牛粪堆肥成型基质块蔬菜育苗灌溉方式

Irrigation method for vegetable seedling using cow dung compressed substrates

为优选蔬菜育苗成型基质的灌溉方式,提高成型基质蔬菜育苗效果,以牛粪好氧堆肥腐熟料和牛粪蚯蚓堆肥腐熟料为主料配方的成型基质块为研究对象,在低位浸泡灌溉和微喷灌溉条件下,其中牛粪好氧腐熟料成型基质块灌溉耗水量体积的处理水平分别为2 500、350、700、1 050、1 400、1 750 m L,用T1、T2、T3、T4、T5、T6表示;牛粪蚯蚓堆肥腐熟料基质块灌溉耗水量体积的处理水平分别为3 000、700、1 050、1 400、1 750、2 100 m L,用TS1、TS2、TS3、TS4、TS5、TS6表示,探讨不同灌溉条件对2种牛粪腐熟料成型基质块中全氮(TN)、全磷(TP)、全钾(TK)的迁移及其吸水特性和育苗效果。结果表明,2种牛粪腐熟料成型基质块在低位浸泡灌溉下,其灌溉充分,淋洗脱盐量相对较小,并且对成型基质块的冲刷,扰动较小;微喷灌溉最小灌溉量T2或TS2下,虽然其淋洗损失的TN、TP、TK小于低位浸泡灌溉,但成型基质块未能被充分湿润,影响育苗效果;微喷灌溉在T3、T4、T5、T6或TS3、TS4、TS5、TS6处理水平下,成型基质块中的TN、TP、TK淋洗损失量均大于低位浸泡灌溉,并且随灌溉量的增大而逐步增大。对牛粪好氧堆肥腐熟料成型基质块,育苗前期应选取微喷灌溉T4进行前充分淋洗,育苗后期采取低位浸泡灌溉保留幼苗生长所需养分;而对牛粪蚯蚓堆肥腐熟料成型基质块,TS1处理下黄瓜幼苗的茎粗(6.23 mm)、株高(138.09 mm)、地上部分干质量(758.85 mg)、地下部分干质量(147.92 mg)和壮苗指数(217.64)均为该试验中最大值,灌溉水利用率为2.79g/kg,该处理水平下幼苗生长及水分有效利用率均较优,即可采取TS1处理对牛粪蚯蚓腐熟料成型基质块进行灌溉。

Compressed substrates had certain mechanical strength, which were produced by application of mechanical pressure to the seedling substrates, such as peats and earthworm compost. In this case, during seedling production the plastic plug was not used, which was helpful for saving resources and protecting environment. More importantly, it would not harm seedlings when transplanting the seedlings, since the compressed substrates and seedling were combined together. Compressed substrate was more suitable for seedlings than incompact substrates, however, the method of irrigation for compressed substrate was different from the traditional irrigation and there was hardly any research on it. So it was interesting to optimize the irrigation of vegetable seedling compressed substrates and improve the growth of vegetable seedling. The experiment was carried out inside a greenhouse at Huazhong Agricultural University(Wuhan City, Hubei Province) for 26 days in March 2017. The cow dung aerobic compost and cow dung earthworm compost were respectively as the main material of compressed substrates for the aims above in 2 groups. There were 6 treatments of irrigation in each group. In aerobic compost group, there were treatments of T1(2500 m L), T2(350 m L), T3(700 m L), T4(1050 m L), T5(1400 m L) and T6(1750 m L). In earthworm compost group, there were treatments of TS1(3500 m L), TS2(700 m L), TS3(1050 m L), TS4(1400 m L), TS5(1750 m L) and TS6(2100 m L). Among them, T1 and TS1 were irrigated in soak irrigation, and the others were irrigated in different gradients of micro spray irrigation. And the migration of TN(total nitrogen), TP(total phosphorus) and TK(total potassium) in different irrigation conditions in compressed substrates for vegetable seedling production was discussed. Results showed that 2 kinds of compressed substrates could be irrigated sufficiently and washed, and the desalt effect of compressed substrates was relatively small under soak irrigation(T1 or TS1). Although the desalt effect and nutrient loss of compressed substrates under the minimum gradient of micro spray irrigation(T2 or TS2) were both smaller than that under soak irrigation(T1 or TS1), these compressed substrates could not be irrigated sufficiently which would hinder the growth of seedlings. With the T3-T6 or TS3-TS6 of micro spray irrigation, the loss of TN, TP and TK in compressed substrates was higher than that in compressed substrates under soak irrigation(T1 or TS1), and then it went gradually higher with the increase of gradient in micro spray irrigation. Based on the results above, for the cow dung aerobic compost, the electric conductivity of compressed substrates is not normal until compressed substrates have been irrigated by 6 times, so compressed substrates in aerobic compost group ought to be irrigated using T4 for 6 times, and then the micro spray irrigation should be transferred to soak irrigation until the end of the seedling stage, which can not only promote the growth of seedlings but also save the irrigating water and decrease the loss of TN, TP and TK in compressed substrate. Under TS1 treatment, the maximum values of thick stems, plant height, dry weight of seedling above-ground and dry weight of root were 6.23 mm, 138.09 mm, 758.85 mg and 147.92 mg on the 26^(th) day after seeding, respectively. And the irrigation water use efficiency of cucumber seedling was 2.79±0.33 g/kg. Compressed substrates ought to be irrigated with soak irrigation in earthworm compost group.