Effect of Deep Loosening on Soil Structure and Maize Root Activity

[Objective] This study was conducted to explore the effects of deep loos- ening on soil structure and the activity of maize root system, to provide a theoreti- cal basis for the efficient and rational use of water resources. [Method] Three differ- ent loosening treatments for maize in ridges were performed in field trials as fol- lows： conventional ridge tillage, loosening the cm in spring （deep loosening in spring）, and depth of 30 cm in autumn （deep loosening in soils between rows to a depth of 30 oosening the soils between rows to a autumn）. Then the soil properties and the development of root system were measured to evaluate the effects of different loosening methods. [Result] Soil compactness was significantly reduced after deep loosening in spring, There were significant differences in soil compactness in 0-20 cm depth and soil bulk density in 0-40 cm depth between deep loosening in spring and deep loosening in autumn, deep loosening in spring and conventional ridge tillage. The soil water holding capacity was also significantly different between the two deep loosening treatments and conventional ridge tillage. Moreover, the root ac- tive absorption area of maize of deep loosening in spring was higher than that of conventionai ridge tillage. [Conclusion] Deep loosening can reduce soil compactness, bulk density, and improve soil water holding capacity, soil water content and the root activity of maize. Deep loosening in spring is better in soil improvement be- cause spring is closer to the growth period of crops than autumn. So, deep loosen- ing is conducive to the improvement of soil compactness and structure.

Design and experiment of bionic stubble breaking-deep loosening combined tillage machine

Under the conditions of straw returning operation,there are three major technical bottlenecks in the Phaeozem region of northeast China,namely low stubble breaking rate,poor tillage depth consistency,and high fuel consumption.In this research,a bionic stubble-deep loosening combined tillage machine(BSD)was designed through bionic prototype analysis,coupled bionic analysis,coupled bionic design,theoretical analysis and application of intelligent control techniques.It consists of a bionic stubble breaking device and a bionic self-excited vibratory deep loosening device.Based on the unique biting pattern of locust mouthparts on maize rootstocks,the bionic stubble breaking device adopted a new multi-segment serrated bionic structure and a symmetrical rotational motion,which could significantly increase the stubble breaking rate(p<0.05)and reduce the resistance to stubble breaking operations(p<0.05).Based on the unique biology of the hare’s paws,toes and nails,the bionic self-excited vibration deep loosening device adopted a new series-parallel composite bionic elastic system and an intelligent tilling depth control system with a fuzzy algorithm,which significantly improved the tilling depth consistency(p<0.05).The operational performance of the BSD was verified at different operating speeds through comparative experiments and reveals the mechanism of its excellent performance through theoretical analysis.The final experiment results showed that,at the same operating speed,the BSD improved the stubble breaking rate by 9.62%and 10.67%,reduced the stubble breaking torque by 28 N·m and 33 N·m,reduced the tillage depth coefficient of variation by 12.73%and 13.48%,and reduced the specific fuel consumption by 36 g/km·h and 40 g/km·h compared to the two most common models.The operating performance of the three kinds of machines will decrease with the increase of operating speed,and the BSD has the least decrease.