Possibilities of using sewage sludge as nitrogen fertilizer for maize

Abstract

The objective of this study was to determine the effects of nitrogen fertilizer sources of ammonium sulphate and municipal sewage sludge on yield, N content and uptake of the maize (Zea mays L.). Nutrient and heavy metals were determined in soil and plant. The experiment with three sludge rates (256, 513 and 1026 kg total N ha^?1 or 9.5, 18.0 and 38.1 t ha^?1 sludge), two nitrogen rates (80 and 160 kg N ha^?1) and zero-N control were conducted on a clay loam soils under irrigated conditions in Eastern Anatolia region in Turkey. Treatments were arranged in a randomized complete block design with four replications. Yield, N content and total N uptake of maize increased significantly with sludge application. 9.5 t and 19.0 t ha^?1 sewage sludge applications did not significantly affect heavy metal content of leaf and grain. However, 38.1 t ha^?1 sludge applications increased leaf Pb and Zn. DTPA-extractable Cd, Cu, Fe, Pb and Zn concentrations of the soil increased at applications of 38.1 t ha^?1 sewage sludge, whereas applications of 9.5 t and 19.0 t ha^?1 sludge only resulted in elevated levels of Cu and Zn, We conclude that if sewage sludge is to be used in production of maize, applications rate up to 19 t ha^?1 could be accepted. However, this means also that the N requirement of maize crop is not covered by the sludge; therefore, the rest of nitrogen could be supplied as inorganic N.     

The Investigation of Relationships Between Some Fruit and Kernel Traits with Canonical Correlation Analysis in Ankara Region Walnuts

Canonical correlation analysis is a multivariate technique, which is employed to examine relationships between two variable sets, each of that consist of two or more variables. In the analysis, by maximizing the relationships between two sets, it is aimed to obtain new variables called as canonical variates that formed by linear combinations of the original variables for each sets. In this study, it is aimed to examine the relationships between some fruit and kernel characteristics of Ankara region walnuts. Thus, the following eight traits Fruit Length (mm), Fruit Width (mm) Fruit Height (mm) Fruit Weight (g), Shell Thickness (mm), Kernel Weight (g), Kernel Ratio (%) and Filled-firm Kernel Ratio (%) of 364 walnut samples were measured. First five of these characteristics were grouped as X variable and the rest of as Y variable. As a result, the correlation between the first canonical variable pair was found as 0.979 (p?<?0.01).     

Response of cotton (Gossypium hirsutum L.) to different tillage systems and intra-row spacing

The earliness is of great importance to cotton production in Mediterranean-type environments due to detrimental effects of autumn rainfall on lint quality. However, farmers commonly avoid early sowing due to risks of cold soil temperature and waterlogging after sowing in spring. Ridge-tillage system is one approach to increase soil temperature and mitigate adverse effects of waterlogging. The ridge-tillage system is also advantageous in reducing inputs in tillage operations. However, a limited experimental data are available about the effects of ridge-tillage system on earliness of harvesting, lint yield and quality of cotton in the Mediterranean-type environments. Thus, the objective of this study was to determine how ridge-tillage (RT)-planting system and intra-row spacing affect cotton lint yield, earliness and fiber quality compared with conventional tillage (CT)-planting system. Field experiments were conducted on a clay soil (Vertisol) in Hatay province (36°39′N–36°40′E, 83 m a.s.l.) in the Eastern Mediterranean Region of Turkey during 2000 and 2001. The experiment was laid out as a split-plot with three replications with tillage systems as main plots and intra-row spacings (13, 17, 21 and 25 cm) as subplots. The effects of tillage systems on lint yield and earliness were inconsistent among years. The RT-planting system resulted in 13.5% higher lint yield and 14.5% more earliness in 2001 when abundant rainfall occurred after sowing, while significant effects of tillage systems were not observed in 2000. The intra-row spacings significantly affected lint yield and earliness in both years. The earliness increased with closer spacing, while the highest lint yield was obtained from 17 cm intra-row spacing in both years. However, the fiber quality parameters were not significantly affected by tillage systems, intra-row spacings and tillage system × spacing interaction in both years. Finally, the results suggest that RT-planting system with 17 cm intra-row spacing can be used in cotton production instead of CT-planting system in the Eastern Mediterranean Region of Turkey. Ridging in 17 cm intra-row spacing also seems to be suitable to mechanical harvesting.     

Fertility of lactating dairy cows inseminated with sex‐sorted or conventional semen after Ovsynch,Presynch–Ovsynch and Double‐Ovsynch protocols

The objective was to compare pregnancy per artificial insemination (P/AI) with conventional (CS) or sex‐sorted semen (SS) in dairy cows subjected to one of the three timed AI protocols. Cows (n = 356) were randomly assigned to synchronization with Ovsynch (OVS), Presynch–Ovsynch (PO) or Double‐Ovsynch (DO) and inseminated on Day 77 ± 3 postpartum with either frozen‐thawed SS (n = 182) or CS (n = 184) of the same bull. More cows were cyclic at the beginning of breeding Ovsynch increased (p < 0.01) with presynchronization and it was greater for DO than PO (OVS = 78.5%, PO = 85.1%, DO = 95.6%). Overall, P/AI for SS and CS increased with presynchronization (p < 0.05) on Days 31 (OVS = 35.5%, PO = 47.1%, DO = 48.3%) and 62 (OVS = 30.1%, PO = 43.8%, DO = 43.9%). Regardless of synchronization treatments, insemination with SS reduced P/AI (p < 0.02) on Days 31 (38.1% vs. 50.6%) and 62 (34.5% vs. 45.6%) compared with CS. No interaction was observed between synchronization treatment and type of semen for P/AI, although in cows receiving CS, P/AI was numerically greatest for PO (OVS = 42.0%, PO = 59.3%, DO = 49.0%), and in cows receiving SS, it was numerically greatest for those inseminated following DO (OVS = 27.9%, PO = 35.5%, DO = 47.6%). Thus, presynchronization improved P/AI in cows inseminated with sex‐sorted or conventional semen.     

Role of Humic Substances on Cr(VI) Removal from Groundwater with Pyrite

Groundwater composition may have a pronounced impact on long-term performance of permeable reactive barriers (PRBs). Here, batch and column experiments were conducted to investigate the effects of humic acid (HA) on Cr(VI) removal by pyrite in systems containing cations such as Ca²⁺ and Mg²⁺. HA was observed to have inhibitory effect on Cr(VI) uptake by pyrite under the experimental conditions studied (e.g., pH 3 to 8). HA sorbed onto pyrite surface and thus (1) competed against Cr(VI) for pyritic surface sites and/or (2) increased electrostatic repulsion between Cr(VI) and pyrite. In systems with HA and Ca²⁺/Mg²⁺, the Cr(VI) uptake by pyrite decreased drastically relative to HA alone due to the aggregation of HA with Ca²⁺/Mg²⁺. The formation of such HA aggregates/precipitates blocked Cr(VI) ions to reach its binding sites, thereby resulting in a substantial decrease in Cr(VI) uptake. Overall, the results have major implications for proper design and operation of PRBs with pyrite as the reactive material.     

Zinc supplementation decreases total thyroid hormone concentration in small ruminants

The effect of dietary zinc (Zn) supplementation on plasma Zn and serum thyroid hormones was evaluated in healthy male Merino lambs and Angora goats. A total of 12 lambs and 12 goats were divided into two equal groups as control and Zn groups in separate experiments. The lambs and goats of the control groups were fed basal rations alone. The Zn contents of these rations prepared for lambs and goats were 40 mg/kg and 35 mg/kg in dry matter (DM), respectively. Both species of animals in the Zn groups were fed a basal ration supplemented with zinc sulphate adjusted to 250 mg Zn/kg diet in DM. The feeding trial lasted for 12 weeks in lambs and 8 weeks in goats. Blood samples were taken from the jugular vein at 4-week intervals. Both animal species in the Zn groups had higher plasma Zn values than the controls throughout the experimental period, except in the 4th week in goats. However, the levels of serum total thyroxine (T4) and triiodothyronine (T3) were lower in the lambs and goats of the Zn groups, except in the 4th week, as compared to those in the controls. Moreover, serum total thyroid hormone levels of the goats were higher at the 4th week than at the 8th week. Although there was a decrease in the levels of free thyroxine and triiodothyronine of both small ruminant species in the Zn groups when compared to the controls, these alterations were not statistically significant. These results may show that zinc supplementation to the diet at this dose reduces total thyroid hormone levels in small ruminants but does not yet impair the euthyroid status of the organism.     

Assessing farm tractor incidents and awareness levels of operators for tractor safety issues in the Hatay province of Turkey

Studies and statistical data on safety issues related to farm tractors and machinery are very limited in developing countries, including Turkey. This study was carried out to investigate tractor-related incidents in the Hatay province, located in the mid-south of Turkey. A questionnaire was conducted with 107 tractor operators using face-to-face interviews. Data were evaluated according to the incident type, machinery involved, and mechanism of injury or fatality. A total of 101 incidents were reported by 77 of the 107 respondents. Most of the incidents were due to tractor rollovers (65.4%), 14.8% of the incidents were due to entanglement of body parts in moving machinery, and 12.9% involved crashing into other vehicles or obstacles. The leading cause of the incidents was personal mistakes (60.4%). Fatalities resulted from 25.7% of the incidents, while 45.5% of the incidents caused non-fatal injuries. Only 5.6% of the tractors had a ROPS-enclosed cab. The percentage of ROPS-equipped tractors was 19.6%, while 41.3% of the tractors had a shade cover and 33.6% had no protective structure. Only one of the respondents used a seatbelt, although 44.9% of them stated that seatbelts should be used. It was also found that only 13.5% of the operators had training in work safety, while 95.1% stated that incidents might be reduced if people were trained. Development of appropriate policies and training programs are needed for safer operation of agricultural machinery to reduce injuries and fatalities due to farm accidents.     

Artificial sex reversal of white grouper (Epinephelus aeneus) utilizing aromatase inhibitor (Fadrozole)

The white grouper is a desirable aquaculture species that adapts to captivity, grows well and commands a high market price. However, little is known about reproductive biology or control of sex reversal of this protogynous hermaphrodite. In this study, female white groupers were implanted with one dose of 17α‐methyltestosterone (10 mg/kg body weight [BW], MT) and two doses of aromatase inhibitor, fadrozole (1 and 3 mg/kg BW, FD1 and FD3) once a month for 4 months (April–July). At the start of the study, the fish had gonads full of oocytes compared to the end of the experiment when the control group mature oocytes compared to the experimental groups MT, FD1 and FD3 that exhibited different stages of testicular tissue. Plasma levels of testosterone were significantly highest in the FD3 group and the highest 11‐Ketotestosterone levels were observed in the MT group. Plasma levels of oestradiol (E₂) were significantly lower in the FD implanted groups, compared to initial individuals and control groups. The use of aromatase inhibitor, FD for sex reversal both gives further insight into the mechanisms controlling sex differentiation and provides an alternative to steroid treatment.