The effect of gypsum formation and content on barley growth and yield under drip irrigation system

Field experiments were carried out in the selected three sites (BeniSuef, Fayoum; Minya, Egypt) that differs in formation conditions and content of gypsum during the two winter successive seasons of 2015 and 2016, to study the effect of gypsum content under two irrigation treatments (100 and 80 % from ETo) on barley drip irrigated growth characters and soil macro and micronutrients content. The obtained results cleared that all profiles contain on specific diagnostic horizons such as salic, calcic and gypsic horizon associated with the formation of gypsic soils. These horizons are dominated in all studied profiles. However the intensity of these horizons varied from one profile to another according to the concentration of soluble salts and thickness of the horizon. The selected three profiles, based on the climatologically conditions, physical, chemical analysis and morphological description, could be classified to TypicCalcigypsids. Barley plant height was enhanced under 100 %ETo than 80%. It could arrange the sites in descending orders as follows: BeniSuef>Fayoum>Minya. Decreasing irrigation treatments from 100 to 80 % decrease plant height by about 13, 12; 17 % for Minya, Fayoum and BeniSuef, respectively, while the reduction percentage relative to irrigation treatment was 13% in same sequence. Both of the no. of spikes and seed index strongly affected by irrigation treatments, where the highest values were attained under 100 %ETo irrigation treatment than 80 %. The percentage reduction of no of spikes and seed index was 7 and 11 % relative to irrigation treatments.Obtained data revealed that the highest grain and straw yield were obtained at BeniSuef (1154; 984 kg/fed) followed by Fayoum sites (612, 504 kg/fed) under 100 and 80 % ETo irrigation treatments. Also, data noticed that increasing irrigation water lead to alleviate salinity effect and increasing the yield of both straw and grains of barley. Irrigation treatment at 100% ETo has a positive effect on the straw and grain yield of the barley. The percentage of the increase of the straw and grain barley yield was about 13%. The highest water use efficiency (WUE) valuewas attained at BeniSuef (80%ETo) 0.74 kg/m(3) and the lowest one was 0.42 kg/m3 attained at Minya (100 %ETo). Data noticed that decreasing irrigation treatment from 100 to 80% ETo led to increase WUE. The highest WUE percentage increase relative to stress treatment (80% ETo) was recorded at BeniSuef (21.1%) followed by Fayoum (14.5%) and Minya (2.4%).The values of macro N, P, K were highly under 100 % ETo than 80 %. Decreasing irrigation treatments from 100 to 80 %ETo associated with decrease the available studied nutrients.