Browsing by Author "Nideesh, P"

Now showing 1 - 4 of 4

Geospatial variability and nutrient dynamics of soils of lateritic wetlands vis-avis coastal wetlands
(Department of Soil Science & Agricultural Chemistry, College of Agriculture , Padanakkad, 2025-01-17) Anzala Shahanas.; Nideesh, P
A research study entitled “Geospatial variability and nutrient dynamics of soils of lateritic wetlands vis-a-vis coastal wetlands” was done with the objective to assess the spatial and temporal variability of the wetland soils in the two AEU’s (northern laterites and northern coastal plains) of north Kerala using GIS and also to assess the soil dynamics as modified by amendments for evolving best management practices. Paddy growing wetland of RARS, Pilicode (AEU 11) and Muppathil kandam at Nileshwar (AEU 2) were selected for the spatial and temporal variability assessment of soil nutrient dynamics. Grid based soil samples were collected from 10 locations at quarterly intervals for one year from these wetlands (from February 2023 to November 2023). Additionally, a pot culture experiment was conducted at the College of Agriculture, Padannakkad, using paddy as the test crop. Experiment was conducted with 2 types of soils (coastal sandy and lateritic alluvial wetland) under 5 levels of treatments using CRD. Treatment combinations were T1 (KAU POP (2016) based fertilizers + lime), T2 (Soil test based fertilizers), T3 (Soil test based fertilisers and lime), T4 (KAU organic POP based FYM + Lime) and T5 (Soil test based fertilisers and dolomite). In the clay loam soils of lateritic wetland (AEU 11), pH was found to be in the range of 4.44 to 5.64 and were non saline. Organic C content ranged from 0.60 % to 2.85 % and available N ranged from 81.54 to 476.67 kg ha⁻¹. Available P was high (>29 kg ha⁻¹) and available K ranged from 56.22 to 263.65 kg ha⁻¹. Available Ca varied between 160.00 and 480 mg kg⁻¹ and available Mg varied between 48.00 and 156.00 mg kg⁻¹. Available S, Fe, Mn, Zn and Cu content were sufficient and available B was deficient. MBC varied between 216.97 and 1390.59 μg g⁻¹ and DHA varied between 1.28 and 13.59 μg TPF released g⁻¹ soil 24 h⁻¹. . In the coastal sandy wetland soils (AEU 2), pH ranged from 5.60 to 6.94 and were non saline. Organic C was in the range from 0.45 % to 1.20 % and available N ranged from 43.90 to 244.61 kg ha⁻¹. Available P was high (>29 kg ha⁻¹) and available K was low to medium (15.68 and 210.13 kg ha⁻¹). Available Ca varied between 160.00 and 480 mg kg⁻¹ and available Mg varied between 72 and 192 mg kg⁻¹. Available S, Fe, Mn, Zn and Cu content were sufficient and available B was deficient. MBC ranged between 54.59 and 338.66 μg g⁻¹ and DHA ranged between 0.65 and 9.66 μg TPF released g⁻¹ soil 24 h⁻¹. On assessing the temporal variability of nutrient dynamics in lateritic wetland soils, it was found that the mean organic C, available Ca and Mg content were highest in August which was on par with May. The mean available S, MBC and DHA were highest in August. The highest mean available N was observed in November, while the mean available P was maximum in August, which was on par with November and May. In coastal wetland soils, the highest mean value of organic C, available N, K, mean MBC and DHA were recorded in November. The mean available Ca, Mg and S were highest in May which was on par with August and mean available P was highest in February. In both wetland soils, the highest mean pH value was observed in May which was on par with February. Results of pot culture experiment showed that there is significant effect of treatments on soil nutrient content and plant growth. Treatments have no significant effect on plant height. In lateritic wetland soils, highest number of productive tillers was recorded in T5 which was on par with T3 and T2. Highest number of grains per panicle was recorded in T3 which was on par with T5 and T2. Highest 1000 grain weight was recorded in T3 which was on par with T5. In coastal wetland soils, number of productive tillers was maximum in T3 which was on par with T5 and T2. Number of grains per panicle was maximum in T5 which was on par with T3 and T2. Highest 1000 grain weight was recorded in T5 which was on par with T3. Available N, K, Ca, Mg and B showed similar trend in both lateritic and coastal wetland soils. Available N was maximum in T1 and available K was maximum in T3 which was on par with T2 and T5. Highest available Ca was recorded in T1 which was on par with T4 and T3. Highest available Mg was recorded in T3 which was on par with T5 and T2. Highest available B was recorded in T3 which was on par with T5 and T2. Total nutrient content in plants (N, Ca, Mg, S and B) showed similar trend in both soil types. Highest plant N content was recorded in T1 which was on par with T3 and T5. Highest plant Ca and S content were recorded in T1 which was on par with T4. Highest Mg content was recorded in T3 which was on par with T5 and T2. Plant B content was maximum in T3 which was on par with T5. Highest plant K content was recorded in T3 in lateritic wetland soils while it was maximum in T3 which was on par with T5 in coastal wetland soils.
Organic carbon-nutrient dynamics and its impact on growth of okra (Abelmoschus esculentus L.) in red sandy loam soils
(Department of Soil Science & Agricultural Chemistry, College of Agriculture, Padannakkad, 2023-06-06) Avinash, rana; Nideesh, P
Soil phosphorus dynamics and its interactions in red sandy loam soils
(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Padannakkad, 2025-06-19) Shiv Prasad, T; Nideesh, P
The study entitled “Soil phosphorus dynamics and its interactions in red sandy loam soils” was carried out at the instructional farm II, College of Agriculture, Padannakkad, to assess the short-term dynamics of phosphorus in the sandy loam soils cultivated with cowpea as modified by different amendments and to study its impact on growth and yield parameters of cowpea. The study was carried out in two parts; an incubation experiment and a field experiment. Soil samples collected from the instructional farm II were incubated at field capacity for three months, and analysis was done after the incubation period. Treatment combinations were T1 (Control), T2 (Soil test-based P fertilizer), T3 (T2 + ZnSO4 @ 20 kg ha-1), T4 (T2 + Borax @ 10 kg ha-1), and T5 (T2 + Lime @ 250 kg ha-1). Analysis of the soil samples before incubation experiment showed that the soil is very strongly acidic, non saline and high in organic carbon. Soil sample analysis after incubation showed a significant effect of lime application on the soil pH. Available P was also significantly affected by treatments and was highest in T4 (T2 + borax) and T5 (T2 + lime) treatments. Treatments have significant effect on the Phosphorus activity coefficient (PAC) also having higher values of 15.82% and 15.79% in T4 and T5 treatments respectively, indicating better conversion of total P to available P in those treatments. On analysing the different P pools, Ca-P and Fe-P pools were found at significantly higher levels in treatment T5 (T2 + lime), whereas the Al-P, loosely bound P, and reductant P were significantly higher in T4 (T2+ borax). The incubation study revealed that boron and lime application could help in enhancing the available P content in the soil. The application of borax has a significant effect on the soil P pools also indicating its role in enhancing the reserve soil P pools. The field experiment was laid out in a randomized block design with eight treatments and three replications. The treatment combinations were T1 (KAU POP based lime and fertilizers), T2 (Soil test-based fertilizers and lime), T3 (KAU organic POP ), T4 (T2 + ZnSO4 @ 20kg ha-1), T5 (T2 + Borax @ 10 kg ha-1), T6 (T2 + PSB), T7 (T3 + PSB) and T8 (T2 excluding P + Nano P @ 10ml L-1). The cowpea variety Kanakamony was used as a test crop for the field experiment. Results of the field experiment showed significant changes in the soil chemical properties and phosphorus pools. At flowering, T3 ( KAU organic POP) treatment showed significantly higher soil pH which was on par with T1 (KAU POP) treatment. Phosphorus pools were significantly affected by treatments. Available P content was significantly higher in T1 (KAU POP) and T2 (KAU organic POP) treatments, Fe bound P and Al bound P were significantly higher in T4 ( T2 + ZnSO4) treatment. Ca bound P and reductant P were significantly higher in T2 (Soil test-based fertilizer and lime) and T3 (KAU organic POP) treatments respectively. Loosely bound P was significantly higher in T1 (KAU POP) and Organic P content was higher in T3 (KAU organic POP) treatment. Total P was significantly higher in T7 (T3 + KAU organic POP) treatment. At post-harvest, there was no significant change in the soil pH, EC and OC. Available P was significantly higher in T1 (KAU POP) treatment which was on par with T2, T3 and T4 treatments. Fe bound P and Al bound P were significantly higher in T4 (T2 + ZnSO4) treatment, whereas Ca bound P and Reductant P were significantly higher in T3 (KAU organic POP) treatment. Organic P was significantly higher in T1 (KAU POP) and T3 (KAU organic POP) treatments. Loosely bound P was significantly higher in T7 ( T3 + KAU organic POP) and total P was highest in T3 and T7 treatments. Treatment T2 (soil test based fertilizer and lime) had significantly higher PAC (Phosphorus activation coefficient) values at flowering and post-harvest stages (14.977 and 11.443% respectively) than the other treatments. The plant analysis results revealed that higher N and P were recorded in treatment T8 and K content was highest in treatment T1. Total Ca, Mg and Fe were highest in treatment T2. Total S was highest in treatments T1 and T7. Total Cu and Mn were highest in treatment T3. Total Zn was highest in T4 and T7 treatments, whereas B was highest in T5. Application of amendments had no significant effect on the growth parameters of cowpea, while yield parameters like pod weight per plant, pod yield and grain weight were significantly affected by treatments. Pod weight per plant was highest in T3, T7 and T8 treatments while pod yield was maximum in T8. Grain yield was significantly higher in T7 and T8 treatments compared to other treatments. The study results revealed a change in the dynamics of phosphorus pools and soil properties with the application of different amendments. Application of lime helps in increasing available P in the soil. The synergistic and antagonistic behaviour of added amendments such as B and Zn were also seen affecting different pools and hence the available P. Even though the available P is very high in the coastal sandy soils, a small amount of fertilizer addition is necessary to ensure the sustainable release of phosphorus from the reserve pools, as is evident from the PAC values. The addition of amendments such as Borax, ZnSO4, etc., could help in fixing excess P in the soil and can thus reduce the negative impact on the environment and soil. Borax can also help in the sustainable release of fixed P from the reserve pools. Foliar application of nano P fertilizer (DAP) was found to increase the yield parameters and is an alternate option for ensuring P supply to plants without adding P to the soils.
Taxonomy and organic carbon-nutrient interactions in selected wetland soils of Kerala
(Department of Soil Science and Agricultural Chemistry, College of Horticulture, Vellanikkara, 2019) Nideesh, P; Sreelatha, A K
A study was undertaken with the objective to classify wet land soils in the agro ecological units AEU 10 (north central laterite), AEU 5 (Kole lands) and AEU 6 (Pokkali lands) of Kerala and to assess the organic carbon stocks and CNPS stoichiometry. The study also aimed in finding out the organic carbon - nutrient interactions and to predict the organic carbon turnover in these soils. Extensive field traverse was conducted to select sites for profile excavation in the lateritic, Kole and Pokkali wetlands. The excavated profiles were studied for their morphological, physical and chemical properties. Based on the results of the study, soils of lateritic wetlands were classified as fine loamy, mixed, super active, acid isohyperthermic, Fluventic Dystrustepts. Soils of Kole lands were classified as loamy, mixed, euic, isohyperthermic, Terric Sulfihemists and Pokkali soils as coarse loamy over sandy, mixed, active, isohyperthermic, Typic Sulfaquepts. Total soil organic carbon (SOC) stock in the north central laterite region (Fluventic Dystrustepts) was 218 Mg ha-1 up to the depth of 120 cm of which maximum amount was stored in the surface 30 cm (86 Mg ha-1). In the Kole land soil (Terric Sulfihemists) maximum SOC was stored in the 90-120 cm layer (1016 Mg ha-1) and a total SOC of 2261 Mg ha-1 was stored up to 120 cm depth. Pokkali soils (Typic Sulfaquepts) stored 209 Mg ha-1 SOC up to 120 cm depth which was almost uniformly distributed in the entire profile. The C/N, C/P and C/S ratios decreased with depth in lateritic soil profile, whereas in the Kole land soil these ratios except C/S ratio increased significantly in the sub surface horizons. In the Pokkali soils the CNPS stoichiometry suffered irregular variation with depth. An incubation experiment was conducted to study the organic carbon nutrient interactions in the three wetland soils. Treatments included control (T1), POP based fertiliser and lime application (T2), soil test based fertiliser and lime application (T3), FYM substituting nitrogen in the T3 treatment (T4) and soil test based fertiliser and dolomite application (T5). In the lateritic soils. the active carbon and organic reserves of N, P and S were high in T3 treatment. The organic N, P and S pools increased in treatment T5 whereas organic P and inorganic S increased in treatment T4. In the Kole land soils, active carbon, organic nitrogen, inorganic P, organic S and inorganic S increased in T3; inorganic N and organic P increased in T4 and organic P and S pools increased in T5. In the Pokkali soils, active carbon content was high in T2 compared to other treatments while active carbon, organic N and inorganic N decreased in treatment T3. Liming decreased organic P in Pokkali soils due to conversion to available forms and higher utilisation. Application of FYM increased organic S in Pokkali soils and inorganic S in all soils. Temporal variation of the nutrient content (mg kg-1 soil) per organic carbon content (g kg-1 of soil) indicates the change in nutrient supply per unit change of organic carbon content. Treatment T1 favoured higher inorganic nitrogen per carbon content in laterite and Pokkali soils, where as in in Kole soils it was increased in T4. Inorganic phosphorus content per carbon was highest in laterite and lowest in Kole soil in control (T1). Inorganic sulphur per carbon content was highest in T4 for laterite, Kole and Pokkali soils. Organic nitrogen per carbon content was highest in the Kole land and minimum in the Pokkali land in the T3 treatment. Organic phosphorus per carbon content was maximum in FYM treatment in Kole and Pokkali soils and was minimum in T2 treatment in laterite and Pokkali soils. Treatment T3 had the highest organic sulphur per carbon content in the laterite and Kole soils and the treatment T1 gave the highest content in Pokkali soil. Wetland DNDC model was used to simulate the organic carbon turn over in the three wetland systems using the climatic data predicted by MarkSIM software. The results of modelling simulated for the year 2050 indicated that application of 100 per cent NPK along with FYM @ 5t ha-1 will ensure maximum organic carbon content in the Kole, Pokkali and lateritic wetlands. Fertiliser application improves the organic carbon storage in lateritic and Kole land soils. But in the Pokkali soils, fertiliser addition will not cause change in the organic carbon turn over processes whereas FYM application can improve the carbon content. Results of the study indicate that cultivation without any fertiliser and lime application causes gradual depletion of all organic and inorganic pools of nutrients in Kole land and lateritic wetland soils. Soil test based fertiliser and lime application along with FYM @ 5t ha-1 is appropriate in these soils for increased sustainability. The Pokkali soils are self-sufficient and can sustain its fertility status without any fertiliser application. However liming and FYM application may be considered as management options to improve sulphur availability and organic carbon turn over processes in these soils.