不同耕作方式对辽西褐土物理性状及玉米根系分布的影响

通过连续3年大田试验，对旋耕、翻耕、深松3种耕作方式下的土壤物理性质、玉米根系分布和产量进行测定。结果表明，与翻耕和旋耕相比，深松显著增加了玉米田土壤耕层厚度和降低了犁底层厚度。在中下层土壤，深松还降低了土壤紧实度和容重，改善了土壤的孔隙状况，有利于玉米根系向下生长，使得中下层土壤的玉米根系不仅更丰富，而且占总根系量的比例也更高，最终提高了玉米产量。本研究表明，深松耕作有利于改善辽西褐土区土壤结构和促进玉米生长。     

耕作方式对主要粮食作物影响的研究综述

笔者通过对相关资料的整理与分析,阐述了常见不同耕作方式对主要粮食作物根系特性、光合效应、品质指标及产量的影响,分析了未来农业生产中进一步加强对耕作方式研究的必要性和重要性,并指出今后农业生产中应在结合中国国情的基础上注重根据区域生态环境、土壤属性、作物种类及茬口类型选择适宜的耕作方式,试图为中国农业生产中耕作方式更加合理的选择与运用及作物产量的提高和耕地的可持续利用提供科学依据和理论帮助。     

有机培肥与耕作方式对稻麦轮作土壤团聚体和有机碳组分的影响

为了明确不同外源有机物和耕作方式对土壤地力培育的影响,以水稻-小麦轮作系统为对象,通过2个年度(2016—2018年)大田试验研究了外源有机物(秸秆和有机肥)和耕作方式及其交互作用[稻麦秸秆还田配合旋耕(SR),稻麦秸秆还田配合翻耕(SP),秸秆不还田、增施有机肥配合旋耕(MR),秸秆不还田、增施有机肥配合翻耕(MP),秸秆不还田、不施用有机肥、旋耕深度15 cm(CKR)]对土壤团聚体和有机碳组成的短期影响。结果表明:SR处理能够降低水稻季土壤容重并增加总孔隙度。相比CKR,小麦季SR处理显著增加0.05mm水稳性团聚体含量,增加量为7.2%。此外,外源有机物和耕作对土壤有机碳活性组分具有显著影响。其中,易氧化有机碳(EOC)主要受耕作与有机物交互作用影响,酸水解有机碳(LPIc和LPII_c)主要受耕作措施的影响, SR处理的土壤EOC和LPI_c含量比CKR提高0.3～2.6 g·kg~(-1)。颗粒有机碳(POC)主要受外源有机物的影响,并且秸秆还田处理POC平均含量高于增施有机肥处理,增加量为0.75g·kg~(-1)。短期内,外源有机物和耕作及其交互作用对稳定性有机碳(黑碳和矿物结合态有机碳)的影响较小。综上,秸秆还田配合旋耕有助于提高土壤水稳性团聚体和活性有机碳的含量(EOC、LPI_c和POC)。     

Relative abundance and damage of some insect pests of wheat under different tillage practices in rice–wheat cropping in India

Tillage changes the physical and chemical properties of soil and can also inhibit or enhance useful and harmful fauna. In agriculture, different tillage technologies are being tried to enhance crop productivity, but little concrete information seems to exist on their effects on pest abundance and damage. To address this lack of information, sowing of wheat was investigated under different tillage systems. In order to monitor pest abundance and damage in altered tillage systems, the present studies on the relative abundance and damage due to insect pests viz. pink stem borer (PSB, Sesamia inferens Walker), termites (Microtermes obesi Holmgren and Odontotermes obesus Rambur) and root aphid (Rhopalosiphum rufiabdominalis Sasaki) were undertaken in a rice–wheat cropping system during 2010–11 and 2011–12. Pest abundance and damage was monitored in four tillage systems i.e. conventional tillage (CT), zero tillage (ZT), ZT + mulch and rotary tillage (RT) under insecticide protected and unprotected conditions. The application of insecticide did not affect root aphid incidence or termite damage. However, significant differences in PSB damage in insecticide protected (0.9%) and unprotected (1.2%) conditions were observed. The investigations demonstrated that in CT, damage by PSB (0.6%) was minimum; however termite damage (2.2%) was maximum as compared to all other tillage conditions. In ZT, PSB damage (1.4%) was maximum and root aphid incidence (3.1 aphids/tiller) was minimum in comparison to other tillage conditions. ZT + mulch resulted in inter-mediate insect pest incidence/damage; however, RT was the least effective practice which showed relatively high incidence/damage of these three insects (1.2% PSB damage, 1.9% termite damage and 5.1 aphids/tiller). The insecticide × tillage interaction indicated that insecticide application is needed only in ZT and RT for PSB management.     

The use of remote sensing to detect the consequences of erosion in gypsiferous soils

Tillage practices on sloping ground often result in unsustainable soil losses impairing soil functions such as crop productivity, water and nutrients storage, and soil organic carbon (SOC) sequestration. A sloping olive grove (10%) was planted in shallow gypsiferous soils in 2004. It was managed by minimum tillage; the most frequent management practice in central Spain. The consequences of erosion were studied in soil samples (at 0–10, 10–20, and 20–30 cm depths) by analyzing SOC, available water and gypsum content, and by detecting spectral signatures using an ASD FieldSpecPro® VIS/NIR-spectroradiometer. The Brightness index (BI), Shape index (FI), and Normalized Difference Vegetation Index (NDVI) were derived from the ASD spectral signatures and from remote sensing (Sentinel-2 image) data. The development of these young olive trees was estimated from the measured diameter of the trunks (17 ± 18 cm diameter). In 20–30 cm of the soil, the carbon stock (38 ± 18 Mg ha⁻¹) as well as the available water content (12 ± 6%) was scarce, affecting the productivity of the olive grove. The above-mentioned indices obtained from the laboratory samples and the pixels of the Sentinel-2 image were significantly (p < 0.01) correlated, with a correlation coefficient of around 0.4. The BI was related to the gypsum content and the slope of the plot. The FI was related to the carbon and water contents. The NDVI derived from the satellite image identified the influence of soil degradation on the trees and the carbon content. The spatial-temporal changes of the indices might help in tracking soil changes over time.     

Can conservation tillage mitigate climate change impacts in Mediterranean cereal systems? A soil organic carbon assessment using long term experiments

Simulation models, informed and validated with datasets from long term experiments (LTEs), are considered useful tools to explore the effects of different management strategies on soil organic carbon (SOC) dynamics and evaluate suitable mitigative options for climate change. But, while there are several studies which assessed a better prediction of crop yields using an ensemble of models, no studies are currently available on the evaluation of a model ensemble on SOC stocks. In this study we assessed the advantages of using an ensemble of crop models (APSIM-NWheat, DSSAT, EPIC, SALUS), calibrated and validated with datasets from LTEs, to estimate SOC dynamics. Then we used the mean of the model ensemble to assess the impacts of climate change on SOC stocks under conventional (CT) and conservation tillage practices (NT: No Till; RT: Reduced Tillage). The assessment was completed for two long-term experiment sites (Agugliano – AN and Pisa – PI2 sites) in Italy under rainfed conditions. A durum wheat (Triticum turgidum subsp. durum (Desf.) Husn.) – maize (Zea mays L.) rotation system was evaluated under two different climate scenarios over the periods 1971–2000 (CP: Present Climate) and 2021–2050 (CF: Future Climate), generated by setting up a statistical model based on canonical correlation analysis. Our study showed a decrease of SOC stocks in both sites and tillage systems over CF when compared with CP. At the AN site, CT lost −7.3% and NT −7.9% of SOC stock (0–40 cm) under CF. At the PI2 site, CT lost −4.4% and RT −5.3% of SOC stocks (0–40 cm). Even if conservation tillage systems were more impacted under future scenarios, they were still able to store more SOC than CT, so that these practices can be considered viable options to mitigate climate change. Furthermore, at the AN site, under CF, NT demonstrated an annual increase of 0.4%, the target value suggested by the 4 per thousand initiative launched at the 21st meeting of the Conference of the Parties in Paris. However, RT at the PI2 needs to be coupled with other management strategies, as the introduction of cover crops, to achieve such target.     

稻田土壤养分特性对不同耕作方式的生态响应

为深入了解耕作措施对稻田耕层土壤的作用效果,笔者在前人研究结果的基础上综述了免耕、翻耕等不同耕作方式对稻田土壤物理性质包括容重、孔隙度、团聚体、水分、温度,土壤化学性质如氮、磷、钾、有机质和微量元素含量以及土壤生物学特性包括微生物、酶活性的影响,分析了不同稻作措施的优缺点。最后对稻田耕层的合理调控提出因地制宜,依据当地的气候、土壤条件、栽培模式选择合理的耕作方式;合理轮耕,免耕、翻耕和旋耕交替运作;配施绿肥和有机肥;推行节水稻作模式等建议。     

Short and long‐term distribution with depth of soil organic carbon and nutrients under traditional and conservation tillage in a Mediterranean environment (southwest Spain)

The impacts of tillage and cropping sequences on soil organic matter and nutrients have been frequently reported to affect the uppermost soil layers, but there is little published information concerning effects at greater depth. This article reports results on the distribution of soil organic carbon (SOC), active carbon (AC), N, Olsen‐P and extractable K within 100 cm in short (4 yr) and long (16 yr) term experiments under different tillage systems. Short (TT₄) and long (TT₁₆) traditional tillage are compared with conservation tillage, reduced (RT₁₆) and non‐tillage (NT₄). The results show more accumulation of SOC in the near‐surface under RT₁₆ and NT₄ in both experiments compared with traditional tillage. Moreover, greater C content occurs to 40 cm depth in the long‐term experiment. The results demonstrate the importance of time on C accumulation, not only in near‐surface layers but also at greater depths. Active C is an indicator of the increase in soil quality in the long‐term experiment. This trend is only apparent for the first 10 cm in the short‐term experiment. Patterns in N, Olsen‐P and extractable K are similar to that of SOC. However, only extractable K is significantly greater in soil under conservation tillage (RT₁₆ and NT₄) after short and long periods. Potassium availability is a good indicator of the changes caused by tillage. Our results indicate that studies of soils at depth could be very useful in long‐term experiments to demonstrate the effect of conservation tillage on C and nutrient distribution.     

耕作方式对灌区春小麦田土壤呼吸的影响

为了从土壤呼吸、水热特征探讨河西灌区耕作方式对春小麦的影响，以连续12年(2005-2016)的保护性耕作长期定位试验为基础，比较分析了垄作固定道(PRB)、平作固定道(ZT)、传统耕作(CT) 3种耕作方式下河西灌区春小麦田土壤水热物理特征、土壤呼吸强度及小麦产量的差异。结果表明，播前与收获后，在0～90 cm土层，PRB处理平均土壤含水量较CT处理分别增加15.06%和18.75%,ZT处理较CT处理平均土壤含水量分别增加7.26%和5.98%;不同耕作方式下，春小麦整个生育期的土壤温度总体表现为先增后降，土壤温度响应气温的变化趋势；秸秆覆盖(PRB与ZT)在春小麦苗期表现出降温效应，而在春小麦苗期至成熟期，PRB处理的0～30 cm土层平均土壤温度较ZT、CT处理分别提高0.56～4.39℃和0.05～2.6℃;小麦生育期土壤呼吸强度先增后降，且随土层深度增加而减弱，不同耕作方式下呼吸强度表现为CT>PRB>ZT;土壤呼吸强度与温度呈显著的指数关系，Q₁₀(温度每增加10℃土壤呼吸所增加的倍数)随土层深度的增加而逐渐增大，且不同耕作方式下表现为Z...     

Effects of different soil conservation tillage approaches on soil nutrients,water use and wheat-maize yield in rainfed dry-land regions of North China

Excessive tillage compromises soil quality by causing severe water shortages that can lead to crop failure. Reports on the effects of conservation tillage on major soil nutrients, water use efficiency and gain yield in wheat (Triticum aestivum L.) and maize (Zea mays L.) in rainfed regions in the North China Plain are relatively scarce. In this work, four tillage approaches were tested from 2004 to 2012 in a randomized study performed in triplicate: one conventional tillage and three conservation tillage experiments with straw mulching (no tillage during wheat and maize seasons, subsoiling during the maize season but no tillage during the wheat season, and ridge planting during both wheat and maize seasons). Compared with conventional tillage, by 2012, eight years of conservation tillage treatments (no tillage, subsoiling and ridge planting) resulted in a significant increase in available phosphorus in topsoil (0–0.20 m), by 3.8%, 37.8% and 36.9%, respectively. Soil available potassium was also increased following conservation tillage, by 13.6%, 37.5% and 25.0%, and soil organic matter by 0.17%, 5.65% and 4.77%, while soil total nitrogen was altered by −2.33%, 4.21% and 1.74%, respectively. Meanwhile, all three conservation tillage approaches increased water use efficiency, by 19.1–28.4% (average 24.6%), 10.1–23.8% (average 15.9%) and 11.2–20.7% (average 15.7%) in wheat, maize and annual, respectively. Additionally, wheat yield was increased by 7.9–12.0% (average 10.3%), maize yield by 13.4–24.6% (average 17.4%) and rotation annual yield by 12.3–16.9% (average 14.1%). Overall, our findings demonstrate that subsoiling and ridge planting with straw mulching performed better than conventional tillage for enhancing major soil nutrients and improving grain yield and water use efficiency in rainfed regions in the North China Plain.