*5.2.1 Crop rotation*

Crop rotation enhances cucumber productivity by improving weed control and soil productivity. Continuous cultivation and tillage systems have negative interaction with each other and results in a shift in weed species composition with consequence difficulty in weed management [58]. A shift from cucumber to other crops of different life cycle, physiology and morphology serves as an important means of preventive weed control when cucumber is grown over time in the same field [42]. This practice has potential to reduce weed density and biomass, particularly when a competitive crop is rotated and an effective direct weed control tillage system is applied [5, 41]. On the other hand, continues cropping increases the risk of resistant weeds as a result of the application of similar cultural practices and herbicides of same chemistry for longer periods [21]. Broad-leaf weeds which are difficult to control in cucumber and other vegetables can be controlled readily in cereal crops. Crop rotation is particularly important in cucumber production because of its disease control benefit and weed control flexibility [59]. Cucumber-tomato, cucumber-pepper and cucumber-eggplants, rotation in farmers' fields showed that the rotation of cucumber with other vegetable crops is agronomically practicable, sustainable, and an eco-friendly technique for better weed control and economic benefits [59, 60].

#### *5.2.2 Primary tillage*

Primary tillage is an integral part of cucumber production system that enhances field preparation for planting operation. The tillage system used directly affect soil structure, plant available moisture and intensity of weed problem. Soil inversion during tillage is considered to be very beneficial for weed control [61]. The implement used and the depth of the tillage operation determines the impact of primary tillage in cucumber farming. The use of moldboard plough is an effective way to reduce weed density during the early growth stages of the cucumber crop [61, 62]. Weed densities and biomass are usually higher in zero or minimum tillage systems than in conventional tillage systems that involves the use mold plough [10, 61–63]. It was reported that cucumbers planted into no tillage rye had greater weed size compared to conventional tillage [61]. Reduced tillage was also reported to encourage increased perennial weed species in weed population in cucumber fields compared with conventional tillage [61, 62].

#### *5.2.3 Stale seedbed*

The use of stale seedbed is another cultural practice for suppressing weeds in cucumber. A stale seedbed is defined as a seedbed prepared several days, weeks, or month prior to planting or transplanting a crop [64]. In this method, resurgent

**117**

planting [73, 74].

**6. Mechanical weed management**

*Weed Interference and Management in Cucumber (*Cucumis sativus *L.)*

weeds in ploughed field are controlled by the use of tillage while irrigation or rain are used to stimulate weed seed germination. The flush of young seedlings is then killed by using shallow tillage or herbicides [65]. This method has been successfully used to reduce competition of several weed species including *Palmer amaranth*, and yellow nutsedge in cucumber [32]. Stale seed bed reduced weed infestation with the applications of glyphosate and paraquat on the seedbeds to control emerged

Soil solarization is another non-chemical weed control technique in cucumber production. This technique involves hydrothermal disinfection of moist soil by transparent polyethylene sheets during the hot summers. These sheets entrap the sunlight and increase the temperature of upper layers of the soil by 8–12 °C compared with the non-mulch soil. The elevated temperature kills some of the seeds and breaks the dormancy of others. While the solar scorching kills the newly emerged weed seedlings [67]. Soil solarization is a simple, non-hazardous method that avoids the use of any toxic materials, does not contaminate the site and therefore suited for organic cucumber farming. The effectiveness of this method of weed control has been reported in cucumber crop [68, 69]. Soil solarization proved to be an excellent method for complete control of parasitic weed specie such as Egyptian broomrape (*Orobanche aegyptiaca*) and other weed species such as *Sorghum virgatum, Chenopodium album, and Purtulaca oleracea* infestation in cucumber [68–70].

Manipulation of crop row spacing and planting density can restrict weed seed germination and enhance the crop competitive ability against weeds [71]. Narrow row spacing and high plant densities are important techniques in enhancing cucumber competitiveness and suppressing weed growth [16, 72, 73]. These techniques are very cost-effective and environmental friendly. When the optimum plant population density is used through appropriate row spacing, cucumber crop is able to develop canopy cover and hence competitive advantage over emerging weed seedlings [73]. Narrow row spacing is known to suppress weed growth by closing crop canopy earlier than wide spacing. Early canopy cover by closely spaced cucumber has been shown to smother weeds, hence reducing weed-crop competition [16, 74]. Cucumber planted at narrow plant spacing of 1 m × 0.3 m resulted in earlier canopy closure and better weed suppression than those planted at 1 m × 0.6 m and 1 m × 0.9 m [73]. In another study, spacing of 75 cm × 25 cm resulted in weed density and biomass suppression compared to spacing of

75 cm × 50 cm and 75 cm × 75 cm in cucumber [73]. Herbicides work well with narrow spacing as it impacts the weeds by decreasing their vigor due to high competition with the cucumber plants in narrow row planting compared to the wide row

Mechanical weed management involves the physical removal of weeds from the field by hand pulling or through the use of farm tools and implements such as hand hoes, cutlasses, cultivators, choppers, mowers disks or weeders [75, 76]. Mechanical weed management is one of the oldest weed control practice. It involves the practices of primary and secondary tillage. With mechanical weed

*DOI: http://dx.doi.org/10.5772/intechopen.99564*

weeds [66].

*5.2.4 Soil solarization*

*5.2.5 Plant density and row spacing*

#### *Weed Interference and Management in Cucumber (*Cucumis sativus *L.) DOI: http://dx.doi.org/10.5772/intechopen.99564*

weeds in ploughed field are controlled by the use of tillage while irrigation or rain are used to stimulate weed seed germination. The flush of young seedlings is then killed by using shallow tillage or herbicides [65]. This method has been successfully used to reduce competition of several weed species including *Palmer amaranth*, and yellow nutsedge in cucumber [32]. Stale seed bed reduced weed infestation with the applications of glyphosate and paraquat on the seedbeds to control emerged weeds [66].
