was a delay in change of soil properties, as humidity and temperature varied. It is shown that in different intervals of soil properties between individual indicators of fertility, the effects of synergism and antagonism are manifested. The degree of mutual influence of soil properties depended on both the degree of soil fertilization and the degree of their cultivation. Information relationships were manifested not only between the soil properties, but also between the processes. Temporary excessive moistening of the soil led to acidification of the soil in the washing type of water mode, and to alkalinization in the non-washing type. It is proposed to account for the relationship of soil properties with humidity, temperature, pH, and Eh to adjust the components of farming systems.

1966 ◽  
Vol 46 (2) ◽  
pp. 155-160 ◽  
Author(s):  
G. R. Saini ◽  
A. A. MacLean ◽  
J. J. Doyle

The relationship of the mean weight diameter of water-stable aggregates to certain soil properties (clay, organic matter, free iron, free aluminum, and polysaccharide contents) and the relationship of the increase in aggregation caused by VAMA to the same properties of 24 New Brunswick soils were evaluated by correlation and regression analyses.Simple correlation coefficients relating aggregation to soil properties indicated that organic matter (r = 0.627), polysaccharides (r = 0.602), and aluminum (r = 0.679) were the most important factors. However, when the influence of each factor was separated by partial correlation, the coefficients were not significant. On the other hand, the combined effects of all factors as indicated by the multiple correlation coefficient (r = 0.743) was significant at the 1% level. The effect of the same soil properties on response to VAMA, as shown by increase in mean weight diameter, indicated that clay exerted the greatest influence. The relationship with other factors was nonsignificant.


2021 ◽  
Vol 3 (45) ◽  
pp. 4-4
Author(s):  
Alexander Saakian ◽  
◽  

The paper proves the need to clarify the agroecological assessment of soils, taking into account the migration of substances, the non-exchange fixation of biophilic elements by the soil, the relationship between the properties of soils, the intensity and speed of soil-forming processes, and the manifestation of the law of decreasing fertility. It is shown that on well-cultivated sod-podzolic soils of the Moscow region, the losses of elements with high water and ground water averaged 19.3 and 6.9 kg/ha of N-NO3, 0.7 and 1.2 N-NH4 in the crop rotation. Losses with surface-runoff waters were: nitrogen-2.2 kg / ha, potassium-7.0; calcium-11.0; magnesium-6.0; phosphorus-0.9 kg / ha per year. When the Ca/K ratio in the soil solution of this soil was 0.44±0.03 and 2.7±0.1, the content of water – soluble iron was 57.9±7.4 and 5.3±0.7 mg/l, respectively; manganese-2.3±0.4 and 1.1±0.2 mg/l. It is shown that plants consume biophilic elements from different soil horizons, which must be taken into account in the balance of biophilic elements. It is shown that the optimal soil properties differ depending on the hydrothermal conditions of the territory, the combination of soil properties. It is proved that in order to choose the optimal crops for growing on certain soils, it is necessary to take into account the alienation of energy with the crop. Keywords: SOIL FERTILITY, FERTILIZERS, BALANCE, ECONOMIC EFFICIENCY


Agriculture ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 447
Author(s):  
Ghizlane Krif ◽  
Fouad Mokrini ◽  
Aicha El Aissami ◽  
Salah-Eddine Laasli ◽  
Mustafa Imren ◽  
...  

Organic farming has been increasing steadily over the last decade and is expected to grow drastically in the future. Plant parasitic nematodes (PPNs) are known as one of the most important pests attacking various plants in conventional and organic farming systems. A survey was conducted in January 2019 to determine the occurrence and diversity of PPNs, their associations with soil properties, and to assess their management methods in organically farmed fields in Southern Morocco. Twelve genera of PPNs were identified in soil and root samples collected from 53 organic fields, including Meloidogyne, Pratylenchus, Helicotylenchus, Tylenchus, Tylenchorynchus, Criconemoides, Trichodorus, and Xiphinema. The root-knot nematodes (Meloidogyne spp.) and the root-lesion nematode (Pratylenchus spp.) were the most prevalent PPNs. Vegetable crops (bean, onion, and tomato) had high nematode diversity indices compared to some aromatic and medicinal crops, including the Shannon, Evenness, and plant parasitic index (PPI). Our study underlined that several PPN genera were significantly correlated with soil physico-chemical properties, in particular, soil structure and organic matter. Therefore, it was concluded that soil properties have a considerable impact on PPN communities in organic farming systems located in Southern Morocco. There are numerous strategies for the control of PPNs in organic farming systems.


2017 ◽  
Vol 23 (3) ◽  
pp. 350-361 ◽  
Author(s):  
Hisham Al-Obaidi ◽  
Mridul Majumder ◽  
Fiza Bari

Crystalline and amorphous dispersions have been the focus of academic and industrial research due to their potential role in formulating poorly water-soluble drugs. This review looks at the progress made starting with crystalline carriers in the form of eutectics moving towards more complex crystalline mixtures. It also covers using glassy polymers to maintain the drug as amorphous exhibiting higher energy and entropy. However, the amorphous form tends to recrystallize on storage, which limits the benefits of this approach. Specific interactions between the drug and the polymer may retard this spontaneous conversion of the amorphous drug. Some studies have shown that it is possible to maintain the drug in the amorphous form for extended periods of time. For the drug and the polymer to form a stable mixture they have to be miscible on a molecular basis. Another form of solid dispersions is pharmaceutical co-crystals, for which research has focused on understanding the chemistry, crystal engineering and physico-chemical properties. USFDA has issued a guidance in April 2013 suggesting that the co-crystals as a pharmaceutical product may be a reality; but just not yet! While some of the research is still oriented towards application of these carriers, understanding the mechanism by which drug-carrier miscibility occurs is also covered. Within this context is the use of thermodynamic models such as Flory-Huggins model with some examples of studies used to predict miscibility.


1986 ◽  
Vol 51 (10) ◽  
pp. 2098-2108 ◽  
Author(s):  
Milan Pospíšil ◽  
Jan Topinka

We investigated the effect of origin and some physico-chemical parameters on the kinetics of reduction with hydrogen of two series of mixed NiO-Fe2O3 oxides differing by their composition, the character of their precursors (mixed crystalline nitrates and coprecipitated hydroxides) and their decomposition temperature.This effect manifested itself by different magnitudes of specific surfaces of the mixed oxides and coherent regions of present phases as well as by different oxidizing abilities of the surface and differences in morphology and phase composition of corresponding samples in both series investigated. Nonlinear or nonmonotonous composition dependences of physico-chemical parameters investigated point to a mutual influence of individual components, which is also a function of the system origin and which modifies its reactivity during its reduction with hydrogen. The kinetics of the reduction was studied thermogravimetrically at 320-410 °C. The reduction of oxides of the hydroxide origin is catalytically accelerated by primarily reduced nickel, whereas in corresponding samples of the nitrate series, the total NiO is bound to the spinel phase and the reduction is delayed. Experimental IR spectra, the effect of preliminary annealing and DTA of the mixed oxides point to an inhibitory effect of water, which is constitutionally bound in trace admixtures of the goethite phase, on the kinetics of reduction of samples in the hydroxide series.


2021 ◽  
Vol 788 (1) ◽  
pp. 012172
Author(s):  
Imran ◽  
Amanullah ◽  
S Naveed ◽  
I Khan ◽  
M Sajid ◽  
...  

Author(s):  
Isaiah Ufuoma Efenudu ◽  
Ehi Robert Orhue ◽  
Ogochukwu Jennifer Ikeh ◽  
Michael Aimiesomon Erhayimwen ◽  
Blessing James

The effectiveness of three different extractants soil mixtures—HCl, HCl + H2S04, and DTPA-TEA, in order to determine Si from soil and the forms of Silicon as influenced by different parent materials under acidic medium. Seven forms of Silicon; namely water soluble, specifically adsorbed, oxides bound, organic matter bound, exchangeable, residual, total viz sequential fractionation. Extractable Si value established in this study was (50.0 mg kg-1), indicating negative effect on plant physiology. The physico-chemical properties decreased significantly with increase in soil depth vs soil parent materials. In addition, the forms of Si in the parent materials decreased in the pattern RES, bound residual fractions > EXC, soluble & exchangeable fractions > OM, organic matter fraction. Among the properties the silt fraction, pH & OM significantly and positively correlated with the forms of silicon, with negative correlation vs clay which maybe due to silicon adsorption by clayey fraction of the soil (redox). Therefore the soil maybe be maintained and conserved for farming activities.


1970 ◽  
Vol 19 (1) ◽  
pp. 63-72 ◽  
Author(s):  
Mohammad Zabed Hossain ◽  
Mihir Lal Saha ◽  
Chaman Binta Aziz ◽  
Sirajul Hoque

This study examined the effect of deforestation on the soil properties (physico-chemical and bacterial) of the Sal (Shorea robusta Roxb. Ex Gaertn.) forests in Bangladesh. Physico-chemical properties and the bacterial colony counts of soil were studied by comparing a natural Sal forest site with deforested and planted with Menjium site, deforested and planted with Mahogoni site, as well as deforested but not planted but covered with profuse growth of Axonopus compressus grass species site. Moisture content was significantly lower in the deforested and planted with Menjium site and deforested and planted with Mahogoni site than the natural forest site and the deforested but not planted site. Total organic carbon, total nitrogen and available nitrogen contents were significantly lower in the natural forest site. Significantly higher number of bacterial colony and higher organic carbon and moisture contents were found in the deforested but not planted site indicating that both organic carbon and moisture content were important for microbial growth. The present study clearly showed that deforestation significantly altered the soil physico-chemical and bacterial communities of the Sal forests. It was also revealed that plantation with different exotic plants were found to be different in influencing soil properties. Key words: Bacterial colony; Deforestation effects; Sal forest; Soil physico-chemical properties DOI: http://dx.doi.org/10.3329/dujbs.v19i1.8945 DUJBS 2010; 19(1): 63-72


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