The Azotobacter Test of Soil Fertility Applied to the Classical Fields at Rothamsted.

1932 ◽  
Vol 22 (4) ◽  
pp. 797-810 ◽  
Author(s):  
Jadwiga Ziemięcka

Summary and abstract1. The kneaded plate (plaque moulée) method of detecting deficiency in lime and available phosphate was applied to seventy-nine soil samples taken from the classical Rothamsted arable plots, and the Azotobacter population from some of these samples was estimated by counts on silica jelly.2. The silica jelly counts showed that Azotobacter cells were very much reduced in number, or even absent in soil receiving 86 lb. per acre or more of mineral nitrogen. It is suggested that this is due to competition with other organisms whose growth is stimulated by added nitrogen compounds.3. The kneaded-plate test correctly indicaṫed whether phosphate had been applied in soils receiving little or no nitrogen manures.4. In those soils receiving 86 lb. or more of mineral nitrogen, the kneaded-plate test usually showed little or no Azotobacter growth even in the presence of phosphate and calcium carbonate. This failure was probably due to the paucity of Azotobacter cells originally present in such soil samples. In some cases the test was modified by inoculating the sample with a culture of Azotobacter and it then gave correct indications as to phosphate content.

2020 ◽  
Vol 4 (2) ◽  
pp. 780-787
Author(s):  
Ibrahim Hassan Hayatu ◽  
Abdullahi Mohammed ◽  
Barroon Ahmad Isma’eel ◽  
Sahabi Yusuf Ali

Soil fertility determines a plant's development process that guarantees food sufficiency and the security of lives and properties through bumper harvests. The fertility of soil varies according to regions, thereby determining the type of crops to be planted. However, there is no repository or any source of information about the fertility of the soil in any region in Nigeria especially the Northwest of the country. The only available information is soil samples with their attributes which gives little or no information to the average farmer. This has affected crop yield in all the regions, more particularly the Northwest region, thus resulting in lower food production.  Therefore, this study is aimed at classifying soil data based on their fertility in the Northwest region of Nigeria using R programming. Data were obtained from the department of soil science from Ahmadu Bello University, Zaria. The data contain 400 soil samples containing 13 attributes. The relationship between soil attributes was observed based on the data. K-means clustering algorithm was employed in analyzing soil fertility clusters. Four clusters were identified with cluster 1 having the highest fertility, followed by 2 and the fertility decreases with an increasing number of clusters. The identification of the most fertile clusters will guide farmers on where best to concentrate on when planting their crops in order to improve productivity and crop yield.


2016 ◽  
Vol 1 (01) ◽  
Author(s):  
Vemavarapu Bhaskara Rao ◽  
Kandlagunta Guru Prasad ◽  
Krishna Naragani ◽  
Vijayalakshmi Muvva

The air dried rhizosphere soil samples pretreated with calcium carbonate was employed for the isolation of actinomycete strains. Serial dilution plate technique was used for the isolation of actinomycetes. A total of 20 actinomycete strains designated as BS1-BS20 were isolated from the rhizosphere of medicinal plant Clitoria ternatea. All the 20 strains were subjected to primary screening for antimicrobial activity. Among the 20 strains screened, 10 strains exhibited high antimicrobial spectrum against Staphylococcus aureus, Escherichia coli and Candida albicans.


2016 ◽  
Vol 41 (4) ◽  
pp. 735-757 ◽  
Author(s):  
NC Shil ◽  
MA Saleque ◽  
MR Islam ◽  
M Jahiruddin

Laboratory studies on soil fertility evaluation was carried out across major agroecological zones (AEZs) of Bangladesh to know the nutrient status of soils and to relate those with soil properties like pH, organic matter, CEC, and clay content. Thirty five composite soil samples were collected from intensive crop growing sites, which covered 17 AEZs of Bangladesh. After proper processing, the samples were analyzed for texture, pH, organic carbon, CEC, exchangeable cations (K, Ca, Mg and Na), total N, available P and S following standard methods. The textural class of the soils collected from AEZ 12 and 13 appeared to be mostly clay. Clay loam soil was found in AEZ 4, 8, 9, 11, 25 and 28. Loamy soil was seen in AEZ 1 while AEZ 22, 23 and 29 were mostly sandy textured. The results revealed that 65.7% of the tested soil was acidic while 25.7% was alkaline in nature. All the tested soils showed lower pHKCl compared to pHH2O thus possessed negative charge. About 68.6% of the collected soils contained low (1.10-1.70%) level of organic matter, 25.7% soils retained it at medium level (1.71-2.40) and 5.7% soils at very low level (<1.0%). All the tested soils appeared to be deficient (< 0.12%) in nitrogen content. 68.6% soil samples had the low level of available P while only 8.6% retained it an optimum amount. About 80% of the tested soils contained low level of available S (7.9- 14.7 mg kg -1) although coastal regions soils hold higher amount of available S. High CEC (20-38 cmol kg-1) was found in clay rich soils of AEZ 10, 11, 12, and 13. Study revealed that 40% of the collected soils were very low, 31.4% were low, 8.6% each of medium and optimum, and 11.4% contained high level of exchangeable K. The calcareous soils (AEZ 10, 11, 12 and 13) contained very high level of Ca. Non calcareous soils also showed fairly good level of Ca content except AEZ 1, 3, 23 and 29. Sandy textured soils of greater Dinajpur, Rangpur, Moulvibazar showed lower level of exchangeable Mg. About 86% of the tested soils had the lower (< 2%) potassium saturation percentage (KSP), which needs K application for sustainable crop production. Estimate showed that 44% variability for CEC may be attributed by clay content and the relationship was significant (p = 0.05). Again, 50.4 and 65.6% variability in exchangeable K and Mg, respectively may be governed by clay content of the soils, while such relationship for Ca was non-significant. CEC may contribute 62.2, 92.3 and 83.9% variability for exchangeable K, Ca and Mg content in soils, respectively. The fertility status of most of the studied soils (except AEZ 10, 12, 13 and to some extent 11) appeared to be low to very low, which demand judicious management in order to achieve food security and to conserve the soil fertility.Bangladesh J. Agril. Res. 41(4): 735-757, December 2016


1974 ◽  
Vol 14 (67) ◽  
pp. 249 ◽  
Author(s):  
AN Smith ◽  
TB Spence

Seventy-one trials were sown to wheat during the years 1964-66, and of these 54 were successfully harvested. They were of 5 x 2 factorial design with five levels of superphosphate and two levels of nitrogen ; there were three replications. Superphosphate increased grain yield in two thirds and nitrogen in about one sixth of the trials. The yield of grain and the increase in grain yield resulting from fertilizer application were markedly affected by seasonal conditions. Soil samples were taken from each site and analysed for pH, and for 'available' phosphate by ten extractant methods. The yield increase was correlated with superphosphate applied and 'available' phosphate in the model : -Y = bo+b1S+b2vS+b3P+b4P2+b5vSP and the highest coefficient of determination was 31.4 per cent. When pH and average annual rainfall were put into the equation -Y = bo+b1pH+b2RA+b3S+b4vS+b5P+b6P2+b7vSP the highest coefficient of determination was 54.4 per cent.


Helia ◽  
2019 ◽  
Vol 42 (71) ◽  
pp. 145-159
Author(s):  
V. A. Lyakh ◽  
N. I. Kostyuchenko ◽  
I. A. Shevchenko

Abstract The bacterial and micromycete complexes in the rhizosphere of sunflower plants non-infected and infected with broomrape (Orobanche cumana Wallr.) have been compared. The investigations were carried out in the conditions of a stationary infectious field which was annually enriched with infected plant residues and broomrape seeds collected in different regions of Ukraine. Soil is leached, low-humic chernozem with acidic pH. The soil samples selected at the end of vegetation from the rhizosphere of healthy and infected with broomrape plants of sunflower breeding samples. The total number of bacteria found in the rhizosphere of sunflower plants infected by the parasite did not differ significantly from the control and was 11.7 and 12.1 million CFU / g of soil, respectively. The numbers of ammonifiers as well as bacterial microflora, using for its life mineral nitrogen, and pedotrophs and oligotrophs in the compared soil samples did not differ significantly, and generally corresponded to this type of soil. Although in general, both tested samples of soil were characterized by a low content of bacteria of the genus Azotobacter, the number of representatives of this genus in the rhizosphere of parasite-infected plants was somewhat less than in control (35 % and 21 %, respectively). However, unlike most bacteria, the number of micromycetes detected on Czapek-Dox and starch-ammonia agar media, in the rhizosphere of plants infected by broomrape almost twice exceeded the number of these microorganisms in the rhizosphere of healthy plants. Analysis of the generic and species composition of microscopic fungi showed that in the rhizosphere of sunflower plants infected by the parasite a very specific mycocenosis was formed that differ from a mycocenosis of healthy plants. This mycocenosis was characterized by a much smaller number of genera and species of micromycetes. At the same time for the structure of the fungal cenosis of diseased plants there was a characteristic increase in the proportion of toxin-forming fungi of the Aspergillus and Penicillium genera with active conidiogenesis. The obtained data testify not only to the differences in the microbial complexes in the rhizosphere of sunflower plants non-infected and infected by broomrape, but also indicate the direction of action of this parasite.


2011 ◽  
Vol 255-260 ◽  
pp. 3018-3021
Author(s):  
Bing Chen Fan

By a method of discriminate analysis, the content of organic matter, alkali hydrolyzadle nitrogen, rapidly available phosphate, rapidly available potassium were used as the identification factors, and soil nutrient data and grain output were analysed. The results of the analysis has indicated that discriminate analysis can determine grades of the soil fertility. The fitting rate was over 80% , and that accuracy of forecast was right. This new method may be tried for determining grades of the soil fertility.


1984 ◽  
Vol 24 (127) ◽  
pp. 595 ◽  
Author(s):  
TG Reeves ◽  
A Ellington ◽  
HD Brooke

Three experiments, begun in successive years, were conducted between 1974 and 1979 in north-eastern Victoria to investigate the effects of rotating wheat (cv. Olympic) and 'sweet' lupins (Lupinus angustifolius cv. Uniharvest) on crop yields, soil fertility and crop diseases. The grain yield of continuous wheat was 2.58 t/ha and of continuous lupins 0.66 t/ha (P<0.05). Wheat, grown after a lupin crop, yielded 750 kg/ha more than wheat after wheat, and a second wheat crop, after lupins, yielded 420 kg/ha more than a third successive wheat crop. Lupins, grown after wheat, yielded 50-165% more than lupins after lupins. Grain nitrogen of wheat was significantly increased after lupins (P<0.01). Differences in soil mineral nitrogen were apparent ten weeks after sowing, with mean nitrogen levels of 37 and 55 kg/ha under wheat and lupins, respectively. Soil mineral nitrogen (0-20 cm) was consistently greater after lupins than after wheat (P<0.01) when measured just before seeding the succeeding crop. Overall, mean accretion of mineral nitrogen under lupins was 4 1 kg/ha.year. Residual nitrogen from lupins, after one succeeding wheat crop had been grown, was also evident (mean 23 kg/ha). Crop rotation influenced the incidence of crop diseases in wheat and lupins. Lupins after lupins suffered severely from brown leaf spot (Pleiochaeta setosa), up to 63% of plants being infected compared with only 18% after wheat. Disease incidence (mainly Gaeumannomyces graminis) in wheat increased from less than 1% in the first year of cropping, to 36% infection in year 3. When wheat was grown after lupins, disease incidence was negligible.


2018 ◽  
Vol 3 (02) ◽  
pp. 108-115
Author(s):  
S. P. Vista ◽  
T. B. Ghimire ◽  
T. S. Rai ◽  
B. S. Kutu ◽  
B. K. Karna

Potato is a staple food crop in high hills and mountains and a major vegetable throughout the country and one of the most important cash generating crops in Nepal. With the efforts undertaken by research and extension sectors, its productivity has significantly increased in last twenty years. However, this is not sufficient for increasing population of the country. Considering its potentiality for income, employment, industrial products, export and processing, appropriate technologies are urgent.Soil fertility evaluation is the most basic decision making tool for the sustainable soil nutrient management. Soil fertility studies and mapping is an effective way to diagnose soil status and recommend as per the need of the nutrient to particular crop in the area. This research aims to assess and prepare soil nutrient map of potato super zone, Kavrepalanchowk in Nepal. The specific objectives of the research were to assess soil texture, pH and organic matter status and simultaneously prepare soil fertility map of the potato super zone. A total of 202 soil samples were collected and nutrients were analyzed using standard procedure in the soil laboratory. Composite soil samples were collected from 6 to 10 different spots of the area at 0-20 cm depth by using soil auger. The GPS location of each soil sampling point was noted. The soil sampling point of each zone was determined by studying various aspects (area, slope, colour, texture, etc.) of the study area. Based on the nutrient status, nutrient maps were prepared and presented. Soil fertility maps were prepared by observing the critical nutrients required for the specific crops and by giving those nutrients certain ranking based on the nutrients role for the crop. The soil of Potato super zone was mostly found to be silty loam, moderately acidic (pH 5.9), medium in organic matter content (2.67%) and total nitrogen (0.13%), high in available phosphorus content (56 kg/ha) and available potassium (356kg/ha). There is also sandy loam, loam and silty clay loam types of soil in the area. Soil fertility maps were prepared by setting criteria based on nutrient status that were tested in the laboratory and on the basis of nutrients that are critical for each crops of the super zones. Vegetable super zone soil was found having medium (50%) and high (30%) fertility status. Based on the soil analysis report, it could be concluded that the soils of potato super zone is fair enough for cultivating potato crop at the moment.


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