اثر سطوح مختلف کود دامی بر ترکیب و تنوع علفهای هرز در کشت مخلوط سیر (Allium sativum L.) و اسفناج (Spinacia oleracea L.)

Abstract

In order to investigate effect of manure rates on diversity and density of weeds in different cropping pattern of spinach and garlic, an experiment was conducted as split plot based on completely randomized block design with three replications at the Agricultural Research Station, Ferdowsi University of Mashhad, during growing season of 2011-2012. Treatment were 3 cow manure rates (0, 10 and 20 ton.ha-1) in main plots and 6 cropping systems (garlic and spinach monocultures and garlic-spinach intercropping with 1:1, 2:2, 3:3 and 4:4 ratio) in sub plots. The results indicated that in 3 weed sampling stages, the effect of different levels of manure on weed density in second and third sampling and weed dry weight in third sampling was significant, statistically. In the second sampling, the highest weed density was obtained in non-application of manure condition that wasn’t different with 10 ton.ha-1.in the third sampling, this parameter did not follow a same trend with the second stage. In the third sampling, the highest weed dry weight was obtained in non-application of manure condition (189.50 g.m-2). at total stages, the highest weed density and dry weight, with the exception of weed density in third sampling, was observed in garlic monoculture. The intraction effect of manure and cropping pattern treatments showed that at the first stage, the hieghest and lowest total weed density was observed in garlic monoculture with 10 ton per hectare of manure and spinach monoculture under non application and 10 ton per hectare of manure, respectively. Also, at the second and third sampling stages, the lowest total weed density was obtained in garlic-spinach intercropping with 3:3 ratio under 20 ton per hectare of manure treatment and garlic monoculture under 10 ton per hectare of manure treatment, respectively. The negative correlation was observed between total dry weight of crops and weed density and dry weight. At all stages, the highest Shannon and Simpson diversity were observed in spinach monoculture under 10 ton per hectare of manure treatment. In general, at completed canopy period (the third sampling), among studied intercropping, the lowest dry weight and density of weed per square meter was observed in garlic-spinach intercropping with 4:4 ratio under 10 ton per hectare of manure treatment, but the lowest Shannon, Margalof and Simpson diversity index was obtained in garlic-spinach intercropping with 3:3 ratio under 20 ton per hectare of manure treatment.