Long-term monitoring of soil chemical properties is the main agricultural practices to improve crop yield and soil fertility. Field monitoring was performed to evaluate the chemical properties of 200 greenhouse soil samples every 4 years from 2000 to 2016 in Gyeongnam province, South Korea. Soil properties such as pH, electrical conductivity (EC), amount of organic matter (OM), available phosphate (P 2 O 5 ), nitrate nitrogen (NO 3 -N), exchangeable potassium (K), calcium (Ca), magnesium (Mg), and sodium (Na) were analyzed. In 2016, the average concentration of soils under greenhouse condition showed 6.8 for pH, 3.52 dS m -1 for EC, 40 g kg -1 for OM, 1,065 mg kg -1 for P 2 O 5 , 154 mg kg -1 for NO 3 -N, 2.35 cmol c kg -1 for K, 12.8 cmol c kg -1 for Ca, 4.0 cmol c kg -1 for Mg, and 0.91 cmol c kg -1 for Na. In addition, the average concentrations of OM, K, Ca, and Na have tended to increase with year. In 2016, the frequency distribution of excessive level of soils under greenhouse condition was 43% for pH, 61% for OM, 94% for P 2 O 5 , 89% for K, 96% for Ca, and 83% for Mg. Soil EC values of green pepper, tomato, and lettuce were significantly higher than those of carrot, strawberry, and squash (p < 0.05), whereas soil pH was significantly lower in the carrot and lettuce than that in the strawberry (p < 0.05). Soil pH was significantly correlated with the EC, NO 3 -N, K, Ca, Mg, and Na. The value of EC was also positively correlated with the OM, P 2 O 5 , NO 3 -N, K, Ca, Mg, and Na. In conclusion, the long-term information on soil chemical properties will be helpful to improve sustainable soil and nutrient management for greenhouse farming.

This study evaluated the effects of biochar from the pyrolysis pine on the soil microbial communities by fatty acid methyl ester (FAME) in upland field. The nutrient management for lettuce cultivation at silt loam soil was treated with four rates of biochar 0 (CFB1), 60 (CFB2), 120 (CFB3), and 240 kg 10a -1 (CFB4) with chemical fertilizer (14.3 kg 10a -1 N, 15.7 kg 10a -1 P 2 O 5 , and 12.1 kg 10a -1 K 2 O), no fertilizer (NF), and pig manure compost 2 ton 10a -1 with chemical fertilizer (CFC). Compared to the NF, the soil microbial biomass (total FAMEs), Gram-negative bacteria biomass, arbuscular mycorrhizal fungi (AMF) biomass, and total glomalin concentration were significantly increased after biochar amendments treatment, while the microbial biomasses were not significant between CFB1 and biochar treatments. CFB3 and CFB4 had a significantly lower ratio of cy19:0 to 18:1ω7c when compared with that of CFC (P < 0.05), which indicates that a decrease in microbial stress was caused by organic matter soil inputs without competition from other microbes. Community of actinomycetes in CFC soil was significantly larger than those in biochar treatment soils (P < 0.05) indicating actinomycetes are potentially responsible for the microbial community differentiation between CFC and biochar treatments in upland field.

Fusarium wilt (Fusarium oxysporum) is responsible for damage or negative effect on sweet potato (Ipomoea batatas L.) cultivation. This study evaluated the effect of curing treatment on the growth of sweet potato and soil microbial communities using fatty acid methyl ester method. We utilized three treatment groups, control, curing treatment of cutting for a day (C1), and curing treatment of cutting for 5 days (C5). Soil chemical properties showed no significant effect for the treatments. The marketable root number per plant and yield of sweet potato in C5 treatment were significantly higher than those in control and C1 (p < 0.05), whereas the Fusarium wilt in C5 treatment showed significantly lower than that of the control and C1 (p < 0.05). In addition, Fusarium wilt showed significantly increase as increasing soil fungi biomass, while the yield of sweet potato significantly decreased as increasing Fusarium wilt (p < 0.05). The soil of C1 and C5 had a significantly lower biomass and community of fungi when compared with that of control (p < 0.05). These results indicate that curing treatment of cutting was more effect on the prevention of Fusarium wilt as well as the productivity of sweet potato.

Biochar is an amendment that can be used for reducing odors, enhancing crop productivity and soil fertility to revitalize the urban agriculture. The objective of this study was to evaluate the effects of biochar from the pyrolysis pine on the soil chemical properties, nutrient uptake, and growth of lettuce plants (Lactuca sativa L.) in an upland field. Lettuce was planted in an silt loam soil amended with four rates of biochar 0 (CFB1), 60 (CFB2), 120 (CFB3), and 240 kg 10a-1 (CFB4) with chemical fertilizer (14.3 kg 10a -1 N, 15.7 kg 10a -1 P2O5, and 12.1 kg 10a -1 K2O), no fertilizer (NF), and animal compost 440 kg 10a -1 with chemical fertilizer (CFC).Leaf number and fresh weight of lettuce plant were higher in CFB4 treatment than in the other treatments.Increasing rates of biochar caused a significant increase in lettuce yield, amount of nutrient uptake, and soil pH. The economically optimum application rate of fertilizer biochar was 200 kg 10a -1 on the basis of the regression curve. The electrical conductivity of the CFB1 soil was significantly higher than in the other treatments, whereas the soil pH was significantly lower in the CFB1 soil than those in the biochar treatments and NF soils. These results showed that biochar amendment increased yield of crops as well as improving soil properties.

Foliar fertilization is a effective application method used in these uplands as it provides good nutrition and increases crop yields. To determine the effect of foliar fertilization with monopotassium phosphate (MKP) on growth and yield of sweet potato, we analyzed plant growth, microbial communities by fatty acid methyl ester and chemical properties in soils from MKP 0 (control), 1, 2, 3, 4, and 5% treatments. Soil pH significantly increased by increasing concentration of foliar fertilization with MKP. Compared with control, the soils of MKP 3% and 4% treatments had a significantly higher community of actinomycetes while the applications of KMP 4% and 5% was significantly decreased soil fungi communities. In addition, the MKP 4% had a significantly lower ratio of cy17:0 to 16:1w7c compared with other treatments, indicating that microbial stress decreased. The highest increase in productivity of sweet potato is reached with foliar fertilization of MKP 3% treatment and optimum concentration of MKP based on regression yield curve was 2.6%. These results indicate that foliar fertilization with MKP was more effect on the productivity of sweet potato.