Hussain Anwaar, Jamil Muhammad Atif, Abid Kulsoom, Chen Lixin, Khan Kashif, Duan Wenbiao, Alam Tajwar, Riaz Umair
School of Forestry, Northeast Forestry University, Harbin 150040, China.
Key Laboratory of Sustainable Forest Ecosystem Management, Ministry of Education, Northeast Forestry University, Harbin 150040, China.
Heliyon. 2023 Jun 14;9(6):e17261. doi: 10.1016/j.heliyon.2023.e17261. eCollection 2023 Jun.
Soil aggregation in forest ecosystem is considered as a significant physical process mainly influenced by manure, fertilizers or combination. This aggregation may directly alter the soil nutrient and their fractions in soil. So, soil samples were collected from two types of forests i.e. Natural Korean pine forests (NKPF) and Korean pine plantation (KPP) in order to know the quantities of organic and inorganic Phosphorus (P) amounts in different aggregate sizes viz. >5 mm, 2-5 mm, 0.25-2 mm, <0.25 mm under forest litter and synthetic fertilizer application below the treatments as undisturbed soil (CK), removed litter (RL), altered litter (AL) while the fertilizer treatments were as control; C: (No added N and P,), L: low (5 g N m a + 5 g P m a), M: medium (15 g N m a + 10 g P m a) and H: high concentration (30 g N m a + 20 g P m a), respectively. The results showed that HO-Pi, NaHCO-Pi, Residual Pi, SOC were highest retained in larger soil aggregates (>5 mm) and decreased with the decreasing aggregate size, while other variables, i.e., NaOH-Pi, NaHCO-Po, pH and T-N were not affected in aggregate size. HO-Pi (48 ppm), NaHCO-Pi (68 ppm), NaHCO-Po (80 ppm), NaOH-Po (623 ppm), HCL-Po (67 ppm), SOC (20.36 ± 1.6) was estimated in medium fertilizer treatment. PCA analysis showed that spread/variance of data points on F1 (62.90%) is more than spread/variance of data points on F2 (57.74%) in NKPF and KPP, respectively, while correlation matrix showed high correlation between HO-Pi and NaOH-Pi (0.63) and HO-Pi and NaHCO-Pi (0.63) while a strong negative correlation was present between Res-Pi and Po (-0.61). Moreover, litter inputs increased the organic-P fractions in soil particularly at medium treatment.
森林生态系统中的土壤团聚被认为是一个主要受肥料、化肥或两者组合影响的重要物理过程。这种团聚可能直接改变土壤养分及其在土壤中的组分。因此，从两种类型的森林中采集土壤样本，即天然红松林（NKPF）和红松人工林（KPP），以了解不同团聚体大小（即>5毫米、2 - 5毫米、0.25 - 2毫米、<0.25毫米）下森林凋落物和施用合成肥料处理后的有机磷和无机磷（P）含量，处理包括原状土壤（CK）、去除凋落物（RL）、改变凋落物（AL），而肥料处理分别为对照；C：（不添加氮和磷），L：低浓度（5克氮每平方米每年 + 5克磷每平方米每年），M：中浓度（15克氮每平方米每年 + 10克磷每平方米每年）和H：高浓度（30克氮每平方米每年 + 20克磷每平方米每年）。结果表明，无机磷（HO-Pi）、碳酸氢钠提取态磷（NaHCO-Pi）、残余磷（Residual Pi）、有机碳（SOC）在较大土壤团聚体（>5毫米）中保留量最高，并随团聚体大小减小而降低，而其他变量，即氢氧化钠提取态磷（NaOH-Pi）、碳酸氢钠提取态有机磷（NaHCO-Po）、pH值和全氮（T-N）不受团聚体大小影响。中浓度肥料处理下，无机磷（HO-Pi）（48 ppm）、碳酸氢钠提取态磷（NaHCO-Pi）（68 ppm）、碳酸氢钠提取态有机磷（NaHCO-Po）（80 ppm）、氢氧化钠提取态有机磷（NaOH-Po）（623 ppm）、盐酸提取态有机磷（HCL-Po）（67 ppm）、有机碳（SOC）（20.36 ± 1.6）被测定。主成分分析（PCA）表明，在天然红松林和红松人工林中，F1上数据点的散布/方差（分别为62.90%）大于F2上数据点的散布/方差（分别为57.74%），而相关矩阵显示无机磷（HO-Pi）与氢氧化钠提取态磷（NaOH-Pi）之间（0.63）以及无机磷（HO-Pi）与碳酸氢钠提取态磷（NaHCO-Pi）之间（0.63）存在高度相关性，而残余磷（Res-Pi）与有机磷（Po）之间存在强负相关性（-0.61）。此外，凋落物输入增加了土壤中的有机磷组分，特别是在中浓度处理下。
