烟秆生物质炭与化肥配施对植烟土壤有机碳组分及微生物的影响

采用盆栽试验,设置空白对照(CK)、化肥(F)、烟秆生物质炭(B)、烟秆生物质炭配施化肥(BF)4个施肥水平,配施化肥参考烟草专用肥养分配比(N︰P2O5︰K2O=12︰7︰22)与烟秆生物质炭混合施用,探究烟秆生物质炭与化肥配施对植烟土壤有机碳组分及微生物的影响。结果表明：(1)与单施烟秆生物质炭相比,烟秆生物质炭与化肥配施土壤pH显著降低6.59%;土壤有机碳(SOC)和易氧化有机碳(EOC)含量显著增加,但土壤可溶性有机碳(DOC)含量显著降低29.63%,土壤颗粒有机碳(POC)和微生物生物量碳(MBC)影响不显著;(2)与单施化肥相比,烟秆生物质炭与化肥配施使得土壤脱氢酶活性大幅提高近2倍;而与单施烟秆生物质炭相比,土壤蔗糖酶、脱氢酶和过氧化氢酶活性则显著降低;(3)烟秆生物质炭与化肥配施,能够提高土壤细菌群落丰富度及物种多样性;同时,与单施烟秆生物质炭相比,配施化肥使参与土壤有机质分解的土壤绿弯菌门相对丰度提高了16.79%,但土壤细菌α、β多样性显著降低;(4)RDA分析表明,土壤SOC、EOC、POC、MBC是影响土壤有机质分解和参与碳循环细菌分布的主要因素。综上所述,...     

Spatial variability of soil penetration resistance in an alluvial delta plain under different land uses in middle Black Sea Region of Turkey

The aim of this study was to analyse the soil compaction and its spatial variability on an alluvial plain in K?z?l?rmak River Delta in Turkey, which is an important agricultural area where vegetable, rice, cereals and other crops have been grown under conventional tillage and irrigation over a long period. Penetration resistance (PR) was measured at 5 cm depth intervals between 0 and 40 cm soil depth, and gravimetric water content (GWC), field capacity (FC) and texture were determined for 0–20 cm and 20–40 cm. Penetration resistance values in some parts of the area were higher than the critical value for root growth limitation, the mean PR values at all depths were considerably lower than the critical value despite a relative increase in PR with soil depth. The areas with values greater than 3.0 MPa, except for 0–5 cm, were generally located in the fields with high sand content, especially near the K?z?l?rmak River. In contrast, for 0–5 cm, the areas with PR greater than 3.0 MPa, which is the value accepted for root growth limitation, were usually located in the west and northwest of the study area and had a high clay content.     

Estimation of critical limit for zinc in rice soils

Abstract

Twenty surface soil samples wore collectod from Nalnltal Tarai (foot‐ hills of Himalya) where ‘Khaira’ disease (Zn deficiency disease of rice) was prevalent. Rice (Oryza sativa L. variety IR ‐ 8) was grown in pots for 8 weeks after transplanting. Experiments were carried out to find the suitability of five soil Zn extractants viz. dilute acid (HC1 ‐ H₂SO₄) mixture, DTPA‐ (NH₄) ₂CO₃, pH 7.3, dithizono, NH₄ ‐ Ac, pH 4.6 and MgCl₂. Critical limits of available Zn in soils were established for rice crop by old and new Cate and Nelson procedures.

Zn extracted from the soil with NH₄ ‐ Ac, pH 4.6, dithlzono, MgCl₂, and DTPA‐(NH₄) ₂CO₃, pH 7.3 was significantly correlated with the uptake of Zn by the rice plants. The correlation of Zn uptake with dilute acid mixture extractable Zn was not significant. The extractant which extracted more Zn gave higher values of critical limit and vice versa. It is concluded that all extracting solutions except dilute acid mixture were found to be suitable for predicting available Zn in rice soils of Taral.     

基于GIS的长江中游油菜种植区土壤养分及pH状况

为了掌握长江中游油菜种植区土壤养分状况,在湖北、湖南、江西三个省份调查和取样分析5 463份土壤数据的6个指标(土壤有机质、全氮、有效磷、速效钾、有效硼和pH),基于Arc GIS平台,采用Kriging插值法分析4个不同油菜种植区域(二熟制山地区、二熟制平原区、三熟制山地区、三熟制平原区)的土壤养分状况。结果表明,长江中游油菜种植区土壤有机质、全氮和有效磷均处于适宜/丰富的含量水平,基本没有5级和6级水平的有机质、全氮、有效磷分布。从不同区域来看,以上3个养分指标总体均表现为三熟制地区养分含量高于二熟制地区。长江中游仍有1.82×10~5 hm~2区域土壤速效钾处于缺乏的水平(30~50 mg kg~(-1))。土壤有效硼含量仍有待提高,尤其是在三熟制地区,土壤有效硼缺乏(5级和6级)的比例仍高达13.6%~20.4%。土壤pH多集中在6.0左右,但是三熟制地区仍然有较高比例(约35.7%)的土壤pH处于4.5~5.5。综上所述,长江中游不同种植区域土壤养分性状存在差异,尤其是三熟制地区仍有相当比例需要提高土壤有效硼和改良酸性土壤。     

半干旱雨养区秸秆带状覆盖种植对土壤水分 及马铃薯产量的影响

水分不足是限制半干旱雨养作物生长的主要因素,地表覆盖能够改善土壤的微环境,从而显著提高作物的产量和水分利用效率。为明确西北半干旱雨养区不同保墒措施下旱地马铃薯的土壤水分特征及其对产量的影响,于2014—2015年设置了玉米秸秆带状覆盖种植(T1)、半膜大垄(T2)、全膜双垄(T3)和露地平作(对照,CK)4种栽培模式,研究了玉米秸秆带状覆盖、地膜覆盖种植对马铃薯产量、土壤水分变化及其利用效率的影响。结果表明:不同覆盖方式能有效改善马铃薯生育期0~200 cm土层土壤水分状况,地膜覆盖对马铃薯生育前期土壤水分保蓄效果较好,秸秆带状覆盖对生育中后期土壤水分状况的改善效果明显。与对照(CK)相比,3种覆盖处理均提高了土壤含水量,其中T1处理效果最好,较CK提高2.8%~7.8%,尤其在伏旱阶段的块茎形成期,0~200 cm土层土壤含水量高于地膜覆盖处理。与CK相比,T1处理马铃薯产量提高10.5%~34.2%,水分利用效率(WUE)提高8.9%~29.8%,达108.9~134.0 kg·hm~(–2)·mm~(–1),商品薯率提高14.7%~38.8%,达82.3%~92.2%。马铃薯产量与生育期耗水量(r=0.836**)呈显著正相关。T1的产量和商品薯率均显著高于T2和T3(P0.05)。可见,玉米秸秆带状覆盖具有显著的纳雨保墒作用,促进马铃薯的生长发育,增产效果显著。其推广应用可有效提高该区降水资源的利用效率,实现马铃薯稳产高产,可作为西北雨养农业区旱地马铃薯生产的高效栽培新模式。     

黄土高原不同封育年限草地土壤与植物根系的生态化学计量特征

黄土高原特别是干草原地区植被演替的研究比较薄弱。当前植物生态化学计量学的研究主要集中在植物叶片方面,对根系的研究较少。选取宁夏云雾山草原植被不同封育年限的土壤和植物样品,以生态化学计量学原理为基础,测定并分析了土壤与根系的碳(C)、氮(N)、磷(P)及其生态化学计量比与相互关系。结果表明:(1)随着封育年限的增加,土壤容重逐渐减小,土壤有机碳和全氮变异性较大,全磷变异性较小,且封育初期土壤有机碳和全氮含量先降后升,至封育20、30年,保持相对平稳。0~20 cm土层土壤的碳氮比(C∶N)、碳磷比(C∶P)、氮磷比(N∶P)分别为9.04~9.63、19.62~32.27、2.14~3.37,20~40 cm土层土壤的分别为8.68~9.22、15.74~26.32、1.80~3.03。土壤有机碳与全氮、全磷之间存在极显著的正相关。(2)植物根系C、N、P含量变化范围分别为357.6~381.4 g kg-1、7.35~8.18 g kg-1、0.54~0.70 g kg-1;根系中的C元素含量随封育年限的增加逐渐升高,N、P元素含量均小于全球平均值。根系C∶N随着封育年限的增加变异性较大,C∶P、N∶P随着封育年限的增加变异性较小。(3)植物根系的C∶N∶P化学计量特征受土壤的影响调控大于其自身,且土壤磷含量对植物根系C∶N∶P生态化学计量特征影响的显著性(p0.01)大于土壤氮含量(p0.05)。此外,该地区封禁后,草地生产力易受到土壤N含量的限制。     

土壤磷素流失的途径、环境影响及对策

土壤长期过量的P肥(包括化肥和有机肥)投入导致土壤P素水平的提高,从而加大了土壤P素流失的风险。大部分水体富营养化的限制因素是P,土壤P的流失是重要的非点源污染。本文对国内外有关土壤P管理的研究做一综述,内容包括土壤P对水体富营养化的贡献、土壤P的流失途径及影响因素、系列水体P和土壤P指数、土壤P流失控制对策(土地利用管理、立法、政策的改变)等。     

湖南衡南县紫色土土壤动物研究

通过对衡南县紫色土5种生境中的土壤动物进行调查研究,共获得土壤动物1657只,隶属于4门9纲37目,其中优势类群2类,常见类群11类。探讨了5种生境中土壤动物群落结构特征,并进行了多样性、均匀性及相似性分析。     

Prediction of the soil structures produced by tillage

Data are presented for the amount of clods >50 mm produced when five different soils were tilled at a range of different, naturally occurring water contents. The optimum water content for soil tillage is defined as that at which the amount of clods produced is minimum. The amount clods produced at this optimum water content is shown to be linearly and negatively correlated with the value of Dexter's index S of soil physical quality. This results in a rational model for soil tillage that enables predictions to be made for all different soils and conditions. Pedo-transfer functions can be used to estimate the input parameters for the model for cases, for which measured values are not available. It is concluded that for soils with good physical condition (i.e. S > 0.035), no clods >50 mm are produced during tillage.     

田间烤烟叶片缺钾症状与钾积累及土壤供钾水平关系

基于田间正常施肥烟株生长中期中、上部叶通常出现缺钾症状的现象,以烤烟品种K326为材料在砂质壤土上进行了田间试验,定期观察无钾(即K0,仅按常规施用氮磷肥,K₂O用量为0 kg·hm^–2)、常规施肥但中后期出现缺钾症状(即CF,按常规施用氮磷钾肥,K₂O用量为364 kg·hm^–2但中后期仍有缺钾症状)、常规施肥且正常生长(即CK,按常规施用氮磷钾肥,K₂O用量为364 kg·hm^–2但中后期无缺钾症状)3处理烟株移栽后生长情况(特别是叶片缺钾症状的出现情况),并及时采集和测定了相应烟株的干物质、钾含量及根区土壤速效钾含量,以阐明正常施肥烤烟中、上部叶出现缺钾症状的可能原因。结果表明:(1)CF和K0烟株在移栽后33 d前叶片均未出现缺钾症状;但根区土壤速效钾含量移栽后42 d低于99.86 mg·kg^–1时,K0烟株第8～第15叶陆续表现缺钾;CF烟株根区土壤速效钾含量移栽后57 d低于131.1mg·kg^–1...