This study was conducted to investigate the effects of cropping sequence and Minjingu Phosphate Rock (MPR) on soil phosphorus (P) availability and yield of selected vegetable crops. The study involved a researcher managed on farm field experiment conducted in Mbeya, Tanzania using a split plot design with three replications. Crop sequence (i) Cabbage - tomato - maize (ii) Maize - tomato -cabbage (iii) Cabbage - cabbage - maize (iv) Maize - tomato – maize, constituted the main plots. The P sources (i) control (no fertilizer), (ii) MPR, (iii) compost + MPR, (iv) crotalaria green manure + MPR (v) NPK (standard), were sub plots. The experiment was repeated three times on the same plots. In the fourth season, bean was planted in all plots without fertilizer to capture residual nutrients. Results indicated more percent increase in soil available P in plots where cabbage was included in the sequence (207.9%) as compared to when it was ommited (85.39%). Compost + MPR treatment significantly increased soil pH from 5.8 to 6.33 while in NPK treated plots it decreased to 5.49. After three seasons there was higher residual P in MPR treated plots (33.33 mg/kg) as compared with NPK (27.65mg/kg). Plots treated with NPK produced the highest maize yield while plots treated with MPR alone or combined with compost or crotalaria produced significantly (P ≤ .01) higher cabbage and tomato yield especially during the first and second seasons. Bean pod yield was higher in MPR treated plots. Therefore, the use of PR and including cabbage in crop rotations should be encouraged in organic vegetable farming systems to restore P on phosphorus deficient soils.
Four Mango (Mangifera indica L.) cultivars: ‘Ewais’, ‘Sidik’, ‘Fajrikalan’ and ‘Zebda’ were investigated to study the electrical conductivity as a tool for determining damage index of mango cultivars and their relationship with the index of injury (Id), the Relative Water Content (RWC), Soluble Solid Content (SSC) and total phenols. ‘Ewais’ had the highest cold tolerance whereas ‘Fajrikalan’ had the lowest cold tolerance. EC and Id values were highest at -4°C and there was a direct proportional among: cold injury, exposure time and the decreasing of temperature. Cold temperature increased the accumulation of SSC with time. Total phenols of ‘Ewais’ and ‘Fajrikalan’ were lower than in ‘Zebda’ and ‘Sidik’. The relationship between the RWC and the Id was not clear from this experiment.
This study was carried out to assess the variation in nitrification inhibition (NI) activity of neem leaves obtained from trees growing in same agroclimate. The study was accomplished in the year 2012, in Lucknow city of Uttar Pradesh State of India. Dried leaves of four neem trees growing at different locations within Lucknow were screened for their NI potential. Treatments comprised of 6 combinations of urea-N and inhibitors as urea with dried leaf powder of New Hyderabad (NH) location tree, urea with dried leaf powder of Gomti Nagar (GN) location tree, urea with dried leaf powder of Hazratganj (HG) location tree, urea with dried leaf powder of Indira Nagar (IN) location tree, urea alone (without any inhibitor) and control (without urea-N and without any inhibitor). Concentrations of NH4+-N and NO3--N present in soil were quantified on 1,3,7,14,21 and 28 day/s after treatment (DAT) by standard methods. Significant difference was observed in NI potential, as high concentration of NH4+-N was maintained during experimental period when dried leaf powder of NH location tree was used whereas low concentration of NH4+-N was obtained with the leaves of HG location tree. In the first week leaves of NH location tree, showed 90% NI which remained 56.98% till the third week, whereas it was least for HG by the third week, i.e., about 23%. Leaves obtained from NH location tree proved to be the best inhibitor for nitrification amongst all treatments. Further, growth response of seedlings of Hordeum vulgare (barley) was used as a biological check of soil nutritive value with the supplementation of dried leaf powder of four trees individually. NH location tree leaves treated soils were found to be the best with respect to growth parameters of barley. Study gives an indication for pre-screening of trees growing in different locations for better results at commercial levels.
Aim: The current study investigated effect of soil amendments; lime (L), manure (FYM) and minjingu phosphate rock (PR) added to soils on soil microbial biomass carbon and nitrogen (SMB-C and SMB-N), available soil nitrogen (N), crop N uptake and grain yields of two maize hybrids (H513 and H614). Study Design: Two experiments, one for each maize hybrid as test crop, were laid out in a randomized complete block design with a 23 factorial arrangement. The factors each at two levels were L (0 and 3 t ha-1), PR (0 and 60 kg P ha-1) and FYM (0 and 5 t ha-1) giving a total of eight treatments; L, RP, FYM, L+RP, L+FYM, RP+FYM, L+RP+FYM and control (nothing applied). Methods: Soil and plant samples for the determination of SMB-C and SMB-N, available soil N, and crop N uptake were collected at maize seedling, tasseling and physiological maturity. Place and Duration of the Study: The experiment was conducted in Molo district of Nakuru County, Kenya during the long rain seasons of 2009 and 2010. Results: SMB-C and N levels were higher in 2010 than 2009, with lower levels obtained at maize tasseling for both maize hybrids. Available soil N and crop N uptake were higher at maize seedling and declined towards maturity. Statistically significant (P<.05) increases in SMB-C and SMB-N and available soil N and uptake were obtained with the application of soil amendments over the control. In all treatments, H513 had lower N uptake than H614 at tasseling and maturity stages of maize growth and correspondingly higher available N in soil. Maize yields (t ha-1) were higher in 2010 than 2009 and in H614 than H513. The H614 yields were significantly higher (P<.05) in L+PR+FYM (3.9) and, L+PR+FYM (4.1) and L+PR (3.9) treatments in 2009 and 2010, respectively. For H513, yields were significantly higher in L+PR+FYM (2.1 and 2.4) and L+PR (1.9 and 2.1) treatments in 2009 and 2010, respectively. Conclusion: The L+PR+FYM treatment is a feasible acid soil amendment for its superiority in the measured soil and crop parameters. The H513 matured faster than H614 and because of this attribute, is a viable option in response to the diminishing rainfall amounts and unpredictable weather patterns experienced in the County.
Heavy metals that exist in municipal wastewater can cause many problems for human hygiene and environment. Therefore, the metals need to be removed from wastewater before being used in irrigation. Materials of high surface reactivity; such as alginit, shale and iron oxide are used as potential sorbents to eliminate Pb and Cd from polluted water. In remediation studies, these materials were added to Pb and Cd polluted water at addition ratios of 1:10000, 1:1000 and 1:100 (remedy agents: polluted water). The mixtures were then gently agitated and submitted to different equilibrium periods of 1, 5 and 24 h. The results showed the efficiency of tested agents (shale, alginit, and iron oxide) in the removal of Pb and Cd from polluted water containing various concentrations of 5, 10 and 50 mg/l. Shale was able to reduce Pb and Cd concentration from 5 to 1.14 and 0.34 mg/l, respectively, in a reaction period of one hour. Shale, alginit and iron oxide, reduced the initial concentration of; 10 mg Pb/l to 0.98, 0.46 and 0.57 mg/l; and of 50 mg Pb/l to 0.21, 6.5 and 1.68 mg/l; respectively. Shale was the most effective material in decontamination of heavy metals polluted water and it could be recommended to be used to decontaminate wastewater. This research aims to use a non expensive, environmentally safe, and efficient technique to remove heavy metals from industrial wastewater to leave them free and suitable for discharging to sanitary sewer system.
The effect of different concentrations of growth retardant "Dextril" (C11 H18Cl2O7P) on tomato (Solanum lycopersicum c.v Huda F1) seedlings quality was studied, at the Agriculture Faculty of Alexandria - Egypt, on 2010. Tomato seedlings were sprayed when the second true leaf was appeared with "Dextril" at (0.02 – 0.04 – 0.06 – 0.08 – 0.1%) levels, to promote seedlings tolerance to heat stress during summer – autumn period and limit stem growth and elongation. The results showed that, "Dextril" treatment of (0.02 -0.04 – and 0.06%) levels improved seedlings quality and decreased stem height by 30, 32 and 35% respectively compared to the control, whereas, 0.08 and 0.1% levels showed toxic effects. Treatment with "Dextril" increased as well, stem diameter, fresh and dry weight of shoots but it did not affect leaf number compared to the control. The results indicate that the spraying with low concentrations of ‘Dextril” is promising measure for improving the stress response and developmental characteristics of tomato seedlings grown under high temperature conditions.