Factors affecting the physical and chemical properties of Argentine kaolins

The continuous obstacle of Dictyophora indusiata has become the one of the main factors affecting the healthy development of D. indusiata industry. In order to study the effects of continuous cropping of D. indusiata on the soil environment, four treatments were used in this study: no planted (CK), planted for 1 years (1Y), continuous cropping for 2 years (2Y) and continuous cropping for 3 years (3Y), to determined of the yield of D. indusiata, soil physical and chemical properties, microbial content and enzyme activity. The results showed that the yield and soil pH value decreased with the increase of continuous cropping years, and the contents of organic matter, total nitrogen, total phosphorus and total potassium, C/N and C/P also increased with the increase of continuous cropping years. Soil availability decreased with the increase of continuous cropping years, the content of alkaline nitrogen, available phosphorus and available potassium decreased by 12.25%, 28.91% and 24.86% at 3Y compared with 1Y, respectively. The biomass of bacteria, actinomycetes and fungi and the total amount of microorganism in soil increased at 1Y compared with CK, but with the increase of continuous cropping years, the biomass of bacteria and actinomycetes and the total amount of microorganism decreased significantly, while the biomass of fungi increased significantly; the continuous cropping of D. indusiata also decreased the value of bacteria/fungi in soil. The enzyme activities of the soil were higher than those of the unplanted plots, however, the activities of urease, catalase, peroxidase, sucrase, phosphatase and protease decreased with the increase of continuous cropping years. In a word, with the increase of continuous cropping, the acidity of rhizosphere soil increased, the availability of soil nutrients and the activity of soil enzymes decreased, the biomass of soil microorganisms, bacteria and actinomycetes decreased. However, the increase of fungal biomass led to the decline of soil texture.

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Factors Affecting Soil Organic Carbon Content between Natural and Reclaimed Sites in Rudong Coast, Jiangsu Province, China

Journal of Marine Science and Engineering ◽

10.3390/jmse9121453 ◽

2021 ◽

Vol 9 (12) ◽

pp. 1453

Author(s):

Peipei Yang ◽

Zhou Hu ◽

Qiang Shu

Keyword(s):

Organic Carbon ◽

Water Content ◽

Chemical Properties ◽

Coastal Areas ◽

Physical And Chemical Properties ◽

Total N ◽

Factors Affecting ◽

Physical And Chemical ◽

Plsr Model ◽

And Chemical Properties

The physical and chemical properties of coastal soils in China have changed due to the development of reclaimed stretches of coastline, which has a significant impact on the dynamics of organic carbon (OC) in the soils. We evaluated changes in the physical and chemical properties of soils in both a natural area and a reclaimed area along the coast of Rudong County, China, as well as the effects that these changes had on the OC content of the soils. A partial least squares regression (PLSR) model was used to determine which factors are most important for driving changes in soil OC at four sites from each area. According to dominant vegetation types, there were significant differences in soil physical and chemical properties and OC content between the reclaimed area and natural coastal area. The mean grain size and pH increased gradually with depth, and values were highest in reclaimed areas. Mean total N (TN), P, and S, salinity, water content, and soil OC were highest in natural areas and decreased with depth. The PLSR model determined that TN, silt content, and sand content were the most important factors affecting soil OC in the reclaimed area, whereas TN, clay content, and water content were important factors affecting soil OC dynamics in the natural coastal areas. This study provides important reference data for correctly assessing the role and status of coastal areas in the global carbon cycle.

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Statistical criteria of stellar population types

Symposium - International Astronomical Union ◽

10.1017/s0074180900053304 ◽

1966 ◽

Vol 24 ◽

pp. 101-110

Author(s):

W. Iwanowska

Keyword(s):

Stellar Population ◽

Chemical Properties ◽

Spectrophotometric Study ◽

Physical And Chemical Properties ◽

Population Type ◽

The Galaxy ◽

Distribution Parameters ◽

Physical And Chemical ◽

Statistical Criteria ◽

And Chemical Properties

In connection with the spectrophotometric study of population-type characteristics of various kinds of stars, a statistical analysis of kinematical and distribution parameters of the same stars is performed at the Toruń Observatory. This has a twofold purpose: first, to provide a practical guide in selecting stars for observing programmes, second, to contribute to the understanding of relations existing between the physical and chemical properties of stars and their kinematics and distribution in the Galaxy.

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Only one sugar offers you such a variety of important physical and chemical properties

Chemical & Engineering News ◽

10.1021/cen-v037n007.p004 ◽

1959 ◽

Vol 37 (7) ◽

pp. 4

Keyword(s):

Chemical Properties ◽

Physical And Chemical Properties ◽

Physical And Chemical ◽

And Chemical Properties

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Response of corn (Zea mays L.) to various organic-based fertilizers in marginal upland of Sta. Rita, Samar

Annals of Tropical Research ◽

10.32945/atr39sa3.2017 ◽

2017 ◽

pp. 31-43

Author(s):

Berta Ratilla ◽

Loreme Cagande ◽

Othello Capuno

Keyword(s):

Block Design ◽

Management Strategies ◽

Chemical Properties ◽

Organic Fertilizers ◽

Growth And Yield ◽

Physical And Chemical Properties ◽

Total N ◽

Randomized Complete Block Design ◽

Physical And Chemical ◽

And Chemical Properties

Organic farming is one of the management strategies that improve productivity of marginal uplands. The study aimed to: (1) evaluate effects of various organic-based fertilizers on the growth and yield of corn; (2) determine the appropriate combination for optimum yield; and (3) assess changes on the soil physical and chemical properties. Experiment was laid out in Randomized Complete Block Design, with 3 replications and 7 treatments, namely; T0=(0-0-0); T1=1t ha-1 Evans + 45-30-30kg N, P2O5, K2O ha-1; T2=t ha-1 Wellgrow + 45-30-30kg N, P2O5, K2O ha-1; T3=15t ha-1 chicken dung; T4=10t ha-1 chicken dung + 45-30-30kg N, P2O5, K2O ha-1; T5=15t ha-1 Vermicast; and T6=10t ha-1 Vermicast + 45-30-30kg N, P2O5, K2O ha-1. Application of organic-based fertilizers with or without inorganic fertilizers promoted growth of corn than the control. But due to high infestation of corn silk beetle(Monolepta bifasciata Horns), its grain yield was greatly affected. In the second cropping, except for Evans, any of these fertilizers applied alone or combined with 45-30-30kg N, P2O5, K2O ha-1 appeared appropriate in increasing corn earyield. Soil physical and chemical properties changed with addition of organic fertilizers. While bulk density decreased irrespective of treatments, pH, total N, available P and exchangeable K generally increased more with chicken dung application.

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