اجريت هذه التجربة في مزرعة الخضر بكلية الزراعة جامعة أسيوط لموسمين متتاليين (2019/2020 و 2020/2021) لدراسة تأثير ثلاثة مواعيد زراعة مختلفة (1 نوفمبر ، 1 ديسمبر ، 1 يناير) على النمو الخضري والمحصول والجودة في أربعة تراكيب وراثية من السبانخ (Dash F1 hybrid ، SCO-017 F1 hybrid ، Green Shine F1 hybrid ، والصنف البلدي المحلي)

أظهر التحليل الإحصائي للبيانات وجود تفاعل معنوي بين أربعة طرز وراثية وثلاثة مواعيد زراعة. تم الحصول على أطول نبات وأعلى عدد من الأوراق لكل نبات وأعلى وزن نباتي طازج فى الهجينين Dash F1 hybrid ،  SCO-017 F1 hybrid عند الزراعة في الميعاد الأول (1 نوفمبر) في الموسم الأول والثاني على التوالي

قد تكون هذه النتائج بسبب الطقس الملائم للزراعة فى الميعاد الأول (1 نوفمبر) وتكييف هذه الهجن F1 مع تلك الظروف. وبالتالي، يمكن استنتاج أن Dash F1 hybrid ينمو بشكل أفضل في الزراعات المبكرة (الزراعة الخريفية / 1 نوفمبر) ويتأثر نموه بشكل كبير في الزراعات المتأخرة (الزراعة الشتوية / 1 يناير).

Toxic elements (TEs) are generally less available in alkaline soils as considerable portions of TEs are precipitated with carbonates/hydroxides or presented in metal–organic complexes. However, intensive anthropogenic activity, the high total concentration of TEs, geochemical behavior of some TEs (e.g., Mo and V), and soil dynamic redox conditions could dramatically increase the TE bioavailability and risks in alkaline soils. This chapter introduces the potential of biochar to immobilize TEs in alkaline soils. It highlights the different factors that affect the adsorption capacity of biochar for TEs in alkaline soils. The possible mechanisms of TEs immobilization process and the development in biochar production and modification methods that could enhance the immobilization capacity of biochar for TEs in alkaline soils are also discussed.

The vision of this study is to find a way for increasing phosphorus release from bone char. An incubation experiment was conducted to study the effect of co-applying different nitrogen fertilizer types with bone char (BC) on the availability and distribution of phosphorus in calcium carbonate-rich soil. The experiment contains the following treatments: soil without any nitrogen fertilizer (BC only), soil + ammonium sulfate (BC + AS), soil + ammonium nitrate (BC + AN), and soil + urea (BC+U). Bone char was added to all treatments at a dose of 4 g kg-1 soil. Co-applying bone char with all nitrogen fertilizers caused a significant decrease in pH and increased significantly phosphorus availability in the soil. The concentrations of soil available phosphorus increased from 8.05 mg kg-1 soil for BC treatment to 8.99, 8.90, and 10.16 mg kg-1 soil for BC + AS, BC + AN, and BC + U treatments, respectively, at the end of incubation. Significant increases in soil available phosphorus were observed with increasing incubation periods in all treatments. The effectiveness of the treatments on the soil available phosphorus increase was in the order of BC + U > BC + AS > BC + AN > BC. Nitrogen fertilization treatments significantly increased the NaHCO 3-Pi concentrations compared to the BC treatment. Urea application to the soil increased significantly the NaOH-Pi fraction compared to other treatments at day 10 of incubation. Changes in HCl-Pi and Res-P fractions were non-significant in all treatments under nitrogen fertilization. According to the findings, co-applying bone char with nitrogen fertilizers is an agronomic practice that improves phosphorus availability in calcium carbonate-rich soil, thence it is preferable to add urea rather than other nitrogen fertilizers. This study explores a sustainable management strategy to find cost-effective and environmentally friendly alternatives to phosphate fertilizers.
 

Several chemical properties of alkaline soils play an important role in dissolving phosphate minerals, which greatly affect the phosphorous availability to plants. The current study was carried out to assess bone char application on the availability and distribution of phosphorus in some alkaline sandy soils. This incubation experiment was performed by selecting some alkaline soils from different locations in Upper Egypt: Arab El-Awamer (Assiut Governorate), West El-Minia (El-Minia governorate), and New Valley Governorate. Bone char was applied at a dose of 4 g kg-1 soil. The incubation periods lasted for 7, 16, 35, 65, and 84 days. Phosphorus availability in Arab El-Awamer soil increased significantly with applying bone char and was greatly influenced by soil chemical properties and incubation periods. Bone char addition caused a relative increase of available phosphorous in the sequence as follows: Arab El-Awamer soil ˃ New Valley soil ˃ West El-Minia soil. Available phosphorous showed a negative correlation with electrical conductivity, soluble calcium, and soluble sulfate. A significant increase of NH4Cl-Pi, NaHCO3-Pi, NaOH-Pi, HCl-Pi, and residual P fractions occurred in some soils with bone char application. Phosphorus fractions distribution in all soils followed: HCl-P ˃ residual P ˃ NaHCO3-P ˃ NaOH-P ˃ NH 4Cl-P. The correlation between phosphorus availability and phosphorus fractions was positive. Our results focus on the importance of using bone char as an amendment in P-poor alkaline soils for improving phosphorus availability. So, bone char is an effective technique for sustainable agriculture because it is a clean and renewable resource of phosphate fertilizers.