• Journal of Environmental Science International
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• v.30 no.12
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• pp.1015-1025
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• 2021

Our research work aimed to evaluate cover crop effects of winter rye on soil characteristics, soil conservation, and yield productivities on potato fields with 15% slope during a fallowed period. There were two controls of bared field without any cultivation and conventional potato cultivation without winter rye. Potato cultivation increased soil pH, organic matter, available phosphate, and exchangeable cation regardless of cover crop cultivation. Sub-soil, particularly, all components of soil chemical properties showed higher value in winter rye cultivation than conventional cultivation. Higher soil density was observed on cover crop cultivation than conventional cultivation resulting from root residues of the cover crop both topsoil and subsoil. Cover crop residues positively affected plant growth and reduced the amount of soil erosion by holding the soil. Although severe soil erosion was seen in conventional cultivation, winter rye cultivation declined soil erosion by 47% during the fallow period on potato slope fields. Distinct soil bacterial communities were detected among treatments and some OTU(Operational Taxonomic Unit)s showed significantly higher abundance in winter rye treatment. Total yield and commercial rate demonstrated no significant differences while higher tuber phosphate, K⁺, and Mg²⁺ contents were observed in winter rye cultivation.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.346-346
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• 2017

In Northern Laos, maize is cultivated in continuous cropping without fertilizer, fallowing nor any other soil conservation practice. It is expected that this inadequate management in maize cultivation will degrade soil and decrease yield. However, there is limited information about the change of soil condition and yield under continuous maize cultivation. We tried to evaluate the change of soil condition and yield under continuous maize cultivation in Northern Laos. Our study was conducted in farmer's flat and slope fields in Sainyabuli province where maize cultivation had been introduced earlier than the other provinces of Northern Laos. Our study was conducted in 21 fields in 2014, and in 19 fields in 2015. We analyzed grain yield and soil characteristic (total carbon (TC), total nitrogen (TN), available phosphorus (Av-P), exchangeable cation, pH, soil texture) at 3 places in each field. The 3 places were set at different elevation level (lower position, middle position, upper position) in slope fields. Further, the period of continuous maize cultivation and crop management practice were investigated. Then, by evaluating the relation between the period of continuous maize cultivation and yield and the soil characteristics, the effect of maize cultivation was estimated. Crop management practices were similar among the investigated fields. Maize was cultivated in rain season. Grain seed and cob were harvested on September or October, but shoot was left on the fields. No crop was cultivated during dry season. Fertilization and fallowing has never been conducted under continuous maize cultivation. On the other hand, the period of maize cultivation was different among the fields, and ranged from 2 years to 30 years. In the slope fields, as the period of continuous maize cultivation was longer, the contents of TC and TN were lower at all 3 positions, Av-P content was lower at the upper position, exchangeable potassium (Ex-K) content was lower at the middle and the upper positions. The other soil characteristics weren't related with the period of maize cultivation in the slope fields. In contrast, soil characteristics weren't related with the period of maize cultivation in the flat fields. Yield was lower as the period of maize cultivation was longer at the upper position of the slope fields. At middle position of slope fields, yield tended to be low with increase of the period of maize cultivation. In contrast, yield wasn't related with the period of continuous maize cultivation in flat fields. From the results about crop management, it was presumed that the period of maize cultivation was one of the main factors causing the difference of yield and soil characteristics among the fields. Therefore, from the result of yield and soil condition, it was considered that the continuous maize cultivation decreased soil productivity in the slope fields with decline of TC, TN, Av-P, Ex-K and yield at upper position of slope fields, and decline of TC and TN in the other positions in Sainyabuli province.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.4
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• pp.335-340
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• 2016

Soil organic carbon plays an important role on soil physico-chemical properties and crop yields in paddy soil. However, there is little information on the soil organic carbon under different forage cultivation during winter season in rice paddy. In this study, we investigated the soil organic carbon and physico-chemical properties in 87 fields of paddy soil cultivated with Barley, rye, and Italian ryegrass (IRG) as animal feedstock during winter season. Organic carbon was 12.9, 14.3, and $16.9g\;C\;kg^{-1}$ in soil with barley, rye, and IRG cultivation, respectively. Among rice-forage cultivation systems, the rice+IRG cropping system was 19.5% higher than in the mono-rice cultivation. Bulk density ranged from 1.17 to $1.28g\;cm^{-3}$ irrespective of cropping systems, and had strongly negative correlation with the soil organic carbon in the rice+IRG cropping system. Carbon storage in rice+IRG cropping systems was average $29.6Mg\;ha^{-1}$ at 15 cm of soil depth, which was 20.4 and 10.3% higher than those of barley and rye cultivation. Increasing carbon storage in paddy soil contributed to the fertility for following rice cultivation. This results indicated that IRG cultivation during winter season could be an alternative and promising way to enhance soil organic carbon content and fertility of paddy soil.

• Korean Journal of Medicinal Crop Science
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• v.28 no.3
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• pp.209-220
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• 2020

Background: This study investigated the effects of soil properties on the soil fungal community in first and continuous cultivation areas of Cnidium officinale Makino. Methods and Results: The soil fungal community was analyzed for relative abundance and principal coordinate analysis (PCoA) was conducted using Illumina MiSeq sequencing. The correlation between the soil chemical properties and the soil fungal community was assessed with distance-based linear models (DISTLM). The soil fungal community showed distinct clusters consisting in the continuous cultivation area of C. officinale Makino. PCoA and DISTLM indicated that soil pH, calcium, and available P₂O₅ significantly affected the soil fungal community in the cultivation area of C. officinale Makino. In addition, considering 5 different pathogenic fungi the relative abundance of Fusarium in the continuous cultivation area was significantly higher compared to that in the first cultivation area of C. officinale Makino. Conclusions: This study is important because it has determinined the effects of soil properties on the soil fungal community in both first and continuous cultivation areas of C. officinale Makino. Moreover, these results will be helpful to investigate the cause of continuous cropping obstacle in C. officinale Makino by examining the changes of soil fungal community.

• Journal of Environmental Science International
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• v.30 no.5
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• pp.379-389
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• 2021

Soil microorganism activity in an agricultural field is affected by various factors including climate conditions, soil chemical properties, and crop cultivation. In this study, we elucidate the correlation between microorganism activity and agricultural environment factors using the dehydrogenase activity (DHA) value, which is one of the indicators of soil microbial activity. As a result, the various factors noted above were related to the DHA value. Annual rainfall, soil Mg2+, bacterial and fungal diversities, types of crops, developmental stages, seasons, and cultivation status were highly correlated with the DHA value. Furthermore, next-generation sequencing (NGS) analysis was used to identify that the type of crop affected soil microbial compositions of both bacteria and fungi. Soil used for soybean cultivation showed the highest relative abundance for Verrucomicrobia, Planctomycetes, and Acidobacteria but Actinobacteria and Firmicutes had the lowest relative abundance. In the case of soil used for potato cultivation, Actinobacteria had the highest relative abundance but Proteobacteria had the lowest relative abundance. Armatimonadetes showed the highest relative abundance in soil used for cabbage cultivation. Among the fungal communities, Mortierellomycota had the highest relative abundance for soybean cultivation but the lowest relative abundance for cabbage cultivation; further, Rozellomycota, Chytridiomycota, and Cercozoa had the highest relative abundance for cabbage cultivation. Basidiomycota had the highest relative abundance for potato cultivation but the lowest relative abundance for soybean cultivation.

• Journal of Environmental Science International
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• v.30 no.2
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• pp.145-152
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• 2021

Soil conservation management is necessary for sustainable agriculture, in highland areas, and cover crops are one of the best soil conservation methods for slopes. In this study, we evaluated the effects of alfalfa cultivation on maize production, as well as soil conservation and quality. There was an outstanding soil conservation effect with alfalfa cultivation in the fallow and maize growing seasons. In particular, alfalfa cultivation reduced soil loss by up to 98% compared with bare field. It also increased the activities of soil microorganisms and the supply of organic matter. Maize production with alfalfa cultivation showed no significant differences in yield. In conclusion, alfalfa is an advantageous perennial cover crop in highland agricultural slope areas, which can have positive effects on soil quality and conservation, as well as maize production.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.6
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• pp.634-643
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• 2017

No-tillage is an effective practice to save labor input and reduce methane emission from the paddy. Effects of tillage and cultivation methods on carbon accumulation and soil properties were investigated in the treatments of tillage-transplanting (T-T), tillage-wet hill seeding (T-WS), minimum tillage-dry seeding (MT-S) and no-tillage dry seeding (NT-S) of rice. Soil carbon was higher in NT-S and MT-S, compared to T-T and T-WS. In NT-S and MT-S, soil carbon contents were the highest in the top soil (5 cm depth) and decreased with soil depth. In T-T and T-WS, however soil carbon contents showed no significant difference up to soil depth of 15 cm from the top. Carbon content was the highest in the soil particle size under $106{\mu}m$ and decreased as the soil particle size increased. Contents of water-stable aggregates in NT-S and MT-S were higher than those of T-T and T-WS. In NT-S and MT-S, contents of water-stable aggregates were the highest in the top soil and significantly decreased with soil depth while no significant difference up to the soil depth of 15 cm in T-T and T-WS. Available $SiO_2$ contents in the top soil were the highest in NT-S and MT-S while the lowest in T-T and T-WS. It is concluded that minimum or no disturbance of soil in rice cultivation can increase carbon accumulation in the soil, especially in the top layer, and subsequently contribute to the formation of the water-stable soil aggregates.

• Korean Journal of Soil Science and Fertilizer
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• v.21 no.1
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• pp.49-54
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• 1988

The present experiment was conducted to investigate causes affecting the reduction of red pepper production in the continuous cultivation upland soil from 1985 to 1986 in Imsil Chonbuk Province. The results obstained are summarized as follows: 1. Area ratio of continuous cultivation 2 years was 12.7%, 3 years 6.8% and over 4 years 48.9%. 2. Soil hardness and volume of solid and liguid of red pepper continuous cultivation soil were higher than those of one year cultivation, while pH and content of organic matter of continuous cultivation soil were low. The exceeding optimum level of phosphorus and potassium appeared factors affecting and reduction of red pepper of continuous cultivation soil. 3. Microflora density in continuous cultivation soil was high but bacteria/fungi (B/F) and actinomycetes/fungi (A/F) ratio were low. 4. The density of soil nematodes in continuous cultivation soil were higher than that in one year cultivation soil, however, the steeper and better drainage soil lowered the density of nematodes. 5. Continuous cultivation over 4 years showed 14.3% of plants diseased by phytophthora while 0.7% in one year cultivation soil.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.5
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• pp.279-284
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• 2008

This study was performed to investigate effect of different soil managements on physical properties and microbial activities in volcanic ash citrus orchard soil. Experiment plots had managed to control weeds on soil for 4 years with clean cultivation (CCM) used with herbicide, natural sod cultivation (NSCM), kentucky blue grass sod cultivation (KBG). Soil samples were taken on October, in both 1998 and 2000 from 3 experimental plots. In NSCM, Soil hardness was lower at 11.8 mm than in CCM. And water stable Aggregation coefficient(>0.5 mm) was high at 26.7% compared with CCM. Soil bulk density and porosity showed no significant among the treatments. Soil acid phosphatase was high in sod cultivation plots and the amount of microbial biomass C was about twice higher at $525.4mg\;kg^{-1}$ in KBG than in CCM. Conclusionally, Sod cultivation improved soil physical properties such as aggregation, hardness and increased microbial activities compared with clean cultivation in citrus orchard soil. Soil total PLFA, acid phosphatase, and microbial biomass C contents were investigated on May in nonvolcanic ash citrus soil. Soil samples were collected at 5 sites each; convention cultivation grown with herbicide, natural sod cultivation grown with 1/2 chemicals, organic cultivation. That sites have been managed for 5 years over. PLFA contents were two times higher at $112.2n\;mol\;g^{-1}$ in organic cultivation than in convention cultivation. According to the PLFA indicator, Gram negative bacteria and actinomycetes in organic cultivation were high compared with convention cultivation, which were at 15.1%, 6.6%, respectively. Soil microbial biomass C contents was about twice higher in organic cultivation than in convention cultivation. Soil acid phosphatase was high at 17.6% in organic cultivation compared with convention cultivation.

• Journal of The Korean Society of Agricultural Engineers
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• v.56 no.2
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• pp.37-46
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• 2014

Water for crop growth were supplied by irrigation in protected cultivation and these are accumulated in the soil and utilized for crop evapotranspiration. The study for analyzing soil moisture characteristics is necessary for adequate irrigation water and soil water management in protected cultivation. Soil moisture content, irrigation water quantity and meteorological data were monitored to analyze soil moisture increment and extraction characteristics in terms of soil layers and cucumber crop growth stages. In first cropping period, the total amount of irrigation water was 5.07 mm/day, soil moisture increment was 4.82 mm/day and soil moisture extraction was 5.56 mm/day. In second cropping period, the total amount of irrigation water was 4.82 mm/day, soil moisture increment was 4.65 mm/day and soil moisture extraction was 4.73 mm/day. Soil moisture extraction rate from 0 to 75 cm is 90.3 % in first cropping period and 79.1 % in second cropping period. The majority irrigation water were consumed in root zone, however, about 15 % of soil moisture were losses by infiltration in lower soil layer. Soil moisture extraction and extraction pattern of cucumber crop calculated in this study can be utilized as a basic data for irrigation water management in protected cultivation.