Studies on conservation agriculture in Egypt

Abstract

Four field experiments were carried out at Gemmieza Agricultural Experimental Research Station, AL-Gharbia Governorate during the four seasons of winter, 2012/2013, summer 2013, winter 2013/2014 and summer 2014 under exhausted clay soil condition to study the effect of three different tillage systems (conventional tillage (CT), conservation agriculture (CA) and semi-CA (SCA)) and two levels of NPK fertilizers (100% of the recommended doses of NPK and 1/2 recommended doses of it) on yield and its components of wheat (Gemmeiza-9 variety) and soybean (Giza-111 variety) through (maize–wheat–soybean–wheat–soybean) (M/W/S/W/S) cropping system.Results revealed that, during the winter season of 2012/2013, all studied wheat traits and gross energy (kcal/kg) significantly were increased by feeding 100% of the recommended doses of NPK fertilizer compared by adding the half NPK doses.The effect of tillage systems during the summer season of 2013 did not differ significantly due to studied soybean traits. During the winter season of 2013/2014, the results showed that, CA tillage system increased significantly all the studied wheat traits as compared with the other tillage systems. Referring to the summer season of 2014, CA system scored significant high values for the studied soybean traits.As for the effect of studied NPK fertilizer levels, results indicated that, 100% of the recommended doses of NPK favored the values of the studied soybean and wheat traits significantly during summer 2013 and winter 2013/2014, as compared by 50% of the recommended dose of NPK fertilizers, while there are no significant differences between the two fertilizer levels for soybean traits in the third season (summer, 2014).With regard to the first order interaction effect between the tested factors, results of the three trial seasons revealed that growing soybean or wheat under the condition of conservation agriculture (CA) and fed by 100% or 50% of the recommended dose of NPK fertilizers scored the greatest values for most of soybean studied traits and wheat, and the differences between them did not reach the significant level. In contrast, the lowest values were resulted under the condition of conventional tillage (CT) and fed by 50% of the recommended dose of NPK fertilizers.As for the recorded improvement of soil fertility, results indicated that, CA led to decrease the EC by 2.21% and increased the organic matter (OM) by 391.5% and available N by 210.7%, P by 272.7% and K by 183.5% under the condition of half recommended dose of NPK fertilizer as compared with the analysis before starting the project plan. It is worthy to mention that the comparison between CT and CA system under the condition of half NPK dose fertilizer cleared, and CA exposed its superiority to improve the soil content of OM by 20.6%, available N by 42.62%, and P by 10.06% and K by 42.5% as compared with CT system.