Open Access Original Research Article

Wheat and Grain Sorghum Yields as Influenced by Long-term Tillage and Nitrogen Fertilizer Application

Augustine K. Obour, Phillip W. Stahlman, Carlyle A. Thompson

International Journal of Plant & Soil Science, Page 19-28
DOI: 10.9734/IJPSS/2015/17295

Tillage, choice of crops in a rotation, and fertilizer management affect crop yields. Limited information exist on long-term interaction effects of tillage and nitrogen (N) fertilizer management on grain yield and precipitation use efficiency (PUE) in intensified cereal-based cropping systems. A study was initiated at the Kansas State University Agricultural Research Center-Hays in 1975 to investigate the effect of tillage intensity [conventional tillage (CT), reduced tillage (RT) and No-till (NT)] and N fertilizer rates (0, 22, 45 and 67 kg N ha-1) on wheat and grain sorghum yields. Grain yields and PUE for both wheat and grain sorghum were significantly (P< 0.0001) affected by year × N application rate × tillage interaction. Across all N rates and tillage practices, grain yields and PUE were greater in years of higher precipitation compared to years when precipitation amounts were below the long-term average. Wheat and sorghum yields for RT plots were equal or greater than CT in most years at each N rate. Grain yields and PUE in the NT plots were lower than CT and RT at lower N rates. However, at the highest N rate, grain yields were not different among the tillage systems. Regardless of tillage practice, grain yield increased with increasing N fertilizer application rate. Based on our findings, higher N application rates (> 67 kg N ha-1) may be required to maximize both wheat and grain sorghum yields with any of the tillage systems.


Open Access Original Research Article

Morphology, Physicochemical Characteristics and Land Suitability in the Western Highlands of Cameroon

D. Tsozué, P. Azinwi Tamfuh, S. M. Ndaka Bonguen

International Journal of Plant & Soil Science, Page 29-44
DOI: 10.9734/IJPSS/2015/17147

The aim of the study was to evaluate the morphology and physicochemical properties of soils and their suitability to potatoes, maize and beans, in order to contribute to stop rural migration, prevent conflicts between farmers and breeders and contribute to the increase of agricultural yields in the eastern slope of the Bambouto Mountain, Cameroon. Morphologically, the studied soil profiles are poorly or more developed, characterized respectively by AC or ABC horizon sequences. All the soil samples recorded acidic pH (4.8 to 5.5) except in the Bawa and in Zavion footslope where this pH is slightly acidic (6.0 to 6.2). Nitrogen contents are low to medium (0.04 to 0.225), except in midslope and footslope of Zavion site where these contents are very high (0.406 and 0.436% respectively). Organic matter contents increase from the Medji (1.42%) site to Zavion site (9.84%). High content of organic matter in Bawa located at the same altitude as Medji is related to the basaltic bedrock which glasses weathering might induce increase of organic matter content, while high content in Zavion might be mostly related to the increase in altitude and the decrease of temperature which slacks up microorganism activities. Phosphorous level is very low and largely under the critical limit (20 ppm) for all the study sites. Calcium is the dominant exchangeable cation, with contents ranging between 0.13 and 7.53 cmol(+)/kg of soil. The cation exchange capacity varied between 2.03 and 29.59 cmol(+)/kg of soil. Base saturation percentage fluctuates from 11.80 to 39.70%. The production of bean, maize and potatoes in the study sites is limited due to high rainfall and wetness, high slope gradient and soil fertility problems which could respectively be solved by promoting crops cultivation at the end of the raining season, terracing of arable land and fertilization and liming.


Open Access Original Research Article

Differing Sucrose Requirements for In-vitro Conservation of Cassava Genotypes

Henry Y. Sintim, Richard Akromah

International Journal of Plant & Soil Science, Page 45-54
DOI: 10.9734/IJPSS/2015/17564

Field conservation of vegetative propagated crops poses a major problem to curators of germplasm, especially in developing countries. An alternative method to ensure security of germplasm is the use of tissue culture techniques in media formulated for slow growth. However, tissues of plant species may require different nutrients for optimum growth. The objectives of this study were to a) assess the effects of sucrose on the performance of different cassava genotypes and b) recommend sucrose levels for in-vitro conservation of the genotypes. Four sucrose levels (0, 10, 20, and 30 g l-1) and apical meristems of five cassava genotypes (Bankye Hemaah, Bankye Botan, Tek Bankye, Doku Duade, and Essam Bankye) cultured in-vitro was studied at the Kwame Nkrumah University of Science and Technology’s plant biotechnology laboratory. Growth media were prepared using hormone-free Murashige and Skoog (MS) basal media formulation. Inoculated cultures were exposed to 16 hours of light and 8 hours of darkness with light illuminance of 3500 lux and also maintained at 24±2°C temperature and relative humidity of 70%. All genotypes showed a direct regeneration without callus formation. Generally, sucrose enhanced the growth performance of plantlets; however, the genotypes responded differently to sucrose in leaf formation, plant height, and rooting ability with time. For long term conservation, growth medium must sustain the health of plantlets with infrequent need for sub-culturing. As such, sucrose levels of 10 g l-1 for Essam Bankye, 20 g l-1for Doku Duade and Tek Bankye, and 30 g l-1 for Bankye Hemaa and Bankye Botan were the recommended rates for in-vitro conservation.


Open Access Original Research Article

Different Rates of Urea as Nitrogen Fertilizer Affect Root and Stalk Rot Diseases of Maize in South West Nigeria

M. O. Abiodun, A. K. Nafiu, S. O. Osunlaja

International Journal of Plant & Soil Science, Page 55-66
DOI: 10.9734/IJPSS/2015/13208

Aside from increasing the yield of crops, it is well known that application of fertilizers, especially Nitrogen, to soil has many other positive and negative effects. One of such effects include increasing or decreasing disease expression and/or severity. Information about the effect of continuous application of Nitrogen fertilizers to important cereals such as maize, in areas where local farmers have low access to information and technology, might go a long way in helping stakeholders to manage diseases. Two commonly cultivated maize cultivars, DMRE–Y and DMR–LSR-W, were planted in a randomized complete block design, first in Abeokuta (early cropping season of year 2000) and then in Ago-lwoye (early cropping season of year 2001) to evaluate the effect of increasing rates of Nitrogen fertilizer (in form of urea) application on stalk rot disease caused by Macrophomina phaseolina and root rot disease caused by Fusarium moniliforme.
Increasing rate of Nitrogen application led to a significant increase in the severity of these diseases with the highest disease expression at 300 kg N ha-1. Although the reactions of the two cultivars were similar, DMRE-Y was found to be more susceptible to these rots than DMR-LSR-W. Simple linear regression analysis indicated a very strong positive relationship between N rates and average disease index. A two year pooled index for DMRE-Y cultivar gave correlation coefficient values 0.9997 and 0.9844 for stalk and root rots respectively while for DMR-LSR-W cultivars, the values were 0.9933 and 0.9815 for stalk and root rots respectively.
Increasing rates of urea increased the grain yield but had diverse effects on yield components. The rates had no effect on plant height and ear length but considerably increased the kernel row and kernel weight. It, however, reduced days to 50% tasseling of maize crops.

Open Access Original Research Article

Dry Matter Yield of Sunflower as Affected by EDTA and EDDS Application in Soil Remediation from Ibadan, Metropolis, Nigeria

E. Y. Thomas, J. A. I. Omueti

International Journal of Plant & Soil Science, Page 67-79
DOI: 10.9734/IJPSS/2015/17379

Phytoremediation has been found to be cost effective in removing heavy metals (HM) from polluted soils. Enhanced phytoextraction with the use of chelating agents for solubility of metal in soils and their uptake in the aerial parts of plants had also been employed. Phytoextraction efficiency of plants will depend on the metal accumulated in the dry matter yield of plant.
An attempt was made to study the influence of Ethylene diamine tetra acetic acid (EDTA) and ethylene diamine disuccinic acid (EDDS) on the growth and dry matter yield content of sunflower planted in heavy metal polluted soils in a greenhouse pot experiment. Total heavy metal contents of five metals (Cu, Cd, Cr, Pb and Zn) were determined by acid digestion with aqua regia solution. A greenhouse experiment was conducted to assess the phytoextraction potential of sunflower with EDDS and EDTA applied at seven weeks after planting. Treatments were laid out in a completely randomized design with four replicates. Data were collected on metal accumulation in root and shoot, Total metal uptake, shoot and root dry matter yield and analyzed using descriptive statistics and ANOVA at α0.05.
The result shows a significant increase in the overall accumulation of metals in the root and shoot of sunflower and dry matter yield with EDDS except for Zn. However, Zinc only recorded significant increase in shoot uptake at 3 mmol/kg EDDS. The application of EDDS at 3 and 9 mmol/kg did better in total uptake of Cu, Pb and Cd. Ethylene diamine disuccinic acid (EDDS) was more efficient than EDTA in mobilizing metal uptake in sunflower root and shoot and also in increasing total dry matter yield. Translocation factor of Cd, Pb and Cu were enhanced by the addition of EDDS than EDTA application.

Open Access Review Article

Forest Dieback as Affected by Soil Pollution with Special Reference to Montane Forests - A Review

H. K. S. G. Gunadasa, P. I. Yapa

International Journal of Plant & Soil Science, Page 1-18
DOI: 10.9734/IJPSS/2015/13255

Forest mortality has an upward trend worldwide but has regional aspects as well. Preventive and suppressive measures are based on regional approaches, which address areas of high, medium and low risk mortality. As far as the existence of montane forest ecosystem is concerned, it will be extremely important to eradicate the threats on this delicate ecosystem. One of the most severe threats to montane forests is “dieback”. Since dieback dramatically deteriorates the richness of the forest stands, the functions offered by the forest will also be affected.
If dieback is somehow linked with a contamination of the forest soil by various pollutants resulted by vehicle emission, industrial waste, agrochemicals etc., remediation of the polluted soil should mitigate dieback. If the necessary measures are taken to improve the soil quality as a whole in the affected areas, the deteriorated forest stands could be restored. For the execution of a successful soil remediation program aiming at mitigating forest dieback, it would be essential to identify the key causes behind dieback first and then, depending on the type of the pollutants and the status of the pollution, the most appropriate soil remediation techniques could be selected. The remediation should be continued until the detectable levels of each contaminant in the soil reaches below the safety levels agreed upon. Finally, the gaps caused by dieback could be filled by a successful reestablishment of trees to bring the affected forest a full recovery.