N. Abu-hamdeh et M. Abu-qudais, The economics of mechanical versus chemical weed control in peas and lettuce under different tillage systems and irrigation regimes, J AGR ENG R, 79(2), 2001, pp. 177-185
A study was conducted to compare the economics of four systems of weed mana
gement under three irrigation regimes and tillage systems. The effects of w
eed management system and irrigation regime and their interactions on peas
and lettuce yields were investigated. The research project utilized a facto
rial design with type of weed management system crossed with irrigation reg
ime and tillage system. The four weed management systems were chemical herb
icides only, chemical herbicides and mechanical cultivation, mulch control
and mechanical cultivation and mechanical cultivation only. The three irrig
ation regimes were 25% of the crop water requirements, 50% of the crop wate
r requirements and 100% of the crop water requirements. The three tillage s
ystems were chisel ploughing as primary tillage followed by disc harrow as
secondary tillage, mouldboard ploughing as primary tillage followed by rota
ry tiller as secondary tillage and zero tillage. The average pea and lettuc
e yields for 2 years for each of the four weed management systems at the th
ree irrigation regimes and tillage systems were analysed and reported. Mach
ine and chemical costs were calculated by using current list prices of mach
inery and actual costs of chemicals. Based on results from field tests, it
was found that weed management method affected pea and lettuce yields. Mech
anical cultivation between the rows and using plastic mulch to cover the ro
ws gave the highest pea and lettuce yields. Tillage system also affected yi
elds of the two crops. It was found that zero tillage produced higher yield
s than chisel and mouldboard tillage systems. Percentage increases in yield
between 8 and 31% were obtained with zero tillage treatments compared to t
he other two tillage systems. Irrigation regime significantly affected pea
and lettuce yields. The irrigation regime (100% of the plant requirement) p
roduced the highest yields. The results of this analysis showed that mechan
ical weed control with zero tillage practice was the alternative with the l
owest machinery investment and total machinery and labour costs per hectare
per year, followed by chisel tillage and finally mouldboard tillage. (C) 2
001 Silsoe Research Institute.