• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.90-90
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• 2022

Nicaragua is located in Central America, climatic conditions are considered tropical dry forest. Statistics reflex that in Nicaragua exits 24,000 rice farmers. National rice production only covers 73% of the national consumption. It exists two sowing system: irrigation and rainfed. Varieties used in both systems are mid-late maturity (120-135 days), there are 14 released varieties for irrigation, eight for rainfed, and eight landraces used in rainfed. The current breeding system (introduction of lines from Colombia) has increased the national production, however, has some limitation due to the lack of enough variability, reducing the proability of finding good genotypes and therefore the possibility of satisfying 100% of the demand. The purpose of this study was to analyze the problems that must be resolved in the short and long term to improve rice productivity in Nicaragua. In this paper we explain some proposal for an improvement plan. The selection of varieties with high adaptability to various cultivation environmental conditions it is necessary, also to thoroughly manage seed purity to supply certified seeds. In rice cultivation technology, it needs to improve seedling standing and weeding effect by improving soil leveling and water-saving cultivation technology. Also, proper fertilization and planting density must be established in irrigated and rain-fed areas. Furthermore, capacity must be strengthened by collecting and training with the most recent agricultural technology information, as well as by revitalizing the union rather than the individual farmer. It is necessary to develop varieties highly adaptable to the Nicaraguan cultivation environment, as well as to expand irrigation facilities and cultivation technology suitable for weather conditions in rain-fed areas. Last, it is necessary to maintain the consistency of agricultural policy for continuous and stable rice production in response to climate change events such as drought or intermittent heavy rain.

• Journal of Ecology and Environment
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• v.43 no.2
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• pp.129-160
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• 2019

Background: Characterizing and describing soils and land use and make a suggestion for sustainable utilization of land resources in the Ethiopian Rift valley flat plain areas of Lake Chamo Sub-Basin (CSB) are essential. Objectives: To (1) characterize soils of experimental area according to World Reference Base Legend and assess the nature and extent of salinity problems; (2) characterize land use systems and their role in soil properties; and (3) identify best land use practices used for both environmental management and improve agricultural productivity. Methods: Twelve randomly collected soil samples were prepared from the above land uses into 120 composites and analyzed. Results: Organic carbon (OC) and total nitrogen (TN) were varied along different land uses and depleted from the surface soils. The soil units include Chernozems (41.67%), Kastanozems (25%), Solonchaks (16.67%), and Cambisols (16.67%). The identified land uses are annual crops (AA), perennial crops (PA), and natural forest (NF). Generally, organic carbon, total nitrogen, percentage base saturation (PBS), exchangeable (potassium, calcium, and magnesium), available phosphorus (P₂O₅), manganese, copper, and iron contents were decreased in cultivated soils. Soil salinity problem was observed in annuals. Annuals have less nutrient content compared to perennials in irrigated agriculture while it is greater in annuals under rainfed. Clay, total nitrogen, available phosphorus, and available potassium (K₂O) contents were correlated positively and highly significantly with organic carbon and electrical conductivity. Conclusion: Management practices that improve soil quality should be integrated with leguminous crops when the land is used for annual crops production.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.1
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• pp.1-18
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• 2013

The elements that determine the success of development projects on goats and the prerequisites for ensuring this are discussed in the context of the bewildering diversity of goat genetic resources, production systems, multifunctionality, and opportunities for responding to constraints for productivity enhancement. Key determinants for the success of pro-poor projects are the imperatives of realistic project design, resolution of priorities and positive impacts to increase investments and spur agricultural growth, and appropriate policy. Throughout the developing world, there exist 97% of the total world population of 921 million goats across all agroecological zones (AEZs), including 570 breeds and 64% share of the breeds. They occupy a very important biological and socioeconomic niche in farming systems making significant multifunctional contributions especially to food, nutrition and financial security, stability of farm households, and survival of the poor in the rural areas. Definitions are given of successful and failed projects. The analyses highlighted in successful projects the value of strong participatory efforts with farmers and climate change. Climate change effects on goats are inevitable and are mediated through heat stress, type of AEZ, water availability, quantity and quality of the available feed resources and type of production system. Within the prevailing production systems, improved integrated tree crops - ruminant systems are underestimated and are an important pathway to enhance C sequestration. Key development strategies and opportunities for research and development (R and D) are enormous, and include inter alia defining a policy framework, resolution of priority constraints using systems perspectives and community-based participatory activities, application of yield-enhancing technologies, intensification, scaling up, and impacts. The priority for development concerns the rainfed areas with large concentrations of ruminants in which goats, with a capacity to cope with heat tolerance, can be the entry point for development. Networks and networking are very important for the diffusion of information and can add value to R and D. Well formulated projects with clear priority setting and participatory R and D ensure success and the realisation of food security, improved livelihoods and self-reliance in the future.

• Korean Journal of Soil Science and Fertilizer
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• v.51 no.2
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• pp.79-89
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• 2018

Subsurface drip irrigation (SDI) system is considered one of the most effective methods for water application. A 2-year field study was conducted to investigate the effect of SDI systems with various dripline spacing (0.7 or 1.4 m) and position (under furrow or ridge) on soybean (Glycine max L.) production at a sandy-loam soil in Miryang, South Korea. For 2016-2017, average grain yield in SDI irrigated plots, $3.16Mg\;ha^{-1}$, was statistically greater than rainfed irrigated plot ($2.63Mg\;ha^{-1}$). Soybean grain yield averaged $3.25Mg\;ha^{-1}$ for the 0.7 m dripline spacing and $3.07Mg\;ha^{-1}$ for the 1.4 m spacing for the two-year period compared to a rainfed irrigated average of $2.63Mg\;ha^{-1}$ for the same period. Soybean treated with SDI system had significantly greater values of normalized difference vegetation index and stomatal conductance, indicating that soybean plants in SDI plots had greater photosynthetic and stomatal activity due to the higher water availability in soil. Irrigation water use efficiency (IWUE) was greatest in the plot of 0.7 m spacing installed under ridge position than any other plot across growing season. Average soil water content in plots with 0.7 m dripline spacing was $0.21m^3\;m^{-3}$ at 5 cm depth layer, which was 45% greater compared to the plots with 1.4 m spacing, even though the gross irrigation amounts were greater in 1.4 m spacing plots. It is concluded that wide dripline spacing (1.4 m) is probably the more economical installation design for SDI system compared to 0.7 m spacing in this study soil because the initial cost for dripline may be reduced with wide spacing design, even though the IWUE is greater in the plot of 0.7 m dripline spacing.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.817-819
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• 2003

Land degradation is a crucial issue in mountainous areas and is manifested in a variety of processes. For its assessment, application of existing models is not straightforward. In addition, data availability might be a problem. In this paper, a procedure for land degradation assessment is described, which follows a four-step approach: (1) detection, inventory and mapping of land degradation features, (2) assessing the magnitude of soil loss, (3) study of causal factors, and (4) hazard assessment by applying decision trees. This approach is applied to a case study in the Middle Mountain region of Nepal. The study shows that individual mass movement features such as debris slides and slumps can be easily mapped by photo interpretation techniques. Application of soil loss estimation models helps get insight on the magnitude of soil losses. In the study area soil losses are higher in rainfed crops on sloping terraces (highest soil loss is 32 tons/ha/yr) and minimal under dense forest and in irrigated rice fields (less than 1 ton/ha/yr). However there is high frequency of slope failures in the form of slumps in the rice fields. Debris slides are more common on south-facing slopes under rainfed agriculture or in degraded forest. Field evidences and analysis of causal factors for land degradation helps in building decision trees, the use of which for modelling land degradation has the advantage that attributes can be ranked and tested according to their importance. In addition, decision trees are simple to construct, easy to implement and very flexible in adaptations.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.272-272
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• 2022

Water and phosphorus (P) fertilizer are two of the most critical inputs in rice cultivation. Under climate change scenarios and urbanization, irrigation and fertilizer are becoming limiting factors often leading to significant decrease in yield whenever supplied scarcely. It has been shown that the Pup1 QTL confers tolerance to P starvation and improved early-stage root vigor in indica rice grown in the tropics. However, whether the QTL works in japonica rice genetic background grown in temperate regions remains to be elucidated. Here, we have introgressed the Pup1 QTL into three temperate rice varieties MS11, TR22183, and Dasan using marker-assisted backcrossing and next generation sequencing. The selected lines all harbored the full Pup1 QTL with recurrent parent genome recovery rates ranging from 66.5% to 99.8%. Evaluation of the introgression rice lines grown in South Korea under low inputs of P and water revealed early vegetative growth advantage relative to that of the recurrent parents. Under rainfed condition, Pup1 introgression lines had yield advantage ranging from 7.2 to 19.9% and 24 to 26% in P non-supplied soil and P-supplied soil, respectively compared to that of the recurrent parents suggesting that Pup1 confers enhanced yield under low P and water inputs in temperate rice genetic background grown in temperate climate. In terms of early vegetative growth, temperate Pup1 introgression lines showed a similar trend on the extent to which Pup1 promotes yield advantage in temperate rice in comparison with indica control Pup1 introgression line IR64-Pup1.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.322-322
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• 2017

To avoid drought stress under rainfed upland conditions, it is important for rice to efficiently utilize water at shallow soil layers supplied by rainfall, and access to water retained in deer soil layers. The root developmental characteristics of rice, which play important role in the adaptability to drought conditions, vary depending on the variety. Moreover, water availability for plant differs depending on the soil types that have different physical properties such as water holding capacity, permeability, capillary force, penetration resistance, etc. In this study, we evaluated growth and yield responses of rice varieties to various soil water deficit conditions under three different soil types. The experiment was conducted in a plastic greenhouse at the Kenya Agricultural and Livestock Research Organization-Mwea from October 2016 to January 2017. Two upland varieties (NERICA 1 and 4) and one lowland variety (Komboka) were grown in handmade PVC pots (15.2 cm diameter and 85.0 cm height) filled with three different types of soil collected from major rice-growing areas of the country, namely black cotton (BC), red clay (RC), and sandy clay (SC). Three watering methods, 1) supplying water only from the soil surface (W1), 2) supplying water only from the bottom of the pots (W2), and 3) supplying water both from the soil surface and the bottom of pots (W3), were imposed from 40 days after sowing to maturity. Soil water content (SWC) at 20, 40, and 60 cm depths was measured regularly. At the harvesting stage, aboveground and root samples were collected to determine total dry weight (TDW), grain yield, and root length at 0-20, 20-40, 40-60, and 60-80 cm soil layers. Irrespective of the watering methods, the greatest root development was obtained in RC, while that in BC was less than other two soils. In BC, the degree of yield reduction under W1 was less than that in RC and SC, which could be attributed to the higher water holding capacity of BC. In RC, the growth and yield reduction observed in all varieties under W1 was attributed to the severe drought stress. On the other hand, under W2, SWC at the shallow soil depth in RC was maintained because of its higher capillary force compared with BC and SC. As the result, growths and yields in RC were not suppressed under W2. In SC, deep root development was not promoted by W2 irrespective of the varieties, which resulted in significant yield losses. Under W1, the rice growth and yield in SC was decreased although shallow root development was enhanced, and the stomatal conductance was maintained higher than RC. It was suspected that W1 caused nutrients leaching in SC because of its higher permeability. Under rainfed conditions, growth and yield of rice can be strongly affected by soil types because dynamics of soil water conditions change according to soil physical properties.

• Korean Journal of Agricultural Science
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• v.47 no.3
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• pp.403-414
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• 2020

Gradient concentrations of Tithonia diversifolia green leaves and phosphate rocks were used to investigate their contributions as a fertilizer to the yield and quality improvement of a rainfed rice cultivar. Six treatments were compared: (1) T0, no fertilization (control); (2) T1, 1.28 g of phosphate rocks; (3) T2, 250 g of organic matter; (4) T3, 500 g of organic matter; (5) T4, 250 g of organic matter + 1.28 g of phosphate rocks; (6) T5, 500 g of organic matter + 1.28 g of phosphate rocks. The results showed that the germination percentage recorded 15 days after sowing varied from 58 - 76% between T0 and T5. The number of panicles ranged between 2 (T0) to 6.3 (T5). Moreover, the recorded length of the panicles ranged between 7.5 (T1) to 15.8 cm (T2), and the number of grains per panicle ranged between 25.5 (T1) to 273.5 (T3). The plant height was significantly increased in the T5 (79.27 cm) group compared to the T1 (33.63 cm) and control treatment (T0) (40.08 cm) groups. Although the plant height in the T2, T3, and T4 groups was slightly lower than the T5 group, the difference was not statistically significant. The average of the grain number per plant was high in the T3 (273.6 grains) group compared to the T1 and T0 (25.5 and 32.8 grains) groups, respectively. These results suggest that the combination of T. diversifolia leaves and phosphate rocks as a natural fertilizer would be beneficial when integrated into soil fertility management strategies and would contribute to improving crop yield and quality.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.1
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• pp.16-19
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• 2012

Increasing rice grain yield is critical for feeding rapid increasing of Asian population. However, global warming effect may be negative for sustainable rice production. Therefore it is essential to develop technologies not only for increasing grain yield but also for reducing global warming effect. Biochar, which is carbonized biomass, has a great potential of carbon sequestration and soil quality improvement, which can contribute grain yield increasing. In this study, rice yield responses to biochar application on the rice cropping system were evaluated with field experiments under different water management practices at the research farm of the University of Missouri-Columbia Delta Research Center, Portageville, MO. Biochar (i.e., $4Mg\;ha^{-1}$) was produced using field scale pyrolyzer and incorporated into the field 4 months prior to planting. Rice was grown under three different water management practices. Result showed that no significant yield difference was found in the biochar application plots compared to rice hull and control plots from the 2 years field study at the very fertile soil. However, rainfed management results in severe reduction of yield. Research concludes that the biochar application does not significantly influence on rice yield increasing especially for very fertile soils.

• International Journal of Industrial Entomology and Biomaterials
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• v.16 no.2
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• pp.49-56
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• 2008

A preliminary survey on the incidence and intensity of root disease complex (association of Meloidogyne incognita and root rot pathogens) was carried out in the sericultural areas of Karnataka. A total of 280 mulberry gardens were surveyed in 14 districts of Karnataka belonging to different types of soil (red sandy, red loamy and black cotton), farming systems (irrigated and rainfed), varieties (V-1, K-2, Local and S-13) and age of the plants (0-5, 5-10 and 10-15 years). It was observed that the association of M. incognita with Botryodiplodia theobromae and Fusarium solani causes the root disease complex in mulberry. Of the 280 gardens visited, 94 were infested with the disease complex and incidence was recorded as 33.6%. The higher intensity of root disease complex was observed when the root system had more than 100 galls/plant with infection of mixed population of B. theobromae and F. solani in sandy soil under irrigated farming. The 5-10 years old mulberry plantation with V-I variety was found to be most susceptible to root disease complex. Districts like Mysore, Kolar, Mandya, Tumkur, Chitradurga and Bangalore were observed as sensitive areas. Further, the wounds caused by M. incognita in mulberry roots favour the easy entry of root rot pathogens, which increased the severity of the disease very fast.