Effects Of Biogas Residue On The Nature Of Substrate And Growth Of Tomato In Greenhouse

In this experiment,three compound substrates with biogas residue and Coal cinder,as well as pure biogas residue and pure coal cinder were used as substrate for greenhouse tomato cultivation.The treatments were as follows:(T1) pure coal cinder,(T2) 1 biogas residue + 3coal cinder(â…´/â…´),(T3) 1 biogas residue + 1 coal cinder,(T4) 3 biogas residue + 1 coal cinder,(T5) pure biogas residue.The experiment was taken by potted plants and the pot was 6 liter.The experiment had 5 treatments,each treatment with 5 pots,one plant each pot,and 3 replicates,and it was designed by randomized block. The physical and chemical properties,enzyme and microbiology of the substrate and the tomato plant growth and development,fruit quality and yeild were determinated.The major results were as follows:1.Biogas residue increased the value of pH and EC of substrate.In the course of plant growth, the value of pH in substrate changed differently,and the pH value of T1 and T2 increased slghly, While the pH value of T4 and T5 decreased slightly,that was the of pH value in substrates with higher content of biogas residue increased,while the pH value in substrate with higher content of coal cinder decreased during the growth of tomato plant.The main reason for the pH increasing was that:first, decomposition of biogas residue released plenty of nutrients,and the more residue biogas the more nutrients were released;second,the transpiration of tomato plants relatively increased,both of which had increased the Ca²⁺,Mg²⁺ and other ions' accumulation in substrates.The EC value of T1,T2,T3 decreased,of which the EC value of T3 was appropriate and decreased little,and the EC value of T4 and T5 increased first and decreased later,which reflected that biogas residue had characteristics of slow and long-lasting nutrient releasing.As result of containing large biogas residue,the EC value of T4 and T5 were as high as 3.14 ms·cm^-1,3.39 ms·cm^-1 respectively which led to a certain degree of salt accumulation It was entirely feasible to use a certain percentage of biogas residue and coal cinder as compound substrates for soilless cultivation,and T3 had the best properties,with bulk density between 0.46g·cm^-3 and 0.48g·cm^-3,EC value between 1.95 ms·cm^-1 and 2.58 ms·cm^-1x.2.Biogas residue improved the number of microorganisms in substrate.The results showed that the number of bacteria,actinomyces,fungi,cellulose-decomposing bacteria increased with the increase of the content of biogas residue in substrates;as compared with pure coal cinder substrate, substrates with biogas residue significantly increased the number of various types of microorganisms, especially improved the distribution of rhizosphere microorganisms in soilless culture substrate.Pure biogas residue treatment had a largest effect on microorganisms,which had the most number of bacteria,actinomyces,fungi,cellulose-decomposing bacteria,they were 8.40～20.85×10⁷cfu·g^-1,3.2～46.00×10⁶cfu·g^-1,26.00～62.02×10⁴cfu·g^-1,0.94～14.03×10⁶cfu.g^-1 respectively.Biogas residue promoted the proliferation of microorganisms to speed up the decomposition of organic matter and nutrients fixed to improve the effectiveness and utilization of nutrients.3.Biogas residue improved the activity of enzyme in substrate.The effects of different substrate treatments on the activity of enzyme showed that,as compared with pure coal cinder,substrates with biogas residue enhanced the activity of phosphatase,invertase,urease proteinase,cellulose significantly, in general,the activity of enzyme enhanced as the content of biogas residue increased in substrate,and the activity of invertase and urease were highest,in T5,while the activity of proteinase and cellulose were highest in T4.Substrate enzymes involved in biochemical processes in substrate,were closely related to the release and storage of nutrients,as well as the formation of humus,substrate structure and physical properties,as a result they could improve substrate activity and ability of nutrients transformation.4.Biogas residue increased tomato plant's height,stem diameter,leaf number and root activity. Tomato plants in substrates with more biogas residue had more vigorous stronger growth on height, stem diameter and leaf number.Biogas residue increased the root activity of tomato plants,highest record of root activity occurred in T4,followed by T5,T3,T2,and there were no significant differences with T4,but T4,T5,T3,T2 were significantly higher than T1 by 118%,67%,63%,20%respectively.5.Biogas residue improved tomato fruit's quality and yield.Biogas residue improved tomato fruit soluble sugar content,lowered titratable acid content,and increased the sugar/acid ratio,of which T3 was highest and reached 6.24;but biogas residue had little effects on vitamin C.Biogas residue increased tomato yield,T4 had the highest yield,followed by.T5,T3,T2,and the yield of T4,T5, T3,T2 were all significantly higher than the pure coal cinder treatment by 200%,190%,142%,129% respectively。6.In compound substrates,it is appropriate for tomato cultivation in greenhouse when the volume ratio of biogas residue is between 50%and 75%.