scholarly journals Effect of Stand Density and Soil Layer on Soil Nutrients of a 37-year-old Cunninghamia lanceolata Plantation in Naxi, Sichuan Province, China

2019 ◽  
Vol 11 (19) ◽  
pp. 5410 ◽  
Author(s):  
Jie Lei ◽  
Hailun Du ◽  
Aiguo Duan ◽  
Jianguo Zhang

In order to study the characteristics of soil nutrient elements and the changes in biomass under different densities and soil layers of forest stand, this paper considers Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) density test forests with five densities (A: 1667 trees·ha−1; B: 3333 trees·ha−1; C: 5000 trees·ha−1; D: 6667 trees·ha−1; E: 10,000 trees·ha−1) as the research objects, located in Naxi District, Sichuan Province, China. Eleven soil physical and chemical property indicators, understory vegetation, and litter biomass were measured. The results were as follows: (1) The stand density had a significant effect on the soil nutrient content, understory vegetation, and litter biomass. A low density is conducive to the accumulation of soil organic matter, hydrolytic N, available P, available K, and total Ca. (2) With the increase in soil depth, the contents of soil organic matter, total N, hydrolytic N, and total P decreased gradually; pH and total Ca decreased gradually; and available P showed a trend of decrease-up-decrease. The soil layers had no significant effect on the total K, total Fe, and total Mg concentrations. (3) Low density (density A or B) was found to be beneficial to the growth of undergrowth vegetation and forest trees, the return of nutrients, long-term soil maintenance, and the stable high yield of Chinese fir plantations.

Author(s):  
Zhiyang Lie ◽  
Zhuomin Wang ◽  
Li Xue

With one-year-old Tephrosia candida trees as experimental material, influence of stand density on soil nutrient content and enzyme activity was studied. The results showed that density had little influenced on pH value in 2, 4 and 8 trees m2 stands. The contents of soil organic matter, effective nitrogen and effective phosphorus significantly increased in 2 trees m2 stands. The contents of soil organic matter and effective nitrogen significantly increased, whereas total N, total P, total K, effective N, effective P and effective K significantly decreased in 4 trees/m2 stand. Soil organic matter and nutrients except for total P significantly decreased in 8 trees m2 stand. Among the three density stands, the activities of urease, catalase and phosphatase were the lowest in 8 trees m2 stand.


Radiocarbon ◽  
1989 ◽  
Vol 31 (03) ◽  
pp. 644-654 ◽  
Author(s):  
S E Trumbore ◽  
J S Vogel ◽  
J R Southon

14C measurements are reported for fractionated soil organic matter from a genetic soil sequence which was sampled several times during the period of atmospheric nuclear weapons testing. Fractionation of the soils by density followed by acid hydrolysis was successful in separating the organic matter into components with mean residence times for carbon ranging from 5 to 20 years (low density fraction) to several thousand years (residue after acid hydrolysis). Comparison of the infiltration of bomb 14C into the vertical soil profile with the distribution of 137Cs, gives clues as to the mechanism (most probably dissolved transport) for importing carbon into deeper soil layers.


2021 ◽  
Vol 13 (7) ◽  
pp. 3957
Author(s):  
Yingying Xing ◽  
Ning Wang ◽  
Xiaoli Niu ◽  
Wenting Jiang ◽  
Xiukang Wang

Soil nutrients are essential nutrients provided by soil for plant growth. Most researchers focus on the coupling effect of nutrients with potato yield and quality. There are few studies on the evaluation of soil nutrients in potato fields. The purpose of this study is to investigate the soil nutrients of potato farmland and the soil vertical nutrient distributions, and then to provide a theoretical and experimental basis for the fertilizer management practices for potatoes in Loess Plateau. Eight physical and chemical soil indexes were selected in the study area, and 810 farmland soil samples from the potato agriculture product areas were analyzed in Northern Shaanxi. The paper established the minimum data set (MDS) for the quality diagnosis of the cultivated layer for farmland by principal component analysis (PCA), respectively, and furthermore, analyzed the soil nutrient characteristics of the cultivated layer adopted soil quality index (SQI). The results showed that the MDS on soil quality diagnosis of the cultivated layer for farmland soil included such indicators as the soil organic matter content, soil available potassium content, and soil available phosphorus content. The comprehensive index value of the soil quality was between 0.064 and 0.302. The SPSS average clustering process used to classify SQI was divided into three grades: class I (36.2%) was defined as suitable soil fertility (SQI < 0.122), class II (55.6%) was defined as moderate soil fertility (0.122 < SQI < 0.18), and class III (8.2%) was defined as poor soil fertility (SQI > 0.186). The comprehensive quality of the potato farmland soils was generally low. The proportion of soil nutrients in the SQI composition ranged from large to small as the soil available potassium content = soil available phosphorus content > soil organic matter content, which became the limiting factor of the soil organic matter content in this area. This study revolves around the 0 to 60 cm soil layer; the soil fertility decreased gradually with the soil depth, and had significant differences between the respective soil layers. In order to improve the soil nutrient accumulation and potato yield in potato farmland in northern Shaanxi, it is suggested to increase the fertilization depth (20 to 40 cm) and further study the ratio of nitrogen, phosphorus, and potassium fertilizer.


Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 823
Author(s):  
Anna Zielonka ◽  
Marek Drewnik ◽  
Łukasz Musielok ◽  
Marcin K. Dyderski ◽  
Dariusz Struzik ◽  
...  

Forest ecosystems significantly contribute to the global organic carbon (OC) pool, exhibiting high spatial heterogeneity in this respect. Some of the components of the OC pool in a forest (woody aboveground biomass (wAGB), coarse root biomass (CRB)) can be relatively easily estimated using readily available data from land observation and forest inventories, while some of the components of the OC pool are very difficult to determine (fine root biomass (FRB) and soil organic matter (SOM) stock). The main objectives of our study were to: (1) estimate the SOM stock; (2) estimate FRB; and (3) assess the relationship between both biotic (wAGB, forest age, foliage, stand density) and abiotic factors (climatic conditions, relief, soil properties) and SOM stocks and FRB in temperate forests in the Western Carpathians consisting of European beech, Norway spruce, and silver fir (32 forest inventory plots in total). We uncovered the highest wAGB in beech forests and highest SOM stocks under beech forest. FRB was the highest under fir forest. We noted a considerable impact of stand density on SOM stocks, particularly in beech and spruce forests. FRB content was mostly impacted by stand density only in beech forests without any discernible effects on other forest characteristics. We discovered significant impacts of relief-dependent factors and SOM stocks at all the studied sites. Our biomass and carbon models informed by more detailed environmental data led to reduce the uncertainty in over- and underestimation in Cambisols under beech, spruce, and fir forests for mountain temperate forest carbon pools.


Forests ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 351
Author(s):  
Aiguo Duan ◽  
Jie Lei ◽  
Xiaoyan Hu ◽  
Jianguo Zhang ◽  
Hailun Du ◽  
...  

Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) is a fast-growing evergreen conifer with high-quality timber and is an important reforestation and commercial tree species in southern China. Planting density affects the productivity of Chinese fir plantations. To study the effect of five different planting densities and soil depth on soil nutrient contents of a mature C. lanceolata plantation, the soil nutrient contents (soil depths 0–100 cm) of 36-year-old mature Chinese fir plantations under five different planting densities denoted A (1667 trees·ha−1), B (3333 trees·ha−1), C (5000 trees·ha−1), D (6667 trees·ha−1), and E (10,000 trees·ha−1) were measured in Pingxiang county, Guangxi province, China. Samples were collected from the soil surface down to a one meter depth from each of 45 soil profiles, and soil samples were obtained at 10 different soil depths of 0–10, 10–20, 20–30, 30–40, 40–50, 50–60, 60–70, 70–80, 80–90, and 90–100 cm. Twelve soil physical and chemical indicators were analyzed. The results showed that: (1) as planting density increased, the organic matter, organic carbon, total N and P, available N, effective Fe, and bulk density decreased. Soil pH, total K, and effective K increased with increasing planting density. Planting density did not significantly influence the exchangeable Ca and Mg. (2) Soil organic matter; organic carbon; total N and P; effective N, P, and K; exchangeable Ca and Mg; effective Fe content; and bulk density decreased with increasing soil depth. This pattern was particularly evident in the top 30 cm of the soil. (3) Excessively high planting density is not beneficial to the long-term maintenance of soil fertility in Chinese fir plantations, and the planting density of Chinese fir plantations should be maintained below 3333 stems·ha−1 (density A or B) to maintain soil fertility while ensuring high yields.


Forests ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 236 ◽  
Author(s):  
Taimoor Farooq ◽  
Wenjing Wu ◽  
Mulualem Tigabu ◽  
Xiangqing Ma ◽  
Zongming He ◽  
...  

Chinese fir (Cunninghamia lanceolata (Lamb) Hook) is a commercially valuable timber species that is widely planted in southern China and accounts for 6.1% of the global plantation forests. However, appropriate planting density that ensures high plantation productivity is largely unexplored in this species. The aim of the study was to examine tree growth, biomass production, and its allocation among different organs in relation to initial planting density, and to examine whether planting density has an impact on root development. Mortality, diameter at breast height and tree-height of all trees were determined and measured in wider (2.36 × 2.36 m), intermediate (1.83 × 1.83 m) and narrow (1.44 × 1.44 m) spacing with stand density of 1450 trees ha−1, 2460 trees ha−1 and 3950 trees ha−1, respectively. In each stand, three plots of 20 × 20 m at a distance of 500 m were delineated as the sampling unit. Biomass was determined by destructive sampling of trees in each stand and developing allometric equations. Root morphological traits and their spatial distribution were also determined by carefully excavating the root systems. The results showed an increase in diameter of trees with decreasing stand density while tree height was independent of stand density. Biomass production of individual trees was significantly (p < 0.05) less in high-density stand (32.35 ± 2.98 kg tree−1) compared to low-density stand (44.72 ± 4.96 kg tree−1) and intermediate-density stand (61.35 ± 4.78 kg tree−1) while stand biomass production differed significantly in the order of intermediate (67.63 ± 5.14 t ha−1) > high (57.08 ± 3.13 t ha−1) > low (27.39 ± 3.42 t ha−1) stand density. Both average root length and root volume were significantly (p < 0.05) lower in the high-density stand than stands with low and intermediate density. Analysis of spatial distribution of root systems revealed no overlap between roots of neighboring trees in the competition zone in low-density stand, a subtle overlap in the intermediate density stand and larger overlap in the high-density stand. It can be concluded that better growth and biomass production in intermediate density stand could be explained by better root structural development coupled with minimal competition with understory vegetation and between trees; thus intermediate stand density can be optimal for sustaining long-term productivity and may reduce the management cost in the early phase of the plantation.


2014 ◽  
Vol 05 (08) ◽  
pp. 743-753 ◽  
Author(s):  
María Daniela Chavez ◽  
Paulus Bernardus Maria Berentsen ◽  
Oene Oenema ◽  
Alfons Gerard Joseph Maria Oude Lansink

Soil Research ◽  
2015 ◽  
Vol 53 (3) ◽  
pp. 338 ◽  
Author(s):  
Yu Gou ◽  
Hui Chen ◽  
Wei Wu ◽  
Hong-Bin Liu

Human activities and topography are main factors affecting soil nutrient variation. However, the relationships between these factors are both site- and scale-specific. In hilly areas of south-western China, the dominant cropping systems are rice, vegetables, oranges, Chinese red pepper and maize–sweet potato intercropping. In the present study, slope position (valley, low slope, flat slope, middle slope, upper slope, ridge) and aspect (north, east, south, west) were derived to investigate the relationships among cropping system, terrain, and soil nutrients at county scale. Crops were mainly planted at middle or flat slope positions. Rice and orange plants were evenly distributed across the aspects whereas vegetables were mostly planted on the northern aspect. Red pepper and maize–sweet potato plants were mainly grown on the western and southern aspects. Rice sites had higher contents of organic matter and available nitrogen (N) and lower contents of available phosphorus (P) and available potassium (K). For dryland cropping systems, vegetable sites had higher contents of organic matter, available N, and available P. Red pepper sites had higher contents of available K. Contents of organic matter and available N were generally higher at lower landscape positions. Contents of available K were higher at lower and flat slope positions. Contents of available P were higher at higher landscape positions. Contents of organic matter and available N were higher on the northern and eastern, and lower on the western aspects. Contents of available P were higher on the western and lower on the northern aspects. No significant differences were found for available K across the aspects. Classification tree algorithms indicated that relative importance of the variables on soil nutrient variation was in the order: (i) cropping system, (ii) slope position, and (iii) aspect.


Sign in / Sign up

Export Citation Format

Share Document