Oregon State University Seed Laboratory

Transcription

1 Oregon State University Seed Laboratory Oregon BEST- Walking Point Industries LLC. Final Report 2014 Effect of Biochar Treatments on Seed and Seedling Performance of California brome and blue wildrye California brome (Bromus carinatus Hook. & Arn.) and blue wildrye (Elymus glaucus Buckley) are two of the most common native grasses in the Pacific Northwest. They are playing an important role in the ecosystem of the region and they are well adapted to local environmental conditions. They are used for habitat restoration, riparian areas, reclamation projects, and as forage crops. It is essential to improve their value for planting to assure a good stand. OBJECTIVE The objective of the study is to evaluate the effect of various Biochar seed coating treatments on seed and seedling performance of California brome and blue wildrye grown in a greenhouse at Oregon State University under two irrigation regimes. MATERIALS AND METHODS Two seed lots from each crop, high and medium quality were used in the study. Seeds were obtained from Pacific NW Natives. California brome: 1. High quality: Lot ID: B Medium quality: Lot ID: B Blue wildrye 1. High quality: Lot ID: M22-M Medium quality: Lot ID: B Treatments The following treatments were applied to seeds prior to planting: No. Treatment 1 Uncoated Seed 2 1/1 coated seed with limestone (CaCO3) 3 1/1 coated seed with ½ limestone and ½ Biochar 4 1/1 coated seed with 100% Biochar 5 1/1 coated seed with ½ Biochar, ¼ lime, ¼ absorbent mineral 6 1/1 coated seed with ½ Biochar, ¼ lime, ¼ absorbent material + macronutrient 7 1/1 coated seed ½ Biochar, ¼ lime, ¼ absorbent mineral + GA3 500ppm

2 Testing the initial quality of seeds The initial seed quality of seed lots was determined by the standard germination test. Four replications of 100 seeds each were planted and evaluated according to the AOSA Rules for Testing Seeds (2012). Also, the tetrazolium test (TZ) was used to determine the initial quality of the seed lots. Two replications of 100 seeds each were tested and evaluated according to the AOSA Tetrazolium Handbook (2010). Greenhouse Studies Soil type and planting: Marginal soil, low in organic matter. Seeds were planted in 50-cell greenhouse trays, one seed in each cell for a total of 50 seeds in each tray on January 28, Three replications of each treatment were planted by hand. The greenhouse study lasted for five weeks. Irrigation regimes: Two watering regimes were used to measure the effect of seed coating on tolerating water stress: 1) regular watering regime every 3 days; and 2) stress watering regime every 10 days. The 50-cell flats were placed in solid bottom trays and filled with water for four days before being emptied. In the first four days, all treatments were watered daily. This initial time of watering was to ensure the seeds had sufficient water available for physiological and enzymatic processes to occur, thereby initiating germination of the seeds to assure the initiation germination. Afterwards, plants were watered in 3 and 10-day intervals throughout the remainder of the study, which lasted 35 days, until March 5, Two exact sets of trays were filled with soil and arranged in completely randomized block design (CRBD) in the greenhouse. One set for regular irrigation regime each 3 days, and the second set was irrigated each 10 days to measure the effect of seed treatments on improving germination and seedling growth under water stress conditions. Seedling trays were arranged on four benches in the greenhouse, with each bench holding two blocks of three replications of the seven treatments. One block contained the seedlings under 3-day irrigation, and the other contained the seedlings under 10-day irrigation. Two benches were designated for blue wildrye and two for California brome. All plants in the greenhouse were grown at 25 C ± 3 C and continuous light of approximately 160 during the day and 80µmol m -2 s -1 during the night. No fertilizer was applied. Seedlings were observed at 3-day intervals, and the total number of emerged seedlings was recorded. Tests used to measure the effect of seed coating treatments on seedling performance. The following observations were collected and used to measure the effect of seed coating treatments, watering regimes, and initial seed quality on seed germination and seedling growth rate under the two irrigation regimes used in the study: o Final germination (emergence) % after 5 weeks. o Speed of germination, at 3-day intervals. o Whole seedling dry weight after 5 weeks (as an index of growth rate). o Linear seedling length (as an index of growth rate). Seedlings performance of the various treatments were compared. 2

3 Speed of germination test The speed of germination test is an index of seed vigor. The faster the seeds germinate, the higher the quality of the seeds. The number of emerging seedlings in the greenhouse was counted at 3-day intervals. A seedling was said to have emerged when at least 1cm of the coleoptile was visible above the soil surface. The speed of germination index was calculated according to the procedures described in the AOSA Seed Vigor Testing Handbook (2009) using the following formula: X = number of normal seedlings days of first count number of normal seedlings days of final count Final germination percent Final germination percentage (emergence) was recorded at the end of the study after five weeks. Seedling growth rate - Dry weight of whole seedlings This test was conducted according to the AOSA Seed Vigor Testing Handbook (2009). The dry weight of total seedlings of each treatment was determined at the end of the greenhouse study period. After 5 weeks, seedlings from each replication of each treatment were placed into Ziploc bags and were stored at 5 C until they were evaluated. Seedlings were then removed from the bags and washed thoroughly under room temperature tap water. Seedlings were then placed in marked with treatments and replications, foil trays and placed in a calibrated oven at 100 C for 24 hours and then were dried. At the end of the drying period, seedlings were immediately removed from the oven and allowed to cool to a manageable temperature, after which they were weighed using a laboratory analytical balance. The dry weight of whole seedlings of each replication of each treatment was recorded. Weights of all replications and treatments were adjusted to 25 seedlings for the purpose of comparison. Seedling growth rate - Linear seedling length test The test was conducted according to the AOSA Seed Vigor Testing Handbook (2009). The linear length of 25 random seedlings of each replication from each treatment was determined at the end of the greenhouse study period. After 5 weeks, the seedling s length (cm) was measured from the tip of the longest leaf to the tip of the longest root. The data was recorded and analyzed. Statistical analysis The experimental design used in the greenhouse study is a 3-factor randomized complete block design (RCBD) with 3 replications. Factor B (high and medium qualities) and factor C (seed treatments) were split plots on factor A (3-d vs. 10-d irrigation regimes). The data were subjected to ANOVA to determine the effect of each treatment on final germination, speed of germination and the growth rate of each sample. The LSD test was used to separate the means whenever the effects were significant. The statistical package MSTAT was used to analyze the data. 3

4 RESULTS AND DISCUSSION Initial seed quality: Both SGT and TZ tests were used to evaluate the initial quality of seeds of each seed lot used in the study. California brome, lot B had 89% germination and 94% viability by TZ and was classified as high quality. Lot B had 77% and 74% viability by TZ; and was classified as medium quality. Blue wildrye, Lot M22-M had 93% germination and 91% viability by TZ and was classified as high quality. Lot B had 86% germination, and 85% viability by TZ, and was classified as medium quality. California brome Effect of seed coating treatments on California brome The analysis of variance (ANOVA) indicated that the final germination, speed of emergence, and growth rate were affected by the seed coating treatments, initial seed quality and watering regimes at P 0.05, P 0.01, and P The exception was that the irrigation regime did not have a significant effect on seedling length or dry matter content, probably because of the initial high quality of seeds. The interactions among treatments, water regimes and seed quality were significant at P 0.05 and P 0.001, with a few exceptions, indicating that treatments behaved differently in response to watering every 3 days and 10 days and to high and medium seed qualities (Table 1). Table 1. Analysis of variance for the significance of effects of seven seed coating treatments and two seed qualities grown under two irrigation regimes on final germination percentage, speed of germination, seedling length, and dry matter content of one California brome seed lot. Source of variation Final germ (%) Speed germ. index Seedling length Treatment (T) *** *** * * Irrigation (I) * ** ns ns DM Quality (Q) *** *** *** *** (T) x (I) *** *** *** ** (T) x (Q) ns ns *** ** (I) x (Q) *** *** * *** (T) x (I) x (Q) ns ** ** * ns, *, **, *** not significant, significant at 0.05, 0.01, and level of probability, respectively. Seeds were watered every 3 or 10 days. Germination represents the average of three-50 seed replicates. Dry matter content adjusted to 25 seedlings for each replication. High and medium quality seed lots were used. 4

5 California brome showed varied responses to the different formulations of seed coating, as well as to irrigation regimes, initial seed quality, and the interactions among these variables. The statistical analysis showed that high quality seeds under 10-day irrigation regime improved seed and seedlings performance of most treatments, with a few exceptions. Final germination percentage The treatment used in this study are: No. 1, uncoated seed; No. 2, limestone (CaCO3); No. 3, limestone and Biochar; No. 4, Biochar; No. 5, Biochar, limestone, absorbent mineral; No. 6, Biochar, limestone, absorbent material, macronutrient; No. 7, Biochar, limestone, absorbent mineral, GA3. The response o germination to seed coating treatments, irrigation regimes, and initial seed quality varied. The high quality seeds germinated better than medium quality seeds of most seed coating treatments. Higher germination rate was achieved under 3-day irrigation regime in some treatments, especially in the high quality seeds. However, the medium quality seeds under 10-day irrigation regime germinated better than 3-day regime. The untreated control seeds germinated better under 10-day irrigation regime than 3-day regime (Fig. 1). This suggests that the most critical period in establishing seedlings is the first four days where seeds have to receive enough water for the initiation of germination. Of course, the type of soil (e.g., sandy, loam, etc.), temperature and wind activities in the field can affect the period under which the young seedlings survive without water or under limited amount of water available in the soil. Under 3-day irrigation regime, high quality seeds of treatments No. 2, 3, 4, and 5 germinated significantly better than the untreated control and the other treatments. Under 10-day irrigation regime, treatments 1, 2, and 4 had better germination than the rest of the treatments, whereas treatment No. 7 had lower germination than the other treatments (Fig. 1). Figure 1. Germination percentage of high and medium quality of California brome seed lots watered every 3 and 10 days at the greenhouse of Oregon State University Seed Lab for 5 weeks. 5

6 Speed of germination index (SGI) The SGI varied among seed coating treatments depending on the irrigation regimes and the initial seed quality. The high quality seeds had better speed of germination index (SGI) compared to the medium quality seeds in all seed coating treatments, including the untreated control (Fig. 2). Under 3-day irrigation regime, treatments No. 2, 3, and 5 of the high quality seeds had significantly better SGI than the untreated control, and the other treatments. Under the 10-day irrigation regime, treatment No. 2 of the high quality seed lot had the best SGI, followed by No. 1, No. 4, and No. 6. Treatment No. 7 had the lest SGI among all treatments (Fig. 2). Treatment No. 6, improved the speed of germination of the medium quality seed lot over the other treatments, but was not significantly different from the untreated control (Fig. 2). Figure 2. Speed of germination index of high and medium quality of California brome seed lots watered every 3 and 10 days at the greenhouse of Oregon State University Seed Lab for 5 weeks. Linear seedling length The linear seedling length varied among seed coating treatments depending on the irrigation regimes and the initial quality of the seed. Seedling length was better under 3-day irrigation regime than 10-day irrigation regime in most seed coating treatments. Also, high quality seeds had longer seedlings than medium quality seed lot in most treatments. Most treatments improved seedling length over the untreated control in the medium quality seed lot under 10-day irrigation regime (Fig. 3). 6

7 Figure 3. Linear seedling length of high and medium quality of California brome seed lots watered every 3 and 10 days at the greenhouse of Oregon State University Seed Lab for 5 weeks. Dry matter content The dry matter content varied among seed coating treatments and between irrigation regimes and the initial seed qualities. For example, treatment No. 6 increased the dry matter content of the high quality seed lot under 10-day irrigation regime over the other treatments (Fig. 4); whereas, treatment No. 2 increased the dry matter content of the high quality seed lot under 3-day irrigation regime over the other treatments (Fig. 4), Under 3-day irrigation regime, most treatments performed better than 10-day regime in the high quality seed lot, but treatment No. 2 had significantly higher dry matter content than the other treatments. In the medium quality seed lot, treatment No. 4 was significantly lower than the other treatments under both irrigation regimes (Fig. 4). Biochar, limestone, and the macronutrients included in the seed coating materials may have supplied the developing seedlings with extra nutrients, which contributed to the higher dry matter content in some treatments. The absorbent minerals may be an advantage in areas with sporadic water resources. 7

8 Figure 4. Average dry matter contents of 25 seedlings of high and medium quality of California brome seed lots watered every 3 and 10 days at the greenhouse of Oregon State University Seed Lab for 5 weeks. Blue wildrye Effect of seed coating treatments on blue wildrye The ANOVA showed that seed coating treatment had significant effects on the final germination percentage, speed of germination, and seedling linear length at P 0.001, and on dry matter content at P 0.05 (Table 2). Irrigation regime did not have significant effect on final germination percentage, speed of germination, or seedling length, but affected the dry matter content significantly at P 0.01 (Table 2). The 3-day watering regime increased the dry matter content compared to the 10-day watering regime (Fig. 8). This is not surprising since the availability of water (in the 3-day irrigation regime) and CO2 (from air) increase the photosynthetic assimilates through the photosynthesis process, leading to the accumulation of dry matter. The initial seed quality affected final germination percentage and speed of germination (P 0.001), and seedling length (P 0.05), but it did not affect the dry matter content significantly. This demonstrated the importance of coating clean seeds with high initial viability levels. 8

9 Table 2. Analysis of variance for the significance of effects of seven seed coating treatments and two seed qualities grown under two irrigation regimes on final germination percentage, speed of germination, seedling length, and dry matter content of one blue wildrye seed lot. Source of variation Final germ (%) Speed germ. index Seedling length Treatment (T) *** *** *** * Irrigation (I) ns ns ns ** Quality (Q) *** *** * ns (T) x (I) *** * *** ns (T) x (Q) *** *** *** ** (I) x (Q) *** *** ns ns (T) x (I) x (Q) *** * ns ** ns, *, **, *** not significant, significant at 0.05, 0.01, and level of probability, respectively. Seeds were watered every 3 or 10 days. Germination represents the average of three-50 seed replicates. Dry matter content adjusted to 25 seedlings for each replication. High and medium quality seed lots were used. DM The interaction between seed coating treatments and irrigation regimes and was significant for final germination and seedling length (P 0.001) and for speed of germination (P 0.05) (Table 2), indicating that some treatments did better under 3-day watering regime, while others did better under 10-day watering regime. However, the interaction was not significant at P 0.05, indicating that treatments behaved similarly towards dry matter contents under both irrigation regimes. Interaction between seed coating treatments and initial seed quality was significant for final germination, speed of germination, seedling length (P 0.001), and dry matter content (P 0.05), indicating that some seed coating treatments work better on medium quality seeds, whereas others work better on high quality seeds (Table 2). The three-way interaction among seed coating treatments, irrigation regimes, and initial seed quality was significant for final germination speed of germination and dry matter content, indicating that coating treatments behaved differently towards high and medium seed quality under 3- and 10- day irrigation regimes (Table 2). Blue wildrye showed varied responses to the different formulations of seed coating, as well as to irrigation regime, initial seed quality, and the interactions among these variables (Figs. 5-8). The statistical analysis showed that high quality seeds under 10-day irrigation regime improved seed and seedling performance of all treatments. 9

10 Final germination percentage The high quality seeds germinated better than medium quality seeds in most seed coating treatments, including the untreated control. The response of germination to seed coating treatments, irrigation regimes, and seed quality varied. Under 3-day irrigation regime, the high quality seeds of treatments No. 3 (CaCO3 and Biochar), No. 4, (Biochar), No. 5, (Biochar, limestone, absorbent mineral), No. 6 (Biochar, limestone, absorbent material, macronutrient), and No. 7 (Biochar, limestone, absorbent mineral, GA3) had high germination percentage, but No. 1, the untreated control, had the highest among all treatments. Under 10-day irrigation regime, the high quality seeds of treatments No. 1, No. 3, No. 5, and No. 6 performed better than the other treatments (Fig. 5). The germination percentage of the high quality uncoated seed was as high as any other treatments under both irrigation regimes. Seed coating treatment No. 6 had the best effect on germination of medium seed quality under 3-day irrigation regime, whereas treatment No. 1 had the best germination of medium quality seeds under 10-day irrigation regime (Fig. 5). Figure 5. Germination percentage of high and medium blue wildrye seed lots watered every 3 and 10 days at the greenhouse of Oregon State University seed lab for 5 weeks. Speed of germination index The high quality seeds had better speed of germination index (SGI) compared to the medium quality seeds in all seed coating treatments, including the untreated control. The speed of germination responses to seed coating treatments, irrigation regimes, and seed quality varied. Under 3-day irrigation regime, the high quality seeds of treatments No. 3, No. 4, No. 6, and No. 7 had the highest SGI, but were significantly below the untreated control. Under 10-day irrigation regime, the high quality seeds of treatments No. 1 and No. 3 germinated faster than the 10

11 other treatments (Fig. 6). In general, the uncoated seeds of the high quality seed lot germinated faster than the other treatments under both irrigation regimes, confirming the importance of initial seed quality before coating seed regardless of the chemicals included in the coating formula. Under 3-day irrigation regime, treatments No. 6 and No. 7 of the medium quality seed lot germinated faster than the untreated control and the other treatments, indicating the benefits of coating for medium quality seeds under such irrigation conditions. Medium quality seed lot, under 10-day irrigation regime, treatments No. 1 and No. 6 germinated faster than the other treatments (Fig 6). Figure 6. Speed of germination index of high and medium quality of blue wildrye seed lots watered every 3 and 10 days at the greenhouse of Oregon State University Seed Lab for 5 weeks. Linear seedling length Linear seedling length is a growth rate index. All seed coating treatments affected seedling length similarly, and was comparable to the untreated control seeds. Treatment No. 6 showed fast growth rate as indicated by the linear length of high quality seed lot at both 3-day and 10-day irrigation regimes. Under 3-day irrigation regime, treatment No. 6 of the high quality seed lot had the highest growth rate compared to the other treatments. However, treatments No. 2, No.3, No. 5, and No. 7 of the medium quality seeds lot improved seedling length under the same irrigation regime, but were not significantly different from the untreated control (Fig. 7) Under 10-day irrigation regime, treatments No. 2, No. 3, and No. 5 of the medium quality seeds improved seedling length, but were not significantly different from the untreated control (Fig. 7). 11

12 Figure 7. Average seedlings length of high and medium quality of blue wildrye seed lots watered every 3 and 10 days at the greenhouse of Oregon State University Seed Lab for 5 weeks. Dry matter content Seeds of most treatments had higher dry matter content under 3-day irrigation regime compared to the 10-day irrigation regime. The accumulation of dry matter in seedlings varied with seed coating treatments, irrigation regimes, and seed quality. Under 3-day irrigation regime, treatments No. 2, No. 3, No. 6, and No. 7 of the high quality seeds improved the dry weight content over the other treatments, but were similar to the untreated control (Fig. 8). Under 10-day irrigation regime, treatments No. 3 and No. 5 of the medium quality seeds improved the dry weight content over the other treatments, but were similar to the untreated control (Fig. 8). Combination of Biochar, limestone, and macronutrients seemed to be important ingredients in the coating treatments used in this study. They had a positive effect on seed performance, especially when considering the interaction between treatments, initial seed quality and watering regimes. The gibberellic acid in treatment No. 7 can help freshly harvested seeds to overcome the dormancy of some native species. The absorbent material would be important if seed planted in areas where water availability is sporadic. 12

13 Figure 8. Dry matter contents of 25 seedlings (mg) of high and medium quality of blue wildrye seed lots watered every 3 and 10 days at the greenhouse of Oregon State University Seed Lab for 5 weeks. CONCLUSIONS Seed treatments used in the study improved germination rate, speed of germination, and growth rate at different levels, depending on the crop, i.e., California brome and blue wildrye, initial quality of seeds, and the irrigation regimes. Combination of Biochar, limestone, and macronutrients seemed to be important ingredients in the coating treatments used in this study. The gibberellic acid (GA3) in treatment No. 7 Biochar, limestone, absorbent mineral + GA3 can help freshly harvested seeds to overcome the dormancy of some native species. No consistent pattern for the response of seedling performance in response to 3-day and 10-day irrigation regime. The absorbent material would be important if seed planted in areas where water availability is sporadic. The study emphasized the importance of using seeds with initial high quality before the coating process. 13

14 PI. Dr. Sabry G. Elias, Oregon State University Matt James, M.S. Candidate, Crop & Soil Science Department, Oregon State University. Collaborator Howard Boyte, Walking Point Industries LLC. Stu Barclay, Summit Seed Coatings, Caldwell, ID 14