Effects of Integrated Organic and Inorganic Fertilizers on Yield and Growth Parameters of Rice Varieties

We investigated the effects of integrated organic and inorganic fertilizers on the growth and yield of indica rice variety Manawthukha and japonica rice variety Genkitsukushi.In a split-plot design,the two rice varieties were assigned as main plot factors,and the integrated treatments were the subplot factors,including no-N fertilizer(N0),50%chemical fertilizer(CF)(CF50),100%CF(CF100),50%CF+50%poultry manure(PM)(CF50PM50),50%CF+50%cow manure(CM)(CF50CM50),and 50%CF+50%compost(CP)(CF50CP50).CF100 was equivalent to N at 85 kg/hm2.Manure was applied based on the estimated mineralizable nitrogen(EMN)level,which is dependent on total N(%)of each manure type.Manawthukha rice plants were taller with higher tiller number and dry matter content.However,higher soil-plant analysis development(SPAD)values were measured in Genkitsukushi throughout the crop growth period,resulting in higher seed-setting rate(%)and greater yield.At the same N level,CF50PM50 application in both rice varieties resulted in higher SPAD values,plant height and tiller number than CF100.CF50PM50 containing total N more than 4%supplied synchronized N for the demands of the rice plants,resulting in maximum dry matter,yield and yield components.CF50CM50 and CF50CP50 treatments containing total N less than 4%resulted in lower yields which were similar to CF100.These results indicated that integrating organic and inorganic fertilizers enhanced growth parameters and yields of Manawthukha and Genkitsukushi,while reducing the dose of chemical fertilizer.

Effects of Combined Application of Inorganic Fertilizer and Organic Manures on Nitrogen Use and Recovery Efficiencies of Hybrid Rice (Palethwe-1)

We conducted two field experiments to investigate combined effects of organic and inorganic fertilizers on nitrogen use and recovery efficiencies of hybrid rice (Palethwe-1) during dry and wet seasons, 2015. Four levels of inorganic fertilizer (0%, 50%, 75%, and 100% NPK), based on recommended rates of 150 kg N ha-1, 70 kg P2O5 ha-1, and 120 kg K2O ha-1, were used with cow manure, poultry manure, and vermicompost (5 t·ha-1each) in a split-plot design with three replicates. In both seasons, with 50% NPK, the N uptake level achieved with poultry manure was similar to that obtained with 75% and 100% NPK. The greatest N use, internal, agronomic N use, and recovery efficiencies were obtained with 50% NPK + poultry manure, but were similar to those obtained from cow manure and vermicompost subplots. As the amount of applied N from organic and inorganic fertilizer increased, the N use efficiency and related parameters decreased, due to similar yields among plots with different NPK application levels. Poultry manure resulted in the highest significant correlations between applied N and N accumulation, followed by cow manure and vermicompost, in both seasons. Neither chemical fertilizer nor organic manure alone led to optimum N use and N recovery efficiencies. The combination of 50% inorganic fertilizer (75 kg N ha-1) and poultry manure (5 t·ha-1) enhanced the N uptake, the N use and recovery efficiencies of hybrid rice. Cow manure (5 t·ha-1) in combination with 75% inorganic fertilizer (112.5 kg N ha-1) was an adequate substitute for reduced chemical fertilizer usage. Therefore, this study highlighted combined application of inorganic fertilizers and organic manures had the benefits not only in reducing the need for chemical fertilizers but also in improving N uptake by hybrid rice (Palethwe-1) leading to the better environment.

Combined Effect of Organic Manures and Inorganic Fertilizers on the Growth and Yield of Hybrid Rice (Palethwe-1)

We investigated the effect of combining organic and inorganic fertilizers on the growth and yield of hybrid rice (Palethwe-1) in the dry and wet seasons of 2015. Four quantities of inorganic fertilizer were used in the main plot [0%, 50%, 75%, and 100% nitrogen, phosphorus, and potassium (NPK)] based on the recommended amounts of 150 kg N ha-1, 70 kg P2O5 ha-1, and 120 kg K2O ha-1, while different organic manures were applied to subplots [no organic manure (O0), cow manure (Oc), poultry manure (Op), and vermicompost (Ov);all at 5 t·ha-1] as part of a split-plot experimental design with three replicates. In both seasons, significant differences in growth parameters including number of tillers hill-1, soil-plant analysis development (SPAD) values, total dry matter, yield, and yield components were observed in plants supplied with different inorganic fertilizers. The 100% NPK (I100) fertilizer produced the maximum yield but similar yields were achieved in plots supplied with 50% NPK (I50) and 75% NPK (I75). Significant differences in growth and yield parameters were also found in crops supplied with organic manures. Although identical quantities were supplied, Op produced the best growth parameters in both seasons including total dry matter, yield, and yield components. Oc also performed well. Combining inorganic and organic fertilizers demonstrated that I50 together with Op (5 t·ha-1) provided similar growth, total dry matter, and yield parameters to I100 in both seasons. Oc (5 t·ha-1) plus I75 also achieved similar yields to I100. This study demonstrates that the combined application of inorganic fertilizers and organic manures has the potential to reduce chemical fertilizer usage without decreasing the yield of hybrid rice, and can enhance the growth, yield, and yield components of Palethwe-1.

Effects of Fermented Nori (<i>Pyropia yezoensis</i>) Liquid Fertilizer on Plant Growth Characteristics and Nutrient Content of Komatsuna (<i>Brassica rapa</i>L. var. Wakana Komatsuna) Cultivated in Vermiculite

We conducted plant growth experiments in microbe-free vermiculite to study the effects of four types of fermented seaweed liquid fertilizer (SLF) made from nori (Pyropia yezoensis) seaweed on the germination, plant growth characteristics, SPAD value, and nutrient content and uptake of komatsuna (Brassica rapa L. var. wakana komatsuna). The four types of fermented nori SLF used in this study were prepared by anaerobic fermentation of unwashed nori (SLF1), aerobic fermentation of unwashed nori (SLF2), anaerobic fermentation of washed nori (SLF3), and aerobic fermentation of washed nori (SLF4). Komatsuna seeds treated with 200-, 300-, and 400-fold dilutions of SLFs exhibited improved relative germination ratios (RGRs) at 3 and 4 days after sowing (DAS). At 4 DAS, the RGRs of seeds treated with 10-, 100-, 200-, 300-, and 400-fold SLF dilutions showed no differential effect. Seeds treated with undiluted SLFs did not germinate by 4 DAS. SLF1 may promote komatsuna seed germination. The nitrogen (N), calcium, magnesium, sodium (Na), and iodine (I) contents of plants treated with SLF1 were significantly increased relative to plants treated with the other SLFs. Moreover, the I and Na contents of plants were significantly increased by foliar spray application of different dilutions of SLF1. However, SLF treatment markedly reduced the shoot dry weight compared with 1/2-strength modified Hoagland nutrient (MHN) solution, although the same amounts of N and K were applied. SPAD values of the plants treated with SLFs were significantly higher than those of plants treated with MHN. Foliar treatment with SLFs had no significant effect on plant growth, SPAD value, or uptake of nutrients (except Na) relative to the control, but the I content was increased. Plants treated with SLF1 and SLF2 exhibited the highest Na uptake. Foliar spray treatments with SLF1 resulted in the highest I contents in plants. Based on our results, SLF1 is suitable for use as a liquid fertilizer to promote germination and increase nutrient content in komatsuna. These results need to be followed up in soil experiments in the presence of microbes in the rhizosphere.

Determining Nodulation Regulatory (Rj) Genes of Myanmar Soybean Cultivars and Their Symbiotic Effectiveness with <i>Bradyrhizobium japonicum</i>USDA110

Soybean (Glycine max L.) plays an essential role in human nutrition as a protein source, and in plant nutrition as a N source. The rate of N fixation varies depending on the cultivars and compatibility between the inoculated Rhizobium strain and the host cultivar. Characterizing the nodulation regulatory (Rj) genes is necessary to determine the compatibility of cultivars and Rhizobium strains. Rj genes were previously identified based on inoculation tests and PCR analyses. The six cultivars Yezin-3, Yezin-7, Yezin-11, Shan Seine (Local), Madaya (Local), and Hinthada (Local) were identified as harboring the Rj4 gene. Two cultivars, Yezin-6 and Yezin-8, were classified as non-Rj-gene harboring. Two other cultivars, Yezin-9 and Yezin-10, were identified as Rj3- and Rj2Rj3-gene harboring, respectively. Ours is the first report on Rj3- and Rj2Rj3-gene harboring cultivars in Myanmar. We evaluated Myanmar soybean cultivars for symbiotic effectiveness, relying on the standard strain Bradyrhizobium japonicum USDA110. In our first experiment, the soybean cultivar Yezin-11 (Rj4) showed the highest N fixing potential. Based on their potential for fixing N and nodulation, the top six soybean cultivars were Yezin-11 (Rj4), Yezin-9 (Rj3), Yezin-6 (non-Rj), Yezin-8 (non-Rj), Yezin-3 (Rj4) and Yezin-10 (Rj2Rj3). These cultivars were selected for a second experiment, which revealed that the N fixation, nodulation, and plant growth of Yezin-11 (Rj4) *Corresponding author. A. Z. Htwe et al. 2800 were superior to the other cultivars. We conclude that Yezin-11 (Rj4) is the most efficient cultivar for nodulation and N fixation when inoculated with B. japonicum USDA110.

Effects of Fermented Nori (<i>Pyropia yezoensis</i>) Seaweed Liquid Fertilizers on Growth Characteristics, Nutrient Uptake, and Iodine Content of Komatsuna (<i>Brassica rapa</i>L.) Cultivated in Soil

We investigated the effects of fermented nori (Pyropia yezoensis) liquid fertilizers on plant growth, soil plant analysis development (SPAD) values, and nutrient uptake of komatsuna (Brassica rapa L. var. wakana komatsuna) plants. The four types of fermented nori seaweed liquid fertilizers (SLFs) evaluated in this study were prepared by anaerobic fermentation of unwashed nori (SLF1), aerobic fermentation of unwashed nori (SLF2), anaerobic fermentation of washed nori (SLF3), and aerobic fermentation of washed nori (SLF4). In Experiment 1, the highest plant growth, SPAD, and nutrient uptake values were obtained from treatment with SLF2 and SLF4. There were no significant differences between the effects of basal and foliar application of SLFs, except for iodine (I) content;plants treated with SLF1 had the highest I content. In Experiment 2, plant growth and nutrient uptake decreased with higher concentrations of SLFs. Plants treated with 25% SLF2 + 75% chemical fertilizer (CF) or 25% SLF4 + 75% CF exhibited significantly higher plant growth and nutrient uptake. The highest I content resulted from treatment with 75% SLF1 + 25% CF or 100% SLF1. Taken together, our results showed that 25% SLF + 75% CF produced the best plant growth characteristics, nutrient uptake, and I content relative to the controls. Therefore, basal application of these liquid organic fertilizers can be used to increase productivity, nutrient uptake, and I content and to reduce nitrate-nitrogen content in komatsuna production.

Phylogenetic Diversity and Evaluation the Effectiveness of Indigenous <i>Bradyrhizobium</i>Strains for Myanmar Black Gram (<i>Vigna mungo</i>L. Hepper) Cultivars

Black gram (Vigna mungo L. Hepper) is one of the main leguminous crops that provide chief source of food. Several Bradyrhizobium species are able to induce effective nodules in black gram cultivars. In the present study, we characterized forty isolates of indigenous black gram bradyrhizobia from Myanmar based on the sequence analysis of the bacterial 16S rRNA gene. The sequence analysis confirmed that all isolates were categorized and identified as the genus Bradyrhizobium and they were conspecific with B. elkanii, B. sp., B. liaoningense, B. japonicum and B. yunamingense. Almost all the collected isolates from major black gram growing regions of Nyaunglebin Bago Regio, Chaungzon Mon State, Sittwe Rakhine State, Danubyu Ayeyarwady Region and Launglon Tanintharyi Region were identified as B. liaoningense. At Danubyu Ayeyarwady Region and Pyinmanar Nay Pyi Taw Region, most of the strains were identified as B. japonicum. On the other hand, more or less all the isolates from Launglon Tanintharyi Region and Hpa-an Kayin State were related to B. elkanii. However, all B. sp. strains were found in Salingyi Sagaing Region black gram growing region. This is the first report describing Bradyrhizobium strains that were isolated from soil samples of major black gram growing areas in Myanmar. Evaluation of the effectiveness of Myanmar Bradyrhizobim strains isolated from soil samples of major black gram growing areas of Myanmar for plant growth and nitrogen fixation was studied in pot experiments with completely randomized design and three replicates. The nodule dry weight, shoot dry weight and acetylene reduction activity of the plant inoculated with Bradyrhizobium elkanii LauBG38 were significantly higher in ARA per plant, nodule and shoot dry weights than the other tested isolates in both Yezin-4 and Yezin-7 black gram varieties. We expect that Myanmar Bradyrhizobium elkanii LauBG38 will be able to use as Biofertilizer for black gram cultivars.