Effect of soyben planting density and weeding on the root characteristics of Maksoy3 variety (Glycine max)

Abstract

Soybean (Glycine max) is one of the world‟s most important legume crop because of its high protein content (40%) and oil (20%) content. It is ranked among the cheapest source of protein for both human food and livestock feeds. The crop can be cultivated in many places with low level of agricultural inputs (Gan et al.,2003). The study aimed at assessment of the effect of soybean planting density and weeding on root characteristics of A Maksoy3 variety at Makerere University agricultural research institute Kabanyolo. The experiment was set up in the field (at MUARIK), with treatments arranged in a Randomized Compete Block Design (RCBD) but in a spit plot arrangement. Soybean variety Maksoy 3N was planted at 400,000 (S); 500,000 (H1); 666,667 (H2); 1,000,000 (H3); 333,333 (L1); and 285,714) plants ha-1 interacted with two levels of weeding (weeded and not weeded). The study investigated the intricate dynamics of weed competition and plant density on soybean crops, with a specific focus on root length, root biomass and nodulation (parameters). By examining the interplay between weed competition and its impact on soybean root development and nodulation, the study aimed to provide insights into optimizing soybean cultivation practices in the unique agricultural environment of Uganda.The field results on different parameters were entered in an Excel spreadsheet and the data subjected to analysis using the R programming language in RStudio to generate Means, Least Significant Differences, and F-probability. Treatment Means were compared using Fisher‟s Least Significant Differences (LSD test) at a significance level of p<0.05. The Means, LSDs and contrasts generated were then extracted from RStudio console and tabulated as shown in the results section. The results showed that soybean plants at low densities (i.e., below 500,000 plants ha-1) accumulated high dry matter, had little nodule activity and had shorter root length than at high densities (above 400,000 plants ha-1), Dry matter accumulation was generally higher in weeded plots than in in the non-weeded plots across all densities. Also, higher root nodule activity and longer root length were observed in the un-weeded plots than the weeded ones. This meant that Maksoy 3N employed different adaptive mechanisms like nitrogen fixation and development of extensive root system to counteract the effect of weeds and high planting density. Therefore, Planting density of 400,000 plants ha-1 is the appropriate density because this configuration provides each plant with an adequate amount of land area to extract the necessary growth resources efficiently hence maximizing soybean production.