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Serious problems in reclaimed land agriculture are high soil salinity and poor vertical drainage, so desalinization in these soils is very difficult. Also, although desalinization is accomplished in reclaimed top soils, before long, soils are resalinized according to capillary rise of salts from the subsurface soils. To resolve these problems, multi-layered soil columns with subsurface layer of macroporous medium utilizing coal bottom ash (CBA) were constructed and the effects of blocked resalinization of these soils were investigated. In this experiment soil samples were collected from Munpo series (coarse-loamy, nonacid, mixed, mesic, typic Fluvaquents). The soil texture was silt loam and the EC was 33.9 dS m -1 . As for groundwater seawater was used and groundwater level of 1 cm from the bottom was maintained. The overall rate of capillary rise was 2.38 cm hr -1 in soil 60 cm column, 0.25 cm hr -1 in topsoil (30 cm) + CBA (5 cm) + subsurface soil (10 cm) column and 0.08 cm hr -1 in topsoil (30 cm) + CBA (10 cm) + subsurface soil (10 cm) column. In multi-layered soil columns with CBA 20, 30 cm layer, wetting front due to capillary rise could not be seen in top soil layer. After 70 days capillary rise experiment water soluble Na+ accumulated in top soil of soil columns with CBA 20, 30 cm was diminished by 92.8, 96.5% respectively in comparison with Na+ accumulated in top soil of soil 60 cm column because CBA layer cut off capillary rise of salts from the subsurface soil. From these results we could conclude that the macroporous layer utilizing CBA placed at subsurface layer cut off capillary rise of solutes from subsurface soil, resulting in lowered level of salinity in top soil and this method can be more effective in newly reclaimed saline soil.

Introduction of rye living mulch in soybean production is important for labor-saving and reduction of herbicide usage for weeding by weed suppression and for soil conservation by mulching of rye. Soybean and rye were row-planted and broadcasted simultaneously at different planting times (May 15, May 25, June 5) and row widths (35 and 70 cm) in 2010, different soybean cultivars (Daepoong, Singi) and planting times (May 15 and June 1) in 2011, respectively, and investigated weed occurrence, early growth and yield of soybean. Acalypha australis, which is known to herbicide-resistant weed, could be controlled ecologically by rye living mulch. Occurrence of Acalypha australis was controlled effectively also by mixture of alachlor and linulon at no mulch in 2011. Early growth amount of soybean plant per area was increased by narrow row width (35 cm) at rye living mulch, which was helpful in the control of weeds, but grain yield of soybean with narrow row was decreased compared to conventional row width (70 cm) at the planting in early June. It is concluded that soybean planting as row width 70 cm in early June is proper at simultaneous planting with rye.

This study was conducted to examine the basis for the information to select the suitable potato varieties grown in new reclaimed land. The potatoes of five varieties were planted in the port with 4 different electrical conductivities of saturated extracts of soil taken the Saemangeum reclamation area, which was made of non-treatment salt and three concentrations of salt treatment, 1.6 dS , 3.2 dS , 4.8 dS , respectively. All of the potato varieties were uniformly emerged without missing plant in all treatment groups, even 4.8 dS treatment group. According to the salt concentration of soil, required date to the emergence of the potato comparing to non-treatment salt was delayed 3-4 days in 1.6 dS , 6-10 days in 3.2 dS , 7-13 days in 4.8 dS , respectively, and the number of its branch decreased by 14-58% comparing to non-treatment salt depending on varieties. Since the increase of the salt concentration of the soil was more serious the decrease of the number of its branch, but plant height tended to increase when branch number per plant was small, which was depending on more number of its branch than salt concentration. Fresh tuber yield of potato comparing to non-treatment salt were decrease 33.7% in 1.6 dS , 59.5% in 3.2 dS , 79.3% 7-13 days in 4.8 dS , respectively. The threshold EC starting the growth inhibition of fresh weight decreased was 1.2 dS for Chudong, 1.8 for Chubeak, 1.9 for Chugang and Chuyeong, and 2.0 for Sumi, and EC which decreased 50% of dry weight index was 2.4 dS for Chubaek, 2.45 dS for Chudong, 2.81 dS for Chugang, 3.03 dS for Chuyeong, and 3.29 dS for Sumi. The present results suggest that Sumi is considered to the suitable potato variety grown on saline soils.

This study was conducted to investigate upland crop at reclaimed sand land `Saemangeum` for early desalination purpose and to investigate the growth and yield of whole crop barley, which was acceded after summer crop of corn and rice. Seedling establishment of whole crop barley were 216 seedlings/(25%) for non-flooding, 43% for 1 month and 58% for 2, 3 month flooding. And it was 60% in rice cultivation. Soil salt concentration was 0.5% in non-flooding treatment, however flooding treatments decreased to 0.2% or less. In general soil salt concentration increased until the middle stage of growing, then became to similar level as the seeding time. Plant height, stem length and number of tiller were increased with flooding treatment. Whole crop barley yield was significantly reduced in non-flooding treatment but rapidly increased by flooding treatment. Yielding at 3 months increased by 504% compared to non-flooding, and rice cultivation was also increased by 536%. Protein and fiber content was low in 1 month flooding treatment, 3 months flooding and rice cultivation showed the similar results in terms of feed value. For desalination purpose in reclaimed land, 3 months flooding treatments of rice cultivation could result in higher yielding for upland crop, such as whole crop barley.

Field experiments were carried out to improve the cultural practice of potato by analysing its tuberization patterns. Tuberization patterns affected by different altitudes was analyzed at two potato cultivation regions, Jinbu (600 m) and Daegwallyung (800 m) using two potato cultivars, ‘Superior’ and ‘Atlantic’. To analyse tuberization patterns affected by different planting time, seed potatoes were planted at every 10 days from April 19 to May 19 in Daegwallyung. Total dry weight was greater in plant grown at the altitude of 800 m than 600 m during the entire growth period and the highest increase was observed at the early growth period, July 6, comparing to other growth period. The total dry weight was the greatest at 110∼112 days after planting (DAP) at the altitude of 800 m and 108～111 DAP at 600 m. There was no significant differences between altitudes and between cultivars. Tuber dry weight per plant at the altitude of 600 m was lower than 800 m on July 6 (58 DAP), but it increased rapidly from July 21 (73 DAP). At both altitudes, the increase of tuber dry weight per plant from July 6 to August 8 was higher than the other growth period. The time of growth period at which tuber dry weight per plant was the highest was similar at both altitudes that was 118～125 DAP at the altitude 800 m and 118～124 DAP at the altitude 600 m. Dry weight per tuber at the altitude 800m was higher than 600 m due to the number of tubers per plant. A higher increase of crop growth rate (CGR) was shown at the altitude 600 m on July 6 (58 DAP), comparing to at 800 m. The highest tuber dry weight per plant of each cultivar was shown when the planting time was April 29 for ‘Superior’ and was April 19 for ‘Atlantic’. Both the tuber dry weight of plant and the total dry weight were lower at a later planting time. Dry weight per tuber increased quickly during the period between June 30 to August 8. Tuberization period was shortened as the planting time was delayed.

Low silage corn yield due to bad soil physical properties in the paddy field converted to upland condition is the chief obstacles to expanding the area for silage maize production. The effect of subsoiling (subsoiling to depth 40 cm) on soil physical properties and silage corn yield were investigated in the first year of paddy field converted to upland condition in 2010 and 2011, respectively. Soil com-paction was loosened much particularly at depth 25∼35cm as much as 1∼1.5 MPa and soil bulk density and porosity at depth 15∼30 cm are improved by subsoiling. Maize growth was increased by subsoiling, particularly in kernel number per ear which increased ear weight. Total digestible nutrients (TDN) yield of silage maize was increased as much as 19 and 39% in 2010 and 2011, respectively showing that yield increase according to subsoiling was higher when maize growth was prohibited much by excess-moisture injury due to heavy rain in 2011. Keywords : paddy field, subsoiling, silage maize, yield, soil physical properties

Previously, transgenic soybeans were generated and reported to produce tocotrienols (α-, γ- and δ-tocotrienols), compounds not normally found in soybean. Three procedures were evaluated to optimize the extraction method for transgenic soybean seeds and germinating seeds. Significant differences were observed among the extraction methods in seeds and germinating seeds. In seeds, the highest analytical values (tocopherols, 37.11 mg 100 g −1 ; and tocotrienols, 1.54 mg 100 g −1 ) were observed by using rapid Soxhlet extraction. In germinating seeds, the content of transgenic soybean (B20 and C5) total vitamin E (tocopherols, 18.04, 20.73 mg 100 g −1 ; and tocotrienols, 0.82 and 0.84 mg 100 g −1 ) by direct extraction was approximately 16% and 9% greater than the amount obtained by saponification. In addition, 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azino- bis -(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) tests demonstrated a direct correlation between the radical-scavenging capacity and the total content of natural tocopherols and tocotrienols. Therefore, these results suggest that an optimal extraction method will provide a fast, simple, reproducible procedure for analyzing tocotrienols and tocopherols. Furthermore, this method may be used to determine novel minor functional compounds such as tocotrienols for the evaluation of biological activity.

Lysine is the first limiting essential amino acid in cereals for humans and monogastric animals, although its content is generally low. A chemically induced high-lysine barley mutant, M98, has an agronomically undesirable shrunken en-dosperm trait. In order to obtain detailed insight into the atypical traits of M98 grains, we characterized amino acid composition and protein profiles of M98 and its parent cultivar Chalssalbori. Among a total of 16 amino acids, the percentage of each of the 7 amino acids, including lysine, was 1.2∼1.8 times higher in M98, comparing to Chalssalbori. The percentage of proline and its precursor, glutamic acid, in M98 was about the half of that of the amino acids in Chalssalbori, but arginine synthesized from glutamic acid was 1.8 times higher in M98, compared that in the parent cultivar. Theses results indicated that the mutation in M98 grains might alter the proportion of amino acids linked to each other in a biosynthetic pathway. A comparison of grain proteome profiles between Chalssalbori and M98 revealed 70 differentially expressed protein spots, where 45 protein spots were up-regulated and 25 protein spots down-regulated in M98 compared to those in Chalssalbori. Of these changed protein spots, 53 were iden-tified using nano-electrospray ionization liquid chromatography mass spectrometry. Most of these identified proteins were in-volved in various biological processes. In particular, 28 protein spots such as β-amylase, serpins and B3-hordein were identified as proteins associated with the atypical traits of M98. It was thought that a genetic study on the unique protein profile of M98 would be needed to develop an agronomically feasible barley cultivar with high-lysine trait.

This research was carried out to choose the suitable seedling type to transplanting in order to stabilize rice yield. The brief of this research to transplant the seedling divided into 10-day seedling, 20-day seedling, 30-day seedling, 33-day pot seedling in the field of Saemangeum Gyehwa, newly re-claimed land were following; Average salt content in 2 years was reduced from 0.16% to 0.04% after transplanting. Heading date of seedling type was Aug. 14 at 33-day pot seedling compared to 2 days at 30-day seedling, 3 days at 20-day seedling, 5 days late at 10-day seedling. Lodging index was highest at 30-day seedling, and also, field lodging was 50%. Ripening ratio and 1,000 grain weight were similar and panicle number was higher 20-day seedling > 10-day seedling > 33-day pot seedling > 30- day seedling. Rice yield was higher 10-day seedling = 20-day seedling > 33-day pot seedling > 30-day seedling. Head rice ratio was higher in 20-day seedling > 30-day seedling = 10-day seedling > 33-day pot seedling. Amylose content and protein content was not significantly different between seedling types. With this results, the suitable seedling types in newly reclaimed land are 10-day and 20-day seedling.

This study was conducted to find out the optimum cropping system for the stable production of forage crops in the newly reclaimed land located at Gwanghwal and Gyehwa region of Saemangum reclaimed tide land from October, 2009 to October, 2011. Whole crop barley (WCB), Rye, Italyan-ryegrass (IRG) as winter crops and Corn, Sorghumsudangrass hybrid (SSH) as summer crops were cultivated. Soil chemical properties, nutrient uptake, feed value, growth and yield were examinated. The testing soil was showed saline alkali soil where the contents of organic matter, available phosphate and exchangeable calcium were very low, while exchangeable sodium and magnesium were higher. Changes of soil salinity during the growing season of forage crops were less than 0.2%, and the growth of forage crops was not affected by salt injury. Standing rates of winter crops were higher in the order of Rye, WCB, and IRG, while the dry matter yield of winter crops was higher in the order of IRG, Rye and WCB. The highest crude protein (CP) content was recorded in IRG, and total digestive nutrients (TDN) contents were increased in the order of WCB, IRG, and Rye. The TDN content was higher in corn, whereas other feed value was higher in SSH. The content of mineral nutrients on stem, leaf and grain in IRG, Corn were high. After experiment pH was lowed, contents of exchangeable magnesium, sodium and organic matter were decreased while contents of total nitrogen, available phosphate and exchangeable potassium, calcium were increased. Winer crops and summer crops after continually cultivating in cropping system, fresh matter yield increased, compared to WCB-Corn (74,740 kg ), IRG-SSH 10%, IRG-Corn 7%, Rye-SSH 6%, Rye-Corn and WCB-SSH 3%. Dry matter yield increased, compared to WCB-Corn (20,280 kg ), IRG-SSH 7%, Rye-SSH 6%, IRG-Corn/Rye-Corn/WCB-SSH 3%. The TDN yield increased, compared to WCB-Corn (13,830 kg ), IRG-SSH 2%, WCB-SSH and IRG-Corn 1%. Therefore, we suggest that the crop combination of IRG-SSH and WCB-SSH would be preferred for silage stable production.

Disease is the major problem in ginseng cultivation from seed stratification, soil preparation prior to planting, right through to drying of the roots. There are many soil-borne disease pathogen in rhizosphere soil environment, furthermore occurrence of diseases by a diverse group of fungi and related organisms are closely related to various soil condition. Observable symptoms for soil-borne diseases include wilting, leaf death and leaf fall, death of branches and limbs and in severe cases death of the whole plant. The fungus Cylindrocarpon destructans is the cause of root rot characterized by a decay of the true root system in many ginseng production areas in Korea. Some pathogens are generally confined to the juvenile roots whilst others are capable of attacking older parts of the root system. However, the relation between the soil environmental characteristics and ginseng root rot by soil-borne disease pathogen is not clearly identified in ginseng field. In this paper, we reviewed soil-borne plant pathogen causing root rot disease of ginseng with respect to soil environment.

This research was carried out to establish perfect-drainage time in order to stabilize rice yield and improve rice quality. Treatments of perfect-drainage were conducted 5 days interval during 25 days to 50 days after heading date in the field of Saemangeum Gyehwa, newly reclaimed land. Accumulated temperature after heading date in 2010 increased about and precipitation amount decreased a little compared to normal year harvesting time. Average panicle number was 16.5 and spikelet per panicle was 88. Perfect drainage time treatment after 40~50 days was 3% higher in percent ripened grain and 0.6 g heavier in 1,000 grain weight than treatment after 25~35 days. There was no difference of rice yield between perfect drainage time treatment after 25 days and 30~35 days, but rice yield was 7~8% higher in treatment after 40~50 days than 25 days. Head rice ratio in treatment after 35 days was the highest and the sooner perfect drainage time, the lower protein content. Soil moisture negatively correlated with soil hardness and EC in this result. With this results, we proposed that the time of perfect drainage in newly reclaimed land to stable rice production is 40~50 days after heading date.

Environment-friendly agriculture (EFA) are aimed to reduce use of chemical inputs as possible the recycling of resources and the environment while preserving the local resources in the long term to ensure a constant productivity and profitability for producing safe food. This study was conducted to investigate characteristics on soil environment at paddy field of environment-friendly agriculture regions (EFARs) in Honam area. Survey point of EFARs Chungnam, Jeonbuk and Jeonnam, rice bran farming method in two districts, rice bran + snail farming method in eight districts, snail farming method in five districts and ducks farming method in three districts a total of 18 districts were selected. Annual of farming method, friendly-environment certification, amount of applied fertilizer, and history of cultivation to the farm household were surveyed. The content of available phosphate and silicate among the soil chemical properties in EFA paddy field were a little lower than optimum level, and those of agricultural methods fertilized with rice bran were a little lower than those of others. Hardness among the soil physical properties in EFA paddy field were a little lower than conventional practices, and that of agricultural methods fertilized with rice bran were a little lower than those of others. We showed fertilizer recommendation dose about soil nutritional shortages according to fertilization prescriptions index by crops.

Transport of heavy metals such as Cd is affected by several rate-limiting processes including adsorption and desorption by exchange reactions in soils. In this study, column transport and batch kinetic experiments were performed to assess Cd mobility in a double-layered soil with a reclaimed saline and sodic soil (SSS) as top soil and macroporous granule (MPG) as a bottom layer. For individual soil layer having different physical and chemical properties, Cd was considered to be nonlinear reactivity with the soil matrix in layered soils. The dispersive equation for reactive solutes was solved with three types of boundary conditions for the interface between soil layers. The adsorption of Cd with respect to the saline-sodic sandy loam and the MPG indicated that the nature of the sites or the mechanisms involved in the sorption process of Cd was different and the amounts of Cd for both of samples increases with increasing amounts of equilibrium concentration whereas the amount of Cd adsorbed in saline-sodic sandy loam soil was higher than that in MPG. The results of breakthrough curve indicating relative Cd retardation accompanied by layer material and sequence during leaching showed that the number of pore volumes to reach the maximum relative concentration of 1 increased in the order of MPG, SSS, and double layer of SSS-MPG. Breakthrough curves (BTCs) from column experiments were well predicted with our double-layered model where independently derived solute physical and retention parameters were implemented.

Daily predation of female/male O. sauteri during nymphal development were 4.2/3.9, 11.4/9.5, 14.3/10.8, and 14.7/12.5 at 17,22,27, and , respectively, and consumed 14.3/10.8 thrips, 7.5/7.2 aphids, 45.9/38.8 mites at , respectively. Adult females ate 42.8 thrips daily during preoviposition period and 63.2 thrips during oviposition period at . Predation by O. sauteri on F. occidentalis increased as the density of F. occidentalis increased. However, the rate of increase gradually lessened, resembling a Holling`s type II functional response. The attack rate of adult female is higher than that of the 5th nymph. Adult female and 5th nymph of O. sauteri appeared to prefer 2nd larva of F. occidentalis.

The experiments were carried out to develop ecological weed control system in wheat field of rice-wheat cropping system. The results were, depression effect on water foxtail by wheat seeding method decreased the seeding after doing soil rotary by 85% compared with the no practices. The occurrence of Water foxtail was 40 piece on October 16, 29 piece on October 26, and 4 piece when surveying based on the standard of seeding the wheat at 15kg which decreased as the seeding time got later. According to the wheat seeding quantity 29 piece occurred at 150kg , and 8-11 piece decreasingly at more than 200 kg of wheat seedlings based on seeding on October 26. As a result of summarizing the above results, crushing the soil by use of rotary before seeding wheat against the end of October, and seeding by increasing the seedling quantity (200 kg ) it is judged that the competition damage by weeds including water foxtail can be reduced without any use of herbicide.

Direct Polymerase Chain Reaction (PCR) method that combines biological and enzymatic amplification of PCR targets was developed for the detection of Xanthomonas axonopodis pv. glycines on soybeen seeds without DNA isolation. Primers Xag F1 and Xag R1 were designed to specifically amplify a 401 bp fragment of the glycinecin A gene of X axonopodis pv. glycines. Xag F1 and Xag R1 were used to carry out the PCR analysis with genomic DNA from 45 different bacterial strains including phylogenetically related bacteria with X axonopodis pv. glycines, and other bacterial strains of different genus and species. The PCR assay using this set of primers were able to detect X axonopodis pv. glycines with DNA concentration as low as 200 fg and cfu/ml. The Xag was detected from the seed samples incubated for 2 hrs with shaking and the intensity of the band was increase with the incubation time of seeds. The Direct PCR assay method without DNA isolation makes detection of X. axonopodis pv. glycines on soybean seeds easier and more sensitive than other conventional methods. The developed seed assay using direct PCR method will be useful for the specific detection of X. axonopodis pv. glycines in soybean seed samples.

We denote by (A) the set of all real matrices with the same sign pattern as a real matrix A. A matrix A is an SN-matrix provided there exists a set S of sign pattern such that the set of sign patterns of vectors in the -space of is S, for each . Some properties of SN-matrices arc investigated.

A real matrix A is called sign-central if A ∼ x = 0 has a nonzero nonnegative solution x for every matrix A ∼ with the same sign pattern as A . A sign-central matrix A is called tight sign-central if the Hadamard(entrywise) product of any two columns of A contains a negative component. Hwang et al. [S.G. Hwang, I.P. Kim, S.J. Kim, X.D. Zhang, Tight sign-central matrices, Linear Algebra Appl. 371 (2003) 225–240] proved that, for a positive integer m , there exists an m × n (0, 1, −1) tight sign-central matrix A with no zero rows if and only if m + 1 ⩽ n ⩽ 2 m . They also determined the lower bound of the number of columns of a tight sign-central matrix with no zero rows in terms of the number of rows and the number of zero entries of the matrix along with the characterization of the equality case. For an m × n matrix A , the sparsity of A is the ratio σ ( A )/ mn where σ ( A ) denotes the number of zero entries of A . In this paper, we determine the maximum number and the minimum number of zero entries of an m × n tight sign-central matrix with no zero rows for each pair ( m , n ) of positive integers with m + 1 ⩽ n ⩽ 2 m . We also determine the maximum sparsity of tight sign-central matrices with m nonzero rows in terms of m for each positive integer m .

A real matrix A is called sign-central if the convex hull of the columns of A contains the zero vector 0 for every matrix A with the same sign pattern as A. A sign-central matrix A is called a minimal sign-central matrix if the deletion of any of the columns of A breaks the sign-centrality of A. A sign-central matrix A is called tight sign-central if the Hadamard (entrywise) product of any two columns of A contains a negative component. In this paper, we show that every tight sign-central matrix is minimal sign-central and characterize the tight sign-central matrices. We also determine the lower bound of the number of columns of a tight sign-central matrix in terms of the number of rows and the number of zero entries of the matrix.

We denote by Q (A) the set of all matrices with the same sign pattern as A. A matrix A has signed null-space provided there exists a set S of sign patterns such that the set of sign patterns of vectors in the null-space of A is S , for each A ∈ Q (A) . We show that if A is an m by n matrix with no duplicate columns up to multiplication by −1 and A has signed null-space, then n⩽3m−2. We also classify the set of matrices satisfying the equality.

We denote by ${\cal Q}(A)$ the set of all matrices with the same sign pattern as A. A matrix A has signed null-space provided there exists a set ${\cal S}$ of sign patterns such that the set of sign patterns of vectors in the null-space of $\widetilde{A}$ is ${\cal S}$ for each $\widetilde{A} \in {\cal Q}(A)$. Some properties of matrices with signed null-spaces are investigated.

Qualitative properties shared by the solutions to the family of linear equations of the form $$Ax=b, \quad (A\in C, b \in B),\eqno(1)$$ where C is a cone in ${\shadR}^{m\times n}$ and B is a cone in ${\shadR}^m$ are studied. In particular, the cones C and B for which the sign patterns of the solutions to (1) are independent of the choice of A e C and b e B are characterized.

This study was conducted to find out the optimum nitrogen application rate for the stable production of rape in the newly reclaimed land located at Gangwhal region of Saemangum reclaimed land in which the soil is sandy loam (Munpo series). There were five treatments of nitrogen fertilization from zero to 60% increment based on the standard fertilization of . The growth of rape (Sunmang) was not affected by salt content while soil salinity was increased at blossoming season of rape. Compared to yield of standard fertilization the yield and the content of oleic acid of rape were increased by 4~26% with the increasing additional nitrogen fertilizer. The results obtained from the growth and yield of rape in this study indicated that it was possible to cultivate rape in a newly reclaimed land if soil salinity was kept below .

The short petiole trait is valuable for the development of plant ideotype with high yield. Soybean breeding line, SS98206SP, showed extremely short petioles in greenhouse and field. In this study, the short petiole of two mutant lines, SS98206SP and D76-1609, were investigated to determine the genetic segregations. These two mutants were crossed with each other and with two normal petiole genotypes. Genetic analysis indicated that the short petioles in D76-1609 and SS98206SP were controlled by a single recessive gene, respectively. The short petiole gene in SS98206SP was non-allelic with lps, conferring short petiole in D76-1609. Two recessive genes showed complementary relationship having short petioles with recessive homozygote (LPS1-lps?lps?, lps1lps1LPS?-, lps1lps1lps?lps?). Our data indicated that the short petioles in SS98206SP were controlled by a single recessive gene designated as lps3.

A square matrix A with per A≠0 is called convertible if there exists a (1, -1) matrix H such that per A=det(H o A) where H o A denote the Hadamard product of H and A In this paper, an upper bound of permanents of maximal convertible (0,1) matrices A with π(A)≥4(n−1) is obtained.

A complex square matrix A is called convertible if there is a matrix B obtained by A from affixing ± signs to entries of A such that per A = det B. In this note it is proved that a complex matrix all of whose entrices are taken from a fixed sector of angle πn is convertible if and only if its support is.

A square real matrix Ais called convertible if there is a matrix  obtained from Aby affixing ± sings to entries of Aso that per A=detÂ. A convertible (0,1)-matrix with total support is called maximal convertible if it is fully indecomposable and no matrix obtained from Aby replacing a 0 with a 1 is convertible. In this paper, the existence of maximal convetible matrices with exactly r1's for each integer rwith 4n−4≤r≤(n 2+3 n −2)/2 is proved.

This paper concerns two notions of column rank of matrices over semirings; column rank and maximal column rank. These two notions are the same over fields but differ for matrices over certain semirings. We determine how much the maximal column rank is different from the column ran for all m×n matrices over many semirings. We also characterize the linear operators which preserve the maximal column rank of Boolean matrices.

This study investigated the runoff from rice paddy located on reclaimed fine sandy loam soil upslope from estuaries to provide data for the development of policies to protect water quality of estuaries. Reclaimed soil nutrient adsorptivity and pollutant runoff loads were monitored from 2006 to 2008. The phosphate adsoptivity of the study soil appeared to be half of those of typical paddy soils because of relatively low clay and high sand content of the reclaimed soil. Phosphate concentration of the paddy water ranged from 1 to 4 mg L-1, which are much higher than typical paddy water which varys 0.5 to 1mg L-1. The observed total nitrogen(TN) runoff loads from the paddy varied between 10 to 24 kg ha-1, which was consistent with the unit pollutant load provided by the Korean Environment Ministry. However, the total phosphorus(TP) load was about 1.5 to 3 times greater than the Ministry endorsed unit load. Thus, nutrient runoff, particularly phosphate from the reclaimed paddy field needs to be managed more thoroughly to protect estuarine water quality.

An n× nmatrix Ais called convertible if there is an n× n(1, -1)-matrix Hsuch that per A= det(H∘A) where H ∘ Adenotes the Hadamard product of Hand A. A convertible (0,l)-matrix is called extremal if replacing any zero entry with a 1 breaks the convertibility. In this paper some properties of nonnegative convertible matrices are investigated and some classes of extremal convertible (0,1)-matrices are obtained.

LetKndenote the set of alln×nnonnegative matrices with entry sumn. ForX∈Knwith row sum vector(r1,…,rn), column sum vector(c1,…,cn), Letϕ(X)=∏iri+∏jcj−perX. Dittert's conjecture asserts thatϕ(X)≤2−n!/nnfor allX∈Knwith equality iffX=[1/n]n×n. This paper investigates some properties of a certain subclass ofKnrelated to the functionϕand the Dittert's conjecture.

Linear systems, Ax=b, for which the sign patterns A and b completely determine the set of sign patterns of vectors in the solution set are studied. These systems generalize the existing notion of sign-solvable linear systems. Linear systems with signed solutions are characterized in terms of two classes of matrices. The first class, L-matrices, plays a central role in the study of sign-solvable linear systems. The second class is new and generalizes the class of S∗-matrices that arise in sign-solvable linear systems. Several constructions for the new class of matrices are given.