覆膜栽培对旱地小麦籽粒产量及硫含量的影响

研究并明确旱地覆膜栽培对冬小麦籽粒产量、硫吸收累积和转运及籽粒硫含量的影响, 调控作物硫营养, 提高籽粒硫含量和营养品质, 对旱地小麦高产优质栽培有重要意义。2014—2015和2015—2016两年在西北三省七点进行田间试验, 比较不覆膜(传统平作栽培)和覆膜(垄覆沟播或全膜覆土穴播)栽培模式的小麦生物量、产量、产量构成, 以及籽粒硫含量和硫吸收利用。与不覆膜相比, 覆膜栽培提高了小麦穗数, 使籽粒产量提高13.7%, 但籽粒硫含量却降低9.0%。覆膜栽培能提高旱地小麦开花期地上部硫累积量, 茎叶、穗和地上部硫累积总量分别提高19.9%、16.1%和19.2%, 并使花后硫转运量和转运率提高36.2%和17.9%, 但开花期土壤有效硫却因覆膜降低24.5%, 花后硫吸收也降低77.9%, 结果使成熟期地上部硫累积总量和硫收获指数未因覆膜而增加。籽粒硫吸收量没能随产量同步提高, 致使籽粒硫含量因籽粒产量增加引起的稀释效应而降低。因此, 在西北旱地小麦覆膜栽培中要注意加强土壤硫的补充, 改善旱地小麦籽粒硫营养, 提高小麦的营养和加工品质。

Effects of Plastic Film Mulching on Grain Yield and Sulfur Concentration of Winter Wheat in Dryland of Loess Plateau

Plastic film mulching is popular in dryland wheat production in China and important to understand to effects on grain yield, sulfur (S) accumulation and remobilization, and grain S concentration in high-yield and nutritional-quality wheat production. In the 2014-2015 and 2015-2016 growing seasons, we carried out field experiments in seven locations of three provinces in Northwest China to compare the biomass, grain yield, yield components, grain S concentration, and S uptake and distribution of winter wheat between conventional flat cropping pattern (no mulching) and the ridge mulch with furrow seeding or flat mulching cropping pattern (plastic film mulching). Compared with no mulching pattern, the plastic film mulching pattern showed 13.7% increase of grain yield through higher spike number, but 9.0% decrease of grain S concentration. The S accumulation in stem and leaf, ear, and aboveground plant parts at anthesis increased by 19.9%, 16.1%, and 19.2%, respectively, in plastic film mulching pattern than in no mulching pattern; however, the S remobilization amount and efficiency increased by 36.2% and 17.9%, respectively, during grain filling. Under plastic film mulching pattern, soil available S at anthesis stage decreased by 24.5%, and the S uptake during grain filling greatly declined by 77.9%. As a result, no significant increases in S accumulation of aboveground plant parts at maturity and S harvest index. The grain S concentration decreased owing to the increased grain yield. Therefore, under plastic film mulching pattern in Northwest China, additional S fertilizer should be applied for improving S nutrition and processing quality in dryland wheat.