Nitrogen management strategies on plant growth and severities of Sclerotinia stem rot of canola in eastern Canada

Effective nitrogen (N) management strategies are important for ensuring a balance between optimizing plant growth and minimizing disease damage. A field experiment was conducted for three years to (i) assess the effects of N fertilizer application on the growth and seed yield of canola, and severities of Sclerotinia stem rot (SSR), and (ii) determine a reasonable N-rate for optimizing plant growth and minimizing the loss from SSR in eastern Canada. The experiment was designed with factorial combinations of eight N treatments and two canola hybrids. All N-treatments reduced canola emergence with increasing preplant N application rates above 100 kg ha–1, but had a positive impact on plant height, fresh weight, dry weight and seed yield. The development of SSR showed differential responses to N application rates. Of all the treatments, the split application (50 kg N ha–1 at preplant plus 100 kg N ha–1 side-dressed at the 6-leaf stage) increased canola growth, and often produced the highest or similar seed yields to those of equivalent N rate applied as preplant. At the 150 kg ha–1 N rate, no severe development of SSR was observed in either preplant-only or split application. Overall, this study demonstrates that the split-N management strategy (50+100 kg ha–1) maintained a balance between enhancing plant growth and mitigating the negative impacts of SSR on canola.

Soil microbial dynamics and enzyme activities as influenced by biofertilizers and split application of vermicompost in rhizosphere of wheat (Triticum aestivum. L.)

Aim: A field experiment was conducted during rabi season to determine the effect of biofertilizers and split application of vermicompost on biological properties (microbial biomass carbon and nitrogen, microbial populations and enzyme activities) in rhizosphere of wheat. Methodology: The experiment was laid out in factorial randomized block design with three replications consisting of twenty treatment combinations. Soil samples were collected from the plots at 0-15 cm depth after harvest of wheat crop and soil biological properties analyzed using standard analytical procedure. Results: The experiment results indicated that among biofertilizers treatments, seed inoculation with Azotobacter + PSB + KMB + ZnSB (B5) resulted in a significant higher soil microbial biomass carbon, microbial biomass nitrogen, population of bacteria, fungi and actinomycetes, dehydrogenase activity and acid phosphatase enzyme activity in comparison to control. Similarly, application of vermicompost as 50 % VC at sowing + 50 % VC at tillering (V3) were obtained improved microbial biomass carbon and nitrogen, microbial population, dehydrogenase activity and acid phosphatase enzyme activity while remaining at par with 75 % VC at sowing + 25 % VC at tillering (V4) proved superior in comparison to rest of the treatments due to continuous supply of nutrients throughout the crop cycle. Grain and straw yield of wheat also increased due to the application of biofertilizers and vermicompost over the control. Interpretation: Biofertilizers (Azotobacter, PSB, KMB and ZnSB) and split application of vermicompost enhanced the soil microbial population and enzymatic activities which sustained the soil health for better wheat production.

Rate and Timing of Meat and Bone Meal Applications Influence Growth, Yield, and Soil Water Nitrate Concentrations in Sweet Corn Production

Using local resources and minimizing environmental impacts are two important components of sustainable agriculture. Meat and bone meal (MBM), tankage, is a locally produced organic fertilizer. This study was conducted to investigate the response of sweet corn (Zea mays L. var. saccharata Stuart.) and soil water nitrate (NO3-N) concentration to MBM application at two locations, Waimānalo and Poamoho, on the island of O’ahu. The objectives were to determine effects of six application rates (0, 112, 224, 336, 448 and 672 kg N ha−1) and two application timings (preplant and split application) on: (1) sweet corn growth, yield, and quality, and (2) soil water nitrate concentration within and below the root zone. The split-plot was designed as four replicates randomly arranged in a complete block. Plant growth of roots and shoots, yield, and relative leaf chlorophyll content of sweet corn increased with increasing application rates of MBM in both locations. At Poamoho, yield was 13.6% greater in preplant versus split application. Nitrate-nitrogen losses were reduced by 20% at Waimānalo and 40% at Poamoho when MBM was applied in split applications. These findings suggest that MBM is an effective nitrogen source for sweet corn and a split application of MBM may reduce the potential for pollution.

The Effects of Single and Split NPK Fertilizer Application on Growth and Yield of Muskmelon (Cucumis melo L.)

Inorganic fertilizer application and the quantity required by the crop for optimum production led agronomists to introduced varying measures in crop production. A study to investigate the effects of single and split NPK 15-15-15 fertilizer application on muskmelon (Cucumis melo L.) production was conducted at the Teaching and Research Farm of Ekiti State University. A 4 × 2 factorial experiment laid out in a Randomized Complete Block Design in three replicates with four varying rates (0, 167, 333 and 500 kg ha-1) of NPK 15-15-15 fertilizer applications and two-mode of applications (single and split) serves as the treatments. Data collected include the number of leaves and branches, vine length, number of fruits, fruit length and width, fruit weight, fruit flesh thickness (fruit pulp width), number of seeds fruit-1 and seed weight. Collected data were subjected to analysis of variance (ANOVA), and treatment means separated with Duncan Multiple Range Test at 5% level of probability. The split application at 333 kg ha-1 NPK fertilizer produced a significantly higher number of leaves (90), leaf area (109.58 cm2) and vine length (110.77 cm) at 10 WAS than other applied fertilizer rates. The split application of 500 kg ha-1 NPK fertilizer produced a higher fruit yield (12.64 t ha-1) than 12.09 t ha-1 from the single application which was not significantly different from the 333 kg ha-1 NPK fertilizer. The results indicated that the split application of NPK fertilizer is a better fertilizer application approach than a single application for muskmelon production.