缓释肥一次性侧位深施对红壤旱地直播油菜产量形成和肥料利用的影响

为明确红壤旱地直播油菜(Brassica napus L.)缓释肥(N-P₂O₅-K₂O=25-7-8)一次性侧位深施效果及适宜用量,2017—2020年在典型的红壤丘陵区(江西进贤)开展缓释肥施用方式对比试验(不施肥、一次性土表撒施和一次性侧位深施)和施用量试验(0、300、450、600、750和900 kg·hm^-2),研究缓释肥一次性侧位深施及不同施用量对油菜产量形成和肥料利用率的影响。结果表明,相比传统土表撒施,侧位深施显著促进了N、P、K的吸收,同步提高了油菜产量和肥料利用率,且对晚熟油菜影响更为显著。菜籽产量与缓释肥用量呈线性加平台关系,适宜施肥量可保证较大的收获密度及较多的每株角果数和每角粒数,从而协同提高籽粒产量和经济效益,同时维持较高的肥料利用率。晚熟和早熟油菜缓释肥侧位深施的适宜用量分别为720和605 kg·hm^-2,产量潜力可分别达2 500和1 750 kg·hm^-2。因此,一次性侧位深施适量缓释肥可显著提高红壤旱地直播油菜生产力,建议结合机械化种植因地制宜地推广应用。

Effects of One-Time Side Deep Application of Slow-Released Fertilizer on Yield Formation and Nutrient Utilization of Direct Seeding Rapeseed (Brassica napus L.) in Red-Soil Dryland

In order to explicate the application effect and quantity of slow-released fertilizer (N 25%, P₂O₅ 7%, K₂O 8%, respectively) with one-time side deep fertilization on direct seeding rapeseed (Brassica napus L.) in red-soil dryland, a three-year field experiment was conducted in the red soil hilly region (Jinxian of Jiangxi) from 2017 to 2020 to analyze its’ impact on yield formation and nutrient utilization of oilseed rape, including three treatments of sowing and fertilizing (sowing in row without fertilizer (F0), sowing in row with surface broadcast fertilizing (F1) and synchronous sowing in row with side deep fertilizing (F2)), and six slow-released fertilizer application rates (0, 300, 450, 600, 750 and 900 kg·hm^-2). The results showed that, compared with F1, F2 treatment increased the uptake of nutrients (N, P and K), effective plant density and maintained sufficient pod number, and thus improved the yield and fertilizer use efficiency of rape. Moreover, these differences were more significant for late-maturity cultivar and poor soil condition than for early-maturity cultivar and relatively rich soil condition. Significant linear plus platform correlations had been shown between seed yield and slow-released fertilizer quantity. Proper fertilizer increased yield and economic benefits significantly, for it maintained effective plant density and promoted sufficient pod number, and maintained high fertilizer use efficiency. On the whole, it could be calculated that the optimal quantity of slow-released fertilizer for late-maturity rape and early-maturity rape were 720 and 605 kg·hm^-2 to target yield of 2500 and 1750 kg·hm^-2, respectively. Present study indicated that one-time side deep application of appropriate slow-released fertilizer has the potential of improving oilseed rape productivity in red-soil dryland of southern China. Therefore, it is recommended for application according to local condition.