Linking organic carbon accumulation to microbial community dynamics in a sandy loam soil: result of 20 years compost and inorganic fertilizers repeated application experiment

2014 ◽  
Vol 51 (2) ◽  
pp. 137-150 ◽  
Author(s):  
Huanjun Zhang ◽  
Weixin Ding ◽  
Hongyan Yu ◽  
Xinhua He
Soil Research ◽  
1988 ◽  
Vol 26 (3) ◽  
pp. 549 ◽  
Author(s):  
KY Chan ◽  
JA Mead

The infiltration behaviour and physical properties of a hardsetting sandy loam soil at Cowra, N.S.W., following 2 years of different tillage treatments are reported. Soil that had not been cultivated for 25 years was also investigated at an adjacent pasture site. Infiltration of simulated rainfall at the end of the wheat-growing season gave moisture profiles that were quite different for cultivated, direct drilled and pasture soils. The moisture profile for the cultivated soil suggested the presence of an impeded layer which retarded the movement of infiltrated rain to the subsoil. Porosity measurements confirmed the presence of a layer with significantly fewer macropores (> 300 �m diameter) at the 50-100 mm depth in the cultivated soil, when compared with the direct drilled soil. The old pasture soil had significantly higher porosity (> 300 �m diameter) in the top 100 mm. Aggregate stabilities and organic carbon contents were measured in narrow increments to 150 mm depth for the three different soils, and revealed that a surface 25 mm layer of high organic carbon and highly stable macro-aggregates was present in the pasture and direct drilled soils but absent in the cultivated soil. The unstable surface layer in the conventionally cultivated soil was a consequence of the mixing and inverting action of cultivation and was not due to a net loss of organic carbon from the profile. The organic carbon content of the pasture soil was not significantly different from the direct drilled soil below 50 mm; however, it was significantly lower than the conventionally cultivated soil between 50 and 150 mm depth. These results indicate a need to adopt tillage practices that can preserve the top 25 mm layer of such fragile soils.


Author(s):  
P. Majhi ◽  
F. H. Rahman ◽  
R. Bhattacharya

Maintenance of soil quality is considered to be the key to attain sustainability in agricultural production and thus to achieve food security. In this study we tried to answer a research question as to whether integrated application of inorganic and organic sources of nutrients can maintain productivity and soil quality in rice-rice cropping system. To address this, total 27 physical, chemical (including organic C and soil fertility parameters) and biological (including enzyme activities) properties of an acidic sandy loam soil, which were subjected to different nutrient management (NM) practices for nine years of rice-rice cropping under submergence in subtropical India were critically assessed. Seven NM practices comprised of organic [farmyard manure (FYM)], inorganic fertilizers (sources of N, P, K, S, Zn, and B) and some of their combinations were tested using randomized complete block design with four replications. Integrated use of inorganic fertilizers (NPK) and organic manure (FYM) sustained productivity of rice-rice cropping system and aggraded soil quality as compared to only inorganic fertilizers even with inclusion of S, Zn and B. The NPK+FYM was superior among the NM practices to improve physical, chemical and biological properties of soil. Cation exchange capacity, non-exchangeable K and microbial biomass C were screened as the most sensitive attributes for assessing soil quality. Although the present study demonstrated the positive influence of integrated NM, application of even 80-17.5-50 kg N-P-K along with 5 Mg FYM ha-1 in each rice season failed to maintain total K content in soil. This suggested for readjustment of dose of inorganic fertilizers and organic manure and their application schedule for adequate replenishment of K in acidic sandy loam soil under rice-rice cropping in subtropical climate.


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