Decreased inorganic N supply capacity and turnover in calcareous soil under degraded rubber plantation in the tropical karst region

Determination of rates of mineralization of organic nitrogen (N) into ammonium-N (NH4+-N) and nitrification of NH4+-N into nitrate-N (NO3−-N) could be used to evaluate inorganic N supply capacity, which, in turn, could guide N fertilizer application practices in crop cultivation systems. However, little information is available on the change of mineralization and nitrification in soils under fruit cultivation systems converted from forestlands in karst regions. In a 15N-tracing study, inorganic N supply capacity in forest soils and three typical fruit crop soils under long-term cultivation was investigated, in addition to factors influencing the supply, in calcareous soils in the karst regions in southwestern China. Long-term fruit crop cultivation decreased soil organic carbon (SOC), total N, and calcium concentrations, cation exchange capacity (CEC), water holding capacity (WHC), pH, and sand content, significantly, but increased clay content. Compared to that of forests, long-term fruit crop cultivation significantly decreased mineralization and nitrification rates to 0.61–1.34 mg N kg−1 d−1 and 1.95–5.07 mg N kg−1 d−1, respectively, from 2.85–6.49 mg N kg−1 d−1 and 8.17–15.5 mg N kg−1 d−1, respectively, but greatly increased the mean residence times of NH4+-N and NO3−-N. The results indicate that long-term fruit crop cultivation could decrease soil inorganic N supply capacity and turnover in karst regions. Both mineralization and nitrification rates were significantly and positively correlated with SOC and total N concentrations, CEC, and WHC, but negatively correlated with clay content, suggesting that decreased soil organic matter and increased clay content were responsible for the decline in mineralization and nitrification rates in soils under long-term cultivation of fruit crops. The results of the present study highlight the importance of rational organic fertilizer application in accelerating soil inorganic N supply and turnover under long-term cultivation of fruit crops in karst regions.

Download Full-text

Response of Gross Mineralization and Nitrification Rates to Banana Cultivation Sites Converted from Natural Forest in Subtropical China

Land ◽

10.3390/land10040376 ◽

2021 ◽

Vol 10 (4) ◽

pp. 376

Author(s):

Xinghua Qin ◽

Cheng Yang ◽

Lin Yang ◽

Erdeng Ma ◽

Lei Meng ◽

...

Keyword(s):

Natural Forest ◽

Natural Forests ◽

Inorganic N ◽

Total N ◽

Effective Measure ◽

Gross Mineralization ◽

N Supply ◽

Banana Plantations ◽

Supply Capacity

Evaluations of gross mineralization (MNorg) and nitrification (ONH4) can be used to evaluate the supply capacity of inorganic N, which is crucial in determining appropriate N fertilizer application. However, the relevant research for banana plantations to date is limited. In this study, natural forest and banana plantations with different cultivation ages (3, 7, 10, and 22 y) were chosen in a subtropical region, and the 15N dilution technique was used to determine the gross MNorg and ONH4 rates. The objective was to evaluate the effect of the conversion of natural forests to banana plantations on inorganic N supply capacity (MNorg + ONH4) and other relevant factors. Compared to other natural forests in tropical and subtropical regions reported on by previous studies, the natural forest in this study was characterized by a relatively low MNorg rate and a high ONH4 rate in the soil, resulting in the presence of inorganic N dominated by nitrate. Compared to the natural forest, 3 y banana cultivation increased the MNorg and ONH4 rates and inorganic N availability in the soil, but these rates were significantly reduced with prolonged banana cultivation. Furthermore, the mean residence times of ammonium and nitrate were shorter in the 3 y than in the 7, 10, and 22 y banana plantations, indicating a reduced turnover of ammonium and nitrate in soil subjected to long-term banana cultivation. In addition, the conversion of natural forest to banana plantation reduced the soil organic carbon (SOC), total N and calcium concentrations, as well as water holding capacity (WHC), cation exchangeable capacity (CEC), and pH, more obviously in soils subjected to long-term banana cultivation. The MNorg and ONH4 rates were significantly and positively related to the SOC and TN concentrations, as well as the WHC and CEC, suggesting that the decline in soil quality after long-term banana cultivation could significantly inhibit MNorg and ONH4 rates, thus reducing inorganic N supply and turnover. Increasing the amount of soil organic matter may be an effective measure for stimulating N cycling for long-term banana cultivation.

Download Full-text

Groundwater Management Based on Vulnerability to Contamination in the Tropical Karst Region of Guntur Spring, Gunungsewu Karst, Java Island, Indonesia

Environmental Processes ◽

10.1007/s40710-020-00460-5 ◽

2020 ◽

Vol 7 (4) ◽

pp. 1277-1302

Author(s):

Indra Agus Riyanto ◽

M. Widyastuti ◽

Ahmad Cahyadi ◽

Romza Fauzan Agniy ◽

Tjahyo Nugroho Adji

Keyword(s):

Groundwater Management ◽

Karst Region ◽

Tropical Karst

Download Full-text

Low nitrate retention capacity in calcareous soil under woodland in the karst region of southwestern China

Soil Biology and Biochemistry ◽

10.1016/j.soilbio.2016.03.001 ◽

2016 ◽

Vol 97 ◽

pp. 99-101 ◽

Cited By ~ 18

Author(s):

Tongbin Zhu ◽

Siman Zeng ◽

Hanlian Qin ◽

Kexin Zhou ◽

Hui Yang ◽

...

Keyword(s):

Calcareous Soil ◽

Southwestern China ◽

Karst Region ◽

Retention Capacity ◽

Nitrate Retention

Download Full-text

Potentially mineralisable nitrogen: relationship to crop production and spatial mapping using infrared reflectance spectroscopy

Soil Research ◽

10.1071/sr08096 ◽

2009 ◽

Vol 47 (7) ◽

pp. 737 ◽

Cited By ~ 9

Author(s):

D. V. Murphy ◽

M. Osman ◽

C. A. Russell ◽

S. Darmawanto ◽

F. C. Hoyle

Keyword(s):

Grain Yield ◽

Crop Production ◽

Soil Analysis ◽

Sampling Strategy ◽

Ease Of Use ◽

Environmental Benefits ◽

Soil N ◽

Wheat Grain ◽

Inorganic N ◽

N Supply

Accurate and rapid prediction of the spatial structure of soil nitrogen (N) supply would have both economic and environmental benefits with respect to improved inorganic N fertiliser management. Yet traditional biochemical indices of soil N supply have not been widely incorporated into fertiliser decision support systems or environmental risk monitoring programs. Here we illustrate that in a low-input, semi-arid environment, potentially mineralisable N (PMN, as determined by anaerobic incubation) explained 21% of wheat grain yield (P = 0.003), whereas there was no significant relationship between wheat grain yield and inorganic N fertiliser application. We also assessed the spatial pattern of PMN using a structured grid soil sampling strategy over a 10-ha area (180 separate samples, 0–0.1 m). PMN in each soil sample was determined by standard biochemical analysis and also predicted using a fourier transform infrared spectrometer (FTIR). Findings illustrate that FTIR was able to significantly predict (P < 0.001) PMN values in soil and has the advantage of enabling high sample throughput and rapid (within minutes) soil analysis. Given the relatively low cost of FTIR machines and ease of use, such an approach has practical application in situations where analysis cost or access to equipped laboratories has hindered the measurement and monitoring of soil N supply within paddocks and across regions.

Download Full-text

Rate and timing of nitrogen fertilization of Russet Burbank potato: Nitrogen use efficiency

Canadian Journal of Plant Science ◽

10.4141/p03-131 ◽

2004 ◽

Vol 84 (3) ◽

pp. 845-854 ◽

Cited By ~ 31

Author(s):

B. J. Zebarth ◽

Y. Leclerc ◽

G. Moreau

Keyword(s):

Dry Matter ◽

N Fertilization ◽

N Use Efficiency ◽

Fertilizer N ◽

Inorganic N ◽

N Accumulation ◽

N Supply ◽

Soil Inorganic N ◽

Use Efficiency ◽

N Use

This study evaluated rate and timing of N fertilization effects on the N use efficiency characteristics of rain-fed Russet Burbank potato. Trials conducted in 1999–2001 included different rates of fertili zer N (0–160 kg N ha-1 in 1999 and 0–200 kg N ha-1 in 2000 and 2001) applied either at planting according to normal grower practice, or at hilling, the latest time that granular fertilizer can practically be applied. Whole-plant dry matter and N accumulation were determined at topkill. Soil inorganic N content was measured to 30-cm depth at planting and at tuber harvest. Soil N supply (plant N accumulation plus soil inorganic N content at harvest with no fertilizer N applied) varied from 77 to 146 kg N ha-1 depending on the year. Crop N supply (soil N supply plus fertilizer N applied) was a better predictor of plant N accumulation than fertilizer N rate, and was used to remove the confounding effect of variation in soil N supply when making among-year comparisons for N use efficiency characteristics. Nitrogen uptake efficiency (NUpE; plant N accumulation/crop N supply) decreased with increasing rates of N applied at hilling N rate in 1999, which was a dry year, but was not influenced by at-hilling N rate in 2000 and 2001, or by at-planting N rate in any year. Nitrogen use efficiency (NUE; dry matter accumulation/crop N supply) and N utilization efficiency (NUtE; dry matter accumulation/plant N accumulation) decreased curvilinearly with increasing crop N supply in each year. Similar relationships between NUE and crop N supply, and between NUtE and plant N accumulation, among the 3 yr of the study suggest that these relationships are largely independent of seasonal climatic variation, and are primarily genetically controlled. Timing of N fertilization had no effect on any N use efficiency parameter, with the exception of reduced NUpE associated with split N application in 1999. This suggests that under rain-fed potato production in Atlantic Canada, timing of N fertilization has no significant effect on N use efficiency of Russet Burbank potato in years of adequate soil moisture, but NUpE may be decreased by split application of N in dry years. Key words: Solanum tuberosum, soil inorganic N, apparent fertilizer N recovery

Download Full-text

Reduced Organic Carbon Content during the Evolvement of Calcareous Soils in Karst Region

Forests ◽

10.3390/f12020221 ◽

2021 ◽

Vol 12 (2) ◽

pp. 221

Author(s):

Hui Yang ◽

Yincai Xie ◽

Tongbin Zhu ◽

Mengxia Zhou

Keyword(s):

Organic Carbon ◽

Calcareous Soil ◽

Total Phospholipid ◽

Calcareous Soils ◽

Base Cations ◽

Karst Region ◽

Organic Carbon Content ◽

Soil Geochemistry ◽

Microbial Composition ◽

Soc Fractions

Understanding the changes in soil organic carbon (SOC) storage is important for accurately predicting ecosystem C sequestration and/or potential C losses, but the relevant information, especially for the evolvement of calcareous soil is limited in karst regions. Three calcareous soils with different evolvement intensities were sampled from an evergreen broadleaved forest in the subtropical region of southwest of China to investigate the changes in different SOC fractions and microbial communities. The results showed that: (1) The contents of SOC, dissolved organic carbon (DOC), mineral protected organic carbon (MOC), and recalcitrant organic carbon (ROC) significantly decreased with increasing evolvement intensity of calcareous soil, but pH and the chemical composition of SOC, including Alkyl C, O-alkyl C, Aromatic C, and Carbonyl C, did not significantly change, suggesting that various SOC fractions synergistically decrease with the evolvement of calcareous soil. (2) The evolvement of calcareous soil had a substantial negative effect on total phospholipid fatty acids (PLFA), bacteria (i.e., Gram positive bacteria and Gram negative bacteria), fungi, and actinomycetes, but did not affect the ratio of fungi to bacteria. This result supported the conclusion that various SOC fractions were synchronously loss with the evolvement of calcareous soil. (3) Results from the multivariate statistical analysis showed a significant correlation between SOC fractions (including SOC, DOC, MOC, and ROC) and soil base cations, mainly calcium (Ca), iron (Fe), and aluminum (Al). This strengthens the fact that SOC stability largely depends on the complex relationship between organic matter and mineral composition in soil. Taken together, the reduction of SOC during the evolvement of soil in the karst areas accords with some mechanisms of previous studies (e.g., microbial composition and soil geochemistry), and also has its own unique characteristics (e.g., the relative contribution of carbons to chemical shift regions of CPMAS 13C-NMR spectra and F:B ratio).

Download Full-text

Increasing SOC sequestration and closing N cycle during post-agricultural restoration in karst region, Southwest China

10.21203/rs.3.rs-708956/v1 ◽

2021 ◽

Author(s):

Man Liu ◽

Guilin Han ◽

Qian Zhang

Keyword(s):

Southwest China ◽

N Uptake ◽

Guizhou Province ◽

Karst Region ◽

Inorganic N ◽

N Cycle ◽

Sequestration Potential ◽

Agricultural Restoration ◽

Time Substitution ◽

N Status

Abstract Purpose Post-agricultural restoration affects soil organic carbon (SOC) sequestration and ecosystem nitrogen (N) cycle. However, the control mechanism of SOC sequestration and alteration of ecosystem N status following post-agricultural restoration are not well understood in karst regions. Methods Croplands, abandoned croplands, and native vegetation forests were selected to represent three stages following post-agricultural restoration using a space for time substitution approach in a karst critical zone in Guizhou province, Southwest China. The variations of soil aggregate associated SOC and relationships between soil Ca and SOC were analyzed to identify SOC sequestration potential. Foliar δ15N composition and soil to plant 15N enrichment factor (EF = δ15Nlitter − δ15Nsoil) were analyzed to determine ecosystem N status. Results Macro-aggregate proportions and their SOC concentrations significantly increased following post-agricultural restoration. Soil Ca concentrations non-linearly increased with increasing SOC concentrations of bulk soils and aggregates. Foliar δ15N values and EF values significantly decreased following post-agricultural restoration, mainly attributed to the increasing plant uptake of 15N-depleted inorganic N, which was produced from soil organic nitrogen (SON) mineralization and nitrification. During post-agricultural restoration, the increasing plant biomass and slow SON mineralization led to more inorganic N uptake and less N loss, i.e., a more closed N cycle. Conclusion Soil aggregates and Ca play important roles in promoting SOC sequestration, and ecosystem N cycles are towards closed during post-agricultural restoration in the karst ecosystem.

Download Full-text

Effects of wildfire and topography on soil nitrogen availability in a boreal larch forest of northeastern China

International Journal of Wildland Fire ◽

10.1071/wf13218 ◽

2015 ◽

Vol 24 (3) ◽

pp. 433 ◽

Cited By ~ 14

Author(s):

Jian-jian Kong ◽

Jian Yang ◽

Haiyan Chu ◽

Xingjia Xiang

Keyword(s):

Soil Nitrogen ◽

Northeastern China ◽

Larch Forest ◽

N Availability ◽

N Mineralisation ◽

Soil N ◽

Inorganic N ◽

Soil N Availability ◽

N Supply ◽

Burned Site

Both topography and wildfire can strongly affect soil nitrogen (N) availability. Although many studies have examined the individual effects of fire and topography on N, few have investigated their combined influences and relative importance. In this study, we measured soil extractable inorganic N concentrations, N mineralisation rates, and in situ soil inorganic N supply rates at 36 plots in three topographic positions (north-facing, south-facing and flat valley bottom) of burned and unburned sites in a boreal larch forest of northeastern China. Our data showed that wildfire significantly increased soil N availability, with mean soil extractable inorganic N concentrations, N mineralisation rates and N supply rates being 63, 310 and 270% higher in the burned site 1 year following fire. Additionally, soil N availability in the unburned site was significantly greater on the north-facing slope than on the south-facing slope, though this pattern was reversed at the burned site. Wildfire and topography together explained ~50% of the variance in soil N availability, with wildfire explaining three times more than topography. Our results demonstrate that wildfire and topography jointly affected spatial variations of soil N availability, and that wildfire decreased the influence of topography in the early successional stage of this boreal larch ecosystem.

Download Full-text

Improving Soil Quality and Potato Productivity with Manure and High-Residue Cover Crops in Eastern Canada

Plants ◽

10.3390/plants10071436 ◽

2021 ◽

Vol 10 (7) ◽

pp. 1436

Author(s):

Judith Nyiraneza ◽

Dahu Chen ◽

Tandra Fraser ◽

Louis-Pierre Comeau

Keyword(s):

Sorghum Bicolor ◽

Pearl Millet ◽

Cover Crops ◽

Red Clover ◽

Potato Yield ◽

Soil Nitrate ◽

Soil N ◽

Manure Application ◽

N Supply ◽

Supply Capacity

Under intensive low residue agricultural systems, such as those involving potato (Solanum tuberosum L.)-based systems, stagnant crop yields and declining soil health and environmental quality are common issues. This study evaluated the effects of pen-pack cow (Bos Taurus) manure application (20 Mg·ha−1) and cover crops on nitrate dynamics and soil N supply capacity, subsequent potato yield, selected soil properties, and soil-borne disease. Eight cover crops were tested and included grasses, legumes, or a mixture of legumes and grasses, with red clover (Trifolium pratense L.) used as a control. Forage pearl millet (Pennisetum glaucum L.) was associated with highest dry matter. On average, red clover had 88% higher total N accumulation than the treatments mixing grasses and legumes, and the former was associated with higher soil nitrate in fall before residue incorporation and overwinter, but this was not translated into increased potato yields. Pearl millet and sorghum sudangrass (Sorghum bicolor × sorghum bicolor var. Sudanese) were associated with lower soil nitrate in comparison to red clover while being associated with higher total potato yield and lower numerical value of root-lesion nematodes (Pratylenchus penetrans), although this was not statistically significant at 5% probability level. Manure incorporation increased total and marketable yield by 28% and 26%, respectively, and increased soil N supply capacity by an average of 44%. Carbon dioxide released after a short incubation as a proxy of soil microbial respiration increased by an average of 27% with manure application. Our study quantified the positive effect of manure application and high-residue cover crops on soil quality and potato yield for the province of Prince Edward Island.

Download Full-text