Open Access Original Research Article

Growth, Yield and Quality of Onion (Allium cepa L.) as Influenced by Nitrogen and Time of Topdressing

M. W. Gateri, R. Nyankanga, J. Ambuko, A. W. Muriuki

International Journal of Plant & Soil Science, Page 1-13
DOI: 10.9734/IJPSS/2018/42135

Onion (Allium cepa L.) is an important commercial vegetable crop grown by small-holder farmers in Kenya for both local and export markets. The national average production is low and quality is highly compromised due to use of low yielding varieties and poor agronomic practices. Field experiments on the influence of nitrogen and time of application on growth, yield, and quality of onion bulbs were conducted in 2014 and 2015 at the National Agricultural Research Laboratories. The experiments were laid out in a Randomized Complete Block Design (RCBD) with a split-split arrangement and replicated three times. Nitrogen (N) was applied as Calcium Ammonium Nitrate at five levels including, 0 (control), 26, 52, 78 and 104 kg N ha-1. These were applied at four different times of applications at three, six, nine and twelve weeks after transplanting. Two onion varieties popularly grown in Kenya were used, the Red Creole and Red Tropicana F1 hybrid. Nitrogen and time of application showed significant differences in all parameters studied except bolting. Nitrogen at 104 kg N ha-1 applied at 6 weeks gave the best results with regard to plant height, number of leaves, bulb ratios, bulb diameter, average bulb weight, yield and marketable yield. Six weeks after transplanting was the best application time with regard to most parameters and maturity of the crop. Yields increased linearly with increased N rates but declined by over 23% with late application at 12 weeks. High rates resulted to thick necks and increased split bulbs especially with late application at 9 and 12 weeks. Red Tropicana F1 hybrid was the best performing variety with regard to most parameters especially total and marketable yield. Nitrogen applied at the right time improves growth, increases yield and improves quality. Since the yield response was linear in both seasons, higher rates should be evaluated to get the optimal rate.

Open Access Original Research Article

Integrated Nitrogen Management on Nutrient Contents, Uptake and Use Efficiency of BRRI Dhan29

Most. Sarmin Ashraf, M. Abdullah Al Mamun, Md. Mizanur Rahman, A. K. M. Mosharof Hossain, Hiroshi Hasegawa

International Journal of Plant & Soil Science, Page 1-10
DOI: 10.9734/IJPSS/2018/42295

A field experiment was performed with BRRI Dhan 29 at Field Laboratory of Soil Science, Hajee Mohammad Danesh Science and Technology University, Dinajpur, Bangladesh. The effects of organic (cowdung) and inorganic (urea) amended N fertilizers were evaluated for NPKS contents and uptakes in grain and straw, and also for observing N use efficiency. Randomized complete block design was set for seven treatments based on recommended dose of N (RDN) @ 150 kg ha-1 using cowdung and/or urea alone or their combinations. The NPK contents as well as their uptake in grain and straw were significantly affected due to different treatments while S content was insignificant. The application of recommended dose of N from urea (T1) showed highest N content in grain (1.11%) and straw (0.71%) which was closely followed by the treatment T6 (20% RDN from cowdung + 80% RDN from urea). The maximum P content was found from the grain and straw of T6 treatment whereas a significant increase in the P, K and S contents were noted due to combined application of N from cowdung and urea. The NPKS uptake of grain and straw as well as total uptake (107.60 kg ha-1 N, 27.84 kg ha-1 P, 71.36 kg ha-1 K and 25.63 kg ha-1 S) were recorded maximum in T1, followed by T6. The treatment T1 yielded maximum apparent N recovery efficiency (45.06%) and agronomic N use efficiency (19.60 kg kg-1) while the maximum physiological N use efficiency (43.55 kg kg-1) was found in T6. Results also suggested that the application of lower doses of urea N with higher doses of cowdung N were not useful for the N recovery due to low N supplying potentiality of manures in a single cropping season. However, the incremental rates of urea N upto 80% along with 20% cowdung N effectively increased the recovery of N in all the parameters of N use efficiency and should be applicable to optimize the need for N requirement and build up a good soil health

Open Access Original Research Article

Response of Chili Pepper (Capsicum spp.) Cultivars Cultivated in Benin to Salt Stress at Germination Stage

Julien Koffi Kpinkoun, Séraphin Ahissou Zanklan, David Montcho, Eliane Kinsou, Françoise Assogba Komlan, Armel C. G. Mensah, Agapit Dossou Wouyou, Christophe Bernard Gandonou

International Journal of Plant & Soil Science, Page 1-11
DOI: 10.9734/IJPSS/2018/42118

Aims: In this study, salt resistance level of six chili (Capsicum spp.) cultivars including five local cultivars (Adologbo, Gbatakin, Pili-pili, Gbatakin d’Agbédranfo, TPS0251) and one imported variety (Démon) grown in Benin was evaluated at the germination stage.

Study Design: The experiment was laid out as a completely randomized design with four replications.

Place and Duration of Study: The experiment was carried out in the Laboratory of Plant Physiologyand Abiotic Stresses Study of University of Abomey-Calavi, Republic of Benin from September through October, 2016.

Methodology: Seeds were submitted to treatment with five NaCl concentrations (0; 30; 60; 90 and 120 mM NaCl) in petri dishes.Seed germination was checked every day during sixteen days incubation period. Four replicates of 40 seeds each were used.

Results: From day 2 to day 16, NaCl delayed seed germination rate proportionately to NaCl concentration except for cultivars TPS0251 and Démon. At the end of the 16 days, NaCl stress effects on seed germination of cultivars were significantly variable. No significant reduction was observed for cultivars Démon and TPS0251 whereas a significant decrease was observed for the four other cultivars with a significant difference among them. The average reduction due to NaCl stress was lower for cultivars Démon (0%) and TPS0251 (4.31%) and higher for cultivar Pili-pili (63.61%). Salt Tolerance Index was significantly variable according to the cultivar with the highest values for cultivar Démon (1.227) and TPS0251 (1.127) and the weakest values for cultivars Pili-pili (0.374) and Gbatakin d’Agbédranfo (0.46).

Conclusion: NaCl stress delayed seed germination and reduced the rate of final germination. Salt Tolerance Index was variable among the six cultivars: cultivars Démon and TPS0251 appeared to be the most salt resistant whereas Pili-pili and Gbatakin d’Agbédranfo appeared as the most salt sensitive at germination stage. For the first time, we demonstrated a variability of relative salinity resistance among local chili pepper cultivars at germination stage.

Open Access Original Research Article

Effects of Pyrolysis Temperature and Residence Time on Rice Straw-derived Biochar for Soil Application

Sisomphone Southavong, Mohd Razi Ismail, Thomas Reg Preston, Halimi Mohd Saud, Roslan Ismail

International Journal of Plant & Soil Science, Page 1-11
DOI: 10.9734/IJPSS/2018/42197

Aims: A study was conducted to assess the rice straw-derived (Rsd) biochar in relation to temperature and residence time.

Study Design: Rsd biochar was pyrolyzed at different temperatures (300ºC, 400ºC, 500ºC and 600ºC) in a combination of different residence times (45 min, 60 min and 120 min) namely 300-45, 300-60, 300-120, 400-45, 400-60, 400-120, 500-45, 500-60, 500-120, 600-45, 600-60, and 600-120, respectively.

Place and Duration of Study: The study was conducted in the laboratory of Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, Malaysia, between July to September 2014.

Methodology: A suite of analytical procedures was performed to evaluate the Rsd biochar characteristics.

Results: The results showed that the biochar yield decreased when the pyrolysis temperature increased. The physicochemical and structural characteristics of the biochar were significantly influenced by pyrolysis temperature. Scanning Electron Microscope (SEM) images indicate significant macro-porosity (size between 1-10 µm) and were clearly visible across the surface of 300ºC (60 min) compared to other temperature values and residence times. Increase in temperature gave rise to a nodule-like visible indicator of silicate presence on the surface. Macro-porosity presence in biochar is an indicator that it can adsorb and retain water and nutrient for plant-root hair uptake. Meanwhile, Brunauer-Emmett-Teller (BET)-N2 surface area ranged from 2.36-6.26 m² g-1, for 300 to 500ºC, respectively. Surface area controls materials’ ability to adsorb chemical compounds, as larger surface area means more porous structures within biochar. H/C and O/C ratio decreased as the temperature increased, indicating condensed carbon in biochar. The pH increased with the increment of pyrolysis temperature.

Conclusion: Rsd biochar at 300-60 and 400-60 showed good potential characteristic with macro-porosity and surface area increases, and should thus be suitable as a soil amendment for agricultural activity

Open Access Original Research Article

Characterization of Enriched Phosphatic Sludge and Studies on Nutrient Releasing Pattern from Enriched Phosphatic Sludge under Submerged Condition

Eresha ., S. S. Prakash, Harsitha Moram

International Journal of Plant & Soil Science, Page 1-9
DOI: 10.9734/IJPSS/2018/38713

A laboratory experiment was conducted to characterize the enriched phosphatic sludge (EPS) and to determine the nutrients release pattern from different levels of enriched phosphatic sludge under flooded condition. Soil sample were collected at the depth of 0-15 cm from “B” block, Zonal Agricultural research Station, V. C. Farm, Mandya. Soil sampling area lies between 76082'01" to 76082'08" E longitude and 12057'03" to 12057'05" N latitude with an average elevation of 699-715 m above SML and incubation study carried out during 2016 at UAS, GKVK, Bengaluru. Seven different levels of EPS (0, 125, 250, 500, 750, 1000 and 1250 kg ha-1) was adopted in this experiment with three replication by using factorial complete randomized design.  Enriched phosphatic sludge supplied by Aditya Birla chemical fertilizers private limited was characterized for various parameters. The analysis of the samples revealed that the pH value of enriched phosphatic sludge was alkaline in reaction (8.03) and medium in salt content (0.97 dS m-1) and OC (11.30%).The enriched phosphatic sludge had high quantity of phosphorus (6.88%) and the total N, K, Ca, Mg and S contents were also appreciable in the enriched phosphatic sludge (1.51, 1.20, 1.50, 1.10 and 1.20%, respectively). Heavy metal content in sludge was much lower than that indicated for PROM (phosphate rich organic manure) and other organic fertilizers listed in the FCO amendment.Significantly higher available nutrients release (NPK) were recorded in treatment T7 which received 1250 kg EPS ha-1