Evaluating the Effects of Silicon and Nitrogen Fertilization on Wheat Production

Silicon (Si) fertilization provides numerous benefits to plants which can in turn lead to improved crop yields. Field studies were established at multiple sites in Louisiana on alluvial flood plain soils to establish an optimum application rate for CaSiO3 slag for wheat (Triticum aestivum) and determine which parameters contribute to grain yield increases. Treatments were arranged in a randomized complete block design with four replications consisting of twelve treatments: a factorial combination of two N (101 and 145 kg ha-1) and five Si rates (0, 1, 2, 4.5, and 9 Mt ha-1 as calcium silicate slag - CaSiO3, 14% Si), and two control plots (with and without lime). Grain yield and yield components were determined. Straw and grain samples were analyzed for Si and essential nutrient content. Soil samples taken at midseason and harvest were analyzed for Mehlich-3 extractable nutrients and Si content by 0.5 M acetic acid extraction procedure. In 2013, higher grain yields were observed at 101 kg N ha-1 compared to 145 kg N ha-1 with the highest yields seen with 2 Mt ha-1 CaSiO3. In 2014, higher yields were achieved at the higher N rate of 145 kg ha-1. Analysis of variance (AOV) at P\u3c0.1 showed effects of N on tiller and panicle number, spike length, and increased weight of 1,000 grains and spikes, and increased grain weight. Silicon effects were observed in spike weight and length, weight of 1,000 grains and the number of grains per spike. Mean separation using Fisher’s LSD (P\u3c0.1) showed effects of Si on further yield components such as the number of grains per spike. Data show an increase in some essential nutrients in the soil (e.g. Ca, Mg, S). Nitrogen and Si both influenced the concentration and uptake of nutrients and certain heavy metals in straw and grain. Increased N application lead to greater leaf rust coverage (P\u3c0.01) but significant effects of Si were not observed. Although further research is necessary, the results of this research will help establish the links among Si fertilization rates, level of soil Si and plant essential nutrients, grain yield and its components