H. Ibrahim Erkovan

Plant Growth-Promoting Rhizobacteria (PGPR) and Phosphorus Fertilizer-Assisted Phytoextraction of Toxic Heavy Metals from Contaminated Soils

Phytoremediation is a remediation technique that involves the use of plants to extract, sequester, and/or detoxify pollutants through physical, chemical, and biological processes. The use of phytoremediation is expanding due to its cost-effectiveness compared with conventional methods. This study was conducted to investigate the effects of autumn and spring application of plant growth-promoting rhizobacteria (PGPR, 108 cfu mL−1 Bacillus megaterium var. phosphaticum sprayed at 250 mL plot−1) and phosphorus (P) fertilizer (0, 11, 22, 33, 44 kg P ha−1) on dry matter yield and heavy metal uptake by plants in soils contaminated with heavy metals. Field experiments were conducted using a randomized complete block design with four replications between 2004 and 2007. The results of the study indicated that P fertilization, but not PGPR application, significantly affected dry matter yield. Application of PGPR increased heavy metal availability in soils and the heavy metal uptake of meadow plants. The heavy metal content of the meadow plants resulting from PGPR application was 4–6 times higher for the spring application than the autumn application. Approximately 16, 30, 10, 10, and 3 growing seasons without PGPR are necessary to remove all lead (Pb), nickel (Ni), boron (B), manganese (Mn), and zinc (Zn), respectively, from polluted soil. The time required for Pb, Ni, B, Mn, and Zn removal could be further decreased to approximately 4, 6, 3, 3, and 1 growing seasons, respectively, with 33 kg phosphorus pentoxide (P2O5) ha−1 and 108 cfu mL−1 PGPR applications at rates of 250 mL plot−1 in the spring season.

Using a companion crop of barley to improve white clover production in the highlands of Turkey

Abstract White clover was established with barley seeded at 0, 60, 120, and 180 kg ha−1 and cut at milk‐dough and ripe grain stage. Sowing barley at 180 kg ha−1 as a companion crop when establishing white clover increased hay production from 3242 kg ha−1 to 6522 kg ha−1. Cutting hay at the milk‐dough stage of barley gave a better response than waiting until the grain was ripe. Although white clover and weeds were suppressed by the companion crop, white clover density was not reduced. There was no reduction in hay in the year following the companion treatments, but weed contamination continued to be less. There was no difference between cutting barley at the milk‐dough stage and harvesting it for grain, in hay production in the second year. Therefore, white clover can be seeded with a barley companion crop sown at about 180 kg ha−1 under irrigated highland conditions.

The History and Current Direction of Rangeland Management in Turkey

On the Ground Turkey is a country with many urban centers (Istanbul has 15 million people) and with a high gross national product (16th in the world). More than one-third of the country is rangeland and livestock production accounts for at least 30% of agricultural income. Rangelands and livestock production on rangelands historically have been at the center of Turkish society, economy, and culture. Roots of many Turkish range management practices can be traced back to the steppes culture of central Asia in 2500 BC. The government established strict policies and regulations on the communal rangelands allocated to each community by the central government. The grazing management regulations were based on strategies to ensure that 1) stocking rates did not exceed carrying capacity, 2) timing of grazing was in balance with seasonal conditions, and 3) grazing units were periodically deferred. The composition and productivity of Turkeys rangelands have degraded considerably since the early 1900s with an increasing density of humans and their livestock on grazing lands and an abandonment of the traditional policies and structure regulating grazing of rangelands. The Rangeland Act of 1998 gave the Turkish government authority to regulate the grazing season, carrying capacity, and rangeland development and use. Consideration of agrarian reform measures is at the center of revitalizing the publicly owned rangelands in Turkey.

The effect of bovine saliva on growth attributes and forage quality of two contrasting cool season perennial grasses grown in three soils of different fertility

The aim of this study was to determine the response of Dactylis glomerata L. (Orchardgrass) and Festuca ovina L. (Sheep fescue), to bovine saliva application in a loamy soil (most fertile), a sandy loam and a sandy soil (least fertile). The effects of cutting and cutting + saliva on relative height growth rate (RHGR), above- and belowground biomass and forage quality attributes [crude protein, NDF (neutral detergent fibre) and ADF (acid detergent fibre)] were investigated. The results showed that the cutting and cutting + saliva treatments resulted in greater RHGR than the control, but only with D. glomerata in the sandy soil did the application of saliva increase the RHGR. However, saliva applied after cutting increased the aboveground biomass averaged over all species and all three soils. Saliva applied to D. glomerata increased the belowground biomass in the sandy loam and sandy soils but decreased it in F. ovina in the sandy soil. The application of saliva had no effect on the crude protein or the NDF content of either species in any of the soils. On the other hand, the application of saliva after clipping increased the ADF of F. ovina but decreased that of D. glomerata averaged over all three soils. Averaged over both species, the ADF was increased by the addition of saliva in the sandy soil, had no significant effect in the sandy loam (P > 0.05) and was slightly increased in the loam.

Farklı Cins Hayvan ile Otlatılan Meraların Sağlık ve Ekolojik Alan Sınıflaması

Meralar ekolojik faktorlerin yonlendirmesine bagli olarak kendisini yenileyebildigi gibi geriye gidis de sergileyebilir. Kullanim ozelliklerine bagli olarak olumlu, olumsuz veya mevcudu muhafaza eden seklinde davranis sergilemektedir. Bu calisma sigir, koyun ve sigir ile koyunun birlikte otlatildigi meralarin saglik ve ekolojik alan siniflamasini belirlemek amaciyla Erzurum ili Kargapazari daglarinda yurutulmustur. Bitki ortusu, toprak ve su ozellikleri yonunden incelenen mera kesimlerinde onemli farkliliklar gozlemlenmistir. Sonuclar bir butun olarak degerlendirildiginde, kisa boylu bugdaygillerin hakim oldugu yuksek rakimli bozkir meralarinda kontrolsuz koyun otlatmanin kontrolsuz sigir otlatmaya gore bitki ortusu ve iliskili kaynaklari daha fazla tahrip edici oldugunu ifade etmemiz mumkundur. Ancak koyunlarin genis yaprakli turleri baski altina aldigi goz ardi edilememelidir. Sonuc olarak bozkir meralarinin surdurulebilir kullanimi acisindan otlatma mevsimi ve kapasitesine uymak sartiyla sigir ve koyun surulerinin karisik otlatilmasinda fayda vardir.

SULU VE KIRAÇ ŞARTLARDA YETİŞTİRİLEN KORUNGADA OT VE TOHUM VERİMİ İLE BAZI ÖZELLİKLERİN BELİRLENMESİ

Korunga (Onobrychis viciaefolia Scop.) yalniz veya bugdaygiller ile karisik yetistirilebilen, hayvanlara yarayisli ve sisme yapmayan bir baklagildir. Kirac sartlara iyi uyum sagladigi gibi sulu sartlarda da yetistirilebilmektedir. Bu calismada sulu ve kirac sartlarda korunganin verim ve bitki sikiligi incelenmistir. Deneme, Erzurum’da Ataturk Universitesi Ziraat Fakultesi deneme sahasinda 2002-2005 yillarinda sansa bagli tam bloklar deneme desenine gore 4 tekrarlamali olarak kurulmustur. Sulu sartlarda ot verimi artmis, fakat sulamanin tohum verimi uzerine onemli bir etkisi olmamistir. Ortalama 4 yillik ot ve tohum verimleri sulu sartlar icin 831.1 ve 62.1 kg/da, kirac sartlar icin 645.0 ve 62.5 kg/da olarak bulunmustur. Yillik ot verimi en yuksek (1016.2 kg/da) 2002 yilinda bulunurken, tohum verimi 2002, 2003 ve 2004 yillarinda 2005 yilindan daha yuksek olmustur.