施肥对轻木生长和非结构性碳水化合物的影响OA

This study evaluated how fertilization regimes affect growth and non-structural carbohydrates(NSCs)in Ochroma pyramidale,with the aim of identifying an appropriate nitrogen(N)rate and fertilizer type for cultivation.The 2-year-old Ochroma pyramidale forest was used as the experimental site,and a randomized block group design was used to set up three gradient urea treatments(N),namely N1(urea 300 g/plant),N2(urea 450 g/plant),N3(urea 600 g/plant),and three gradient slow-release nitrogen fer-tilizer treatments(H),namely H1(slow-release nitrogen fertilizer 300 g/plant),H2(slow-release nitrogen fertilizer 450 g/plant),H3(slow-release nitrogen fertilizer 600 g/plant),and a control treatment,CK(no nitrogen fertilizer applied),were used to measure diameter at breast height and tree height of Ochroma py-ramidale,and to determine the content of nonstructural carbohydrates and their fractions in leaves,bran-ches,and roots.The results showed that:1)Fertilizer application,time and method of sampling and testing significantly affected the diameter at breast height and tree height of Ochroma pyramidale.At different sampling and testing times,the tree height and diameter at breast height increased with the increase of fer-tilizer application,tree height and diameter at breast height were the greatest and significantly increased by 14.0%and 16.9%,respectively,in H2 compared to the CK treatment at 90 d sampling,respectively,com-pared with the CK treatment.2)Fertilizer application amount and time significantly affected the NSC and its component contents of the three organs of Ochroma pyramidale,and different types of fertilizers pro-moted the increase of leaf NSC and its component contents,with the increase of fertilizer application amount,under different sampling and testing time,the increase of leaf NSC content of urea treatment was smaller than that of the application of slow-release nitrogen fertilizer(55.3%＜59.3%),and the addition of slow-release nitrogen fertilizer compared to urea was more favorable to the accumulation of leaf NSC content.3)Tree height,diameter at breast height,leaf soluble sugars and NSC content could better reflect the effect of fertilization.Tree height and diameter at breast height were positively correlated with leaf NSC content,and fertilization would improve the correlation between growth and NSC.Tree height,diame-ter at breast height,leaf soluble sugars,leaf starch,branch soluble sugars,branch starch,and root soluble sugars were the most important indexes of response of Ochroma pyramidale to fertilization.In summary,fertilization significantly affected the growth and NSC accumulation of balsa wood,balsa wood leaf NSC content determines the growth of balsa wood,H2 fertilization treatment is the most conducive to the growth of balsa wood,so it is recommended that the balsa wood nutrient additions using slow-release nitro-gen fertilization of 450 g/plant.