Impact of Some Soil Amendments and Different Tillage Depths on Saline Heavy Clay Soils Properties and Its Yield Water Productivity

Soil salinity and sodicity are core limiting factors to sustainable agriculture activities in several parts of Nile Delta, Egypt. To such, we investigated the effects of combined applications of compost, gypsum and tillage practices on both soil physical, chemical properties in relation with wheat (Triticum aestivum L.) and maize (Zea mays L.) yields. Two field trials over two seasons (winter 2015/2016 and summer 2016) were conducted at the Experimental Farm, Sakha Agricultural Research Station, Kafr Elsheikh Governorate. Experiment was performed under split-plot design with 12 treatments and three replicates. Results showed that soil salinity, sodium adsorption ratio and exchangeable sodium percentage were highly significantly decreased due to application of gypsum and compost which recorded the lowest values under tillage depth at 60 cm. Data showed that the lowest values of soil bulk density and highest values of porosity were obtained by application of gypsum+compost, under tillage depth at 60 cm. Both of soil infiltration rate and hydraulic conductivity as well as water productivity and productivity of irrigation water took the same trend. Water application efficiency (%) and water consumptive use efficiency (%) were decreased with increasing tillage depth up to 60 cm as compared to plowing depth at 15 cm and 30 cm. Application of gypsum and compost individually or together highly significantly (p < 0.01) increased yield of wheat and maize, and recorded the highest values with gypsum+compost under tillage at 60 cm depth. Total income and net income were highly significantly increased with gypsum, compost or the combined application of these amendments, the net income recorded the highest value by 50% from soil gypsum requirements +5 Mg compost Fed.-1 (2.4 Fed.= hectare) under plowing depth at 60 cm for wheat. While the net income for maize recorded the highest values with 100% from soil gypsum requirements under the same plowing depth.