Asian Journal of Soil Science and Plant Nutrition

Soil aggregate stability is a key indicator of soil quality. Changes in aggregate stability may serve as early indicators of recovery or degradation of soils. We have applied laboratory based aggregate fractions method where fine and coarse soil aggregates fixed by set of sieves for two types of soil to estimate aggregate stability. Co-efficient of vulnerability and mean weight diameter was calculated for each aggregate size fractions. Stability index (SI) and aggregate size distribution was determined to conclude on soil erodibility and compaction. Mean weighted diameter (MWD) of the Nurkerke and Hesteert soil after wet sieving is 2.03 mm and 1.56 mm respectively. The instability index of the Nurkerke soil is 2.41 and of Hesteert soil is 2.89.  The aggregate stability index of the Nukerke is 0.41 and Hesteert soil is 0.35. The coefficient of vulnerability (Kv) of Nukerke soil is 2.18 while the Hesteert has 2.81; hence the Nukerke soil seems more stable than the Hesteert soil of Belgium. Results revealed that the Nukerke soil is less vulnerable for erodibility and compaction than the Hesteert soil under investigation.

Effects of topsoil removal and amendments on soil bulk density and maize production in the Southern Guinea Savanna of Nigeria were studied during 2012 and 2013 cropping seasons. A split-split plot experiment in a Randomized Complete Block Design, with three replications was conducted. The factors were topsoil removal; cropping systems and amendments. Soil physical and chemical properties were analyzed before planting and after harvest. Maize (Zea mays L.) growth and yield parameters were evaluated. Bulk density increased significantly (P = .05) at Otobi from 1.39 to 1.58 g cm^-3 in 2012 and from 1.40 to 1.54 g cm^-3 in 2013, as topsoil removal increased from 0 to 20 cm. There were significant relationships between topsoil removal and the organic matter (OM) content of the soil. For every centimeter (cm) of topsoil removal, OM decreased by 0.04 g kg^-1 in 2012 and 0.10 g kg^-1 in 2013 at Makurdi. Meanwhile, at Otobi, the loss of 0 – 1 cm depth of topsoil resulted in the decrease in OM content by 0.06 g kg^-1 (2012) and 0.07 g kg^-1 (2013).The application of poultry manure (PM) significantly improved maize grain yield at Makurdi (2868 and 2804 kg ha^-1)and Otobi (2836 and 2393 kg ha^-1) in 2012 and 2013 seasons. The interaction between topsoil removal and soil amendments suggests that at higher depth, application of either PM or inorganic fertilizer may not differ significantly in maize grain yield after first season cropping. The yield advantage of PM relative to other treatments suggested the efficacy of PM as a better soil management option that enhances the restoration of the productivity of an eroded soil.

Aims: The aim of the experiment was to evaluate the effects of time and rate of application of poultry manure (PM) on the performance of an early maturity okra (Abelmoschus esculentus (L.) Moench) variety ‘Clemson spineless VGTH-014K. 

Study Design: The experimental design was the randomized complete block design (RCBD) with three replications.

Place and Duration of the Study: The field experiment was conducted the University of Calabar Teaching and Research Farm from June to September, 2016.

Methodology: The treatments consisted of 5 and 10 PM t/ha incorporated each into the soil at 1 and 2 weeks before planting, at planting, 2 weeks after planting, and zero poultry manure (0 t PM /ha) served as the control to give a total of 9 experimental units.

Results: The results obtained indicated that application of poultry manure at different times significantly (P £ 0.05) influenced the vegetative and fruit yield parameters okra evaluated. Statistically, 10 t of PM/ha had the best effect on okra performance irrespective of the time of application. However, early application at two weeks before planting produced the tallest plants (39.70 cm), highest number of leaves (22.67) and branches (9.67) per plant and highest leaf area index value (44.96). Also the highest fresh (1.43 t/ha) and dry pod yield (0.55 t/ha) as well as highest dry seed yield of 308 kg/ha were obtained in this treatment.

Conclusion: PM rates incorporated before planting were more effective than the corresponding rates applied at other periods. The optimum performance of okra was obtained at 10 t PM/ha and could be recommended for enhanced productivity of the crop in the study area.

The climate is changing and communities all over the world are affected. Changing climate cause severe negative impacts on the natural resources and consequently on food and livelihood security. As such societies need to learn to cope with the changes predicted, warmer temperatures, drier soils, changes in weather extremes and rising sea levels. Therefore, a field experiment was conducted during two successive summer seasons of 2014 and 2015 under open field conditions at Dokki protected cultivation experimental site, Agricultural Research Center (ARC), Egypt. The study aimed to test the effect of non-classic N fertilizer forms such as coffee husk (organic waste), humic acid (organic acid) and proline (amino acid) as compared to ammonium nitrate (traditional mineral fertilizer), through ground and foliar applications, on some soil chemical properties of the studied clay soil i.e. pH, EC_e, chemically available concentrations of N, P and K. Growth and yield parameters of zucchini plants were also studied. In addition, greenhouse gases (GHGs) emission from different applied nitrogen fertilization types and its impact on warming and air pollution were calculated. Data revealed that the treatment of coffee husk can replace, at least partially, the traditional mineral fertilizer; can increase soil fertility, growth and yield of growing plants, and reduce GHGs emission. Also, proline and humic acid can consider as activator of phytohormones and growth substances, and recover the effect due to unfavorable climatic conditions or stresses. Obtained values of CO₂ emission varied between 984 for coffee husk treatment and 1629 kg ha^-1 for mineral fertilizer treatment which increased air pollution.

A field experiment was conducted during the two successive seasons of 2014 and 2015 on pomegranate trees cv. Wonderful (Punica granatum L.). The trees were grown in newly reclaimed sandy soil located at the 64 km on the Cairo-Alexandria desert road, El-Behira Governorate, Egypt. The studied soil was treated with different levels of soil conditioner (polyacrylamide polymer) i.e. 500 and 1000 g/tree/two years, in addition to control (without polymer addition). Also, different levels of irrigation water were applied i.e. 70% (3610 m³/fed), 85% (4105 m³/fed) and 100% (4790 m³/fed) of ET_o. The experiment was designed in a split plot with three replicates. Irrigation water levels were randomly arranged in the main-plots and the applied polymer treatments were distributed randomly in the sub-plots. Data revealed that using irrigation water level 85% of ET_o gave, in general, the highest values of growth and yield indices compared to other treatments. Soil conditioner level at 1000 g/tree showed, also, the highest values, followed by 500 g/tree with significant difference between the studied treatments. The irrigation water treatment of 4105 m³/fed with soil conditioner 1000 g/tree was the best combined treatment in giving high fruit yield. This treatment caused, also, significant effect on water and nutrients saving, and improved the tested soil physical and chemical properties rather than the other treatments.