Open Access Original Research Article

Application of Linear Mixed Model: The Effect of Climatic Factors on the Wood Anatomy of Two Eucalypt Clones

Dawit Getnet Ayele, Temesgen T. Zewotir

International Journal of Plant & Soil Science, Page 1-12
DOI: 10.9734/IJPSS/2016/27726

Eucalypt trees are one of tree species used for the manufacturing of papers in South Africa. The manufacturing of paper consists of cooking the wood with chemicals until obtaining a pulp. The wood is made of different cells. The shape and structure of these cells, called wood anatomical characteristics are important for the quality of paper. In addition, the anatomical characteristics of wood are influenced by environmental factors like climatic factors, soil compositions etc…. Therefore, in this study we investigated the effect of climatic factors on wood anatomical characteristics of two Eucalyptus clones. In the experiment, two sets of data were recorded daily, the climatic parameters and the tree growth. After cutting the trees, the anatomical properties of the wood were measured using microscope and image analysis. The longitudinal linear mixed model with age, season, temperature, rainfall, solar radiation, relative humidity and wind speed as the fixed effects factors and tree as random effect factor was fitted to the data. Lagged effects climatic variables were identified and included in the model. To account for the physical characteristics of the trees we included the effect of diameter at breast height (DBH), stem radius, daily radial increment, and the suppression or dominance of the tree in the model. It was found that wood anatomical characteristics of the two clones were more affected by climatic variables when the tree was on juvenile stage as compared to mature stage.


Open Access Original Research Article

Selection of Salt- tolerant Triticale (X triticosecale Wittmack) and Genetic Variation Assay for Agronomic and Physiological Traits

Bahram Heidari, Mahtab Latifi, Ali Dadkhodaie, Nikwan Shariatipour

International Journal of Plant & Soil Science, Page 1-13
DOI: 10.9734/IJPSS/2016/27098

Salinity is a major limiting factor of growth and grain yield in most crop plants. In the present study, the response of 12 triticale genotypes, 3 wheat commercial cultivars and a rye genotype to four levels of salinity (1:1 ratio of NaCl and CaClsalts with EC=0, 7, 14 and 21 dS/m) were assayed in a pot experiment. Salt stress was applied at the four-leaf stage. Variations in two sets of agronomic and physiological traits were analyzed. Most of triticale genotypes had higher grain yield than wheat and rye genotypes under saline conditions. K+/Na+ discrimination ratio which explained 61.7% of the total grain yield variation in linear regression analysis was higher in most of triticales compared with wheat genotypes. Correlation analysis indicated that awn length had the highest correlation with grain yield. Acute angle between grain yield and K+/Na+ discrimination vectors in principal components analysis showed tight association of these traits under salt stress levels. Calculation of genotypic coefficients of variation indicated the existence of higher genetic variation for K+/Na+ (19.82%), awn length (21.64%) and grain yield (26.55%) compared with maturity (4.72%) and total protein (4.63%). Cluster analysis results indicated that TRT808 and TRT806 joined in second group in tree dendrogram under salt stress conditions. This group had higher grain yield mean and K+/Na+ discrimination ratio and its genotypes matured earlier compared to other genotypes. Overall, it can be concluded that triticale performed better than wheat under different levels of salt stress. High genetic variation for some of salt stress- adaptive traits provides the opportunity for production of high-yielding triticales.


Open Access Original Research Article

Effect of Conservation Tillage on the Physical and Mechanical Properties of Silty-Clay Loam Soil

M. Zaraee, S. Afzalinia

International Journal of Plant & Soil Science, Page 1-7
DOI: 10.9734/IJPSS/2016/26327

Effect of different tillage methods on the physical and mechanical properties of silty-clay loam soil was evaluated in corn-wheat system during 2011 in Fars Province, Iran. Field trial was conducted in the split plot design with two factors (tillage methods and soil depth) and six replications for soil bulk density and penetration resistance. Main plots were tillage methods including conventional tillage, reduced tillage, and zero tillage. Soil depth of 0-10, 10-20, and 20-30 cm were considered as sub plots. A randomized complete block design with three treatments and six replications was used for the soil coefficients of friction, adhesion, and cohesion. Soil bulk density, soil penetration resistance, coefficients of soil internal and external friction, adhesion, and cohesion were measured. Results showed that tillage methods had significant effect on the soil bulk density so that the conventional and reduced tillage methods had the lowest soil bulk density, and zero tillage method had the highest. Soil bulk density was also affected by soil depth in such a way that bulk density increased when soil depth increased from 0 to 20 cm, and then decreased by increasing soil depth from 20 to 30 cm. The maximum soil penetration resistance was recorded from the zero tillage, and the conventional tillage had the minimum soil penetration resistance. Soil penetration resistance increased with increasing soil depth from 0 to 30 cm. Results also indicated that zero tillage significantly decreased the coefficient of soil internal friction; whereas, the coefficient of soil external friction was not affected by tillage methods.


Open Access Original Research Article

Productivity of Sweet Potato (Ipomoea batatas L.) as Influenced by Water Stress and Variety in Sokoto Sudan Savannah, Nigeria

Mohammed B. Sokoto, K. A. Sadiq

International Journal of Plant & Soil Science, Page 1-9
DOI: 10.9734/IJPSS/2016/25963

Field trial was conducted at the Usmanu Danfodiyo University Sokoto Teaching and Research Fadama Farm, Sokoto, during the 2015 dry season. The objective of the research was to determine the productivity of sweet potato (Ipomea batatas L.) as influence by water stress and variety in Sokoto, Treatments consisted of factorial combination of water stress imposed at vegetative growth phase, tuber initiation growth phase, and control (unstressed), three variety of sweet potato Ex-Bakalori, Ex-kano and Ex-Fateka, laid out on a split plot design replicated three times, water stress was allocated to the main plot and variety was assigned to the sub plot. The result indicated that water stress and variety had no significant effect to leaf number, vine length, and leaf area index (LAI) at 3, 6, 9, 12, 15, and 18 Weeks After Planting (WAP). Interactions between water stress and variety also have shown no significant different to number of leaves per plant, vine length, and leaf area index. Similarly vine yield and culled tuber weight indicated no significant effect to water stress and variety. Water stress significantly affected the number of tubers per plants, number of marketable tuber per plants and number of non-marketable tuber per plant, average weight of marketable tubers and tuber yield t ha-1. Water stress imposed at vegetative and control (unstress)  plots did not differ significantly but differed significantly from plots imposed with water stress at tuber initiation with higher, number of tuber per plant, marketable tuber per plant and tuber yield t ha-1. Water stress at the tuber initiation plots produced smaller tubers and lower tuber yield. Therefore water stress at tuber initiation should be avoided for maximum yield of sweet potato.


Open Access Original Research Article

Phosphorus Adsorption and Phosphorus Use Efficiency in Calcareous Alkaline Soils Influenced by Humic Acid

Muhammad Numan Khan, Dost Muhammad, Sajjad Raza, Abdul Haseeb, Mubasher Nasir, Asad Shah, Farmanullah Khan, Tanveer Ali

International Journal of Plant & Soil Science, Page 1-10
DOI: 10.9734/IJPSS/2016/25805

The effect of lignitic coal derived humic acid (HA) was evaluated on phosphorus adsorption and desorption capacity in calcareous alkaline soils collected from Research Farm of the University of Agriculture, Peshawar, Pakistan. The P adsorption capacity was determined by adding 0, 10, 20, 40, 60, 120, 240 and 360 mg P L-1 (initially P applied, IPA) to 5 g soil with absence (alone P) or presences of 0.15% HA (P+HA) solution in duplicate. The mixture was shaken on horizontal shaker for 30 h continuously followed by 5 min centrifugation at 2500 rpm to collect the aliquot/supernatant. The soils were then added 45 mL distilled water followed by same shaking and centrifugation for desorption studies. The P+HA treatments yielded significantly higher EPC (equilibrium phosphorus concentration) and lower P adsorption (x/m) at each level of IPA than alone P rendering that HA reduced the P adsorption. The P adsorbed (x/m) expressed in percent of IPA (Xad) and the ratio of x/m to ECP (Kd) simply decreased with each increments of IPA in case of alone P but first increased and then decreased in case of P+HA indicating different behavior of P in presences of HA solution. The higher Xad and Kd in case of alone P revealed its comparatively higher affinity and more adsorption of P at any levels of IPA than the soil which received HA treatments. Similarly, the P+HA treated soils produced comparatively higher desorption of P at any IPA than the alone P treated soils suggesting that HA not only reduces the adsorption but can also increase their release from the soil surfaces into solution. The alone P was best fit to Langmuir modified two surface model whereas the P+HA was best fit to Freundlich isotherm models. These results indicated that humic acid application can improve the P use efficiency in field condition through changings in dynamics of P sorption and hence should be applied for better crop nutrient management.


Open Access Original Research Article

Changes in Levels of Soluble Sugar, Reducing Sugar and Lipid during Germination of Seeds of Albizia procera

Rupnarayan Sett

International Journal of Plant & Soil Science, Page 1-15
DOI: 10.9734/IJPSS/2016/27203

The biochemical levels of total lipid, soluble sugar and reducing sugar in early germinating seeds collected from 3 trees of Albizia procera aged around 25 years were estimated from the 1st day of germination till the 15th day. With progression of germination, total lipid content decreased in all the 3 trees. No such continuous trend could be drawn regarding the levels of total soluble sugar and total reducing sugar when the results showed ups and downs in their concentrations at different days of germination. However, in both the cases, retaining a considerable level up to 12th day of germination was noticed. The recorded results might be beneficial for further studies on the metabolic activities of germinating seeds in Albizia procera or related tree species.