Subsoiling facilitating accumulation and transportation of dry matter and phosphorus of spring maize

Abstract: Years of small power mechanical shallow rotary tillage often lead to shallow top soil layer and thick plough pan in the root layer. In addition, available phosphorus (P) content is relatively low in calcareous soil, so the nutrient use efficiency of P is low, limiting the maize yield. Subsoiling is an effective mean to solve those issues. In this study, the effects of subsoiling on dry matter, P accumulation and transportation of spring maize were studied. Zhengdan 958 and Xianyu 335 were used as materials and 2 treatments (rotary tillage vs. subsoiling plus rotary tillage) were set through field experiments consecutively for 2 years. The results showed that under the subsoiling plus rotary tillage, the yields of the 2 varieties were increased, and the yield difference between the 2 treatments was significant (P<0.05); and the main reason was that the 1000-grain weight was increased, but grain number per spike and effective spike had no significant difference. From the point of view of yield, Zhengdan 958 was more sensitive to subsoiling plus rotary tillage than rotary tillage in 2 years. The leaf area index of maize in subsoiling plus rotary tillage was higher than rotary tillage in trumpeting stage, and it was more obvious from silking stage to milk stage; the leaf area index became smaller and smaller from milk stage to mature stage in 2 tillage types. The weight of dry matter of stem and leaf was the most in silking stage, and subsoiling plus rotary tillage was higher than rotary tillage (P<0.05); the dry matter weight of stem and leaf in subsoiling plus rotary tillage was also higher than rotary tillage at mature stage, but the difference was not significant. For the dry matter per plant, subsoiling plus rotary tillage was higher than rotary tillage. Transportation amount of dry matter was improved in subsoiling plus rotary tillage (P<0.05). Contribution rate of dry matter transportation to grain was improved in subsoiling plus rotary tillage. P accumulation amount of stem was increased in subsoiling plus rotary tillage (P<0.05); P accumulation amount of leaf was also increased in subsoiling plus rotary tillage, but not significantly. P accumulation amount of stem and leaf were reduced at mature stage in subsoiling plus rotary tillage, but the difference was not significant. Transportation amount of P was improved in subsoiling plus rotary tillage, and it was significant for stem but not significant for leaf; and contribution rate of P transportation to grain was improved in subsoiling plus rotary tillage. P harvest index, absorption efficiency and partial productivity in subsoiling plus rotary tillage were higher than those in rotary tillage (P<0.05) for Zhengdan 958, but not for Xianyu 335. Subsoiling plus rotary tillage promoted the dry matter weight, transportation amount of dry matter, and P accumulation and transportation of spring maize, and contribution rates of P and matter transportation to grain were also higher in subsoiling plus rotary tillage; and subsoiling plus rotary tillage increased harvest index, absorption efficiency and partial productivity of P as well as yield, but different varieties existed significant difference, and the yield and P efficiency of Zhengdan 958 were more sensitive to subsoiling tillage. This study can provide a basis for the high yield and high efficiency cultivation of spring maize.