Vermicompost and Gypsum Amendments Improve Aggregate Formation in Bauxite Residue

Improving aggregate formation and stability of bauxite residue is essential for the development of a soil on the residue. Effects of gypsum and vermicompost on related chemical and physical conditions of bauxite residue were studied in a laboratory incubation experiment. The addition of gypsum at 2% and 4% w/w reduced pH and exchangeable sodium percentage while increasing exchangeable calcium content. The addition of vermicompost reduced bulk density while significantly increasing porosity and total organic carbon. Vermicompost had a positive effect on the formation and stabilization of water‐stable aggregates in the residue, while gypsum was more beneficial to silt‐sized microaggregate flocculation. Amendments also enhanced the erosion resistance of bauxite residue. Furthermore, wet sieving using the modified Le Bissonnais' method revealed that in comparison with differential clay swelling and mechanical breakdown, slaking was the major disaggregation mechanism of residue aggregates. The combination of gypsum and vermicompost converted the residue from a sheet‐like structure to a granular macroaggregated structure while converting microaggregates from a grain to a granular or prismatic structure. The findings of this work suggest that application of gypsum and vermicompost to bauxite residue may directly influence aggregate size distribution and its micromorphology, resulting in the improvement of both aggregate stability and structure. Copyright © 2017 John Wiley & Sons, Ltd.     

蚓粪复合基质对康乃馨育苗及其生长的影响

以蚓粪、椰糠、泥炭、珍珠岩、蛭石为原料,按不同比例混合,研究其对康乃馨出苗率、株高、茎粗、叶长、叶片数、分支数、地上部干重、地下部干重、根冠比、壮苗指数等生长指标的影响,筛选出最佳基质配方.结果表明:椰糠和蚯蚓粪明显地促进康乃馨的生长发育,以60％蚓粪+10％椰糠+30％混合矿物(珍珠岩:蛭石=1∶1)处理综合效果最理想,最有利于康乃馨形成壮苗.所得到的复合基质的容重、总孔隙度、毛管持水量、通气孔隙度和pH均符合育苗基质的要求.     

Towards sustainable production of peppermint (Mentha piperita L.) through integrated use of vermicompost and cowpea green manuring with synthetic nitrogen fertilization

A field experiment with peppermint (Mentha piperita L.) was conducted in a sandy loam (Typic ustifluvent) soil during 2007 and 2008 at Lucknow, India. Ten treatments consisting of control (no synthetic or organic nitrogen fertilization), synthetic nitrogen fertilization (SN) 75, 150 and 225 kg ha^?1 alone, vermicompost (VC) 3 t + 37.5 kg SN ha^?1, VC 6 t + 75 kg SN ha^?1 and VC 9 t + 112.5 kg SN ha^?1 and intercropping of one, two and three rows of cowpea for green manuring in combination with 50, 100 and 150 kg SN ha^?1, respectively, were evaluated in a randomized block design. Integrated use of VC 9 t with 112.5 kg SN ha^?1 produced maximum essential oil (94.3 kg ha^?1), increased the herb and essential oil yields by 104 and 89%, respectively, over control and reduced SN use by 50%, without affecting the quality of essential oil. Application of VC and intercropping of cowpea for green manuring significantly improved the organic carbon, available N, P and K content in soil over SN alone. To get sustainable production of peppermint, application of VC 9 t ha^?1 along with 112.5 kg N ha^?1 through synthetic fertilizer is recommended for light textured sandy loam soils.     

EFFECTS OF ORGANIC AMENDMENTS APPLICATION ON GRAIN YIELD,LEAF CHLOROPHYLL CONTENT AND SOME MORPHOLOGICAL CHARACTERISTICS IN SOYBEAN CULTIVARS

A field experiment was conducted to evaluate the effect of organic amendments on grain yield, leaf chlorophyll content, and some morphological characteristics of three soybean cultivars in Mazandaran province located at north of Iran in 2006. Chemical fertilizer (75 kg ha^?1 potassium sulfate and triple superphosphate), two levels of municipal solid waste, vermicompost and sewage sludge biosolid (20 and 40 Mg ha^?1) enriched with%50 chemical fertilizers needed by soil were applied to soybean cultivars (‘032’ and ‘033’ promising lines and ‘JK’ cultivar). The experiment was carried out in split plot based on randomized complete block design with three replications. Some important plant characters such as grain yield, leaf chlorophyll content, number of branches, number of nodes on the main stem, length of internodes, stem diameter, first pod height and plant height were determined. Results showed that application of 40 Mg ha^?1 sewage sludge enriched with chemical fertilizers increased plant grain yield and stem diameter and application of 40 Mg ha^?1 vermicompost enriched with half chemical fertilizer increased the number of nodes on the main stem, significantly. The maximum length of internodes, first pod height and plant height were obtained when the 40 Mg ha^?1 sewage sludge and vermicompost enriched with half chemical fertilizer in ‘032’ line was used. Biomass, number of branches, stem diameter, number of nodes on the main stem of soybean cultivars had a positive and significant correlation with grain yield.     

Impact of integrated management of nitrogen fertilizers on yield and nutritional quality of potato

Abstract

The aim of this study was to investigate the influence of different compositions of nitrogen (N) sources on yield and nutritional quality in potato cultivars (Solanum tuberosum L.). The experiment used a factorial arrangement as two factors in randomized complete block design. Factor (A) was nitrogen sources: control, 75% M?+?25%V, 50% M?+?50%V, 100% M, where M plots received nitrogen from mineral fertilizer and V plots received nitrogen from vermicompost. Factor (B) was potato cultivars (Sante and Savalan). In Sante cultivar, 75% M?+?25%V produced the highest total and marketable yield. In Savalan, cultivar application of vermicompost in 75% M?+?25%V and 50% M?+?50%V increased significantly total and marketable yield as compared with 100% M. Application of vermicompost significantly decreases tuber nitrate content and increases nitrogen-use efficiency. In Savalan, cultivar 50% V?+?50%M and in Sante cultivar 75% V?+?25%M can effectively be used for improving yield and nutritional quality of tuber.     

Influence of PGPR-enriched liquid organic fertilizers on the growth and nutrients uptake of maize under drought condition in calcareous soil

In order to study the effect of water deficit stress (WDS), plant growth promoting rhizobacteria (PGPR)-enriched and non-enriched vermicompost tea(VT) and vermiwash(V) on the growth and nutrients uptakes of maize, a greenhouse experiment was conducted. The two-factor experiment was set up in a completely randomized design with three replications. The factors included: 1) liquid organic fertilizers (LOFs) with five levels (control, VT, V, vermicompost tea enriched with bacterium (VTB) and vermiwash enriched with bacterium (VB)) and 2) WDS with three levels (Field Capacity (FC), 80% FC and 60% FC(. At each irrigation interval, the volume of the used LOFs was equivalent to 60% of the volume of water required for 60% FC. At 60% FC, shoot dry matter (SDW), shoot N, P, Zn, Cu, and Fe uptake significantly decreased compared with those of FC and 80% FC, whereas shoot K uptake significantly increased. At all WDS levels, application of LOFs led to increase in SDW and shoot nutrients uptake. The highest amount of studied traits was obtained in VTB and VT treatments. Generally, VT treatments were more effective than V. Furthermore, PGPR-enriched LOFs were more effective than non-enriched ones. Application of LOFs may be considered as a practical approach for amplifying drought tolerance and reducing the risk of water scarcity in maize cultivation.     

Influence of Chromium with Vermicompost on Growth and Accumulation by Brahmi

Abstract

A pot experiment was conducted under glasshouse conditions during 2004 on brahmi (Bacopa monnieri) at the Central Institute of Medicinal and Aromatic Plants (CIMAP) in Lucknow. The study was conducted to evaluate the influence of different levels of chromium (Cr), with and without vermicompost, on growth and yield, as well as on accumulation of Cr by Bacopa. Rooted cuttings of Bacopa were grown under three levels of Cr (10, 20, and 40 ppm), two levels of vermicompost (2.5 and 5 g kg^?1 soil), and a combination of both. The results indicated that herb yield increased with the joint application of vermicompost and chromium, as compared to compost and Cr alone. Application of Cr only decreased nitrogen (N) and increased phosphorus (P) concentration in plants with increase in its supply, whereas application with vermicompost raised N concentration. Chromium concentration in plant tissue was found to be highest at supply of Cr at 40 ppm+vermicompost 5 g kg^?1 soil. Increase in the supply of Cr only (10, 20, and 40 ppm) decreased iron (Fe), copper (Cu), and zinc (Zn) concentration in plants. The experiment suggests that brahmi, because of its high accumulation ability, could be used as a scavenger to clean Cr‐contaminated soil.     

Studies on the Effects of Vermicompost on Physicochemical Properties and Growth of Two Tomato Varieties under Greenhouse Conditions

This research was conducted to investigate effects of different vermicompost rates on breeding quality and growth of two tomato varieties. Six treatments were applied, combining vermicompost (VC) with rice husk ash (RHS) and coconut fiber (CF) with the following proportions: 3/3 VC (control treatment, T1), 2/3 VC + 1/3 RHS (T2), 2/3 VC + 1/3 CF (T3), 1/3 VC + 2/3 RHS (T4), 1/3 VC + 2/3 CF (T5), and 1/3 VC + 1/3 RHS + 1/3 CF (T6). The results demonstrated that there was significant difference between combining VC, RHS, and CF into EC and combining those into macronutrients of substrates with increasing VC mixture proportion; however, water-holding capacity (WHC), zinc (Zn), manganese (Mn), and iron (Fe) contents were significantly increased with reduced VC mixture proportion. A mixture of VC with RHS and CF made with the rate of 1:1:1 significantly influenced emergence and elongation of seedlings of both varieties. Biomass allocation was affected by VC amendments for two varieties in seedling stage and one field-grown tomato variety. The VC amendment did not affect the phosphorous (P), Fe, and Zn contents but significantly influenced nitrogen (N), potassium (K), calcium (Ca), magnesium (Mg), and Mn concentrations in the shoots. The mixture of VC with RHS and CF made with the rate of 1:1:1 was found to provide optimum conditions for seedling performance of the two tomato varieties.     

Soil Zinc Transformations as Affected by Applied Zinc and Organic Materials

Information on soil zinc (Zn) distribution is essential for understanding its chemical reactions and bioavailability. An experiment was conducted to evaluate the effect of wheat straw, cow manure, and vermicompost applied with Zn rates on Zn distribution in a calcareous soil. A sequential extraction scheme was used to fractionate Zn into soluble and exchangeable, bound to carbonate, organically bound, bound to manganese (Mn) oxide, bound to amorphous iron (Fe) oxide, bound to crystalline Fe oxide, and residual forms. In untreated soil, Zn was mainly in the residual fraction. Increasing rates of applied Zn increased all forms of Zn. Carbonate and residual forms showed the greatest increase. Organic materials application increased all fractions, except Mn-oxide form, and this increase was more pronounced for the organically bound form. Concentration of soluble, exchangeable, and organically bound forms was greatest in cow manure–amended samples as compared to other organic materials, suggesting that cow manure contained more bioavailable Zn than other organic materials.     

Enriching Vermicompost Using P-solubilizing and N-fixing Bacteria under Different Temperature Conditions

In the present study we evaluated changes in phosphorus (P), nitrogen (N), and humic acid (HA) contents of vermicompost (VC) in response to temperature increases, and inoculation with N₂-fixing and P-solubilizing microbes. Inoculants of Pseudomonas and Azotobacter were prepared and used to inoculate VC that was kept at 28 and 41 °C. Biological and chemical parameters of the VC were evaluated at 0, 20, 40, and 60 days. As incubation duration increased, bacterial population, N, available P, and HA content increased while organic carbon and pH decreased. These changes were most rapid during the initial 40 days of the experiment, and slowed subsequently. Increasing temperature from 28 to 41 °C reduced bacterial population and the efficiency of these bacteria in improving VC quality. Overall, our results indicate that inoculation of VC with microbes holds promise as a means of increasing the quality of VC, while our increased temperature treatment was less effective.