The use of synthetic soil conditioners such as polyvinyl alcohol (PVA), bitumen (Bit.) and polyacrylamide (PAC) can be considered as a specific management to improve the efficiency of the use of nitrogen fertilizers and some chemical properties of calcareous soils that are reflected in crop productivity. Two rates of synthetic soil conditioners (PAV, Bit. and PAC) and three rates of nitrogen fertilizer (50, 75 and 100% N of recommended dose) were included in this study to evaluate their effects on some chemical properties, nutritional status and yield components of both maize and wheat crops along with nitrogen use efficiency. Field experiments were conducted in calcareous soil at Nubaria Agriculture Research Station farm during two successive seasons, summer season cultivated with maize (Zea mays L., cv Giza 10) and winter season cultivated with wheat ( Triticum aestivum L., cv Giza 168). Results showed that the highest significant yield components of maize and wheat crops along with their total content of the indicated macronutrients were observed when applied high rate of polyvinyl alcohol (0.2 %) accompanied with high rate of nitrogen fertilizer (100% N of recommended dose) as compared to other tested treatments. On the contrary, application of high rate polyacrylamide combined with low rate of nitrogen fertilizer generally was inferior for yield components of both maize and wheat plants. Also, data revealed that the nitrogen use efficiency was the highest (65.0 and 42.4) for maize and wheat plant, respectively, receiving 50 % nitrogen fertilizer rate in presence of 0.2 % polyvinyl alcohol. However, applied high rate of polyvinyl alcohol accompanied with low rate of nitrogen fertilizer was superior decreased pH values of soil as compared to either control or other tested treatments. An opposite trend for EC values which were superior increased in presences of all nitrogen fertilizer rates. Also, CaCO 3 values were lower when applied high rate of polyacrylamide in two seasons. The highest values of available nitrate and ammonium in soil were due to applied 0.2 % of polyvinyl alcohol combined with 75 % of nitrogen fertilizer rate compared to the other tested treatments.

A field experiment was conducted at Malawi Agric. Res. Station, Minia Governorate, Egypt during two successive winter seasons of 2014/2015 and 2015/2016 to study the effect of calcium humate (Ca-H), as organic soil conditioner, and nitrogen fertilizer rate under irrigation regime on soil chemical properties and faba bean productivity. The experiment was designed in a split plot design with three replicates, the main plots were occupied by three irrigation regimes: Farmer irrigation (I 1 ), irrigation requirement with 100% WR (I 2 ) and irrigation 75% WR(I 3 ) while sub-plots consists of four treatments (control, 100% N(recommended dose) , Ca-Humate (40 Lfed -1 ) and 75% N + Ca-Humate (40 Lfed -1 ). Results showed that seasonal water consumptive use increased by increasing available soil moisture as a result of increasing applied water, in general, in both growth seasons. The greatest values of seasonal consumptive use was recorded under farmer practice while the lowest value was recorded under irrigation treatment 75% WR (I 3 ).Also, the interaction effect between irrigation regime and N rates in combination with Ca-H data show that the highest water use efficiency is 1.00 kg seeds/m 3 water consumption was obtained by irrigation at 75% WR combined with 75% N+Ca-H at second season. The lowest water use efficiency is 0.30 kg seeds/m 3 water consumption was obtained by control treatment under farmer practice. Results revealed that mean values of different irrigation regimes had significantly increased growth characters of faba bean crop (yield, biological yields, 100 seed, plant height, number of branches, number of pods) were observed with I 2 (100% WR ) followed by I 1 (farmer practices) and I 3 (75% WR ), respectively. Applied Ca-H individually or in combination with mineral nitrogen fertilizer were significantlyincreased growth characters of faba bean (yield, biological yield, 100 seed, plant height, number of branches, number of pods) as compared to control treatment. The superior treatmentis75%N+Ca-H at 1 2 irrigation levels (100% WR). In addition, data reveal that I 2 irrigation treatment with 75% N+Ca-H was significantly increased macronutrients total content in (straw and seeds), protein content and protein yield in faba bean crop as compared to control treatment at two successive seasons. On the other hand, chemical soil parameters (pH and EC values) were slightly affected with all applied treatments and increased gradually by decreasing irrigation water. The maximum increased was observed with I 2 and applied 75%N+ Ca-H treatment. On the other hand, OM value was decreased with I3 more than I 1 and I 2 , as well as, it was increased by applied calcium hamates application.In conclusion, the application of Ca-H in combination with mineral nitrogen fertilizers was enhanced faba bean crop production and increased NPK content, protein content and protein yield along with improved soil chemical properties under irrigation regimes. Also, Ca-H can be saved about 25% from nitrogen fertilizer dose under low amount...

Cultivation of calcareous soils faces many difficulties due to its properties, as it lacks organic matter, as well as low availability of nutrients, especially phosphorous. This study, using two cereal crops (wheat and barley) to study the effect of compost as a source of organic matter and nano-hydroxyapatite as a source of phosphorus onsome properties of calcareous soil and P content in plants. The main plots were compost (C) with three doses C0 (without C), C1 (12 ton/ha) and C2 (24 ton/ha), the sub plots were different sources of phosphorous [the traditional P CaH6O8P2 (S0) and nano-hydroxyapatite (nHAP) with two rates of S1 (1.5 g/L) and S2 (3 g/L)]. The nano-hydroxyapatite is characterized by X-ray powder diffraction (X-ray), scanning electron microscopy (SEM). Obtained results stated that the biological yield, grain and straw of both wheat and barley were significantly increased with treatments as compared to C0 and S0, especially with C2 and S2. In addition, there is a positive trend between treatments rate and P contentin straw and grain of both crops, the maximum increase was observed with C2 and S2.Also, the application of compost led to a change in soil chemical properties, pH wasdecreased at treatments applied and such decreases were proportional to treatments concentration increase. An opposite trend was observed with organic matter (OM) and available phosphorus. In addition, there is a positive and highly significant correlation between grain yield with P content in plants.

A field experiment was carried out for two successive winter and summer seasons (2016)(2017) at Ismailia Agric. Res. Station in Ismailia Governorate, Egypt using wheat (Triticum sativa cv Giza 168) and peanut (Arachi shypogaea cv Giaz 5) crops to study the effect of organic soil conditioners individually or mixed with synthetic soil conditioners on physical and chemical properties of sandy soil, nutritional status and plant productivity. The experiment was arranged in split plots design with three replicates. Five forms of organic soil conditioners were applied as main plot consists of control (NPK), yeast sludge (YS) at rate of 2 kgfed -1 , commercial humic acids (HA at rate of 1 kgfed -1) , seaweed extract (SWE) at rate of 100 g fed -1 and filter mud (FM) at rate of 5 kgfed -1 ). While the sub main plot using synthetic soil conditioners as zero addition, carboxymethyl cellulose (CMC) at rate 2% and polyvinyl alcohol (PVA) at rate 0.2 %. Results cleared that the interference usage of organic soil conditioners in combination with synthetic soil conditioners had positively affect hydro-physical properties of the soil, i.e., decreasing soil bulk density, increasing total porosity along with dry stable aggregate, as well as, the superior treatment is SWE + CMC. In general, there is no valuable difference between SWE and organic residues, whereas, YS and FM have the same trend over to control. In addition, organic matter (OM) and available macronutrients N, P and K content in soil were increased significantly with all treatments applied compared to control, the maximum increases were observed with SWE application mixed with CMC. An opposite trend was obtained with both pH and EC values which generally decreased at all applied treatments especially with (SWE+ CMC) Therefore, the application of seaweed as organic soil conditioner individually or mixed with CMC or PVA which increased significantly both wheat and peanut biological yields, straw grain and/or seed, along with total N, P and K content as compared to either control or other organic treatments application. Moreover, obtained results showed highly significant correlation ( p< 0.05) between grain and/or yield and soil EC, OM, P and N in spite of none significant correlation with pH and K. Finally, it can be concluded that organic soil conditioner especially seaweed and sugar cane byproduct was enhanced and became more effective when applied with polymers especially CMC.

The use of biochar as soil conditioner, either alone or in association with fertilizer, may be considered a specific management for improving the soil properties which adverse crops productivity. A field experiment was carried out in a sandy soil, winter season cultivated with lupine and summer season cultivated with peanut, to study the effectiveness of applying particle size of biochar at different depths to improve soil properties, nutritional status and yield components of crops. The experiment included four particle sizes of biochar S1, S2, S3and S4 and three application depths D1, D2 and D3. Results indicated that, generally, the application of biochar particle sizes with different application depths led to increase lupine and peanut yields as well as their total content of macronutrients as compared to control treatment. Also, application of 10 mm biochar at D2 and 2mm bichar at D1 were significantly superior for lupine and peanut yields along with their total content of macronutrients, respectively. Data showed that the application of S1biochar and S4 biochar were superior decreased of pH values in the first and second seasons, respectively. The electric conductivity and organic matter were increased gradually with increase of biochar particle sizes in lupine soil, while these parameters in peanut soil being decreased. In conclusion, application of biochar, with different sizes and depths, as soil conditioners led to improve soil chemical properties and increased fertility in sandy soil which reflected on both tested yield components along with their total content of macronutrients under conditions of experiment.