Integrated effects of controlled traffic farming and irrigation scheduling on water productivity and yield of pumpkin under semi-arid sprinkler irrigation
Water-use efficiency in semi-arid agriculture is strongly influenced by irrigation management and soil structural conditions within the crop root zone. Repeated machinery traffic can degrade soil pore continuity and hydraulic conductivity, reducing infiltration efficiency and limiting productive water use under sprinkler irrigation systems. This study evaluated the combined effects of controlled traffic farming (CTF) and irrigation depletion regimes on seasonal crop evapotranspiration (ETc), growth, yield, and water productivity of pumpkin (Cucurbita pepo L.) under semi-arid field conditions in Kirkuk Governorate, Iraq, during the 2024 growing season. A split-plot randomized complete block design was used with three irrigation depletion levels (30%, 45%, and 60% of available soil water) as main plots and two traffic systems (CTF and random traffic farming [RTF]) as subplots. Seasonal ETc was higher under RTF (445–455 mm) compared to CTF (350–375 mm), indicating reduced water loss under controlled traffic. The highest yield (28 Mg ha−1) and water productivity (0.95 kg m−3) were achieved under the combination of CTF and 45% depletion. Severe depletion (60%) reduced growth and yield due to excessive water stress, while 30% depletion likely caused over-irrigation, reducing aeration and increasing non-productive water use. Overall, CTF improved soil hydraulic behavior and enhanced irrigation efficiency by minimizing traffic-induced compaction. Regression analysis revealed strong relationships among ETc, irrigation depletion, traffic system, and water productivity (R2 = 0.91). The results suggest that integrating controlled traffic farming with moderate irrigation depletion optimizes soil water availability and root-zone aeration, thereby improving productive water use in semi-arid irrigated agriculture.
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