Effects Of Subsoiling Tillage And Returning Straw On Maize Growth And Nutrient Absorption

Maise is one of main grain crops. The shallow arable layer, irrational agricultural structure, poor soil fertility and the serious wind erosion in Liaoning Province have restricted the growth of root and influenced maize growth and nutrient uptake at present. It turned into a pivotal limiting factor in corn production. This research experimented with Zhengdan 958 as the test material in Tuchengzi village, Pingandi township, Fuxin city. We analyzed differences of root morphology, root activity, plant growth and development, nutrient absorption, photosynthetic function and maise yield under the treatment of rotary tillage (T1), rotary tillage+subsoiling 25 cm (T2), rotary tillage+subsoiling 25 cm+returning straw 6000kg/hm2 (T3), rotary tillage plus returning straw 6000kg/hm2 (T4) to ascertain the influence of subsoiling tillage and returning straw on maise nutrients absorption and growth and development, the main results as follow:1. Among the 4 treatments, T3 was largest increase for improving the root length, specific root length, root surface area, root volume and root dry weight and the second is T2. T4 restrained the root growth at early stage and promoted it at the mid-later growth stage. In the aspect of root activity, T2, T3 and T4 were higher than the control significantly. Among these treatments, subsoiling tillage treatment had the largest sap bleeding rate and root reducing power at jointing stage, while T3 had the largest bleeding rate and root reducing power at tasseling and flowering stage and filling stage.2. Subsoiling tillage and returning straw promoted growth and development of maize. T2 had the largest plant height at seedling stage. It’s up to 80.26cm. T3 had the largest plant height and stalk basal circumference from jointing stage to tasseling and flowering stage. With the growth of the process, dry matter accumulation (including ear) showed a gradual upward trend. Amount of dry matter accumulated to the highest after the maturity, and T3 is 28.64%higher than the control.3. Subsoiling tillage and returning straw promoted photosynthetic capacity of maize and exerted photosynthetic potential as well. At tasseling and flowering stage, T3 was 53.97% and 12.44% higher than the control in 2 years respectively. In the aspect of photosynthetic parameter, T3 had the largest net photosynthetic rate, that was 7.52% higher than the control. T2 had the largest stomatal conductance and transpiration rate that was 12.19% and 23.01% more than the control respectively. In the aspect of chlorophyll fluorescence parameters, T3 had the largest Fm andFm/Fv, that was 40.01%,6.67% higher than the control respectively.4. Subsoiling tillage and returning straw promoted nutrient absorption of maize. In the aspect of nitrogen absorption, T3 had the highest absorbing rate and absorption amount among the 4 treatments, which were 43.79% and 55.80% higher than the control respectively. T2 had the highest nitrogen absorption intensity, which was 45.83% higher than the control. In the aspect of phosphorus absorption, T3 had the largest phosphorus absorbing rate and absorption amount, which was 21.69% and 21.84% higher than the control respectively. T4 had the highest phosphorus absorption intensity, which was 38.98% higher than the control. In the aspect of potassium, T3 had the highest absorbing rate,absorption amount and absorption intensity.5. Subsoiling tillage and returning straw improved the yield of maize significantly. Among the 4 treatments, T3 had the largest yield in 2013 and 2014. The yield was 11460.02 kg/hm2and 11505.04 kg/hm2 in two years, which were 12.88% and 11.64% higher than the control. Ear weight and length, weight of 100 seeds were higher than the control. Therefore, under the condition of similar to the test area, subsoiling tillage along with returning straw was more suitable for farming, amomg them rotary tillage+subsoiling 25 cm+returning straw 6000kg/hm performed the best. The reason was that subsoiling tillage improved arable layer structure and promoted the growth and development of plants. Returning straw increased nutrient content in the soil, promote the the root to absorb nutrients. The combination of these, provided good condition for maize photosynthesis, accumulated more assimilation product and ensured the high yield of maize.