Integrated Reducing Fertilization Management With GA₃ Application For Higher Yield And Fiber Quality Of Ramie ?Boehmeria Nivea L.?

Ramie ?Boehmeria nivea L.? is one of the most important sources of natural fiber.Yield and fiber quality are the most important factors in ramie production. However, it is also important to recognize the optimal dose and effects of different levels of nitrogen,phosphorus, and potassium fertilizers and growth regulator GA₃ ?gibberellic acid? on the growth, fiber quality,and yield of ramie. N ?Nitrogen?,P ?Phosphorus?,and K ?Potassium?are macronutrients that are involved in most biochemical processes. However, excessive use of fertilizers with these nutrients wastes expensive inputs, is responsible for polluting the environment, and results in excessive vegetative growth while reducing yield. To maximize the yield and fiber quality of ramie, it is important to determine the optimal fertilizer doses. For this purpose, we used ramie cultivar 'Huazhu 5' and conducted pot experiments in a greenhouse for two years. The main results were as follows:1. Effects of reducing fertilization on ramie growth, yield, and fiber qualityAcross all fertilizer treatments, NPK, followed by NK, had the largest significant effect of increasing plant growth, yield, and fiber quality as compared with control plants,whereas P application had the smallest effect. Plants fertilized with NPK showed strong positive correlations among fiber yield and quality traits with morphological parameters such as plant height, biomass, stem diameter, and number of stems.Fiber yield and quality, including the fiber fresh and dry weights, breaking strength,elongation rate, and diameter, also showed positive responses to fertilizer treatment. The fibers with the lowest fresh and dry weights ?0.02 kg and 0.019 kg, respectively? were obtained from unfertilized plants ?CK?, although these values were not significantly different from those observed for fibers from K₁₅₀-,N₁₅₀-, and P₇₅-fertilized plants, and the heaviest fresh and dry fiber weights were obtained from N₁₅₀P₇₅K₁₅₀- ?0.058 kg and 0.049 kg, respectively? and N₁₅₀K₁₅₀-fertilized plants ?0.053 kg and 0.042 kg,respectively?. The lowest breaking strength ?21.6 cN? was observed for fibers from unfertilized plants ?CK?, whereas the highest breaking strength ?47 cN? was observed in fibers from N₁₅₀K₁₅₀-fertilized plants, followed by those from N₁₅₀P₇₅- ?42.9 cN?andN₁₅₀K₁₅₀-fertilized ?40.4 cN? plants. The lowest elongation rate was observed for fibers from unfertilized plants ?2.3%?, although this rate was not significantly different from that of fibers from K₁₅₀-fertilized plants. The highest elongation rate was recorded in fibers from N₁₅₀K₁₅₀-fertilized plants ?3.92%?, although this rate was not significantly different from that of fibers from N₁₅₀K₁₅₀-fertilized plants ?3.72%?. Similarly, the thinnest fibers were obtained from unfertilized plants ?14.8 ?m?, although these fibers were not significantly thinner than those from K₁₅₀- or P₇₅-fertilized plants. The thickest fibers were obtained from N₁₅₀P₇₅K₁₅₀- and N₁₅₀K₁₅₀-fertilized plants ?30 ?m and 27.1 ?m,respectively?.The N and P contents of stems, leaves, petioles, and fiber bark also increased with fertilizer application. The lowest N and P contents were observed in unfertilized plants?CK?,whereas higher N contents were observed in N₁₅₀P₇₅K₁₅₀- and N₁₅₀K₁₅₀-fertilized plants, and higher P contents were observed in N₁₅₀P₇₅K₁₅₀- and P₇₅K₁₅₀-fertilized plants.In addition, the highest N content was observed in the leaves of N₁₅₀P₇₅K₁₅₀-fertilized plants, and the highest P content was observed in the petioles in N₁₅₀P₇₅K₁₅₀-fertilized plants.The significant correlations of fiber breaking strength with stem diameter ?r2 = 0.79?,stem biomass ?r2 = 0.88?, N contents ?r2 = 0.91?, and P contents ?r2 - 0.83? indicated that the combined application of NPK ?at 150, 75, and 150 kg ha-1? significantly enhances yield and fiber quality in ramie.2. Interactive effects of gibberellic acid and NPK fertilizer combinations on ramie yield and fiber qualityRamie was harvested three times from each plant. Ramie grown without fertilizers had significantly lower biomass and yield than plants grown with fertilizers. At both high and low fertilization rates, application of NPK resulted in greater growth and yield than application of N, P, K, NP, NK, or PK. Fiber yield and fiber quality were also improved by application of fertilizers and GA₃. Maximum fiber yield was obtained by a combination of low NPK with GA₃, which had 65-81% more yield than low NPK fertilization alone. Low NPK+ GA₃ treatment also significantly improved fiber diameter,fiber elongation, and breaking strength as compared to both NPK alone and control treatments. The height of plants fertilized with NPK varied among treatment groups: plant height was 29-72% greater than controls in the low NPK group, 31-83% greater than controls in the normal NPK group, and 54-106% greater than controls in the low NPK+GA₃ group.Measurements of fiber yield and quality, including the fiber breaking strength,elongation rate, and diameter, were positively affected by fertilizer treatment. Fiber diameter increased with the application of NPK fertilizers. The thinnest fibers were from unfertilized plants ?22-24 ?m?, and the thickest fibers were from plants in the low NPK+GA₃treatment group that received the NP treatment ?47.6 ?m?. The lowest elongation rate was observed for fibers from unfertilized plants and the highest was in the low and normal NPK treatment groups that received NK treatment and the low NPK+ GA₃ treatment group that received NP treatment. The lowest breaking strength was observed for fibers from unfertilized plants, and the highest in the low NPK+ GA₃ treatment group that received NK treatment, followed by those from the low NPK treatment groups that received N and NP treatments.3. Effect of NPK Fertilizers and GA₃ application on the Growth and Yield of RamieThe use of efficient rates of NPK fertilizer and GA₃ ?gibberellic acid? foliar application is important with regard to increasing ramie crop productivity and maintaining environmental sustainability. Therefore, a field experiment was carried out during 2015 in Wuhan. to identify the interactive effects of different combinations of nitrogen ?N?,phosphorus ?P? and potassium ?K? fertilizers along with foliar spray of GA₃ ?gibberellic acid? on light interception, growth and fiber yield of ramie. Experiment in randomized complete block design using with three replications each. Using of low NPK ?N140P70K140,140:70:140 kg ha-1?, normal NPK ?N280P140K280, 280:140:280 kg ha-1?, and low NPK +GA₃ ?10 mg L-1?. For each treatment group, following fertilizer treatments were applied:no fertilizer ?CK?, N, P, K, NP, NK, PK, and NPK. The results revealed that the application of low NPK with GA₃ significantly increases the biomass, fresh stem weight?2.27 kg?, fresh yield weight ?0.831 kg?, dry yield weight ?0.181 kg?, and significantly decrease the low NPK. Overall,results demonstrated that the combined application of low NPK with GA₃ improved the growth and yield of ramie.