Dissertation for doctor of philosophy in agriculture: Study on the growth and development ability of some imported soybean varieties and cultivation techniques for prospect variety in Thai Nguyen

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Research Objectives: selecting the imported soybean varieties that have good growth and development, are suitable with the ecological conditions of Thai Nguyen; determining some intensive cultivation techniques that are suitable for the prospect variety.

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Nội dung Text: Dissertation for doctor of philosophy in agriculture: Study on the growth and development ability of some imported soybean varieties and cultivation techniques for prospect variety in Thai Nguyen

1 MINISTRY OF EDUCATION AND TRAINING THAI NGUYEN UNIVERSITY XUYEN THI LUU STUDY ON THE GROWTH AND DEVELOPMENT ABILITY OF SOME IMPORTED SOYBEAN VARIETIES AND CULTIVATION TECHNIQUES FOR PROSPECT VARIETY IN THAI NGUYEN Major: AGRONOMY Code: 62 62 01 01 DISSERTATION FOR DOCTOR OF PHYLOSOPHY IN AGRICULTURE THAI NGUYEN - 2011
3 RELATED PUBLICATIONS 1. Xuyen Thi Luu, Dep Thi Luan, Tam Minh Hoang (2008), “Effect of planting season of soybean variety 99084 - A28 in Spring and Winter Crop in Thai Nguyen”, Journal of Science and Technology, 3(47) - Vol. 2/2008, Thai Nguyen University Press , pp: 29 - 32. 2. Xuyen Thi Luu, Dep Thi Luan, Tam Minh Hoang (2010), “Study on the effect of planting densities on the growth and development of soybean varieties 99084 - A28 in winter crops 2007 - 2008 in Thai Nguyen”, Journal of Agriculture and rural development, October, 2010, Press of Sciences and technology, 18 Hoang Quoc Viet, Hanoi; pp: 126 - 130.
1 INTRODUCTION 1. Background Soybean (Glycine max (L) Merr) is industrial and short growing - duration crop that is multi-purpose plant with high economic value. Its products supply food for human and livestocks; they are also materials for processing industry and high valueable for exporting. Besides, soybean plants are short growing-time crops that are very suitable for crop rotation, intercroping, crop overlaping with many other plants and soil improvement crop (Dan The Ngo et al., 1999) [10]. Soybean is popularly planted in all seven ecological areas over Vietnam. Northern midland and mountainous region has the biggest area (69425 ha) which holds 37.01% the total area of soybean in Vietnam but the lowest yield (1.03 tons/ha). There are many reasons for low yield of soybean in this region such as unavailability of high-yielding soybean varieties, low investment and unreasonable cultivation methods. It is noted that lack of high-yielding soybean varieties and suitable cultivation techniques are the main limitation to soybean yield. The result of variety investigation in 2003-2004 of Department of Crop Production, Ministry of Agriculture and Rural Development (2006) [9] showed that: The Northern Midland and Mountainous Region is one of three areas planting high percentage of local varieties of soybean and low percentage of new soybean varieties (37.5 - 38.4% areas with local soybean varieties). In recent years, Vietnam has imported many good varieties; however their adaptability to ecological region is very different. For that reason we carried out the research titled:” Study on the growth and development ability of some imported soybean varieties and cultivation techniques for prospect variety in Thai Nguyen”. 2. Research Objectives - Selecting the imported soybean varieties that have good growth and development, are suitable with the ecological conditions of Thai Nguyen. - Determining some intensive cultivation techniques that are suitable for the prospect variety.
2 3. Scientific and reality significance 3.1. Scientific significance The research intends to select imported soybean varieties and determining suitable techniques for selected variety in Thai Nguyen. The research results laid the pavement for developing some imported soybean varieties in Thai Nguyen. The research selected prospect soybean variety from the testing imported varieties, suitable for ecological environment in Thai Nguyen and determined the technical methods suitable for selected variety in spring and winter in Thai Nguyen. 3.2. Reality significance - The thesis found out the limitation and prospects for developing soybean production in Thai Nguyen. - Determining and providing some soybean varieties that have good growth and development in spring and winter in Thai Nguyen. - The study results from some technical methods for cultivating soybean contributed on cultivation guideline improvement for soybean intensive farming in winter and spring in Thai Nguyen. - The using new and high yielding variety of soybean and new technical methods resulted in higher economic efficiency, raising the incomes for farmers that planting soybean and promoted the development of soybean production in Thai Nguyen. 4. New findings of the thesis - Based on investigating, analyzing and assessing some advantages and disadvantages effecting on production and results from research on selecting soybean varieties from imported varieties and on determining some technical methods, the scientific basement for developing soybean in winter and spring in Thai Nguyen was confirmed. - Determined the growth and development ability of some soybean varieties in spring and winter crop in Thai Nguyen and two high yielding varieties T2000 and 99084 - A28 were selected. In winter crops, the average yield were from 1.71 to 1.77 tons/ha that were higher than the control variety DT84 by 0.38 to 0.45 tons/ha. In spring crops, the average yield were from 2.16 to 2.24 tons/ha that were higher than the control by 0.37 to 0.45 tons/ha.
3 - Suggested some techniques for completing cultivation guideline for new soybean variety (99084 - A28) with optimum planting time in spring crop is from 15th, February to 6th, March and 5th to 25th, September in winter. The optimum density in spring was 35 plants/ha and 45 plants/ha in winter. The most suitable fertilizer combination was 5 tons of manure + 40 kg N + 80 kg P2O5 + 40 kg K2O + 300 kg of lime/ha. - Trial of soybean planting in winter and spring in three places of Thai Nguyen was successfully built and implemented. The trial locations are Trang Xa Commune - Vo Nhai District, Hoa Thuong Commune - Dong Hy District and Son Cam Commune - Phu Luong District with the variety 99084 - A28 and new technical methods that got the yield from 2.54 to 2.83 tons/ha, raising by 52,8 - 53,9% compared to the control in winter; 2.32 - 2.75 tons/ha raising by 52,6 - 63,5% than the control; the interest were from 20.2 to 24.5 millions VND/ha in spring and 20.3 to 23.3 millions VND in winter. 5. Thesis structure The dissertation was fulfilled with 102 pages, 31 tables, 3 figures and 2 diagrams. Beside the introduction, the dissertation was divided into 3 chapters where chapter 1: Literature review (25 pages); chapter 2: Research content and methods (13 pages); chapter 3: Results and discussion (58 pages), Conclusion and suggestion (2 pages) and 55 pages for appendices. The dissertation used 115 references in Vietnamese and 58 references in English. CHAPTER 1: LITERATURE REVIEW 1.1. Soybean production status in Vietnam and in the world 1.1.1. Soybean production in the world The data collection from Dan The Ngo et al., (1999) [10], Duc Van Hoang (1982) [23], FAO Statistic Database, 2009 [75] showed that the soybean production of the world has increased rapidly in area - yield and output. In the period of 1963 - 1964, the planting area of soybean over the world was 27.3 millions hectare and increased to 96.87 hectare in 2008. In 1960 the yield of soybean over the world was
4 only 1.20 tons/ha but increased to 2.384 tons/ha in 2008, by 98.87% compared to 1960. The output in 1960 was 26.00 millions ton and 230.95 millions ton in 2008, increased 8.85 times. 1.1.2. Production of soybean in Vietnam According to Dan The Ngo et al., 1999 [10], Thieu Van Pham, 2006 [44], soybean has been grown in Vietnam for a very long time but the area was only 32000 ha (1944) and yield was very low (0.41 tons/ha). In recent years, the soybean has developed rapidly in both area and yield. In 1995, the soybean area of whole country was 121.1 thousands hectare; it increased gradually through the years and got 191.5 thousands hectare in 2008. In 1995, the yield of whole country was 1.03 tons/ha and continuously increased through the years and reached the highest in 2007 at 1.47 tons/ha. Although there were some changes in area and yield, the output increased gradually through the years. In 1995, the output of whole country was 125.5 thousands tons and reached the highest in 2005 at 292.7 thousands tons. 1.2. Status of soybean research 1.2.1. Research on soybean over the world The 1st international soybean variety evaluation experiment (ISVEX) in 1973 was conducted in ranges of 90 places in 33 countries representing for environmental zone. Nowadays, the soybean research is received a great deal of attentions, especially in developed countries that are big producers of soybean.Beside the research on selecting and creating varieties, the scientist over the world still study on technical methods such as planting time, density and fertilizer for soybean production. 1.2.2. Soybean research in Vietnam In the period of 2001 - 2005, Vietnam imported 540 samples of soybean varieties from other countries that supplemented to collection of varieties and tested 9482 soybean variety samples; found out 83 samples of varieties that have precious characteristics. In the period of 1985 - 2005, Vietnam created 15 samples of soybean varieties by cross-breeding that were certified as national varieties (Long Dinh Tran
5 and Chinh Thi Nguyen, 2005) [35]. Creating and selecting by mutation treatment method resulted in 4 national varieties (Vinh Quang Mai et al., 2005)[52]. Besides, scientists also studied on technical methods such as planting time, density and fertilizer. Research of some authors such as Dan Thi Nguyen (1996) [11], Thieu Van Pham, 2006 [44], Xiem Tu Nguyen and Phien Thai (1998) [56], Kha Minh Vo (1996) [29], Hinh Tan Nguyen et al, (2006) [25], Truong Thi Tran et al, 2006 [46] showed that: The actual amount of fertilizer required depended on season, soil types, the previous plants and varieties. Hence, there is no fertilizer combination for all of different seasons, regions and soil types. CHAPTER 2: REASERCH CONTENTS AND METHODS 2.1. Materials The experiment included 10 varieties of soybean: T12, TQ, VX92, VX93, T2000, 95389, CM60, 99084 - A18, 99084 - A28, DT84 (control). The whole experiment was applied the same fertilizer combination of Lam Thao Super phosphorus 16,50%, Urea Nitrogen 46,0%, Chloride potassium 50,0%, manure and lime. 2.2. Contents 2.2.1. Survey for existing production of soybean in Thai Nguyen 2.2.2. Assessing growth and development of imported varieties of soybean in Thai Nguyen 2.2.3. Determining some main technical methods for prospect variety 99084 - A28 (timing, density and fertilization) 2.2.4. Trial for testing newly developed techniques in farmer fields. 2.3. Methodology 2.3.1. Survey for existing production state of soybean in Thai Nguyen - The data of climate and weather was collected in Hydro-meteorological station in Thai Nguyen Province. - Determining the texture and characteristic of soil conducting experiment and trials, the soil samples was taken before carrying out the experiment (5samples/place).
6 - Determining the status of soybean production in Thai Nguyen by collecting secondary data and interviewing the staffs of Agricultural and rural development Department of Thai Nguyen Province. - Determining the status of soybean production in some districts, using Participatory Rural Appraisal method (PRA), interviewing farmers by questionnaire (Appendix 3). 2.3.2. Assessing growth and development of the imported soybean varieties in Thai Nguyen 2.3.2.1. Experiment 1: Study on the growth and development of some imported soybean varieties in spring and winter crops in 2004 and 2005 in Thai Nguyen a/ Materials: 10 soybean varieties. b/ Time and place: Soybean was sowed on 15th, February, 2004 and 18th, February, 2005 in spring season and on 15th, September, 2004 and 17th, September, 2005 in winter crops in Thai Nguyen University of Agriculture and Forestry. c/ Experimental conditions: The experiment was conducted in one rice crop land, the soil texture is light, pHKCl = 4.85; Total Nitrogen = 0.11%; Total potassium = 0.55%; Total phosphorus = 0.07%; Organic matter = 1.82%. d/ Experimental design: Randomized Complete Block Design - RCBD with 3 replications. The plot area is 1.4m x 5 m= 7m2. - Technical guideline: Based on the soybean variety testing guideline No. 10TCN 339 - 2002 (MARD, 2001) [4] and No. 10TCN 339 - 2006 (MARD, 2006) [38]. The planting density was 35 plants/m2, the distance between lines was 35 cm and between plants was 8.2 cm. The applied fertilizer combination was 5 tons of manure + 30 kg N + 60 kg P2O5 + 30 kg K2O + 300 kg lime/ha. e) Research monitoring indicators and method: The monitoring indicators and method were carried out based on the soybean variety testing guideline No. 10TCN 339 - 2002 (MARD, 2001) [4 ] and No. 10TCN 339 - 2006 (MARD, 2006) [38].
7 2.3.2.2. Experiment 2: Testing some prospect varieties of soybean in spring, 2006 in Thai Nguyen a/ Research sites: Trang Xa Commune - Vo Nhai District, Hoa Thuong Commune - Dong Hy District, Son Cam Commune - Phu Luong District. b/ Materials: 3 prospect varieties were selected through 4 testing seasons (VX93, 99084 - A28, T2000) and DT84 (control). The testing area is 500m2 for each variety in each place. c/ Experiment conditions: The experiment was implemented on one rice-crop land with light texture of soil. The chemical properties of soil in experiment places are shown below: Table 2.2. The chemical properties of soil in experiment sites Indicators Dong Hy Vo Nhai Phu Luong pHKCL 4.6 4.5 4.3 N (%) 0.11 0.10 0.11 P2O5 (%) 0.13 0.15 0.11 K2O (%) 0.73 0.62 0.67 OM (%) 1.92 1.74 1.85 (The soil was sampled in 2005) The dosage of fertilizer and other experimental procedure are as the same as experiment 1. 2.3.3. Studying some main technical methods for the prospect soybean variety 99084 - A28 2.3.3.1. Experiment 3: Determining the planting time for soybean variety 99084 - A28 in spring and winter in Thai Nguyen. a/ Time and place: Spring and winter crops in 2005 and 2006 at Thai Nguyen University of Agricultural and Forestry. Table 2.3: Sowing date of the treatments Spring crop Winter crop Treatment 2005 2006 2005 2006 Date 1 5/2 5/2 5/9 5/9 Date 2 15/2 15/2 15/9 15/9 Date 3 25/2 25/2 25/9 25/9 Date 4 7/3 6/3 5/10 5/10 Date 5 17/3 16/3 15/10 15/10
8 b/ Experiment design: Randomized Complete Block Design - RCBD with 3 replications. The plot area is 2.8m x 5m = 14 m2. c/ Experiment condition, fertilizers, densities and other technical methods were similar to the experiment 1. 2.3.3.2. Experiment 4: Determining the planting density of soybean variety 99084 - A28 in spring and winter crops in 2007 - 2008 in Thai Nguyen. a/ Time and place: In spring and winter crops in 2007 - 2008 at Thai Nguyen University of Agriculture and Forestry. b/ Testing densities: + Density 1: 25 plants/m2 (distance between lines: 35cm; distance between plants: 11,4 cm) + Density 2: 35 plants/m2 (distance between lines: 35cm; distance between plants: 8,2 cm) + Density 3: 45 plants/m2 (distance between lines: 35cm; distance between plants: 6,3 cm) + Density 4: 55 plants/m2 (distance between lines: 35cm; distance between plants: 5,2 cm) + Density 5: 65 plants/m2 (distance between lines: 35cm; distance between plants: 4,4 cm) 2.3.3.3. Experiment 5: Determining the optimum N-fertilizer rate for soybean variety 99084 - A28 in spring, 2007 - 2008 in Thai Nguyen. Fertilizer base: 5 tons of manure + 60 kg P2O5 + 30 Kg K2O + 300 kg lime/ha. a/ Time and Place: Spring, 2007- 2008 at Thai Nguyen University of Agriculture and Forestry. b/ Experiment design: Randomized Complete Block Design - RCBD with 5 treatments, 3 replications. The plot area is 2.8m x 5m = 14 m2. + Treatment 1: Base + 20 Kg N + Treatment 2: Base + 30 Kg N + Treatment 3: Base + 40 Kg N + Treatment 4: Base + 50 Kg N + Treatment 5: Base + 60 Kg N.
9 c/ Experiment condition: As the same as the experiment 1. d/ Indicators and monitoring method: Growth duration, plant height, the leaf area index, pest and disease, lodging resistance ability, yield components, yield and calculation for treatment economic efficiency. 2.3.3.4. Experiment 6: Determining the optimum P-fertilizer for soybean variety 99084 - A28 in spring crops in Thai Nguyen. Base Fertilizer: 5 tons of manure + 30 Kg N + 30 Kg K2O + 300 kg lime/ha. a/ Time and place: Spring, 2007-2008 in TUAF. b/ Experiment design and monitoring method: As the same as experiment 5. c/ Experiment conditions: As the same as experiment 1. + Treatment 1: Base + 40 Kg P2O5; + Treatment 2: Base + 60 Kg P2O5. + Treatment 3: Base + 80 Kg P2O5; + Treatment 4: Base + 100 Kg P2O5. + Treatment 5: Base + 120 Kg P2O5. 2.3.3.5. Experiment 7: Determining the optimum K-fertilizer for soybean variety 99084 - A28 in spring crops in Thai Nguyen. Base fertilizer: 5 tons of manure + 30 Kg N + 60 Kg P2O5 + 300 kg lime/ha. a/ Time and place: Spring crops, 2007 - 2008 in TUAF. b/ Experiment design, norms and monitoring methods: as experiment 5. c/ Experiment condition: As the same as the experiment 1. + Treatment 1: Base + 20 Kg K2O + Treatment 2: Base + 30 Kg K2O + Treatment 3: Base + 40 Kg K2O + Treatment 4: Base + 50 Kg K2O + Treatment 5: Base + 60 Kg K2O. 2.3.3.6. Experiment 8: Determining the optimum fertilizer combinations for soybean variety 99084 - A28 in spring crops in Thai Nguyen Experiment included 7 treatments which are selected as the highest yield and economic efficiency in experiments 3,4,5,6,7.
10 a/ Time and place: Spring, 2009 in TUAF. b/ Experiment design: RCBD with 7 treatments, 3 replications. The plot area is 2.8m x 5m = 14,0m2. Fertilizer base was 5 tons of manure + 300 kg lime per hectare. The rates of N, P2O5 and K2O (kg/ha) for each treatment are as follows: + Treatment 1: 30: 60 : 30 (Control); + Treatment 2: 30: 80 : 40 + Treatment 3: 30 :100 : 50 + Treatment 4: 40 : 80 : 40 + Treatment 5: 40 : 80 : 50 + Treatment 6: 40 : 100 : 40 + Treatment 7: 40 : 100 : 50 2.3.4. Trials for testing soybean variety 99084 - A28 in spring, 2010 in Thai Nguyen a/ Places: Trang Xa Commune - Vo Nhai District, Hoa Thuong Commune - Dong Hy District, Son Cam Commune - Phu Luong District. b/ The experiment conditions: As the same as the experiment 2. - Trial 1: New variety + New technical methods (optimum sowing date, density and fertilizer combination were determined in experiments 3, 4, 8). - Trial 2: Old variety (DT84) + New technical methods c/ Monitoring indicators: The farmers participated in conducting and evaluation of the trials: Yield (tons/ha), economic efficiency of the trials (expenditure - outcomes) and farmers’ acceptance to the new variety and technical methods. 2.4. Data analysis - The survey information was analyzed by the software Excel 5.0 and SAS program. - The data from the field experiment was calculated, analyzed by the software Excel 5.0, SAS and IRRISTAT programs.
11 CHAPTER 3: RESULTS AND DISCUSSION 3.1. Nature condition and status of soybean production in Thai Nguyen 3.1.1. Climate condition of Thai Nguyen Province Based on the ecology requirements of soybean and analyzed the weather and climate in years conducting experiments it showed that: Although the climate and weather in Thai Nguyen varieties complicatedly but it was still suitable for the growth and development of soybean, in general. Therefore, it needs to be based on the climate data to adjust the suitable planting season. 3.1.2. The survey results of existing soybean production in Thai Nguyen 3.1.2.1. The survey results The area of soybean in recent years has continuously reduced. In 2003, the area was 3656 ha, after 5 years it reduced by 36,6% and got to 2316 ha (2007). It got the big reduce in 2008 (2000 ha). The yield of soybean in Thai Nguyen in recent years has an increasing trend from 1.131 tons/ha to 1.403 tons/ha because some farmers started to use new varieties. Soybean have been planted in all districts and city in Thai Nguyen Province but the planting area are mainly in Pho Yen, Phu Binh, Vo Nhai, Dong Hy district and Song Cong town. Soybean has been planted in 2 main cropping seasons which are spring and winter. 100% households interviewed planted spring soybean and 66.7 - 95.2% households planted winter soybean. The number of households planted summer-autumn soybean was very low (14.6 - 26.2%). The using of old varieties in soybean production is one of the reasons for low soybean yield. At investigated places, we realized that the variety DT 84 was still popularly grown in 52.8% households. Some varieties have transferred to the production recently such as AK03, DT9, DT96, T80... planted by 20.8% of interviewing households. The variety Cuc Luc Ngan was grown in Vo Nhai and Phu Luong District by 29.2% and 25.7 % households, respectively. Investigating in applying the technical methods for soybean production showed that planting soybean mainly based on experiences (21.4 - 52.1%). The number of households applying the old technical methods was also fairly high (31.4 -37.5%). Almost households applied fertilizer unreasonably; the fertilizer rate for soybean was still lower than the guideline. Investigating in the status of soybean pests and diseases showed that the pests were mainly Bean pyramid (Lamprosema indicata Fabricius) and Lima bean pod-borer (Etiella zinckenella Treitschke).
12 3.1.2.2. Advantages and disadvantages to soybean production in Thai Nguyen Investigating in advantages of soybean Production showed that the most optimum factors are the easy-consuming products and the low investment; these are confirmed by 100% households in all investigated places. The other optimum factor is the land: 100% households in Vo Nhai and Phu Luong District and 97.6% households in Dong Hy District claimed that there were many areas that can be grown soybean, because the crop may grow in many soil types. Besides, planting soybean can use labor at the beginning of the spring crops. The fact that soybean crop is very easy to plant was the opinion of 66.7 - 85.7% households. They considered that soybean is easy to plant because it may be grown in many soil types and may be grown with minimum tillage, even though no tillage as in planting the winter soybean. The investigating results showed that there were many disadvantages of soybean production in Thai Nguyen. The main disadvantaged factors were lack of good varieties, improved technical guidelines, pest and diseases and drought at the beginning of spring crops and the end of winter crops. 3.1.2.3. Some solutions for soybean production in Thai Nguyen - Study on determining the suitable varieties in Thai Nguyen Province and designing good service for soybean seeds for soybean Production. - It needs to have a policy that promotes soybean production through agricultural extension activities: Opening training courses for farmers in technical methods for soybean production, building suitable demonstration trials for each region. - Extending and enhancing the cooperation with some scientific organizations (VAAS, TUAF) in research and transferring technology in soybean production. - Long-term plan for soybean production for development of planting area, yield, output and marketing. 3.2. Results of assessing growth and development of the imported varieties of soybean in Thai Nguyen 3.2.1. Results of assessing growth and development of the imported varieties of soybean in spring and winter crops, 2004 - 2005 in Thai Nguyen - Estimated yield (EY): The EY was low or high depending on the yield components. In this experiment, the variety 99084 - A28 and T2000 had the yield components ranging from fair to good level; therefore these varieties had the highest yield (2.72 tons/ha and 2.78 tons/ha in spring crops; 2.42 tons/ha and 2.21 tons/ha in winter crops, respectively), significantly higher than the control at the confidence interval of 95% in 2 crops. The variety VX93 and 95389 had the EY equivalent to the control (DT84: 2.29 tons/ha in spring and 1.84 tons/ha in winter). Other varieties had the EY significantly lower than the control at the confidence interval of 95%.
13 Table 3.12. Yield of testing varieties Estimated yield (tons/ha) Actual Yield (tons/ha) Variety VX V VX V DT84 (control) 2.29 18.4 17.9 13.3 T12 1.66 1.64 1.47 1.06 TQ 1.57 1.52 1.32 1.16 VX92 1.65 1.55 1.27 1.27 VX93 2.15 1.89 1.72 1.50 T2000 2.78 2.21 2.16 1.71 95389 2.37 1.78 1.78 1.48 CM60 1.70 1.59 1.33 1.26 99084-A18 1.76 1.52 1.49 1.29 99084-A28 2.72 2.42 2.24 1.78 CV (%) 8.2 4.4 7.6 8.1 LSD (0.05) 0.383 0.179 0.284 0.252 (Data were averaged over tow years 2004, 2005. For data analysis in each season, see appendices 8 and 13) - Actual yield (AY): The AY of testing varieties ranged from 1.27 to 2.24 tons/ha (spring crops) and from 1.06 to 1.78 tons/ha (winter crops); whereas the variety DT2000 and 99084 - A28 had the highest AY (2.16 tons/ha and 2.24 tons/ha in spring and 1.71 tons/ha and 1.78 tons/ha in winter), higher than the control at 95% confidence interval. The varieties VX93 and 95389 had the AY equivalent to the control (DT84:1.79 tons/ha in spring and 1.33 tons/ ha in winter). Other varieties had the AY significantly lower than the control at 95% confidence interval. The results were similar to those reported by Dien Van Tran et al., (2008) [22], Dung Trung Duong et al., (2010) [15]. 3.2.2. Results of assessing growth and development of the prospect variety in spring - 2006 in Thai Nguyen Based on the results of 4 seasons ( 2 spring crops and 2 winter crops in 2004 - 2005), the 3 varieties VX93, T2000 and 99084 - A28 had the AY and AY equivalent and significantly higher than the control in all crops. We had intended to
14 test these there varieties in spring crop - 2006 on 3 districts Vo Nhai - Dong Hy - Phu Luong of Thai Nguyen Province. The results in table 3.13 showed that, the growing duration of varieties in testing places are 1-2 days different; the varieties had the growing duration ranging from 90 - 120 days which were similar to the results obtained in spring crops in 2004 - 2005. Table 3.13. Growing duration and actual yield of prospect varieties in spring, 2006 Indicators Growing duration (days) Actual yield (tons/ha) Phu Phu Vo Nhai Dong Hy Vo Nhai Dong Hy Variety Luong Luong VX93 95 93 94 17.5 20.7 19.4 T 2000 102 101 102 18.6 20.5 20.3 99084-A28 100 99 99 21.0 23.8 22.5 DT84 (Control) 91 90 90 15.5 18.6 17.3 Yield is the integration indicator reflecting the adaptation ability of varieties in each ecological condition and resistance ability to each pests and environments. The results showed that all varieties had AY higher than the control (DT84: 1.55 - 1.86 tons/ha). The AY in Dong Hy District was the highest (1.86 - 2.38 tons/ha), next to was that in Phu Luong District (1.73 - 2.25 tons/ha) and the lowest was in Vo Nhai District (1.55 - 2.10 tons/ha). In all 3 places, variety 99084 - A28 had the highest AY ranging from 2.10 to 2.38 tons/ha, next to that of variety T2000 reaching 1.86 - 2.05 tons/ha, and the lowest AY belonged to the variety VX93 (1.75 - 2.07 tons/ha). The main advantaged characteristics of the prospect variety 99084 - A28 which be confirmed by farmers in the experiment and field seminars were: + The high yield + Resistance to pests and diseases + Good seed outlook: big, round, light yellow colour and small hilum. Based on the results above, we selected the variety 99084 - A28 to conduct some research on technical methods serving for proposing the technical guideline for cultivating new variety of soybean.
15 3.3. Results from research on some technical methods for the prospect soybean variety 99084 - A28 in Thai Nguyen 3.3.1. Results of determining the optimum sowing date for the soybean variety 99084 - A28 in spring and winter crops in Thai Nguyen Table 3.18. Effect of planting season on yield of variety 99084 - A28 in Thai Nguyen Estimated yield Planting Planting date Actual yield (tons/ha) (tons/ha) season SC WC SC WC SC WC PS1 5/2 5/9 2.67b 24.4a 18.0c 15.7a PS 2 15/2 15/9 2.86ab 23.0b 20.9ab 15.3a PS 3 25/2 25/9 3.04a 18.7c 21.9a 12.2b PS 4 6(7)/3 5/10 2.75ab 12.9d 20.0ab 8.3c PS 5 16(17)/3 15/10 2.67b 10.6e 19.6b 6.9d CV (%) 4.1 2.9 3.9 7.7 LSD(0.05) 0.319 0.110 0.217 0.250 (Data were averaged over two years: 2005, 2006. For data analysis in each season, see appendices 17 and 22) The EY of the variety 99084 - A28 in other planting dates had big variation. In spring, the EY ranged from 2.67 to 30.4 tons/ha whereas the EY of PS3 was equivalent to PS2 and PS4 and higher than PS1 and PS5, significantly at confidence interval of 95%. In winter, the EY ranged from 1.06 to 2.44 tons/ha and reached the highest in PS1. The AY in spring crops ranged from 1.80 to 2.19 tons/ha in which the AY of PS3 was equivalent to PS2 and PS4 and significantly higher than PS1 and PS5 at the confidence interval of 95%. The AY in winter ranged from 0.69 - 1.57 tons/ha whereas the highest AY was in PS1 and PS2 (1.57 - 1.53 tons/ha), significantly higher than in other dates at 95% confidence interval. This result was line with that reported by Thieu Van Pham (2006) [44], Dung Trung Duong et al., (2009) [14]. 3.3.2. Results of determining the optimum density for soybean variety 99084 - A28 in spring and winter crops in Thai Nguyen. The table 3.22 showed that, in all spring and winter crops, the different densities resulted in different AY and EY. In spring, the EY ranged from 1.86 to 2.78 tons/ha, the AY ranged from 1.66 to 2.50 tons/ha. In Spring, both and AY increased from
16 treatment 1 and reached the highest value in treatment 2 (65plants/m2) (The EY got 2.78 tons/ha and the AY was 2.50 tons/ha), then gradually reduced and rapidly reduced when the densities was 65plants/m2 (the EY was 1.86 tons/ha and the AY was 1.66 tons/ha). Table 3.22. Effect of densities on the yield of variety 99084- A28 in Thai Nguyen Spring Winter Norm Estimated Estimated Actual Yield Actual Yield Yield Yield Treatment (tons/ ha) (tons/ ha) (tons/ha) (tons/ha) T1 (25) 2.32c 1.95c 2.00c 1.46d T 2 (35) 2.78a 2.50a 2.20b 1.62c T 3 (45) 2.61b 2.30b 2.47a 1.90a T 4 (55) 2.22d 1.90cd 2.34ab 1.78b T 5 (65) 1.86e 1.66d 1.99cd 1.46d CV (%) 0.9 1.5 2.4 2.5 LSD(0.05) 0.058 0.085 0.145 0.112 (Data were averaged over two years: 2007, 2008. For data analysis in each season, see appendices 27 and 31) In winter, both the EY and the AY increased basing on the raise of density from Treatment 1 to treatment 3 (45 plants/m2), but then reduced even though the raise of density. The EY ranged from 1.99 to 2.47 tons/ha, the AY ranged from 1.66 to 1.90 tons/ha and reached the peak of yield in treatment 3 at 45 plants/m2 (the EY was 2.47 tons/ha, the AY was 1.90 tons/ha). The planting densities affected on the growing and developing indicators of the soybean varieties 99084 - A28 in spring and winter crops in Thai Nguyen. The high densities caused an increase of some indicators such as the plant height, the leaf area index, pest infected index. On the contrary, an increase of densities caused the short growing duration, the low number of primary branches , number of filled pods/plant, number of filled kernels/pod and 1000-kernel weight. The yield rose basing on the increase of densities to a given point (35 - 45 plants/m2), then reduced when continuously increased the planting densities (65 plants/m2). From the collected data, the most optimum density for soybean variety 99084 - A28 in Thai Nguyen was 35 plants per m2 in spring crop and was 45 plants/m2 in winter. At these planting densities, the AY was the highest.
17 3.3.3. Study on optimum N-fertilizer rate for the variety 99084 - A28 in spring in Thai Nguyen Table 3.24. Effect of N-fertilizer rate on yield and interest of the soybean variety 99084 - A28 in spring in Thai Nguyen Norm Filled Filled 1000- EY Interest AY pods/plant kernels/pod kernel (tons/ (Millions (tons/ ha) Treatment (pods) (kernels) weight (g) ha) VND/ha) 1 (20N) 21.0d 1.86b 162.8cd 2.23c 1.93c 11.82 2 (30N) 24.7c 1.93ab 165.9b 2.76b 2.34b 17.89 3 (40N) 27.9a 2.00a 167.6a 3.28a 2.77a 24.23 4 (50N) 26.5b 1.95ab 165.8b 3.00ab 2.31b 17.17 5 (60N) 23.7cd 1.88b 163.3c 2.54bc 1.85cd 10.17 CV (%) 2.0 2.0 0.3 3.3 1.4 LSD (0.05) 1.40 0.10 1.3 0.248 0.087 (Data were averaged over two years: 2007, 2008. For data analysis in each season, see appendices 34, 35, 46 and 47) The table 3.24 showed that the number of filled pods/plant, number of filled kernels/pod and 1000-kernel weight increased with an increase of N-fertilizer rate from T1 to T3, then reduced when continuously increasing N rates. Applying N-fertilizer at different rate got the different EY and the AY. The EY were 2.23 - 3.28 tons/ha, the AY were 1.85 - 2.77 tons/ha. Treatment 3 (40 kg N/ha) had the highest EY and AY, significantly higher than other treatments. The economic efficiency analysis of applying N-fertilizer (appendices 46 and 47) showed that the interest increased from the treatment 1 (11.82 millions VND/ha) to treatment 3 and reached the highest interest in Treatment 3 (40 kgN/ha) with 24.23 millions VND/ha, then the interest gradually reduced wh en increasing the N-fertilizer rate; the lowest interest was in treatment 5 (10.17 million VND/ha). Based on the results from two cropping seasons we found that the applied N- fertilizer rate affecting on most growth and development indicators of the soybean variety 99084 - A28. The higher rate resulted in the longer growing duration, the higher plant height, LAI and the level of Bean pyramid and Lima bean podborer. The yield components and yield gradually increased from the treatment 1 (20 kg N/ha) and reached the peak in treatment 3 and then gradually reduced. In short, for the soybean variety 99084 - A28 in spring in Thai Nguyen with the fertilizer base of 5
18 tons of manure + 60 P2O5 + 30 K2O + 300kg lime/ha, the optimum N-fertilize rate was 40 kgN/ha which had the highest AY and interest. 3.3.4. Study on the optimum P-fertilizer rate for the soybean variety in spring in Thai Nguyen The different P-fertilizer rates clearly effected on number of filled pods/plant, 1000 kernel weight of the soybean variety 99084 - A28. Different P-fertilizer rate treatments significantly effected on different indicators at 95% confident interval and the yield was obtained in treatment 4 and 5 (100 and 120 kg P2O5 /ha). Applying P-fertilizer at different rates affected on the EY and the AY of the variety 99084 - A28. The AY ranged from 1.65 - 3.4 tons/ha and had the significant differences among treatments. The higher rates of P-fertilizer clearly resulted in higher EY. When increasing 20 kg P2O5/ha resulted in increasing yield of 0.22 - 0.53 tons/ha. The AY ranged from 1.42 - 2.78 tons/ha in which treatment 5 (120 kg P2O5/ha) had the highest AY and significantly higher than treatment 1, 2, 3 at the confidence interval of 95%. Table 3.26. Effect of P-fertilizer rate on yield components and yield of the soybean variety 99084- A28 in spring in Thai Nguyen Filled Filled 1000- Interest Effciency Norm EY AY pods/ kernels/ kernel (Millions (kg (tons/ (tons/ plant pod weight VND/ha) soybean/ Treatment ha) ha) (pods) (kernels) (g) kg P2O5) 1(40P2O5) 16,3e 1,83b 158,32d 16,5e 14,2d 4,4 - 2(60P2O5) 20,3d 1,87b 161,63c 21,4d 18,5c 10,6 22,0 3(80P2O5) 24,3c 1,94ab 163,25b 28,1c 24,0b 18,5 28,0 4(100P2O5) 27,8b 1,98a 164,58a 31,8b 26,9ab 22,6 15,0 5(120P2O5) 29,5a 2,00a 164,75a 34,0a 27,8a 23,5 4,0 CV (%) 1,5 2,0 2,0 2,1 1,8 LSD(0,05) 1,01 0,07 1,21 1,52 1,12 (Data were averaged over two years: 2007,2008. For data analysis in each season, see appendices 38, 39, 40, 48 and 49)