Effect Of Calcium-nitrogen Application On Ramie Two-harvest Planting Mode Of Fiber And Feed

Ramie is one of the important fiber crops in China.China accounts for more than90%of the world’s planting area and output.The conventional planting mode is to harvest three seasons of raw hemp every year,but the hemp harvesting process faces the problem of labor shortage.The output of first hemp accounts for 50%of the annual output and the quality is the best.The tender stems and leaves have high feeding value.The main ramie production area is basically consistent with the southern animal husbandry area.The new planting mode of feed is of great significance to solve the plight of the ramie industry and alleviate the shortage of feed in the southern region.Nitrogen and calcium in the shoots of ramie are the two mineral nutrition elements with the highest content.Nitrogen and calcium significantly affect the yield and quality of ramie.When tender stems and leaves are used as feed,crude protein content and calcium are important forage quality indicators.In the two-harvest planting mode of ramie fiber feeding,the number of cuttings increased,and the shoot harvesting took away a large amount of calcium and nitrogen.It is necessary to explore the effect of calcium-nitrogen application on yield and quality in this mode.The following experiments were carried out Using"Huazhu No.5"as the material,:（1）The effect of exogenous calcium（Ca Cl2 concentration of 0 mmol/L,5 mmol/L,10mmol/L,20 mmol/L）on the growth and development of ramie seedlings and nitrogen assimilation.（2）The first fiber harvest and the cutting of tender stems and leaves are combined as the forage planting mode.Yield,quality and comprehensive benefit of the two-harvest model.（3）Under the fiber feeding two-harvest planting mode,3 Ca fertilizers（Ca O 12.5 kg/667m²,25 kg/667m²,37.5 kg/667m²,recorded as Ca₁,Ca₂,Ca₃）and 3 N fertilizers（CH₄N₂O 10 kg）/667m²,20 kg/667m²,30 kg/667m²,denoted as N₁,N₂,N₃),a field experiment of 9 fertilization combination treatments,to explore the effect of calcium and nitrogen combined application on fiber,feed quality and yield of ramie,and obtained the most suitable calcium and nitrogen fertilization scheme for the fiber-feed two-harvest planting mode.The main results are as follows:1.Under the condition of hydroponics,the regulation of calcium on the growth and development of ramie and nitrogen assimilation is reflected in the aspects of ramie stem elongation,biomass accumulation,root growth and development,calcium and nitrogen content,and key enzymes of nitrogen assimilation.Compared with CK（5mmol/L Ca Cl₂）,the plant height and fresh weight per plant of ramie seedlings treated with medium and high concentration of calcium（10 mmol/L Ca Cl₂）were significantly increased by 13.73%and 40.94%,the root growth was significantly improved,and the calcium content in the shoots was significantly increased.63.77%.Calcium deficiency（0 mmol/L Ca Cl₂）and high concentration calcium（20 mmol/L Ca Cl₂）treatments significantly reduced the nitrogen content of shoots by 23.98%and 18.98%,and significantly inhibited the activities of nitrate reductase（NR）and glutamine synthase（GS）.2.The production cost is 14.92%higher than that of the two-harvest planting mode of fiber and feed,and the harvest cost is 1.91 times that of two-harvest planting mode of fiber and feed.The profit of the two-harvest planting mode of fiber and feed is 23.58%higher than the conventional fiber planting mode.The two-harvest planting mode of fiber and feed can save costs and increase efficiency,reduce labor input,and can try to promote it.3.Under the two-harvest planting mode of fiber and feed,the combined application of calcium and nitrogen had a significant effect on the yield of first hemp fiber.The biomass,fresh stem weight,hemp rate of fresh stems and raw hemp weight of the plot increased significantly with the increase of nitrogen application,and the biomass of the plot increased significantly.The amount,fresh tare weight and raw hemp weight first increased and then decreased with the increase of calcium application,and better yield of head hemp could be obtained under the combination of N₃Ca₂.The fiber breaking strength and fiber diameter decreased significantly with the increase of nitrogen application rate and then increased,while the glue content and fiber diameter of head hemp increased significantly with the increase of calcium application rate and then decreased.Under the N₃Ca₁ treatment combination,the glue content was the lowest,the breaking strength and elongation at break were higher,the fiber diameter was smaller,and the fiber quality was better.4.Under the two-harvest planting mode of fiber and feed,increasing nitrogen fertilizer can significantly increase the fresh grass yield,hay yield and crude protein yield of ramie feed,and increasing calcium fertilizer can increase fresh grass yield,but reduce hay yield and crude protein yield,N₂Ca₁and N₃Ca₂ two treatment combinations have higher levels of feed yield.The application of nitrogen fertilizer significantly increased the crude protein content and calcium accumulation of ramie,and the appropriate amount of calcium fertilizer significantly increased the calcium content of ramie.Calcium-nitrogen application had a significant effect on the calcium content and calcium accumulation.At the N₂ level,the total calcium accumulation increased with the calcium application.However,under the N₃ level,the total calcium accumulation first increased and then decreased with the increase of calcium application,and the calcium content and calcium accumulation of the combination of N₃Ca₂ and N₂Ca₁ were higher.The relative feeding value（RFV）decreased significantly at first and then increased gradually with the increase of nitrogen application.The annual average RFV decreased significantly with the increase of calcium application,and the RFV of N₃Ca₂combination was larger.Feed yield and quality were relatively high under the combination of N₃Ca₂ and N₂Ca₁ treatments.5.Adding calcium fertilizer significantly improved the partial productivity of first harvest ramie fiber nitrogen fertilizer and significantly reduced the partial productivity of hay.Increasing nitrogen fertilizer application significantly improved the partial productivity of calcium fertilization in first harvest ramie fiber and hay.N₂Ca₁ is23.68%,41.07%and 11.59%higher than N₃Ca₂ in first harvest ramie fiber nitrogen partial productivity,hay nitrogen partial productivity and hay calcium partial productivity.Under the level of ensuring higher yield and quality,N₂Ca₁ combination can improve nitrogen and calcium fertilizers.utilization.In summary,calcium can promote ramie stem elongation,biomass accumulation and root growth and development,and high concentration of calcium can reduce the nitrogen content and key enzyme activities of nitrogen assimilation in the shoots of ramie,and inhibit nitrogen assimilation.The two-harvest planting mode of fiber and feed can achieve the effect of saving cost and increasing efficiency and reducing labor input,which can be tried to promote.Under the two-harvest planting mode of fiber and feed,during the planting period,the combination of N₃Ca₂ fertilization can obtain higher yield of the first hemp;the combination of N₃Ca₁ fertilization can obtain better quality of the first hemp.During the period of ramie feed planting in first ramie fiber harvest,the N₃Ca₂ fertilization combination can obtain higher feed yield and quality;the N₂Ca₁fertilization combination can improve the utilization rate of nitrogen fertilizer and calcium fertilizer while ensuring the feed yield and quality.