Studies on weed control in sugarcane and allelopathic effect eucalyptus on field crops

Abstract

Different herbicides were evaluated for the control of the weed Conyza slricta in sugarcane planted at different geometrical pattems under agro-ecological conditions of I. Khan during 2000-2001 and 2001-2002. The experiments were conducted in randomized complete block design with split plot arrangement with treatment replicated thrice. Main plots comprised of various planting geomelries whereas sub plots were of herbicidal treatments. Weed parameters recorded were population, height, branches, leaves, fresh and dry weight per single weed plant. Sugarcane parameters recorded were stalks stool", height, weight with and without top. slem girth and Inter- nodes per cane and yield in Ions per hectare. Benefit cosl ratio (BCR) was computed for determining economic benefit. Means of various parameters depicted that planting geometries Significantly differed weed and sugarcane. The planting geometry of triple rows al120 em produced the highesl in the weed populalion and gave the highest yield of 58.2 t ha-' as compared 10 other geometries used in this study. All the herbicides signi1icanUy decreased weed population and increased cane yield ha-' compared to control. The herbicide Oleuran MA60 alone gave the highest cane yield of 59.33 t ha-' at planting geometry of triple rows at 120 em and t ha-' when averaged across geometries. The control gave Significantly lowest yield of 33,381 ha-'. The herbicide Dieuran MA60 gave the highest benefit cost ratio (BCR) of 2.19 and the highesl gross income of Rs, 51,9131- at planting geometry of triple row at 120 em, The lowest BCR ratio of 1 with the lowest gross income of 36,164/- was depicted in the control on the same planting geometry. It is suggested that for obtaining economic yield firom sugarcane at D, I. Khan. it may be planted at triple rows 120 em apart with ix application of Dlcuran MA60 30 days after planting for control of Conyza slricta. Eucalyptus has become an Integral part of agro-forestry. It is notorious for having allelopathic effsicts on growth 0/ agricultural crops growing In its vicinity. The allelopathic effects of Eucalyptus camaldulensis leaf extracts were evaluated on the growth parameters of cotton and maize with the objective to develop recommandation for growing these aops dose to eucalyptus The different extrects were preparad by soaking, boiling and crushing leaves in water. All the eucalyptus leaf extracts significantly reducad seed germination and other growth parameters of both the crops compared to control. Soaked extract ellt1ibited the highest decrease in root and crushed extract in shoot growth parameters of maize, In cotton, root and shoot growth parameters except length, the highest decrease was LelU"",,, by crushed soaked extracts, respectively. The boiled extract decreased germination of maize and cotton to 66 and 57% respectively compared to and 97% germination In control. It is recommended that maize and cotton may not be planted very close to eucalyptus trees due to likely adverse effects on seed germination and other growth parameters.