Conservation versus conventional tillage on performance of three different crops
Conservation tillage, besides being more economical, prevents soil erosion and has other beneficial effects on our environment, but few studies have been conducted on differential responses of different crops to conservation tillage. The main objective of this study was to examine the interaction of tillage with crop species. Rainfed field experiments in a strip-plot design with four replicates were conducted in the semiarid, central Bekaa Valley of Lebanon for 2 yr. There were three tillage treatments: conventional (CT), minimum (MT), and no tillage (NT). Crops studied were barley (Hordeum vulgare L.), chickpea (Cicer arietinum L.), and safflower (Carthamus tinctorius L.). The experiment was initiated in 2005–2006 on a field in which CT was practiced for years. In 2006–2007, the experiment was conducted on the exact site following the same 2005/2006 randomization. In each year, NT had similar weed density and dry weight m–2 as CT, and mean weed infestation over years was lower in CT and NT than in MT. Year x tillage x crop interaction was significant for plant height in April, days to flowering/heading, seed yield, and harvest index. Tillage x crop interaction existed for seed and straw yields, harvest index, and plant height at maturity. Barley yielded poorer in NT than in CT, but similar yields were obtained in NT and CT for chickpea and safflower, suggesting that the tap root system of chickpea and safflower may be more adapted to NT than the fibrous root system of barley. Results of this study could be used to organize demonstration trials to help encouraging farmers to try practicing NT.