• Korean Journal of Agricultural and Forest Meteorology
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• v.2 no.2
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• pp.47-61
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• 2000

Agroclimatic zoning was done for paddy rice culture in North Korea based on a simulation experiment. Daily weather data for the experiment were generated by 3 steps consisting of spatial interpolation based on topoclimatological relationships, zonal summarization of grid cell values, and conversion of monthly climate data to daily weather data. Regression models for monthly climatological temperature estimation were derived from a statistical procedure using monthly averages of 51 standard weather stations in South and North Korea (1981-1994) and their spatial variables such as latitude, altitude, distance from the coast, sloping angle, and aspect-dependent field of view (openness). Selected models (0.4 to 1.6$^{\circ}C$ RMSE) were applied to the generation of monthly temperature surface over the entire North Korean territory on 1 km$\times$l km grid spacing. Monthly precipitation data were prepared by a procedure described in Yun (2000). Solar radiation data for 27 North Korean stations were reproduced by applying a relationship found in South Korea ([Solar Radiation, MJ m$^{-2}$ day$^{-1}$ ] =0.344 + 0.4756 [Extraterrestrial Solar Irradiance) + 0.0299 [Openness toward south, 0 - 255) - 1.307 [Cloud amount, 0 - 10) - 0.01 [Relative humidity, %), $r^2$=0.92, RMSE = 0.95 ). Monthly solar irradiance data of 27 points calculated from the reproduced data set were converted to 1 km$\times$1 km grid data by inverse distance weighted interpolation. The grid cell values of monthly temperature, solar radiation, and precipitation were summed up to represent corresponding county, which will serve as a land unit for the growth simulation. Finally, we randomly generated daily maximum and minimum temperature, solar irradiance and precipitation data for 30 years from the monthly climatic data for each county based on a statistical method suggested by Pickering et a1. (1994). CERES-rice, a rice growth simulation model, was tuned to accommodate agronomic characteristics of major North Korean cultivars based on observed phenological and yield data at two sites in South Korea during 1995~1998. Daily weather data were fed into the model to simulate the crop status at 183 counties in North Korea for 30 years. Results were analyzed with respect to spatial and temporal variation in yield and maturity, and used to score the suitability of the county for paddy rice culture.

• Korean journal of applied entomology
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• v.16 no.3 s.32
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• pp.163-170
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• 1977

Potato diseases, especially mosaics and leaf roll, appear to reduce potato yield in Korea more than any other factor. A seed potato certification program was established at the Alpine Experiment Station (AES) in 1961 to produce high quality seed potatoes for distribution to Korean farmers. The present program for production of certified seed of Namjak (Irish Cobbler), the only variety recommended for spring plantings, is outlined. In 1976, approximately 10,000 MT of certified grade Namjak seed was produced by members of two Seed Producers Cooperatives in the Daekwanryeong area for distribution by the Office of Seed Production and Distribution (OSPD). The seed was inspected and certified by officers of the National Agricultural Products Inspection Office (NAPIO). Although the quality of the certified seed is far superior to that used by many farmers, the supply planted less than 1/5 of the 1977 potato crop. Certified seed of Shimabara, the variety recommended for autumn plantings, is not produced in Korea. The yield response of virus infected seed to improved cultural practices is poor. Therefore, an increase in potato acreage and yields appears to be possible only if more good quality seed is used by Korean farmers. A two or three fold increase in seed supply would be desirable. The volume of seed could be increased by expanding the production area and by improving yield in seed fields. More land is available in the alpine area and good seed potatoes could be grown in other parts of Korea. Planting better quality seeds and using better cultural pracitces would improve seed yields. Several techniques could be used to improve the quality of elite seed produced at AES. Changes in seed potato certification program should be made so that healthy seed stocks of new varieties can be released rapidly.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.1
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• pp.23-31
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• 2013

Microwave remote sensing can help monitor the land surface water cycle and crop growth. This type of remote sensing has great potential over conventional remote sensing using the visible and infrared regions due to its all-weather day-and-night imaging capabilities. In this paper, a ground-based multi-frequency (L-, C-, and X-band) polarimetric scatterometer system capable of making observations every 10 min was developed. This system was used to monitor the wheat over an entire growth cycle. The polarimetric scatterometer components were installed inside an air-conditioned shelter to maintain constant temperature and humidity during the data acquisition period. Backscattering coefficients for the crop growing season were compared with biophysical measurements. Backscattering coefficients for all frequencies and polarizations increased until dat of year 137 and then decreased along with fresh weight, dry weight, plant height, and vegetation water content (VWC). The range of backscatter for X-band was lower than for L- and C-band. We examined the relationship between the backscattering coefficients of each band (frequency/polarization) and the various wheat growth parameters. The correlation between the different vegetation parameters and backscatter decreased with increasing frequency. L-band HH-polarization (L-HH) is best suited for the monitoring of fresh weight (r=0.98), dry weight (r=0.96), VWC (r=0.98), and plant height (r=0.96). The correlation coefficients were highest for L-band observations and lowest for X-band. Also, HH-polarization had the highest correlations among the polarization channels (HH, VV and HV). Based on the correlation analysis between backscattering coefficients in each band and wheat growth parameters, we developed prediction equations using the L-HH based on the observed relationships between L-HH and fresh weight, dry weight, VWC and plant height. The results of these analyses will be useful in determining the optimum microwave frequency and polarizations necessary for estimating vegetation parameters in the wheat.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.7 no.1
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• pp.1-29
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• 1969

Experiments on rice concerning it s varieties, fertilization, seedling dates and herbicides have been conducted to determine the most desirable method of direct sowing cultivation on dry paddy field land in the middle part of Korea. The results obtained at the Office of Rural Development of Choongnam Province are as follows:. 1. Sixteen different derivatives from the main varieties of low land rice were cultivated on a dry paddy field by the direct sowing method; at the same time, a few varieties were tried adopting the common transplanting cultivation method. The yield and yield factors from these two groups were examined to give the following results: a) Compared to the common transplanting cultivation, the direct sowing method showed remarkably increased number of panicles while the number of flowers per panicle was shown to be significantly decreased. The maturing ratio was detected to be lowered. The yield horn them differed according to the different varieties : good yield was obtained from Hokwang while Norin ＃25 proved poor when compared with the common transplanting cultivation method. b) Among sixteen varieties tested, Sunsou, Norin ＃25, Jaigou, Hokwang, Palkueng and Gosi showed comparatively high yields, their yield being more than 325 kilograms per 10 Are, but Nampoong, Paldal, Nongkwang, Norin ＃29, Eunbangju ＃101 and Shiro gane showed less yield, their yield being less than 271 kilograms per 10 Are, the relations between the yield and the yield factors can be summarized as follows; Number of varieties and their rice yield. 1) The varieties which were great in the, number of panicles and high in yield=Jaigoun, Hokwang Palkueng and Gosi. 2) The varieties which were low in the number of panicles and high in yield=Sounsou and Norin ＃25. 3) The varieties which were great in the number of panicles and poor in yield=Eunbangju ＃101 and Sirogane. 4) The varieties which were poor in the number of panicles and poor in yield: Nampung, Paldal and Norin ＃29. Number of flowers per panicle and yield. 1) The varieties which were great in the number of flowers per panicle and high in yield: Sounsou, Norin ＃25 and Gosi. 2) The varieties which were poor in the number of flowers per panicle and high in yield ; Jaigoun, Hokwang and Palkueng. 3) The varieties which were great in the number of flowers per panicle and poor in yield: Paldal and Nampung. 4) The varieties which were poor in the number of flowers per panicle and poor in yield: Norin ＃29. Eunbangju ＃101 and Sirogane. Maturing ratio and yield. 1) The varieties which were high in the maturing ratio and high in yield: Jaigoun, Sounsou, Norin ＃25 and Palkueng. 2) The varieties which were low in the maturing ratio and high in yield: Hokwang and Gosi. 3) The varieties which were early maturing rat io and low in yield: Hokwang and Gosi. 4) The varieties which were late maturing ratio and poor in yield: Eunbangju ＃101, Nampungand Sirogane 1, 000 grain weight and yield. 1) The varieties which were heavy in 1, 000 grains weight and high in yield=Norin ＃25 and Hokwang. 2) The varieties which were light in 1, 000 grains weight and high in yield=Sounsou and Jaigoun. 3) The varieties which were heavy in 1, 000 grains weight and poor in yield=Nongkwang and Eunbanju. 4) The varieties which were light in 1, 000 grains weight and poor in yield=Norin ＃29 and Sirogane. 2. The experiment on fertilization showed that the most desirable amount to be given per 10 Are was 10 kilograms of Nitrogen, 5 kilograms of phosphate and 6 kilograms of potassium; and when the Nitrogen given exceeded 8 kilograms, its effect was better when given in amsll consecutive (split) amounts, while the maturing ratio and the number of the flowers per panicle increased when Nitrogen was given in large amount during the later stage of growth of rice. 3. The experiment on the date and amount of seedling showed that the tested variety, Sunsou gave the best results when planted on the days between 25 April and 10 May. Eight liters per 10 Are were preferable if planted early and 12 liters per 10 Are if planted late. The reason why the later planting gave a lower yield was that the number of flowers per panicle was fewer. 4. The experiment on the irrigation for rice with direct sowing cultivation immersed in water showed that it was the most satisfactory when irrigated on 25th June, 55 days after its seedling, its plot giving the best yield. The plots 10th June and 15th July showed just as good results. However, irrigated later, than 15th July it showed lower yields. 5. Compared to the yield of the plot controlled by the common method, the yield from the plots treated with chemical herbicide such as LOROX, TOK, PCP, SWEP, Mo-338 on dry condition soil seemed poorer, but significant difference was not found statistically. On the other hand in the case where chemical herbicides such as TOK, Mo-338, Stam F-34 or ORDRAM were used after irrigation, the yield from the ORDRAM and TOK treated plots did not show significant differences compared to the common hand weed controling method, but those treated with chemicals other than the above showed a lower yield.

• Korean Journal of Agricultural Science
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• v.3 no.1
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• pp.39-51
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• 1976

As an accempt to increase thc efficiency of land use and the food production to achieve the national goal in the food self-sufficiency, nine cropping systems on the upper-land were examined in pure-stand and in mixtures of soybean, corn, potato and radish. The important conclusions of this study were summarized as follows; 1. The flowering date of soybean was two or three days earlier in pure-stand than in the mixture with corn. The maturing date two days earlier in the pure-stand than in the mixture with corn. The flowering and maturing dates were not different among various cropping systems in corn. 2. The stem length of soybean was significantly different among various cropping systems. Soybean in pure-stand was shorter in stem length than with corn. 3. The number of pods per soybean plant did not give any significant differences among various cultivation methods. 4. The length of internode and the number of nodes per soybean plant in the mixture with corn were greater than in the pure-stand. In the number of branches per plant this was reversed. 5. The average stem dry weight of soybean per 10a was not significantly different among various cultivation methods. 6. The soybean yield per 10a in the pure-stand was obviously greater than the mixture and there were significant differences among cultivation method within the mixture with corn in soybean yield. 7. The 1,000-grain weight of soybean was significantly different and those in the pure-stand was heavier than those in the mixture with corn. 8. Grain weight per soybean plant and the stem diameter in the pure-stand were significantly lesser than those in the mixture with corn. 9. In the comparisons of corn in the pure-stand and in the mixture with soybean, plant height, number of ear per 10a, mean ear weight and remember of grain per plant, 100-grain weight, ear length, ear girth and number of ear pel plant were not significantly different among various cultivation methods except for the grain yield per 10a. 10. In the economic analysis, the mixture with soybean and corn gave the greatest gross income. The combination 7 was the best which was 47.6% increase income comparing with the soybean pure-stand. 11. As it can be assumed, soybean plant was influenced greatly than corn by various cropping system. It is necessary to study more complex cropping system finding and giving more desirable multiple cropping system for the farmer.

• Journal of Animal Environmental Science
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• v.12 no.3
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• pp.141-150
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• 2006

To optimise the efficient use of nutrients in pig slurry is to cultivate friendly environmental crops. This field survey is to investigate the actual conditions of pig slurry utilization for cultivation of crops in the agricultural farm, based on the survey for 407 selected farms in 9 provinces included 78 counties in Korea. The results obtained in this survey were summarized as follow ; The motive which came to use pig slurry in the agricultural farm were production of friendly environmental crops (29.7%), economy of chemical fertilizer (25.1%), spontaneously (19.2%), inducement of neighboring farmhouse (16.0%), increase of soil fertility (9.3%), and the others (0.7%), respectively. The proportions of pig slurry application land were 56.5% for.ice paddy, 22.6% for dry field, 13.3% for orchard, 4.4% for controlled agriculture and 3.2% for other, respectively. The number of times of pig slurry utilization per year were once (48.9%), twice (31.9%), thrice (14.0%), and the others (5.2%), respectively. The controversial points of pig slurry utilization were malodor (54.1%), insufficiency of spread equipment (22.1%), inconvenience (14.5%), over application (3.4%), over cost (2.9%), heavy metal (1.7%), sanitation (1.0%) and the other (0.2%), respectively. The results indicated that pig slurry could be used as fertilizer source of friendly environmental crops, but further studies are needed to determine the application method and value of the pig slurry for crop cultivation.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.2
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• pp.177-184
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• 2012

This experiment was carried out to investigate soil properties and the requirement of livestock manure compost in a large-scale environment-friendly agricultural complex (EFAC), Gosan, Wanju-gun, Jeonbuk. Total cultivation area of major crops was 2,353 ha. This complex area included different types of environment-friendly cropping sections (402.9ha) and livestock farming including 21,077 Korean beef cattle, 1,099 dairy cow, and 32,993 hog. Amount of livestock waste carried in to Resource Center for Crop and Livestock Farming (RCCLF) was 32 Mg per day and the production of manure compost was 9,600 Mg per year. The manure contained 1.4% total nitrogen (T-N), 2.7% phosphorus as $P_2O_5$, 2.1% potassium as $K_2O$, 0.9% magnesium as MgO, 2.5% calcium as CaO. Amount of compost used in the EFAC was 6,588 Mg per year. Soil pH values in the EFAC were varied as follows: 78.1% of paddy field soil, 58.2% of upland soil, 60.3% of orchard field soil, and 62.1% of greenhouse soil were in proper range. For the content of soil organic matter, 41.7% of paddy field soil, 46.5% of upland soil, 40.5% of orchard field soil, and 81.4% of greenhouse soil were higher than proper range. The content of available phosphorus was mostly higher than proper value on the different fields except upland soil. The contents of exchangeable $K^+$, $Ca^{2+}$, and $Mg^{2+}$ were also exceeded in the orchard field and greenhouse soils. In addition, microbial population, especially aerobic bacteria, in the EFAC was higher than that in regular farming land.

• Journal of Korean Society of Forest Science
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• v.106 no.4
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• pp.487-496
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• 2017

The marketization in North Korea is spreading rapidly. This study proposes forest rehabilitation strategy for North Korea in light of their major shift toward market economy. This current trend of marketization in North Korea is now affecting the forest sector, especially the way the residents utilize small forest land. For analyzing the influence of marketization on forest management in North Korea, we reviewed the official documents issued by North Korea and related materials of North Korean marketization. The government of Kim Jong Eun has set up policies and systems regarding the spread of marketization, such as guaranteeing individuals a right to dispose certain products on their own and establishing a special economic zone to attract foreign investments. In the forestry sector, the North Korean government has been trying to fully implement its forest restoration plan by carrying out measures like re-claiming of sloping lands that had been previously used by residents. However, as marketization progresses, it is expected that there lies much difficulty in government-led massive mobilization for forest restoration due to the increase of illegal logging to meet high demand for timber, illegal firewood harvesting, collecting non-timber products for livelihoods and illegal crop cultivation to sell in the market. Therefore, South Korea's support for forest restoration should also consider the recent marketization phenomenon in North Korea. It is necessary to formulate strategic measures such as conducting joint commercialization project on agroforestry management using cooperative farming unit, helping to improve income source from small forest lands, and to activate a comprehensive mountain village special economic zone by utilizing forest business. We do hope that our proposed forest rehabilitation strategy in this paper regarding the changes in North Korea's marketization and forest policy can give a meaningful suggestion on supporting forest restoration in North Korea in an effective way.

• Korean Journal of Environmental Agriculture
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• v.19 no.3
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• pp.201-205
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• 2000

Eleven runoff $plots(3{\times}15\;m)$ were built on a sloping field of a high plateau in Kangwon Province, Korea. The plots were treated with different tillage, residue covers and fertilizers, corn and potato were cultivated, and sediment discharge was measured from the plots for 3 years. Agricultural management practices were monitored around the plots to develop adequate best management practices. The least sediment occurred from the plots with no-till and 100% residue cover $(corn,\;0.1{\sim}2.2\;t/ha/year)$ and with contour tillage and vinyl sheet cover plots $(potato,\;0.1{\sim}0.2\;t/ha/year)$. The largest sediment was measured from the plots with up-and-down till and no cover ($11{\sim}33$ and $16{\sim}31\;t/ha/year$ from corn and potato plots, respectively). The type of organic and commercial fertilizers seemed not to affect sediment discharge. Sediment discharge from contour plots were largely dependent on the collapse of ridges due to the flush of water stored in furrows. The sediment discharge from contour corn and potato plots with no residue cover was $10{\sim}27$ and $16{\sim}24\;t/ha/year$, respectively. No-till with residue cover, vinyl cover for tuber crops, construction of furrow dam, frost heave research, furrow and ridge tillage with furrow dam after tuber crop harvest, limited stalk harvest of row crops, use of winter cover crops, and other common best management practices were recommended to minimize the sediment discharge from a high plateau sloping land culture.

• Korean Journal of Soil Science and Fertilizer
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• v.11 no.1
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• pp.31-36
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• 1978

A field experiment was conducted on a recently reclaimed hillside land to investigate the effectiveness of newly formulated compound fertilizer (10-14-11) containing fused phosphate as phosphorus source. Winter barley was adopted as a crop and commercial compound fertilizer (22-22-11), triple superphosphate, and ordinary fused phosphate were compared with the new compound fertilizer. The result of present study is summarized as follows. 1. When viewed from the plant hight and dry matter yield observed at different growth stages, it was indicated that newly formulated compound fertilizer seemed to be more effective in late stage than early stage. 2. Grain yields were higher in the compound fertilizer plots compared to the triple superphosphate and fused phosphate plots. The yield was specially high in the newly formulated compound fertilizer plot. In this plot, the number of grain per panicle and the rate of maturity were higher than the other plots. 3. The amount of phosphorus uptake by plant in the newly formulated compound fertilizer was lower in early stage and higher in late stage. In this experiment, the magnesium and silica contained in fused phosphate did not influence the growth and yield of barley because the soil was relatively high in these components. 4. Because of the unprecedented severity of winter weather during the experiment, the result obtained in present study may not be generalized until some studies confirm present findings.