Grapevine row orientation affects light environment, growth, and development of black nightshade (Solanum nigrum)

Abstract

Row orientation in vineyards can affect the quantity of light intercepted by the crop's canopy. Consequently, the light available to weeds growing under the canopy might also be affected, with potential implications for their physiology, growth, and productivity. This hypothesis was tested in 2003 and 2004 in a central California vineyard having rows oriented east–west (EW) and north–south (NS) in a randomized complete block design. In April of both years, potted black nightshade seedlings were placed under grapevines of both row orientations and grown for about 10 wk. Photosynthetically active radiation (PAR) at the weed canopy zone (WCZ) of NS rows was bimodal, with peaks occurring at about 09:30 A.M. and 4:30 P.M. At those times, PAR approached 500 μmol m−2 s−1 (between 30 and 40% of full sun). In contrast, maximum PAR in the WCZ of EW rows was generally less than 75 μmol m−2 s−1 throughout the day. The ratio of red to far-red light was also greater in NS than EW rows in the morning and afternoon. In both row orientations, PAR was suboptimal for nightshade because maximum net photosynthesis occurred at light levels ≥ 500 μmol m−2 s−1, but nightshade in the NS rows had higher net photosynthetic rates than those in EW rows when subjected to higher ambient PAR. Stem extension and phenology of nightshade was not affected by vine row orientation, but plants in EW rows had greater leaf areas, leaf area ratios, leaf weight ratios, and lower specific leaf weights than plants in NS rows. Berry mass, seeds per berry, and estimated seed production was 40, 7, and 20% lower, respectively, for plants in the EW than in the NS rows. Dry mass and total nonstructural carbohydrates (TNC) of nightshade roots were also 25 and 45% lower, respectively, in EW than in NS plants. Thus, grapevine row orientation may affect nightshade fecundity by reducing light in the WCZ.

Weed growth and crop yield loss in wheat as influenced by row spacing and weed emergence times

“…Studies with a number of crops like wheat (Kristensen et al, 2008;Mashingaidze et al, 2009), rice (Chauhan and Johnson, 2010a;Khaliq et al, 2014a,b), barley (Kolb et al, 2010), cotton (Reddy, 2001), millet (Shinggu et al, 2009), sorghum (Grichar et al, 2004), and soybean (Hock et al, 2006), have shown inverse relationships between narrow crop rows and weed growth. Although wider crop rows facilitate weed control by intercultural operations, weed growth in wheat is usually suppressed by narrow row spacing (Shrestha and Fidelibus, 2005).…”

Manipulating crop row orientation and crop density to suppress Lolium rigidum

“…In a field crop agro‐ecosystem, the intense competition for light indicates that maximising light availability to crops while minimising light availability to weeds will suppress weed growth (Holt, ; Ballare & Casal, ; Zimdahl, ). Physically orientating crop rows, such that they shade the weeds in the inter‐row space, can substantially reduce weed growth (Shrestha & Fidelibus, ; Borger et al ., ; Alcorta et al ., ). The biomass of Conyza canadensis (L.) Cronq.…”

“…(Canadian fleabane, horseweed) was reduced by 30% in east–west (EW) orientated grapevines ( Vitis vinifera L.) compared with north–south (NS) vines (Alcorta et al ., ). Likewise, the dry biomass and seed production of Solanum nigrum L. (black nightshade) were reduced in EW grapevines by 25% and 20% respectively (Shrestha & Fidelibus, ). Biomass of several weed species (predominantly Lolium rigidum Gaudin and Raphanus raphanistrum L.) in EW orientated wheat ( Triticum aestivum L.) or barley ( Hordeum vulgare L.) crop rows was reduced by 51% and 37% in Western Australia (WA) (Borger et al ., ).…”

Manipulating Crop Row Orientation to Suppress Weeds and Increase Crop Yield

“…The growth of poison ryegrass (Lolium temulentum L.), littleseed canarygrass (Phalaris minor Retz. ), wild oat (Avena fatua L.), and common vetch (Vicia sativa L.) in wheat ('308') crops and black nightshade (Solanum nigrum L.) in vineyards (Vitis vinifera L.) were influenced by crop row spacing and orientation (Angiras and Sharma 1996;Sharma and Angiras 1996a,b;Shrestha and Fidelibus 2005). Furthermore, in the absence of weeds, orientation affected crop yield or soil moisture relations in olive (Olea europaea L.) and apple (Malus domestica Borkh.)…”