Reduced tillage with residue retention improves soil labile carbon pools and carbon lability and management indices in a seven-year trial with wheat-mung bean-rice rotation     

Rafeza BEGUM  Mohammad M. R. JAHANGIR  Mohammad JAHIRUDDIN  Mohammad Rafiqul ISLAM  Shaikh M. BOKHTIAR  Khandakar R. ISLAM 《土壤圈》2022,32(6):916-927

Soil total organic carbon (TOC) is a composite indicator of soil quality with implications for crop production and the regulation of soil ecosystem services. Research reports on the dynamics of TOC as a consequence of soil management practices in subtropical climatic conditions, where microbial carbon (C) loss is high, are very limited. The objective of our study was to evaluate the impact of seven years of continuous tillage and residue management on soil TOC dynamics (quantitative and qualitative) with respect to lability and stratification under an annual wheat-mung bean-rice cropping sequence. Composite soil samples were collected at 0-15 and 15-30 cm depths from a three-replicate split-plot experiment with tillage treatment as the main plots and crop residue levels as the sub-plots. The tillage treatments included conventional tillage (CT) and strip tillage (ST). Residue levels were high residue level (HR), 30% of the plant height, and low residue level (LR), 15%. In addition to TOC, soil samples were analyzed for particulate organic C (POC), permanganate oxidizable C (POXC), basal respiration (BR), specific maintenance respiration rate (qCO₂), microbial biomass C (MBC), potentially mineralizable C (PMC), and TOC lability and management indices. The ST treatment significantly increased the TOC and labile C pools at both depths compared with the CT treatment, with the effect being more pronounced in the surface layer. The HR treatment increased TOC and labile C pools compared with the LR treatment. The ST + HR treatment showed significant increases in MBC, metabolic quotient (qR), C pool index (CPI), C lability index (CL_I), and C management index (CMI), indicating improved and efficient soil biological activities in such systems compared with the CT treatment. Similarly, the stratification values, a measure of soil quality improvement, for POC and MBC were > 2, indicating improved soil quality in the ST + HR treatment compared with the CT treatment. The ST + HR treatment not only significantly increased the contents of TOC pools, but also their stocks. The CMI was correlated with qCO₂, BR, and MBC, suggesting that these are sensitive indicators of early changes in TOC. The qCO₂ was significantly higher in the CT + LR treatment and negatively correlated with MBC and CMI, indicating a biologically stressed soil condition in this treatment. Our findings highlight that medium-term reduced tillage with HR management has profound consequences on soil TOC quality and dynamics as mediated by alterations in labile C pools.  相似文献   

硅肥对甘蔗光合特性和产量的影响   总被引：3，自引：0，他引：3  

黄海荣  BOKHTIAR S M  徐林  李杨瑞  杨丽涛 《广西农业科学》2009,40(12):1564-1569

在温室条件下,以每桶施用26g N＋1.76g P＋20g K为对照,进行6个不同硅肥施用水平处理（20,40,60,80,120和150 g/桶）桶栽试验,探讨硅肥对新台22号甘蔗产量构成因素、光合特性、N、P、K和Si的影响。结果表明,大部分硅肥（硅酸钙）处理较对照显著提高甘蔗叶片光合速率、蒸腾速率及气孔导度;不同硅肥处理之间的甘蔗叶片P含量差异不大,部分处理的P含量略有增加;施用硅肥可显著降低叶片N、K含量,但随着硅肥施用量的增加,叶片Si含量逐渐提高。硅肥处理较对照显著提高每桶甘蔗干物质含量（26%～70%）和甘蔗产量（30%～60%）。此外,在收获期,硅肥处理的甘蔗植株硅含量可达2.64%。  相似文献   

硅肥对蔗地土壤性状、甘蔗叶片营养及产量的影响   总被引：1，自引：0，他引：1  

黄海荣  徐林  BOKHTIAR S M  李杨瑞  杨丽涛 《广西农业科学》2011,42(7):756-759

【目的】在大棚条件下进行甘蔗硅肥施用量研究,阐明硅肥对甘蔗生长、营养以及土壤特性等的影响。【方法】以新台糖22号为试验材料,以每桶26gN＋1．76gP＋20gK为对照,设置T1～T6（20、40、60、80、120 and 150g／桶）6个不同硅肥用量,研究不同施硅水平对甘蔗的影响。【结果】硅肥处理的甘蔗＋1叶N、P、Ca、Mg、Si含量较对照有一定提高,其中120旆处理的甘蔗＋1叶含硅量比对照增加92％。不同施硅水平对甘蔗土壤理化性状具有显著影响,SOM和有效P较对照显著降低,120g／桶处理的有效Si含量较对照增加137％,150g／桶处理的交换性Ca和Mg分别较对照增加117．9％和86．0％,pH均有一定提高。硅肥处理对甘蔗株高和产量增加有显著影响,对甘蔗干物质和产糖量的提高也有促进作用,但不显著。【结论】硅肥对甘蔗生产以及土壤理化性状具有一定正效应,可结合常规施肥进一步推广从而提高甘蔗生产。  相似文献