Mechanism of Intermittent Deep Tillage and Different Depths Improving Crop Growth From the Perspective of Rhizosphere Soil Nutrients, Root System Architectures, Bacterial Communities, and Functional Profiles

Long-term conventional shallow tillage reduced soil quality and limited the agriculture development. Intermittent deep tillage could effectively promote agricultural production, through optimizing soil structure, underground ecology system, and soil fertility. However, the microecological mechanism of intermittent deep tillage promoting agriculture production has never been reported, and the effect of tillage depth on crop growth has not been explored in detail. In this study, three levels of intermittent deep tillage (30, 40, and 50 cm) treatments were conducted in an experimental field site with over 10 years of conventional shallow tillage (20 cm). Our results indicated that intermittent deep tillage practices helped to improve plant physiological growth status, chlorophyll a, and resistance to diseases, and the crop yield and value of output were increased with the deeper tillage practices. Crop yield (18.59%) and value of output (37.03%) were highest in IDT-50. There were three mechanisms of intermittent deep tillage practices that improved crop growth: (1) Intermittent deep tillage practices increased soil nutrients and root system architecture traits, which improved the fertility and nutrient uptake of crop through root system. (2) Changing rhizosphere environments, especially for root length, root tips, pH, and available potassium contributed to dissimilarity of bacterial communities and enriched plant growth-promoting species. (3) Functions associated with stress tolerance, including signal transduction and biosynthesis of other secondary metabolites were increased significantly in intermittent deep tillage treatments. Moreover, IDT-30 only increased soil characters and root system architecture traits compared with CK, but deeper tillage could also change rhizosphere bacterial communities and functional profiles. Plant height and stem girth in IDT-40 and IDT-50 were higher compared with IDT-30, and infection rates of black shank and black root rot in IDT-50 were even lower in IDT-40. The study provided a comprehensive explanation into the effects of intermittent deep tillage in plant production and suggested an optimal depth.

Deep tillage reduces the dependence of tobacco on AMF and promotes the growth of tabacco(Nicotiana tabacum L.) in dryland

The traditional shallow tillage method makes the soil quality declining, and affects the efficiency of agricultural production. Taking the conventional rotary tillage(12 cm) as the control, Yunyan 87 as the test variety, and the soil type of the test site is paddy soil, we studied the effects of deep tillage(Subsoiling 30 cm) on soil nutrients, arbuscular mycorrhizal fungi (AMF) and tobacco（Nicotiana tabacum L.）growth. The results showed that deep tillage increased the contents of organic carbon, available phosphorus(AP) and available potassium(AK) in 20 ~ 40 cm soil layer. The community of AMF was changed by deep tillage. Glomus, the dominant genus in both group, increased significantly in the soil after deep tillage. The colonization rate of AMF was lower than that of conventional rotary tillage. Deep tillage was beneficial to the growth of tobacco in the middle and late stages. Root growth and nutrient content of tobacco increased. Deep tillage significantly improved the output value of tobacco. It can be seen that deep tillage is conducive to improving soil fertility, promoting the vigorous growth of root, reducing the dependence of tobacco on AMF, and promoting the high quality and yield of tobacco in drylands of Hunan.

​Quality Characters of Tannia [Xanthosoma sagittifolium (L.). Schott] as Affected by Tillage, Planting Methods, Plant Nutrition and Application of Soil Conditioners

Background: Tannia is one of the six most important root and tuber crops grown world-wide. Tannia possess good keeping quality compared to other vegetables. The tubers are considered more nutritious than colocasia and potato. But the crop is still under-exploited compared to other tuber crops. Hence the study was undertaken to identify the effect of tillage and nutrition on quality characters of tannia. Methods: A field experiment was conducted at College of Agriculture, Vellayani, Kerala during 2014-15 to study the effect of organic nutrition on quality characters of tannia. The design used was split plot design with four replications. The treatments consisted of tillage and planting methods as main plot treatments (L1- conventional tillage followed by pit system, L2- conventional tillage followed by mound system, L3- deep tillage followed by pit system and L4- deep tillage followed by mound system). The sub plot treatments were combinations of soil conditioners (S1- control, S2- coir pith, S3- rice husk) and two nutrition systems (N1- integrated nutrient management (INM) and N2- organic nutrition). Result: Results of the experiment revealed that the quality characters of tannia was improved by deep tillage to a depth of 30 cm followed by pit system of planting, application of coir pith as soil conditioner @ 500 g plant-1 and organic nutrition (FYM @37.5 t ha-1 + wood ash @ 2 t ha-1).

Applying the Response Surface Methodology (RSM) Approach to Predict the Tractive Performance of an Agricultural Tractor during Semi-Deep Tillage

This study aimed to evaluate the ability of the response surface methodology (RSM) approach to predict the tractive performance of an agricultural tractor during semi-deep tillage operations. The studied parameters of tractor performance, including slippage (S), drawbar power (DP) and traction efficiency (TE), were affected by two different types of tillage tool (paraplow and subsoiler), three different levels of operating depth (30, 40 and 50 cm), and four different levels of forward speed (1.8, 2.3, 2.9 and 3.5 km h−1). Tractors drove a vertical load at two levels (225 kg and no weight) in four replications, forming a total of 192 datapoints. Field test results showed that all variables except vertical load, and different combinations of this and other variables, were effective for the S, DP and TE. Increments in speed and depth resulted in an increase and decrease in S and TE, respectively. Additionally, the RSM approach displayed changes in slippage, drawbar power and traction efficiency, resulting from alterations in tine type, depth, speed and vertical load at 3D views, with high accuracy due to the graph’s surfaces, with many small pixels. The RSM model predicted the slippage as 6.75%, drawbar power as 2.23 kW and traction efficiency as 82.91% at the optimal state for the paraplow tine, with an operating depth of 30 cm, forward speed of 2.07 km h−1 and a vertical load of 0.01 kg.

Effects of Different Tillage Practices and Cropping Patterns on Soil Physical Properties and Crop Productivity

A series of experiments using nine treatment combinations comprising three tillage practices (zero tillage, conventional tillage and deep tillage) and three cropping patterns (wheatfallow- T. aman, wheat–mungbean-T. aman and wheat-dhaincha-T. aman) were examined in a split- plot design at Bangladesh Agricultural Research Institute (BARI), Gazipur, Bangladesh during 2008-2009 and 2009-2010 to study the effect of different tillage practices and cropping patterns on soil physical properties and crop productivity in a previously puddled soil. Soil physical properties viz. bulk density, particle density and porosity showed insignificant result due to tillage practices and cropping patterns but soil moisture retentive properties demonstrated significant outcomes. Deep tillage with dhaincha (Sesbania rostrata) and mungbean (Vigna radiata L. Wilczek) biomass incorporation conserved moisture in the soil profile and improved other soil physical properties i.e. reduced the bulk density, increased porosity and available water content of soil. The highest grain yield of wheat and rice was recorded in the deep tillage with wheat-dhaincha-T. aman cropping pattern and lowest in zero tillage with fallow based cropping pattern.

EFFECTS OF DEEP TILLAGE OF COTTON ROWS ON COTTON YIELD

Из-за убеждения, что «чем больше хлопка выращивается между рядами, тем лучше обработка (долото)», тем глубже размягчение рядков будет продолжаться в период цветения.

Fine-Crush Straw Returning Enhances Dry Matter Accumulation Rate of Maize Seedlings in Northeast China

In the conventional straw returning operation, the maize straw is broken into pieces of about 10 cm and degraded naturally in the farmland. Under the conventional straw returning mode, maize straw does not easily decompose quickly in cold climate conditions, which can cause a significant decrease in the dry matter accumulation rate of next maize seedlings. Therefore, it is difficult to popularize conventional straw returning in the maize-growing regions of Northeast China. In order to solve the above-mentioned problems, a new agronomic technology of straw returning is proposed in this study, and a corresponding Bionic Straw Fine Crusher is developed to match the agronomic requirements. The key function of fine-crush straw returning is to significantly increase the contact area between the straw pith and the external environment by significantly shortening the crushing length, thus accelerating the rate of straw decomposition. In this study, the differences in operational effects between fine-crush straw returning, conventional straw returning, and no returning are clarified through 6 consecutive years of field experiments. At the same time, statistical analysis of the experimental data reveals the influence of fine-crush straw returning on the dry matter accumulation of maize at the seedling stage under the conditions of different returning modes, and determines the optimal agronomic parameter combination. The results of this study show that fine-crush straw returning significantly increased the decomposition rate, soil organic matter content, and soil accumulated temperature, thus creating a seedbed more favorable for maize seedling development. The experimental results showed that the optimal crushing length values of fine-crush straw returning were 1.5 cm, 3 cm, and 1.5 cm under mulching returning, shallow burial returning, and deep tillage returning conditions, respectively. Compared with conventional straw returning and no returning operations, the fine-crush straw returning operation can increase the maximum seedling dry matter accumulation of the maize crop by 5.1 g/plant and 2.8 g/plant (shallow burial), 4.2 g/plant and 1.8 g/plant (deep tillage), and 4.3 g/plant and 1.9 g/plant (mulching returning). The findings of this study may provide a viable new agronomic technology to accelerate the spread of straw returning in maize-growing areas of Northeast China.