Effects Of Different Organic Substrates On The Growth, Yield And Quality Of Lettuce

This eco-organic soilless culture experiment on lettuce was conducted using mushroomresidue, corn straw, sheep manure and perlite as substrate materials, V（sand soil）: V（sheepmanure）=10:2as CK1and Mei-Ting organic substrate from Taiwan as CK2. A random blockdesign was used to study effects on physiological indicators, yield and quality of consecutivethree stubbles of lettuce and mineral elements’ release condition of different substrates.Duncan repeat range method was used to do the significance test and analysis method ofsubordinate function was used to evaluate the pros and cons of different organic substrates.Results are as follows:1.12kinds of organic cultivation substrates all have better physical and chemicalproperties than CK1. With the smaller bulk density, higher porosity, slightly alkaline, slightlylarger EC value, higher levels of total N and K but lower P content, and the content ofavailable N, P, K were higher than two controls, organic cultivation substrates can meet thelettuce growth.2. Compared with soil, organic cultivation substrate is more conducive to the growth oflettrce. Organic cultivation can increase the plant height, promote the accumulation of grounddry and fresh weight, and promote the leaf growth of lettuce effectively. Especially thelettuces on T9(V（mushroom residue）: V（corn stalk）: V（sheep manure）: V（perlite）=3:4:1:4), T4(V（mushroom residue）: V（corn stalk）: V（sheep manure）: V（perlite）=4:3:1:4),and T5(V（mushroom residue）: V（corn stalk）: V（perlite）=4:4:4)are more vigorous thanothers.3. Organic cultivation substrates can increase the first stubble of lettuce yield, the rateof increase was226.51%to746.86%compared with CK1, and6.19%to31.58%comparedwith CK2. Compareing the consecutive third harvest lettuce yield per plant, we can find thatlettuces on T9(V（mushroom residue）: V（corn stalk）: V（sheep manure）: V（perlite）=3:4:1:4), T4(V（mushroom residue）: V（corn stalk）: V（sheep manure）: V（perlite）=4:3:1:4),T5(V（mushroom residue）: V（corn stalk）: V（perlite）=4:4:4)and T3(V（mushroom residue）: V（corn stalk）: V（sheep manure）: V（perlite）=4:2:2:4) have higher total yield than others.4. Quality of lettuces on organic substrates is significantly better than CK1. Differentproportions of organic substrate can significantly reduce the nitrate content of lettuce. Nitratecontent of the consecutive third harvest lettuces is much lower than CK1, and belows thenational standard. Compared with others, lettuces on T8(V（mushroom residue）: V（cornstalk）: V（sheep manure）: V（perlite）=2:4:2:4)and T9(V（mushroom residue）: V（cornstalk）: V（sheep manure）: V（perlite）=3:4:1:4) always have a lower nitrate content. Organicsubstrates can significantly improve quality of the lettuce in higherVC, reducing sugar,soluble protein and starch content, but have less impact on the content of cellulose.5. Taking yield and quality as measurement index, the preferred substrates wereT9,T8,T4and T5.6. Total N, P and K contents of organic substrates are always reducing in theconsecutive three stubbles of lettuce growth period. There is a smaller decline in total Ncontent, but a larger decline in total K content. The decline of T8, T9, T5and T4is smallerthan other substrates.7. Available N, P and K contents of organic substrates are reducing firstly and thenascending slowly in the consecutive three stubbles of lettuce growth period. The decline ofT8and T9is smaller than others.