Open Access Original Research Article

Seed Germination and Seedling Emergence of Shepherd's needle (Scandix pecten-veneris) as Affected by Seed Weight or Burial Depth

Spyros D. Souipas, Petros Lolas, Theofanis Gemtos, Emmanouil Vardavakis

International Journal of Plant & Soil Science, Page 810-823
DOI: 10.9734/IJPSS/2014/8827

Shepherd's needle (Scandix pecten-veneris L.) is a very common broadleaf weed of winter cereals and also an edible weed used in many regions in Greece. Knowing the behavior of the weed seeds in the soil may help in designing its management strategy and its future cultivation. Field and laboratory experiments were conducted to evaluate the effect of seed weight or burial depth on seed germination and seedling emergence in 2008 and 2010. For seed weight effect on germination and seedling emergence light and heavy seeds were tested by Petri dish assay and in the field (sowing depth 4 cm). For burial depth study six depths - 2.5, 5, 7.5, 10, 12.5 and 15 cm - were examined in field trials made in two periods of time: 25 November and 15 March for two years. Percentage of seed germination, seedling emergence and mean emergence time were measured. Results showed that light seeds germinated better (74±2.2-95±2.2%) and earlier (20.5±0.64-31.0±0.45 days) than heavy seeds (34±3.2-58±5.1% and 25.4±0.57-33.8±0.46 days, respectively). The burial depth influenced seedling emergence and mean emergence time (MET) in most cases. Low emergence percentage (1.7±1.1-33.8±7.2%) was found at the depth of 15 cm and high at depth of 2.5, 5, 7.5 cm. Seeds sowed 15.0 cm deep had higher MET (27.0±0.9-55.1±1.1 days) than those sowed at 2.5 cm (20.9±0.9-41.6±0.5 days).

Open Access Original Research Article

Using the CROPGRO Model to Predict Phenology of Cowpea under Rain-fed Conditions

David Lomeling, Mustafa Mogga Kenyi, Abdelrahman Abakr Abass, Sebit Mathew Otwari, Yahya Mohammed Khater

International Journal of Plant & Soil Science, Page 824-844
DOI: 10.9734/IJPSS/2014/9491

Field experiments were conducted in November of 2012 at the University of Juba demonstration farm on cowpea cultivar UCR 368 and local variety JUBA1. In this study, the DSSAT Cropping System Model, CROPGRO-Cowpea, was employed to simulate and predict cowpea yield in a 3-year production period under rain-fed conditions. The treatments selected were then subjected to sensitivity analysis under varied irrigation levels and seed planting dates. The model showed that the grain weight under default rain-fed conditions was on average at 111 kg/ha in all three years while this was between 250-300 kg/ha after varied planting date and over 1000 kg/ha after increased irrigation schedules in Years 2 and 3. For the three years, the model adequately simulated vegetative weight (RMSE=25.03, r²=0.92, d=0.72) and grain weight (RMSE= 20.93, r²=0.99, d=0.99) as well as Leaf Area Index (LAI) (RMSE=0.04, r²=0.92, d=0.61) under the combined treatment effects of varied planting date and increased irrigation schedules. However, increased irrigation frequencies during pre- and post a thesis tended to increase Water Stress in Photosynthesis Days (WSPD) to between 0.7-0.8 but did not negatively influence the total grain weight and biomass. Phenology and yield were lowest under rain-fed conditions but increased with an integrated irrigation management option. The results in our study shows that the model could be used to improve our understanding of the long-term effects of management practices on cowpea yield under varied planting dates and water supply.

Open Access Original Research Article

Variability and Heritability Estimates in Some Reproductive Characters and Yield in Chilli (Capsicum annuum L.)

M. K. Pandit, S. Adhikary

International Journal of Plant & Soil Science, Page 845-853
DOI: 10.9734/IJPSS/2014/7236

Forty one chilli genotypes were grown in a randomized block design with three replications during autumn-winter season of 2010-11, at the AB block Farm, Kalyani, Bidhan Chandra Krishi Viswavidyalaya, India, to estimate variability and heritability for important reproductive and yield characters. In the present experiment genotypic coefficient of variation and phenotypic coefficient of variation estimates closely corresponded with regard to days to 50% flowering, fruit length, placenta length and 1000 seed weight; in others it differed moderately, altogether suggesting low to medium influence of environment in the expression of these characters. Close estimates of phenotypic coefficient of variation and genotypic coefficient of variation were noted in all characters except fruit width, which imply that contribution towards final phenotypic expression of these characters are mostly genetic rather than environmental. Very high genetic advance as % of mean was recorded in fruit yield/plant and moderately high genetic advance as % of mean was recorded in days to 50% flowering, placenta length, fruit length, number of fruits/plant and number of seeds/plant, indicating that these characters are most likely governed by additive gene action and hence would be rewarding in selection.

Open Access Original Research Article

Residual Effect of Intercropping on the Yield and Productivity of Oil Palm

S. Anim Okyere, F. Danso, E. Larbi, I. Danso

International Journal of Plant & Soil Science, Page 854-862
DOI: 10.9734/IJPSS/2014/9038

The oil palm industry in Ghana is dominated by small scale farmers who normally intercrop oil palm with food crops (maize, cassava and plantain). A trial was conducted on a four year old oil palm field which had been intercropped with food crops for three years (1994-1997). Observations were carried out on the field from 1997-2007to find out the residual effect of the intercrop on the yield of oil palm. The field was compared with the standard system of cover cropping oil palm with Pueraria sp. The experiment was laid out in a randomised complete block design with 4 treatments and four replications. Each plot measured 35.2 x 22.7 m and had 12 palms. Vegetative and yield data were collected on the palms. There were no significant differences between the vegetative and yield data of the fields that were intercropped and sole cropped. Intercropping oil palm with maize, plantain and or cassava had no adverse effect on the growth, development and yield of the oil palm.

Open Access Original Research Article

Sustainable Management and Improvement of Soil Physical Properties and Rice Grain Yield in Degraded Inland Valleys of Southeastern Nigeria

J. C. Nwite, B. A. Essien, C. I. Keke, C. A. Igwe, T. Wakatsuki

International Journal of Plant & Soil Science, Page 863-878
DOI: 10.9734/IJPSS/2014/8879

Nigeria is relatively blessed with rain and high potential of inland valleys. The major constraints in the utilization of these inland valleys for sustainable rice based cropping include, poor soil properties maintenance, inadequate weed and water control. In an attempt to replicate the successful Japanese Satoyama watershed management model in the African agro-ecosystems, sawah rice cultivation technology has been introduced to West Africa in the last two decades. This study was conducted in an inland valley at Akaeze, Ivo Local Government Area of Ebonyi State, Southeastern Nigeria, in 2010, 2011 and 2012 cropping seasons, to evaluate the effects of four different tillage specifications and different amendments under sawah water management system on soil properties and rice grain yield. Sawah has been described as an Indo-Malaysian word for padi (Malayan word for paddy) or lowland rice management system comprising bunding, puddling, levelling and good water management through irrigation and drainage. A split- plot in a randomized complete block design was used to evaluate these two factors. The four tillage specifications for rice growing are; complete sawah tillage- bunded, puddled and leveled rice field (CST); farmers tillage environment- no bunding and leveling rice field (FTE); incomplete sawah tillage- bundding with minimum leveling and puddling rice field (ICST) and partial sawah tillage- after bunding, no puddling and leveling rice field (PST). The five levels of manure application including the control, which were replicated three times included; rice husk at 10 ton/ha; rice husk ash at 10 ton/ha; poultry droppings at 10 ton/ha; N. P. K. 20: 10: 10 at 400kg/ha and the control (Zero application). The study was undertaken in 3 cropping seasons (2010, 2011 and 2012) using the same watershed and treatments. The effects of additive residual effects of the amendments were not studied in the course of this research. A bulk soil sample at 0-20 cm depth and core samples were collected in the location before tillage and amendments for initial soil characteristics. At the end of each harvest of the three cropping seasons, another soil sampling was carried out on the different treated plots to ascertain the changes that occurred in the soil due to the treatments application. Selected physical analyses were carried on those soils collected, while the soil amendments were analyzed for N, P, K, Ca, Mg, Na, and organic carbon. The soil physical properties analyzed for included; soil BD, total porosity, mean weight diameter, water retention and saturated hydraulic conductivity. The soil bulk density (BD) was significantly reduced differently by the tillage environments and soil amendments in the three years of study. It was observed that the interaction of the environments and amendments did positively (P<0.05) reduced the soil BD in the first and second year of study. The total porosity was also improved in the same periods of study in the location by the studied factors and their interactions. The mean weight diameter water retention (WR) and saturated hydraulic conductivity (Ksat) were also significantly improved upon in different forms by the factors and the interaction. The effects of tillage types and amendments were observed to have significantly (P<0.05) improved the rice grain yield.

Open Access Original Research Article

Effects of Salinity on the Growth and Survival of the Seedlings of Mangrove, Rhizophora stylosa

Hiromi Kanai, Mitsuki Tajima, Atsushi Sakai

International Journal of Plant & Soil Science, Page 879-893
DOI: 10.9734/IJPSS/2014/9812

Aims: There are contradictory views on whether mangroves are obligate halophytes or facultative halophytes. In this study, we examined: (1) if seedlings of a mangrove, Rhizophora stylosa, require NaCl for their survival and (2) whether the growth response of R. stylosa seedlings under varying salinities was explained from the context of carbon economics.
Methodology: Seedlings of R. stylosa were hydroponically grown under varying salinities (0 - 480 mMNaCl) and their growth, mortality, photosynthetic and respiration rates were analyzed.
Results: Most of the seedlings grown under NaCl-free condition died during the 34-week culture, demonstrating their salt dependency. The best growth was accomplished under moderate salinity (240 mMNaCl) with highest stem elongation, maximum biomass gain and lowest leaf mortality. Whole-plant photosynthetic production was highest under the moderate salinity and declined towards high and low salinity ranges whereas whole-plant respiration did not increase towards high and low salinity ranges. The lower photosynthetic production under high salinity involved reductions in both leaf area and photosynthetic potential per area while the lower photosynthetic production under low-salinity involved reduction in leaf area only.
Conclusion: Rhizophora stylosa appeared to require salt for survival. The maximal growth under moderate salinity might be explained by reduced photosynthetic production under low and high salinity ranges. The reduced photosynthetic potential and leaf area causing lower photosynthetic production under high salinity might be ultimately explained by the accumulation of excessive salt in leaf cells. In contrast, the ultimate causes for the reduced leaf area and increased mortality under low salinity remained unclear. Several possible mechanisms are discussed in relation to ion metabolism.

Open Access Original Research Article

Evaluation of Genotypic Variation in Lead and Cadmium Accumulation of Rice (Oryza sativa) in Different Water Conditions in Egypt

Howida B. El-Habet, Elsayed S. Naeem, Taher M. Abel-Meeged, Saber Sedeek

International Journal of Plant & Soil Science, Page 911-933
DOI: 10.9734/IJPSS/2014/8993

Lead (Pb) and cadmium (Cd) can be absorbed and transported effectively by rice plants and could easily enter into the food chain. This research aimed at identifying rice germplasm with low Pb and Cd concentrations, and to assess their potential risks to human health. A 2-year pot experiment if 30 rice genotypes were conducted in a greenhouse at Rice Research and Training Center (RRTC) Sakha Kafr El-Sheikh, Egypt during 2012 and 2013 rice growing seasons, under irrigating with fresh water from the River Nile (FW), drainage water from El-Gharbia main drain Kitchener (DK) and drain No. 8 (D8). The pots were arranged in a randomized complete block design with four replications. All genotypes tested in this study gave high grain and straw yield under irrigation by DK than irrigation by D8 and FW. The concentrations of Pb and Cd in all organs of tested rice genotypes (roots, straw and grains) decreased in the sequence of Indica > Japonica >Indica /Japonica types under all sources of irrigation water in this study. Pb and Cd concentrations in grains of some rice genotypes were above the safety limits 2.00 and 0.40 ppm, respectively. In the same time grains of 13 genotypes were below the safety limits. The risk assessment of Pb and Cd through consumption of some rice genotypes indicated that the target hazard quotient of Pb (THQPb) and Cd (THQCd) in some rice genotypes exceeded the permissible limits (1.00) for an adult but not in all tested genotypes. THQPb and THQCd values for Pb and Cd through the consumption of rice decreased in the order Indicia > Japonica >Indicia /Japonica. Rice germplasm with a strong tendency for accumulating Pb and Cd should be avoided when using poor water quality in irrigation.

Open Access Review Article

Effects of Bradyrhizobium japonicum and Phosphorus Supplementation on the Productivity of Legumes

Daniel Nyoki, Patrick A. Ndakidemi

International Journal of Plant & Soil Science, Page 894-910
DOI: 10.9734/IJPSS/2014/8412

Most soils in sub-Saharan Africa are depleted and lack important nutrients for proper plant growth and development. The declining trend of soil fertility pronounced in different parts of Africa is attributed to different factors such as continuous cropping without soil replenishment and land degradation leading to poor grain yield of legumes. Nitrogen and phosphorus are among the most limiting nutrients for plant growth as they play different roles in the biochemical processes of plants. Phosphorus is a fundamental component of substances that are building blocks of genes and chromosomes. Adequate supply of phosphorus is essential for development of new cells and the transfer of the genetic code from one cell to another during cell formation. Nitrogen is an essential constituent of plant cells at structural, genetic and metabolic levels, involved in many processes of plant growth and development leading to yield and quality of harvested organs. Traditionally, small-scale farmers use little or no farm-yard manure and chemical fertilizers to improve soil nutrition. However, these fertilizers are expensive to be afforded by small-scale farmers. The alternative to this is the use of cheap and easily applied biofertilizer such as Rhizobium bacteria that can fix atmospheric nitrogen to the form that can be taken by plants. The potential role of rhizobia inoculants and P application with respect to growth, nitrogen fixation, nutrient uptake, total leaf chlorophyll content, and grain yield of legumes are given attention in this review. The results from different researchers showed that Rhizobium inoculation and supplementation of phosphorus independently or in combination had positive effects on growth, leaf chlorophyll content, nutrients uptake, grain yield, and nitrogen fixation. Therefore, reducing N and P deficiencies in the soil through the use of biofertilizers such as Rhizobium inoculants and phosphorus supplementation is a good option in promoting legume yield.