Study On Tomato Seedling Substrates Screening Formula And SAPs Application Effect

Using the decomposition of cow dung and corn stalks, peat, vermiculite as the mainraw material in experiment, formulated5kinds of different volume ratios substrates, whichare used to cultivate the tomato(Lycopersicon esculentum Mill) plug-seedling and to do thescreening test of water retention agent. The physical and chemical properties of thesubstrates, nutrient content, the growth and physiological indices and photosyntheticfluorescence indicators of tomato seedlings are studied to filter out the appropriate substrateand water retention agent. The experiment is designed to get the best substrate formulationsuitable for tomato seedlings in this region and the most appropriate water retention agent,which provides a theoretical basis for tomato plug-seedlings. The main results are asfollows:1. The bulk density of substrates formulated by a certain proportion of agriculturalwaste cow manure and corn stalks are in the range of ideal substrates, the pH values slightlytend to be alkaline, which can meet the tomato growth needs. The treatment T5substrate's(cattle: straw: peat: vermiculite=5:1:2:2, by volume) total porosity is appropriate,andthe EC value is lower, but the contents of nitrogen, phosphorus and potassium are at higherlevels, the growth and physiological indexes of tomato plug-seedlings nurtured by T5havemet or exceeded CK(peat: vermiculite=2:1, volume ratio) level, which can substitute theCK as the appropriate substrate of tomato plug-seedling.2. The SAP of2010and3005K have the strong hydroscopic property and swellingcapacity in distilled water, and the smaller the particle size is, the higher the waterabsorbency is. Add water retention agent in the substrates at a rate of0.1percent, thesubstrates' contents of nitrogen, phosphorus and potassium are increased, in the experimentsafter7days of holding water based on70%of full water capacity, the plant height, stemdiameter, fresh and dry weight of tomato seedlings nurtured by the treatment S are higherthan other treatments, which do not suffer from drought stress, the formation rate andpacking degree of plug-seedling are high, so they are suitable to be nurtured in plug-seedlingsubstrates, the substrate can provide a good rhizospheric environment and nutrientconditions for the growth of tomato seedlings to ensure the normal growth of tomatoseedlings and cultivate strong seedlings.3. The dynamic changes of the nutrient contents have showed that the contents ofnitrogen, phosphorus and potassium of CK are lower than which of the compound substrates,and nutrient contents have a gently varying tendency in the breeding process. Each nutrient content of T5substrate is higher than the highest nutrient content of Chinese soils, in thebreeding process, water without handling needed, without additional fertilizer, the seedlingswill be able to growth well.4. The different kinds of water retention agents have adsorption effects on substratenutrient. The water retention agents have stronger adsorption effects on nitrogen andpotassium than on phosphorus. The capacity of adsorption of the mixed-water retentionagent is better than the single–water retention agent. For the same kind of water retentionagent, different particle sizes have the different adsorption capacity of the nutrient.