Long-term fertilization increases soil nutrient accumulations but decreases biological activity in navel orange orchards of subtropical China

2016 ◽  
Vol 17 (9) ◽  
pp. 2346-2356 ◽  
Author(s):  
Song-Ze Wan ◽  
Han-Jiao Gu ◽  
Qing-Pei Yang ◽  
Xiao-Fei Hu ◽  
Xiang-Min Fang ◽  
...  
2018 ◽  
Vol 69 (10) ◽  
pp. 2608-1612 ◽  
Author(s):  
Alina Dora Samuel ◽  
Simona Bungau ◽  
Delia Mirela Tit ◽  
Carmen Elena Melinte (Frunzulica) ◽  
Lavinia Purza ◽  
...  

Long term productivity and conservation of soils is critical for sustaining agricultural ecosystems. The specific objective of the work reported was to determine the effects of long term application of organic and mineral fertilizers on soil enzyme activity as an index of soil biology and biochemistry. Three key soil enzymes involved in intracellular metabolism of microorganisms and two soil enzymes involved in phosphorus metabolism were selected. Actual and potential dehydrogenase, catalase, acid and alkaline phosphatase activities were determined in the 0-20 cm layer of an eroded soil submitted to a complex fertilization experiment. Results showed that addition of mineral fertilizers to organic (green manure and farmyard manure) fertilizers led to a significant increase in each activity because of increased plant biomass production which upon incorporation stimulates soil biological activity. The enzymatic indicators of soil quality calculated from the values of enzymatic activities depending on the kind of fertilizers showed that by the determination of enzymatic activities valuable information can be obtained regarding fertility status of soils. A weak positive correlation between enzymatic indicators of soil quality and maize yield was established. The yield data demonstrate the superiority of farmyard manure which provided greater stability in crop production. Substantial improvement in soil biological activity due to application of organic fertilizers with mineral fertilizers contribute in maintaining the productivity and soil health.


2008 ◽  
Vol 88 (4) ◽  
pp. 451-460 ◽  
Author(s):  
M A Bolinder ◽  
O. Andrén ◽  
T. Kätterer ◽  
L -E Parent

The potential for storage of atmospheric CO2-C as soil organic C (SOC) in agroecosystems depends largely on soil biological activity and the quantity and quality of annual C inputs to soil. In this study we used the Introductory Carbon Balance Model (ICBM) approach driven by daily standard weather station data, specific soil properties and crop characteristics at the scale of Canadian agricultural ecoregions. The objectives were to calculate a climate-dependent soil biological activity parameter representative for annual agricultural crop production systems (re_crop) and to estimate the effect of fallow (re_fallow). These parameters are based on the daily product of soil temperature and stored water that influence biological activity in the arable layer, and are used to adjust the decomposition rates of the ICBM SOC pools. We also tested re_crop and re_fallow on SOC stock change data for different site and treatment combinations from long-term field experiments located in some of the ecoregions. An re_crop value of 0.95 for western ecoregions was on average 0.23 units lower than that of the eastern ecoregions, indicating a lower decomposition rate of SOC. Although the estimated annual C inputs to soil for small-grain cereals were on average ≈7.5% higher in the eastern ecoregions (305 vs. 285 g C m-2 yr-1), the overall results suggest that the western ecoregions would have a greater potential to maintain high SOC levels in the long term. However, these parameters varied between ecoregions and, consequently, the SOC sequestration potential was not always higher for the western ecoregions. The effect of fallow was on average ≈0.04, i.e., SOC decomposed slightly faster under fallow. Predictions for 24 out of 33 site and treatment combinations across Canada were significantly improved (P = 0.003), compared with a previous application with the ICBM that did not differentiate between crops and fallow. The methodology used here enabled us to examine regional differences in the potential for SOC sequestration as a balance between annual C inputs to soil and soil biological activity. Key words: Annual C inputs, climate, fallow, soil biological activity, agroecosystems


2007 ◽  
Vol 29 (3) ◽  
pp. 115-134 ◽  
Author(s):  
Gilbert C. Sigua ◽  
Mary J. Williams ◽  
Samuel W. Coleman

2014 ◽  
Vol 60 (No. 8) ◽  
pp. 344-350 ◽  
Author(s):  
M. Jiang ◽  
Shen XP ◽  
W. Gao ◽  
Shen MX ◽  
Dai QG

We studied the heterogeneity of soil weed seed-bank in a rice-wheat rotation system after long-term application of different organic or non-organic fertilizers, and the effects of major nutrients on the characteristics of the weed seed-bank. The soil was sampled in the Taihu area after a 31-year long-term fertilization experiment. Weed seeds were identified and counted in the surface soil of 12 differentially treated areas using microscopic examination, and analyzed by the Simpson, Shannon, Margalef, and Pielou indexes. The long-term application of organic fertilizers could significantly reduce the density of soil weed seed-bank; non-organic fertilizers and a combination of non-organic and organic fertilizers had a significant influence on the number of species and diversity of weeds. The application of organic fertilizers improved the Simpson, Shannon and Pielou indexes of soil weed seed-bank community and stabilized the community structure. In terms of the soil nutrient system itself, the soil organic materials and total nitrogen content are the main environmental factors affecting the distribution of soil weed seed-bank.


Soil Research ◽  
2013 ◽  
Vol 51 (6) ◽  
pp. 503 ◽  
Author(s):  
Weijun Fu ◽  
Keli Zhao ◽  
Peikun Jiang ◽  
Zhengqian Ye ◽  
Hubert Tunney ◽  
...  

Field-scale variation of soil nutrients in grassland is becoming important because of the use of soil-nutrient information as a basis for policies such as the recently introduced EU Nitrates Directive. This study investigates the field-scale variability of soil-test phosphorus (STP) and other nutrients in two grasslands with a long-term history of poultry litter application. Two fields (field 1 for silage and field 2 for grazing pasture) were selected, and soil samples were collected based on 12 m by 12 m (field 1) and 15 m by 15 m (field 2) grids. Data were analysed using conventional statistics, geostatistics, and a geographic information system (GIS). In field 1, STP values ranged from 12.4 to 90 mg L–1 (average 38.5 mg L–1). In field 2, STP values ranged from 4.3 to 130.0 mg L–1 (average 21.4 mg L–1). Attention should be paid to long-term poultry application, as the average STP values in both fields were much greater than the recommended agronomic optimum STP status in Ireland of 8 mg L–1. Coefficient of variation values of soil nutrients in field 2 were much higher than those in field 1. Log-transformation and Box–Cox transformation were applied to achieve normality. Statistically significant (P < 0.01), positive correlations between P and other nutrients were found in both fields. Exponential and spherical models were fitted to the experimental variograms of STP in fields 1 and 2, respectively. Compared with the counterparts in field 1, soil nutrients in field 2 had larger ‘nugget-to-sill’ values, revealing that sheep grazing could weaken the spatial auto-correlation of soil nutrients. A grid of 60 m by 60 m was recommended for soil sampling in grassland, based on this study. High STP concentrations in field 1 were in the north-eastern side, which was related to uneven poultry litter application. Strong spatial similarity of low STP, magnesium, and pH values in their spatial distribution were found in field 2, confirming their strong statistical correlation.


Soil Research ◽  
2017 ◽  
Vol 55 (3) ◽  
pp. 215
Author(s):  
Maria Luísa Arosa ◽  
Sofia R. Costa ◽  
Helena Freitas

This study compared litter decomposition dynamics of cork oak at three sites under different land-uses (grassland, shrubland and woodland), in a montado ecosystem in Southern Portugal. The montado is a protected habitat within the EU Habitats Directive, but the long-term persistence of cork oak is endangered in these ecosystems, with health of poor cork oak and low natural regeneration rates being the main causes of degradation. Moreover, human management has resulted in the conversion of woodlands to grasslands and may have long-term effects on soil nutrient availability, eventually modifying soil nutrient budgets. Knowledge of the ecological processes is therefore relevant for ecosystem management and species conservation. In the study, the estimated amount of leaf fall from cork oak showed no significant differences between land uses, despite the positive influence of tree crown size on leaf fall. Decomposition was affected by season, vegetation cover, leaf thickness and litter quality. Differences in land use that exposed soil to harsh climate conditions negatively affected soil microbial dynamics, resulting in lower decomposition rates in the more disturbed sites with lower canopy cover.


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