Tillage and Lime Rate Effects on Soil Acidity and Grain Yields of a Ten-Year Corn–Soybean Rotation

Reduced tillage and no-tillage systems provide shallow incorporation of surface applied materials at best. Due to concern of over-liming the surface of agricultural soils, producers either reduce lime rates (and apply more often) or perform some sort of soil inversion to mix the lime deeper into the soil profile. The objective of the authors in this field study was to evaluate the effects of tillage, lime rate, and time of limestone application on corn and soybean growth, and assess the changes in soil acidity to an already acidic soil. Treatments consisted of a no lime check, two no-tillage systems with either a 4.5 ton ha^?1 lime application every two years or an annual application of 450 kg pelleted lime ha^?1, a continuous annual chisel tillage system with a 9.0 ton ha^?1 lime application every four years, and two inversion systems utilizing a rotary tiller (Howard Rotovator) where 9.0 ton lime ha^?1 was mixed into the soil followed by either continuous chisel tillage or continuous no-tillage. Inversions occurred in 1999, 2003, and 2007. Soil samples were collected annually in increments of 5 cm to a 30 cm depth for pH determinations. After 10 years, the continuous chisel system increased soil pH in the top 20 cm and had grain yields comparable to the no-tillage system, but not different than the no lime treatment. The no-tillage system increased the pH in the surface 15 cm of soil. The inversion treatments after soybean mixed the lime more thoroughly in the top 15 cm than inversion after corn and also increased the pH to a deeper depth. The pelleted lime had no effect on soil acidity. Soybean yields were affected by lime treatment with the no lime and pelleted lime having the lowest yields. This is most likely due to manganese (Mn) toxicity with these treatments. There was no perceived benefit of inversion of the soil with no-till or chisel systems.     

Effect of tillage and crop on arbuscular mycorrhiza colonization of winter wheat and triticale under Mediterranean conditions

Large‐scale inoculation with arbuscular mycorrhizal fungi (AMF) is generally impractical in most regions and we have little understanding of the factors that determine inoculation success. Nevertheless, the ability to take full advantage of indigenous AMF for sustainable production needs to be developed within cropping systems. We used part of a long‐term field experiment to understand the influence of tillage and the preceding crop on AMF colonization over the growing season. Arbuscular mycorrhiza colonization rate was more affected by treatment (tillage or the combination of crop and preceding crop) than by the total number of AMF spores in the soil. Conventional tillage (CT) had a statistically significant negative effect (P ≤ 0.05) on spore numbers isolated from the soil, but only in the first year of study. However, the AMF colonization rate was significantly reduced by CT, and the roots of wheat, Triticum aestivum, L, cv. Coa after sunflower, Helianthus annuus L., were less well colonized than were those of triticale, X Triticosecale Wittmack, cv. Alter after wheat, but the affect of tillage was more pronounced than was the effect of crop combination. Under no‐till there was a significant increase in AMF colonization rate throughout the sampling period in both wheat and triticale, indicating that the extraradical mycelium previously produced acted as a source of inoculum. In general, triticale showed greater AMF colonization than wheat, despite the preceding crop being less mycotrophic. Under these experimental conditions, typical of Mediterranean agricultural systems, AMF colonization responded more strongly to tillage practices than to the combination of crop and preceding crop.     

宁夏旱作农业区应用全膜双垄沟播技术的效应分析

摘要：通过对宁夏旱作农业区应用全膜双垄沟播技术效应、存在问题的分析，肯定了该项技术是旱作农业的一项突破性技术，针对其在生产应用中存在的技术问题，提出了提高认识、强化技术培训、提高技术到位率、加强技术创新力度、坚持地膜补贴惠民政策、建立旧膜回收机制、加强领导等对策，以加快全膜双垄沟播技术的应用速度，发挥更大的增产、增效作用。     

Effect of Tillage and Plant Residue Management Practices on Shrinkage of a Vertisol

A study was carried out to determine the effects of different tillage and plant residue management practices on different soil moisture and shrink-swell properties of a Vertisol (very fine, semctitic, thermic, chromic Haploxerert (with less than 1 % slope). The core samples were collected in July (after harvesting of lentil) and in November (after planting of wheat) 1993. The two tillage methods were moldboard (T1) and chisel (T2). The two plant residue incorporation dates were in August (R1) and in October (R2). Results indicated that T2 tends to give higher water holding capacity and available moisture than T1. Immediate incorporation of plant residue (R1) tends to increase the bulk density and to decrease soil specific volume and void ratio when compared to late incorporation treatment (R2). In general, the two tillage treatments tend to decrease moisture availability, shrinkage characteristics, soil specific volume, and void ratio. They also tend to increase the soil shrinkage (subsidence and cracks volume) and bulk density. Chisel plough is recommended in Vertisols, if it is to be used before the rainfall.     

Effect of Tillage System on Soil Strength and Bulk Density of Vertisols

Improving the soil environment for seedling emergence and plant growth is possible using a good tillage system. From March 1993 until June 1994, the effect of tillage system and plant residue incorporation practices on the bulk density and the soil strength of the surface layer of a vertisol (very fine, smectitic, thermic, chromic Haploxerert), on a less than 1 % slope, was investigated. The two tillage methods were moldboard (T1) and chisel (T2). The two plant residue incorporation dates were in August (R1) and in October (R2). Results indicated that R1 gave significantly higher bulk density than R2, while the different tillage treatments had no significant effect. Soil strength was significantly lower under T1 and R2 than under the other treatments.     

南方水田耕整机械发展趋势及探讨

我国南方水田耕整机械经过了30多年的发展,已基本形成了多功能、多机型的格局.随着科学技术的创新与进步,水田耕整机械正朝高标准、智能化、自动化方向发展;但实现这一目标的任务还很艰巨,政府须给予政策和资金支持,保障科研成果及时转化、推进农机研发"产学研"结合.     

我国耕整地机械化技术研究

耕整地机械化技术是最基本的农田作业机械化技术，在农业生产中占有极其重要的地位，因此，世界各国的耕整地机械在不断更新发展。结合我国实际．阐述耕整地机械化技术的概念及技术内容，介绍国外耕整地技术的发展趋势，分析我国耕整地技术的发展现状和趋势。     

轮胎压实对机具牵引阻力的影响

研究了华北平原小麦、玉米一年两熟区固定道保护性耕作对机具田间牵引阻力的影响,对比分析了固定道与非固定道处理下机具田间作业的滚动阻力、开沟器牵引阻力和总牵引阻力.与非固定道保护性耕作时深松、小麦和玉米播种作业相比,固定道保护性耕作下机组总牵引阻力分别降低14.6%、13.3%和13.3%;滚动阻力分别降低26.9%、21.9%和19.7%,平均降低22.9%;机具牵引阻力分别降低7.5%、7.2%和12.4%,平均降低8.8%.固定道处理的开沟器牵引阻力平均比非固定道处理降低22.0%.与非固定道相比,固定道总牵引油耗在3种作业时分别降低17.6%、12.4%和9.1%.试验结果表明,固定道保护性耕作显著降低机具田间牵引阻力,减少了机具田间作业油耗.     

2BMJ-7型高速气吸式原茬精密播种机的研制

针对目前保护性耕作中垄作免耕播种机技术不完善的问题,研制了2BMJ-7型高速气吸式原茬精密播种机。介绍了该机的整机结构、主要特点及主要技术参数,并对该机采用的关键技术进行了研究。该机采用了电液自控仿形、种肥电子监测和分层精量施肥等先进技术,能一次完成破茬、开沟施肥、播种和覆土镇压等项作业,较好地满足了东北地区原茬精密播种技术的发展需要。