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Growth Stage-Based Fertigation Guideline for Greenhouse Spring Chinese Cabbage
Seul-Bi Lee,Yang-Min Kim,Ye-Jin Lee,Yo-Sung Song,Deog-Bae Lee,Jwakyung Sung 한국토양비료학회 2019 한국토양비료학회지 Vol.52 No.4
With increasing fertigation, the precise fertigation schedule by crop growth stage has been consistently required as a guideline for stable crop production. The aim of this study is to develop the fertigation guideline for spring cabbage. To achieve this goal, we firstly investigated the nutrient uptake pattern of Chinese cabbage, which grown in pots filled with sandy loam soil in a greenhouse from April to June in 2018, and determined optimal nutrient (N, P and K) supply by growth stages. Based on soil NO₃-N based recommendation, nitrogen (N) supply was divided into 4 levels (0.5N, 0.75N, 1.0N and 1.5N). Soil NO₃-N concentrations somewhat differed from growth stages, and 1.5N represented the highest level. Chinese cabbage showed linear growth patterns and there was no clearly significant difference in growth and nutrient uptake by N supply levels except for 0.5N treatment. The relative growth (expressed as a dry weight) of Chinese cabbage occupied 60% and 40% of total accumulated growth (average of 0.75 and 1.0N) at 40 and 60 days, respectively. Mineral uptake (N, P, K) of Chinese cabbage by growth stages showed a linear pattern in general. N was taken up 54% and 46% of total uptake, P uptake 56% and 44%, and K uptake 59% and 41% at 40 and 60 days, respectively. Conclusively, we carefully suggest that the fertigation guideline for Chinese cabbage could save fertilizer supply through daily nutrient demand and target yield, and thus alleviate the problems in relation to nutrient accumulation in greenhouse soils.
Seul-Bi Lee,Yang-Min Kim,Ye-Jin Lee,Yo-Sung Song,Cheol-Hyun Ryu,Deog-Bae Lee,Chan-Wook Lee,Chang-Hoon Lee,Jwakyung Sung 한국토양비료학회 2019 한국토양비료학회지 Vol.52 No.4
Given continuous needs for a public duty of agriculture and rural area, an effort to improve nutrient management in agricultural sector is strongly required. As a measure to solve these problems, Korean government (MAFRA) introduced the promotion policy called as “Agro-Environment Conservation Program (AECP)” in 2018 and has expanded 5 projet sites in 2019 from 3 in 2018. The program has a variety of agricultural activity to conserve soil, water, air, ecology and landscape. Of those, the nutrient input activity which is one of sub-activities is closely involved in not only crop productivity but also water quality and air pollution. Therefore, in order to lead a soft landing of AECP, it is essential to evaluate the conservation effects in a scientific point of view. In this respect, we focused on evaluating the effect of recommended nutrient input activities, standard fertilization and soil test fertilization, on rice productivity and nitrogen balance. The effect of nutrient management which is explained by rice yield and nitrogen balance was estimated with the combination of soil characteristics and rice varieties. Rice yield by recommended fertilization was 654 kg per 10a, 6% lower than control, but there was no statistical significance. By contrast, nitrogen balance was 4.7 kg lower, which means great improvement, in the recommended than the control. Conclusively, the recommended fertilization like soil test fertilization is expected to be useful as a measure to reduce nutrient balance, to ensure crop productivity, and finally to perform a public role of agriculture.
Analysis of Soil Total Nitrogen and Inorganic Nitrogen Content for Evaluating Nitrogen Dynamics
Seul-Bi Lee,Jwa-Kyung Sung,Ye-Jin Lee,Jung-Eun Lim,Yo-Sung Song,Deog-Bae Lee,Suk-Young Hong 한국토양비료학회 2017 한국토양비료학회지 Vol.50 No.2
Various methods for assessing soil total nitrogen (TN) and inorganic N content have been developed to manage nutrient and to understand N cycle in soil. This paper address the technical procedures in arable soil samples to conduct soil sampling, sample preparation, and measuring total N and inorganic N. Among various methods for measuring soil total nitrogen contents, Kjeldahl distillation and Indophenol blue method have widely used due to reliability and economic advances. Also, two methods can analyze more samples at the same time compared with other nitrogen measuring methods. For evaluating inorganic N content, mainly in forms of nitrate-N (NO₃<SUP>-</SUP>-N) and ammonium-N (NH₄<SUP>+</SUP>-N), extraction with a single reagent such as 2M KCl has been employed, followed by Kjeldahl distillation or indophenol blue methods.