The Pedospheric Variation of DTPA-Extractable Zn, Fe, Mn, Cu and Other Physicochemical Characteristics in Major Soil Orders in Existing Land Use Systems of Punjab, India

The agricultural production in Punjab has increased manifold that aggravated the deficiencies of micronutrients in soils and plants. The availability of soil micronutrients in different soil orders depends upon the soil mineralogy, topography, climatic conditions and cropping sequences. Hence, to study the pedospheric variations of DTPA-extractable micronutrients, viz., zinc (Zn), iron (Fe), manganese (Mn) and copper (Cu), in three prominent soil orders of Punjab, a total of 144 depth-wise soil samples were collected from four major land-use systems (cultivated, horticulture, forest and pasture lands). The DTPA extractable micronutrients varied from 1.74–2.81, 1.83–2.82 and 1.81–2.80 for Zn; 5.3–6.8, 5.6–6.9, 4.3–6.3 for Fe; 5.1–7.8, 5.5–7.9, 5.4–7.5 for Mn; and 0.84–1.40, 0.93–1.68, 0.87–1.65 for Cu in soil orders Aridisol, Entisol and Inceptisol, respectively. The average content of DTPA-extractable micronutrients was highest under soil order Entisol followed by Inceptisol and Aridisol. The content of micronutrients showed a declining trend with increase in soil depth in all orders. Among different soil properties, the pH and EC showed significantly negative correlation, however, OC had non-significant correlation with DTPA-extractable micronutrients in soils. Therefore, it is concluded that parent material, land use systems and soil depth affected the distribution of DTPA extractable micronutrients in different soil orders.

The Effects of Cultivating Tobacco and Supplying Nitrogenous Fertilizers on Micronutrients Extractability in Loamy Sand and Sandy Soils

This research was conducted to evaluate the trends of the extractable micronutrients boron (B), copper (Cu), iron (Fe), manganese (Mn), and zinc (Zn) in soils differing in textures and collected before tobacco cultivation, and in after unfertilized and fertilized (N10P18K24 and CAN 27%) plots. The soils and tobacco leaves were assessed on the contents of the micronutrients after unfertilized and fertilized tobacco cultivation. In soils, tobacco cultivation with fertilization increased the extractable Cu, Fe, Mn, and Zn by 0.10, 11.03, 8.86, and 0.08 mg kg−1, respectively, but decreased the extractable B by 0.04 mg kg−1. The effects of fertilization increased the extractable Cu, Fe, Mn, and Zn by 0.14, 14.29, 9.83, and 0.24 mg kg−1, respectively, but decreased B by 0.08 mg kg−1. The combination effects of tobacco cultivation and fertilization increased the extractable Cu, Fe, Mn, and Zn by 0.24, 25.32, 18.69, and 0.32 mg kg−1, respectively, but decreased the extractable B by 0.12 mg kg−1. The results revealed that the solubility of the extractable Zn, Mn, Cu, and Fe in soils were increased by both tobacco and fertilization, but the extractable B was decreased. The fertilization of the studied soils with NPK + CAN fertilizers significantly increased the concentration of the extractable micronutrients in tobacco leaves. Based on the findings of this study, further research must be conducted to investigate the effects of tobacco cultivation on soil health and fertility beyond considering only soil pH, SOC, micronutrients, and macronutrients. These studies should include the relationship between soil fertility (pH, texture, CEC, base saturation, etc.), micronutrients, and agronomic practices on the effect of tobacco cultivation on the extractability of B, Cu, Fe, Mn, and Zn.

Distribution of DTPA Extractable Micronutrients in Soils of Central Telangana Region of Telangana

Forty soil samples from ten pedons of the Central Telangana region, Telangana were studied for the vertical distribution of DTPA extractable. Zn, Cu, Fe and Mn and their relationship with some soil properties. Soil pH, CaCO3,, organic carbon and particle-size distribution had a strong influence on the distribution of these micronutrients. The content of the micronutrient increased with the an increase in organic carbon and decreased with an increase in pH and CaCO3. There was a decreasing trend for the distribution of these micronutrients with respect to depth. As per the critical limit prescribed for Zn, and Fe, 55 and 12% of the soil could be rated as deficient in available zinc and iron, respectively. Copper and manganese were found to be adequate.

Variability of Soil Extractable Micronutrients in the Upland and Lowland Topoposition Soils of Gubi Village, Bauchi State, North Eastern Nigeria

The aim of this study was to assess the variability of extractable micronutrients in the varying topoposition soils of Gubi village. Four profile pits were dug at each of the designated topopositions making a total of eight profiles. The profiles were dug at the crest, upper slope, middle slope and valley bottom positions of the two toposequences and were named URFGU1, URFGU2, URFGU3 to URFGU4 and URFGL1. URFGL2, URFGL3 to URFGL4 for upland and lowland respectively. The content and profile distribution of extractable micronutrients copper (Cu), Zinc (Zn), manganese (Mn) and Iron (Fe) were extracted using 0.1 m HCl solution and determined using atomic absorption spectrophotometer (AAS) at appropriate wavelengths (Ca at 247 nm, Zn at 214 nm, Mn at 279 nm and Fe at 248 nm. Data generated was statistically analyzed using analysis of variance in nested experimental design. The significance of difference between treatments was determined using fishers LSD. Means that were significantly different were separated using the Least Significant Difference (LSD). The result reveals that Copper (Cu), iron (Fe) and manganese (Mn) varied significantly due to location. Iron and manganese were significantly higher in the upland soil (47.35 and 47.50 mg/kg respectively) than in the lowland soil (17.67 and 27.38 mg/kg respectively). The lowland soil had significantly higher Cu (1.31 mg/kg) than the upland soil (0.37 mg/kg). Zinc (Zn) did not vary significantly due to location however the lowland soil (0.86 mg/kg) had a higher Zn content than the upland soil (0.26 mg/kg).

Evaluation of Soil Fertility Status for Maize (Zea mays) Production in Moshi Rural, Kilimanjaro Region Tanzania

This study was carried out to assess the soil fertility status for maize (Zea mays) production in soils of sixteen villages of Moshi Rural, Kilimanjaro region in February 2019. Sixteen field soil samples were collected through random sampling approach. A total of sixteen soil parameters including soil reaction (pH), Organic carbon (OC), nitrogen (N), Phosphorus (P), and Sulfur (S) Exchangeable bases (Calcium (Ca), magnesium (Mg), sodium (Na), and potassium (K), Extractable micronutrients (Manganese (Mn), aluminum (Al), Zinc (Zn), Iron (Fe) and Boron (B) was tested in the soil laboratory in Agricultural Research Institute Mlingano Tanzania. The soil analysis results indicated that, the studied soils were strongly acidic (5.0-5.9) indicating the need for liming to raise up the soil pH. The concentration of total nitrogen in Moshi Rural maize growing farms was very low to low (0.01 to 0.1%). The concentration of phosphorus ranges from 1-3 mg/l with an average of 2.742 suggesting that all studied areas should be considered for P supplementation. Exchangeable Na in the studied soils varies from 0.01 to 0.1 cmol (+) kg-1 with the average of 0.0154. This value suggests that exchangeable Na in the studied soils is very low with the implication that the studied soils are not salt affected. Micronutrients were seen as not a problem in the studied soils. The studied soils generally are poor in soil fertility. Total nitrogen levels are very low, phosphorus is very low to medium and exchangeable bases and extractable micronutrients and equally very low to medium. Application of farm yard manure available in the locality, in combination with Diammonium phosphate or NPK is recommended at the average rate of 50 Kg per acre during planting and CAN, MOP and NPK during top-dress.

Role of Different Cover Crops on DTPA-Extractable Micronutrients in an Apricot Orchard

This study was conducted to compare the effect of different cover crop treatments on DTPA-extractable micronutrients (Fe, Mn, Zn, Cu) and soil pH in an apricot orchard with clay texture located in Malatya province of Turkey. For this purpose, 5 different experimental groups (Vicia villosa Roth (VV), Vicia pannonica Crantz (VP), Vicia pannonica Crantz and Tritikale mixture (70% + 30%, respectively) (VPT), Phacelia tanacetifolia Benth (PT), Fagopyrum esculentum Moench (FE)) and 3 control groups (mechanically cultivated (MC), herbicide treatment (HC) and bare control plot (BC)) were used in the apricot orchards. The soils were sampled from 0–20 cm and 20-40 cm depths in each plot for soil analyses. According to the obtained results, while cover crop treatments reduced pH values of soils according to the bare control, the cover crops increased the Fe, Mn and Zn contents of soils in the 0-20 cm soil depth. The highest Ext-Fe, Mn and Zn contents were obtained in the VV (14.83mg kg-1, 8.42 mg kg-1, 1.03 mg kg-1, respectively) at the 0-20 cm soil depth. As compared to bare control, highest percent increases in Fe, Mn and Zn contents were determined in the VV 27.73%, 31.69% and 37.54%, respectively. The greatest significant negative correlations in the VV treatment were observed between pH and Fe (-0.985**), between pH and Mn (-0.945**) and between pH and Zn (-0.764*). The greatest significant negative correlations in the VP treatment were observed between pH and Fe (-0.948**), between pH and Mn (-0.928**) and between pH and Zn (-0.722*). It was concluded based on current findings that cover crops, especially Vicia villosa Roth and Vicia pannonica Crantz could be incorporated into cropping systems to improve micronutrients and to provide a sustainable soil management.