Allelopathic Activity of Crop Residue Incorporation Alone or Mixed Against Rice and its Associated Grass Weed Jungle Rice (Echinochloa colona [L.] Link)

Abstract

Weed suppression is one of the several benefits achieved by soil incorporation of crop residues and such suppression is believed to be allelopathic in nature. The allelopathic potential of different crop residues: viz. sorghum (Sorghum bicolor [L.] Moench), sunflower (Helianthus annuus L.), brassica (Brassica campestris L.) was evaluated in rice (Oryza sativa L.) and jungle rice (Echinochloa colona [L.] Link). Chopped crop residues were soil-incorporated alone and mixed at 6 g kg-1 soil (12 t ha-1) and compared with a control without residues. Soil incorporation of residues substantially delayed germination of jungle rice. The time to start germination, time to 50% emergence, mean emergence time, emergence index, and final germination percentage were all depressed by residue incorporation. Final germination of rice and jungle rice dropped by 11 to 15% and 11 to 27% with residue application alone and by 18 to 22% and 8 to 34% with a combination of crop residues, respectively. Residues were more suppressive to germination dynamics of jungle rice than rice. Crop residues exerted a pronounced negative influence on the shoot (25 to 100% and 14 to 44%) and root lengths (22 to 100% and 10 to 43%) of rice and jungle rice, respectively. Shoot and root dry weight of both rice and jungle rice also decreased significantly. An appreciable quantity of phenolics was recorded in soil amended with sorghum+sunflower+brassica residues. Since soil incorporation of allelopathic crop residues was detrimental to both rice germination and seedling growth, it is suggested that the time of residue application for jungle rice suppression and rice seeding time need to be adjusted so as to minimize rice crop damage.

Allelopathic Effect of Spinacia Oleracea L. And Psidium Guajava L. On Vigna Radiata L. Var. KM-2 and Vamban-2

“…Only on 5 th day the utmost germination observed (Table 1 and 2). This result correlates with the results of Khaliq et al (2011), where delayed seed germination observed in rice treated with crop residues of sorghum, sunflower and brassica. In the present study, phytotoxicity of both plants is presented in Figure 1 and 2.…”

Wheat Residue Management Options Affect Crop Productivity, Weed Growth, and Soil Properties in Direct‐Seeded Fine Aromatic Rice

“…Crop residues can suppress weeds through physical hindrance, or by posing chemical effects (allelopathy). Wheat is a potent allelopathic crop [14] and inhibitory effects of wheat residues upon decomposition to certain weeds have been well documented [14][15][16]. Incorporation of crop residues suppresses weeds through the release of phytotoxins [16], while mulching of crop residues produces a smothering effect on weeds [17].…”

Bio-Economic and Qualitative Impact of Reduced Herbicide use in Direct Seeded Fine Rice Through Multipurpose Tree Water Extracts

“…Although efficient, the judicious use of herbicides has also been questioned since it is widely believed that they cause resistance in some previously susceptible weed species; serious environmental concerns also arise due to their high residual effects in the soil (Ahn et al, 2005;Khaliq et al, 2011b). An international survey conducted in 70 000 fields revealed that over 383 biotypes of 208 weed species (122 dicots and 86 monocots) have evolved to be resistant to herbicides (Heap, 2012).…”