Allelopathy

Allelopathic potential of crop equalizers for weed management in wheat under semi-arid conditions of Pakistan Muhammad Ashraf professor of Agronomy, PMAS-Arid Agriculture University, Rawalpindi, Pakistan. emailprotected com RATIONALE Rainfed Wheat- Main pass crop grown by about 80% of the farmers on residual soil moisture, received during monsoon1. stools infestation- a major ease up reducing grammatical constituent (25-30%v) If widows weeds are controlled, crop yield can be enhanced by about 37%2. 1 Khaliq et al. , 2007) 2 (Bibi et al. , 2005). Cont..Existing Weed instruction sy topics traditionalistic weed control methods ( baseball mitt weeding) are time consuming, weather dependent and labor intensive1 + Socio-economic issuessmall land holdings, family size =8, p overty, migration to cities Herbicides use is limited in drylands + these are expensive with environmental hazards2 Reduced Nutritive value of many crops 3 and Herbicide resistance4. 1 (Naveed et al. , 2008 ) 2 (Mancini et al. , 2008) 3 (Nazarko et al. , 2003). Cont.. WM programs should focus on environmental safety along with benefits to the farmers. skip weed management sy fundaments need to be developed aimed to control weeds and raise the income of resource-poor farmers (increased crop yields) without despoiling the natural resource base. ALTERNATE WEED MANAGEMENT OPTIONS Allelopathy ? a mechanism of plant interference1 is a natural, inexpensive, environmentally safe and an organic approach to control weeds and increase crop yields while conserving the ecosystem2. genus sorghum molasses is highly allelopathic3 genus sorghum molasses residue may be effectively used to manage some of the important weeds in rainwaterfed wheat without affecting crop in semi-arid environment4. (Weston, 2005) 2 (Inderjit and Duke, 2003) 1 (Weston and Duke, 2003) 2 (Inderjit and Duke, 2003) Cont.. Water Extracts of different plant parts have different allelopathic potential 1. helianthus poss essed weed stifling ability 2 . The combination of 2 or more allelopathic aqueous chicken outs may act synergistically and cause more phyto-toxic effect on weeds 3. Mixing and applying sunflower and sorghum molasses residue water extract (WE) may increase the spectrum of phytotoxic effects and may result in synergistic phytotoxic influences on weeds growth. 1 (Ben-Hammouda, et al. 001 Chung, et al. , 2003 Roth et al. , 2000) 2 (Bertholdsson, 2004 Singh et al. , 2001 ) 3 (Duke et al. , 2000 Cheema et al. , 2010) Cont.. OBJECTIVES OF RESEARCH Overall objective Evaluate the use of allelopathic crop residue collected from summer crop plants grown under drought and mineral seek conditions for weed management in wheat in semi-arid areas of Pakistan Specific Objectives Test water extracts (WE)of different plant parts of sorghum residue for weeds suppression in wheat. Evaluate the effects of sorghum residue mulch and sorghum WE for weed management in wheat. Investigate the influence of sole and combined sorghum and sunflower WE spray on weeds in wheat. EXPERIMENTAL DETAILS Location Three experiments were conducted at University Research Farm, PMAS-Arid Agriculture University, Rawalpindi, Pakistan (33o 46 N, 73o 08 E). / / 500 m above the sea level Experimental years successive Rabi (winter) seasons from 2007-2010. Cont.. Environmental Characterization Climate Rainfall and ET o 200 clx Rainfall and ET0 (mm) 160 143 120 ETo 80 40 0 Oct Nov Dec Jan Feb Mar Apr Rain 140 121 Mean Monthly Rainfall (mm) 20 100 80 67 60 40 26 57 56 Sever Stress Period 27 21 7 15 39 43 20 0 Month Rainfall Distribution (1977-11) Source Soil and water conservation Research Institute, Chakwal, Pakistan Growing Season Rainfall Period Monthly rain (mm) Oct Nov Dec Jan Feb March April Total 2006-07 2007-08 2008-09 2009-10 Long-term Av. (1977-07) 0 42 30 0 166 147 14 20 7 15 27 39 56 43 Soil characteristics Rawal soil series (Inceptisol-silty-clay-loam, Typic Ustochrept USDA classificati on and Calcaric Cambisols FAO classification scheme) with Organic matter 0. 5%. pH 7. 40 Ece 3 dSm-1 Cont.. Weed Flora Anagallis arvensis L. (Blue pimfernal), Chenopodium album L. (Lambs quarter), Fumaria indica L. (Fumitory), Medicago polymorpha L. (Bur clover) Avena fatua L. (Wild oat), Convolvulus arvensis L. (Field bindweed), Medicago denticulata L. (Denticulate Medick), Rumex dentatus L. (Toothed dock) and Melilotus indica L. (Sweet clover) The experimental area was free of noxious and unending weed species. Treatments (Exp-1) Control (Un-weeded check) WE Water extract Hand weeding at 60 days after sowing ( coney) Herbicide (Logron) 250 g ha-1 at 60 das genus Sorghum root WE spray 10 L ha-1 at 60 and 80 DAS Sorghum stem WE spray 10 L ha-1 at 60 and 80 DAS Sorghum folio WE spray 10 L ha-1 at 60 and 80 DAS Sorghum stem + root WE 5+5 L ha-1 at 60 and 80 DAS Sorghum stem + leaf WE 5+5 L ha-1 at 60 and 80 DAS Sorghum root + leaf WE 5+5 L ha-1 at 60 an d 80 DAS Treatments (Exp-2) WE Water extract Control (Un-weeded check) Hand weeding at 50 and 80 DAS Sorghum mulch 5 Mg ha-1 (Soil incorporated) Sorghum mulch 10 Mg ha-1 Soil incorporated) Sorghum WE 10 L ha-1 at 50 DAS. Sorghum WE 10 L ha-1 at 50 and 80 DAS. Sorghum WE 20 L ha-1 at 50 DAS. Sorghum WE 20 L ha-1 at 50 and 80 DAS Treatments (Exp-3) Control (Un-weeded check) WE Water extract Sunflower WE 20 L ha-1 at 50 DAS Sorghum WE 20 L ha-1 at 50 DAS Sunflower WE + sorghum WE 10 +10 L ha-1 at 50 DAS Sunflower WE 20 L ha-1 at 50 and 80 DAS Sorghum WE 20 L ha-1 at 50 and 80 DAS Sunflower WE + sorghum WE 10 + 10 L ha-1 at 50 and 80 DASResearch Methodology Preparation of water extract Sunflower and sorghum plants were harvested at maturity, grains were separated and residue was sundried and chaffed with fodder cutter into 2 cm pieces. Chaffed residue was soaked in de-ionized water in 110 (1 kg each of grass in 10 L of water) in separate containers for 24 h at room temperature to prepare water extract (WE) . WE from respective containers were obtained by filtering the mixture by means of a screen. The volume of respective filtrate was reduced twenty times by continuously boiling at 100 0C to prepare water extract (Cheema and Khaliq, 2000). Sowing and cultural practices Seedbed was prepared by giving four cultivations each followed by planking. Fertilizer 125- kg N and P2O5 ha-1 was applied at the time of seedbed preparation. Wheat cv. Inqilab-91 was spill 125 kg ha-1 was during November with a single row achieve drill in rows 30 cm apart(predicate). Layout design RCBD with 4R Eight rows 30 cm apart per treatment were maintained in plot size of 7. 0 x 2. 4 m. The wheat variety, sowing time, layout plan and other cultural practices were almost same for all(prenominal) year. Measures Weeds Weed assiduousness Weed dry weight (biomass) Wheat Spike length (cm), bradawls spike-1 Grains spike-1 Fertile tillers m-2 1000-gra in weight. Statistical analysis The data were subjected to analysis of edition technique. F-statistic was based on residual mean square error.The LSD at 5% level of probability was used for comparison of treatment means (Montgomery, 2001). RESULTS & parole Experiment 1 Phyto-toxic effects of root, stem and leaf water extract of mature sorghum on Weeds density & Dry weight Treatments Control (Un-weeded check) Hand weeding at 60 DAS Exp-1 Weed density ( m-2) 80 DAS 105 DAS Weeds dry weight (g m-2) 80 DAS 105 DAS 147 a 79 d (-46*) 132 a 78 f (-41) 36. 7 g (-72) 102 c (-22) 112 b (-15) 113 b (-14 88 e (-33) 94 de (-29) 102 cd (-23) 8. 52 2 a 12 e (-45) 5. 5 f (-75) 18 cd (-16) 20 b (-8) 20 b (-8) 17 d (-22) 17 cd (-20) 19 bc (-14) 1. 54 27 a 17 e (-38) 8. 77 f (-67) 21 c (-21) 24 b (-11) 23 b (-14) 18 e (-34) 20 d (-27) 27 c (-20) 1. 57 Herbicide (Logron) 250 g ha-1 34 e (-77) at 60 DAS Sorghum root WE spray 10 L 117 c (-21) ha-1 at 60 and 80 DAS Sorghum stem WE spray 10 L 129 b ( -12) ha-1 at 60 and 80 DAS Sorghum leaf WE spray 10 L 127 b (-14) ha-1 at 60 and 80 DAS Sorghum stem + root emailprotected 5+5 L 113 c (-23) ha-1 at 60 and 80DAS Sorghum stem + leaf emailprotected 5+5 L 111 c (-24) ha-1 at 60 and 80 DAS Sorghum root + leaf WE 5+ 5 121 bc (-18) L ha-1 60 and 80 DAS LSD (0. 05) 10. 41 * Figures in parenthesis show % decrease in weed density/dry weight compared to control. accomplishment of root, stem and leaf water extract of mature sorghum on yield components and wheat grain yield Treatments Control (Un-weeded check) Tillers (m-2) Spike length (cm) Spikelet spike-1 Grains 1000-Grain spike-1 weight (g) Exp-1Grain yield (T ha-1) 345e Hand weeding at 60 DAS 396b Herbicide (Logron) 250 g 427a ha-1 at 60 DAS Sorghum root WE spray 10 L ha-1 at 60 and 80 DAS Sorghum stem WE spray 10 L ha-1 at 60 and 80 DAS Sorghum leaf WE spray 10 L ha-1 at 60 and 80 DAS Sorghum stem + root emailprotected 5+5 L ha-1 at 60 and 80 DAS Sorghum stem + leaf emailprotect ed 5+5 L ha-1 at 60 and 80 DAS Sorghum root + leaf WE 5+ 5 L ha-1 60 and 80 DAS LSD (0. 05) 9. 0e 10. 3abcd 11. 2a 10. 0bcde 9. 5de 9. 8cde 10. 9 ab 10. abc 10. 7 abc 1. 03 20. 7 21. 0 20. 9 21. 1 20. 5 21. 1 20. 2 21. 0 20. 2 41. 7c 47. 3ab 49. 4a 48. 8ab 47. 3ab 46. 1b 49. 0ab 48. 0ab 48. 0ab 3. 04 32. 5e 33. 7d 34. 6bc 35. 6a 33. 6d 33. 1de 36. 0a 33. 9cd 35. 2ab 0. 90 2. 76f 3. 2bc (+18) 3. 5a (+26) 3. 1cde (+12) 3. 0de 2. 9ef (+8) (+6) 365cde 353de 349e 357de 385bc 376bcd 54. 45 3. 3ab (+20) 3. 3abc (+19) 3. 2bcd (+14) 213. 2 * Figures in parenthesis show % decrease in weed density/dry weight compared to control.FINDINGS FROM EXPERIMENT 1 Sorghum stem + root emailprotected 5+5 L ha-1 at 60 and 80 DAS treatment caused 33% reduction in weed density and dry weight by about This reduction was 41% in hand weeding and 72% by the application of Logron 250 g ha-1 at 60 DAS The increase in grain yield in stem + root and stem + leaf WE treatments were statistically same as in hand weeding and herbicide application. Cont.. Experiment 2 RESULTS & DISCUSSIONFINDINGS FROM EXPERIMENT 2 Data showed that incorporation of sorghum herbage mulch 10 Mg ha-1 and twotimes sprays of Sorghum water extract 20 L ha-1 at 50 and 80 DAS decreased weeds density by about 42%, and weeds dry weight by 34%, respectively compared to control measured at 95DAS. Maximum increase (33%) in wheat grain yield was recorded in plots where two times Sorghum WE 20 L ha-1 was sprayed at 50 and 80 DAS over control. Cont.. Experiment 3 RESULTS & DISCUSSIONFINDING FROM EXPERIMENT 3 Sorghum water extract was more effective than sunflower water extract and combination of both these extracts performed expose than their sole application. Cont.. CONCLUSION I. Stem + root water extract suppressed weed density by 33% over control i. e. about half(prenominal) of the effects of herbicide Logron application (72%) in wheat. The increase in grain yield in stem + root and stem + leaf WE treatments w as statistically at par with hand weeding and herbicide application.Although root WE alone and in combination with stem or leaf WE was more effective in suppressing weeds and improve wheat yields but using whole plant sorghum herbage seems more practicable. II. Incorporation of sorghum herbage mulch 10 Mg ha-1 and two times sprays of sorghum WE 20 L ha-1 at 50 and 80 DAS decreased weeds density by about 42%, and weeds dry weight by 34%, respectively compared to control measured at 95 DAS. Maximum increase in wheat grain yield by 33% over control was recorded in plots where two times sorghum WE 20 L ha-1 was sprayed at 50 and 80 DAS.III. Sorghum WE was more effective than sunflower WE and mixture of sorghum and sunflower reduced weed density and weed dry weight by 27% and 26% over control respectively, and increased wheat yields by 48% over control. RECOMMENDATION The mixture of preceding allelopathic crop herbage use as mulch or water extract for weed management both for summer and winter crops need to be further investigated under different ecological zones of Pakistan. Muhammad Ashraf Professor of Agronomy emailprotected com