where FGP is the total seeds that accomplished their germination process (Ʃn1) in relation to the total of seeds used in the assay (NSi);
The pH presented an interaction with nutrients. KCa treatment, presenting higher RL values (3.32, times, respectively) greater at pH 4.8 than at pH 6.5. The KMg, PCa and PMg treatments presented higher RL values (1.72, 2.14, 8,72 times, respectively) greater at pH 6.5 than at pH 4.8.
A two-way analysis of variance, ANOVA (P < 0.05) was performed in a bi-factorial randomized design (14 nutrient treatments + control vs 2 pH) with post-hoc Tukey’s range test (P < 0.05) where all means of treatments were compared together 49 .
In the average of all nutrients, the GSI was not affected following the pH levels. In addition, pH interacted with KMg, Ca, PMg, K, and control treatment. At pH 4.8, the GSI values were higher for the KMg (4.69), Ca (3.8), K (5.2) presenting 1.20, 1.53, 1.78, and 1.34 times greater than pH 6.5, respectively. At pH 6.5, PMg (4.08) and control (3.9) treatments were higher compared to the pH 4.8, presenting 2.02 and 1.51 times greater, respectively.
Experimental design and assay conditions
In the laboratory, the nutrient solutions were prepared using distilled water combined with phosphoric acid (H3PO4) as a P source, potassium sulfate (K2SO4) as a K source, calcium hydroxide (Ca(OH)2) as a Ca source, and magnesium oxide (MgO) as a source of Mg. High chemical purity reagents were used (P.A. Merck Co). The doses were calculated taken into account the surface area of plastic boxes for germination test—gerbox (10 cm × 10 cm × 3.5 cm).
From an agronomic perspective, the genus Conyza Less. is responsible for decreasing soybean yields up to 30% 9,10 . The species of this genus are easily found in no-till system, where they became a great issue in the cereal crop production worldwide 3,8 . Recently, agronomists have found Conyza spp. biotypes with herbicide resistance mechanisms to several herbicide molecules, including glyphosate 4,11 . In South Brazil, 78% of the Conyza spp. biotypes showed herbicide resistance to glyphosate 4 . In summary, a good chemical horseweed control became arduous 4,12,13 . Furthermore, because this species is stress-tolerant and strong competitors 10,14 , alternative management strategies should be considered in the no-till system. Those strategies based on the species biology/ecology and soil management applied in an integrated manner seem to be promising to reduce the pollution pressure on the environment 8,15,16 . In this sense, Conyza sp., a dicot weed of the Asteraceae family commonly known as horseweed, stands out among weed species because can produce large quantities of easily disseminated seeds 8,15 . Germination is stimulated by light and may occur on bare topsoil in all seasons 8,17,18 . The wind may carry horseweed seeds over a hundred meters 15 , while seeds can migrate from infested fields to new areas a few thousand kilometers distant attached to cattle hair 19 . Horseweed seeds reach cropland topsoil easily, enriching the soil seed bank 8 . The horseweed seeds in the soil seed bank may germinate under favorable conditions from few years to decades 8 . The horseweed germination may occur by neutral to alkaline pH, saline and not disturb soil conditions, but maybe disturbed in the presence of Aluminum (Al) and when temperature and humidity conditions are out of the ideal range 3,8,18,20,21 . Furthermore, the species respond to factors such as salinity (NaCl) 7 , nutrient availability (N, P, and K), elements’ toxicity, and soil pH 7,22,23,24,25 . Thus, we expect that other nutrients available in soil may favor weed establishment and their dominance 26,27 .
The reduction of pesticide application is a major challenge in modern agriculture for the twenty-first century. No-till system (NT) implemented in the 1970s decade promoted better soil quality since soil cover, crop rotation, low soil disturbance, adequate traffic load, and adequate dose and fertilization method were practiced 1 . However, when these aspects are mismanaged, agricultural areas are subject to soil degradation 2 , low productivity and weed occurrence 3 , increasing pesticide uses 4 , and environmental risks 5 . Weeds present high seed production, dissemination, and cropland infestation capacities, causing mainly yield reduction. The species ability to complete germination and grow in a large range of edaphic conditions engender competitive advantages to the weeds over crops 6 . It is a key mechanism of success in plant establishment in different environments 7 , but the seed germination process can be affected by several factors such as light regime, temperature, and soil moisture 8 .
Root length (RL) and nutrients
Final germination percentage (FGP) of Conyza canadensis in response to the nutrients (alone or in combination) under solutions at pH 4.8 (a) and at pH 6.5 (b). Bars with the different colours, comparing means among treatments, are significantly different, according to the Tukey’ test (p < 0.05). Different letters represent a statistical difference for the same treatment between the two pH tested while ns represents not significant; The results in the Bars represent means, while error bar marks represent standard deviation (n = 4) from the mean value.
Overall, the studied species had important requirements to germinate, considering the germination traits (FGP and GSI) verified in the control treatment (
The best germination method depends on the cultivator’s choice. Here are some of the most common ways to pop your cannabis seeds.
Germination is the process that brings a cannabis seed out of its hibernation period and starts the cannabis growth process. Photo by: Gina Coleman/Weedmaps
Preparing to germinate cannabis seeds
It’s essential to acquire high-quality cannabis seeds for germination, as these will go on to become high-quality cannabis plants. Seeds that are fresh-feeling or too green indicate that they haven’t reached full maturity, while pale-green, white, or very dark cannabis seeds may have trouble sprouting. However, it’s tricky to know the outcome of a popped seed, so trying may be worthwhile. If you’re not ready to pop your seeds yet, store them in a dark, cool place until it’s time for germination.
What is germination?
The paper towel method is also a common way cultivators pop their seeds. Some even use this method with cotton pads instead of paper towels, but the necessary steps are the same.