Short Term Enhancement of Nutrients Availability in Zea mays L. Cultivation on an Acid Soil Using Compost and Clinoptilolite Zeolite

To avoid environmental pollution due to excessive use of inorganic fertilizers, it is essential to increase the availability of nutrients using environmentally friendly resources, such as composts and clinoptilolite zeolite, in soil fertility management. In this study, an attempt was made to use different rates of inorganic fertilizers, compost, and clinoptilolite zeolite to correct the ongoing excessive use of inorganic fertilizers. A pot study using maize (Zea mays L.) as a test crop was carried out to determine the effects of amending inorganic fertilizers with compost and clinoptilolite zeolite on: (i) selected soil chemical properties, and (ii) N, P, and K uptake and use efficiency in maize cultivation. The pot study was conducted for 45 days (tasseling stage of maize). Amending inorganic fertilizers with compost and clinoptilolite zeolite increased soil total N, exchangeable Ca, Mg, K, and available P. Furthermore, P and K uptake and use efficiency of maize were significantly improved upon amending inorganic fertilizers with compost and clinoptilolite zeolite. Soil chemical properties and productivity of maize on acid soils can be improved through co-application of compost and clinoptilolite zeolite. However, field application of the authors’ findings is being evaluated in an on-going field experiment.     

Effect of Organic Amendment Derived from Co-Composting of Chicken Slurry and Rice Straw on Reducing Nitrogen Loss from Urea

Co-composting of chicken slurry and rice straw with clinoptilolite zeolite and urea as additives was conducted to determine the characteristics of a compost and their effects on controlling ammonium (NH₄⁺) and nitrate (NO₃^?) losses from urea. Quality of the compost was assessed based on temperature, moisture content, ash, pH, electrical conductivity, carbon/nitrogen (C/N) ratio, NH₄⁺, NO₃^?, macronutrients, heavy metals, humic acid, microbial population, germination index, and phytotoxicity test. Moisture content and C/N ratio of the compost were 43.83% and 15, respectively. Total N, humic acid, ash, NH₄⁺, NO₃^?, phosphorus (P), calcium (Ca), magnesium (Mg), potassium (K), and sodium (Na) increased after co-composting rice straw and chicken slurry. Copper, iron (Fe), manganese (Mn), zinc (Zn), and microbial biomass of the compost were low. The germination rate of Zea mays on distilled water and Spinacia oleracea growth on peat-based growing medium (PBGM) and compost were not significantly different. Urea amended with compost reduced N loss by retaining NH₄⁺ and NO₃^? in the soil.     

Reducing Soil Phosphorus Fixation to Improve Yield of Maize on a Tropical Acid Soil Using Compost and Biochar Derived from Agro-Industrial Wastes

Phosphorus is an essential element required to maintain profitable crop production. Most soils of the tropics, such as Ultisols, are acidic and fix phosphorus because of their characteristically high contents of aluminium and iron. Compost and biochar could be used to mitigate phosphorus fixation by reducing the phosphorus sorption sites. This study aimed to: (i) improve soil phosphorus availability, nutrient uptake, and yield of maize using biochar and pineapple leaf residue compost; and (ii) determine if the use of biochar and compost could exert a residual effect on phosphorus nutrition in the second cycle of the field trial. Field trials were carried out using a Zea mays L. hybrid as the test crop. At harvest, the plants were harvested, partitioned into leaves and stems, and analyzed. Soil samples were also collected and analyzed. Ears were harvested to determine the yield from each treatment. The results suggest that the soil total phosphorus and available phosphorus recovered from the treatments with the organic amendments were higher compared with the non-organic amendments. The availability of soil nutrients (nitrogen, potassium, calcium, magnesium, and sodium) in the soils and yield of maize were higher in the treatments with the organic amendments in the first and second field trials. These results further confirm that amending chemical fertilizers with organic amendments have a larger residual effect than chemical fertilizers only. Amending chemical fertilizers with organic amendments can be used to ameliorate phosphorus fixation of acid soils to improve maize production on acid soils.     

Comparison of various potting media for their influence on nutrients supply,germination, and growth of muskmelon (cucumis melo L.) seedlings

Peat moss is used as potting mix for growing muskmelon (Cucumis melo L.) seedlings. However, it is not economical for most of the farmers in developing countries. The objectives of the present study were to compare various sources of composts as substitutes for peat moss, evaluate their physicochemical properties, and their effects on germination and growth of muskmelon (Cucumis melo L.) seedlings under greenhouse conditions. The treatments included pure peat moss (control), and composts prepared from guar (Cyammopsis tetragonoloba L.), jantar (Sesbania aculeate L.), and wheat (Triticum aestivum L) straw, at three air-filled porosity (AFP) levels (10, 15, and 20%) and rice (Oryza sativa) hulls at 10% AFP level. The second factor was the addition and devoid of nitrogen (N), phosphorus (P), and potassium (K) fertilizers. The addition of fertilizers in all potting media at 10% AFP level showed a small increase in total nitrogen, extractable phosphorus, and potassium. In the guar and jantar compost at 10% AFP, the values of total N (92.43 and 85.32%), extractable P (68.13 and 76.65%), and K (63.33 and 49%) were higher than in peat moss. It is concluded that composts of guar, jantar, wheat straw, and rice hulls at 10% AFP level can be used as a substitute of peat moss for growing muskmelon seedlings, but the addition of N, P, and K fertilizers is required in wheat straw and rice hulls compost for better nutrition of muskmelon seedlings.     

不同堆肥原料的有机无机复合肥对油菜生长及土壤供氮特性的影响

通过田间试验,研究了采用猪粪堆肥、中药渣堆肥和鸡粪堆肥为原料制成的有机无机复合肥与无机复合肥等氮量施入对油菜产量、氮素利用率、土壤供氮特征以及土壤微生物多样性的影响。结果表明:各施肥处理油菜籽产量均显著高于对照的油菜籽产量。与化肥处理比较,三种堆肥原料的有机无机复合肥的油菜籽产量显著高于化肥处理,较化肥增产12.7%～33.2%。各有机无机复合肥处理均能增加油菜单株有效角果数。三种有机无机复合肥处理均能显著促进油菜对氮素的吸收,从而提高了氮素利用率。与化肥处理和不施肥处理比较,三种堆肥原料的有机无机复合肥处理能够明显提高土壤有效态氮的含量,调节土壤氮素的释放速度。采用邻接法分析各处理土壤DNA条带表明:5个处理土壤样品的细菌群落共分为三大族群,化肥处理与对照处理为一种族群,中药渣处理为一种族群,猪粪处理和鸡粪处理属一种族群。说明施入外源有机物质(猪粪、鸡粪与中药渣)可能改变土壤的细菌群落结构,而施入化肥对土壤的细菌群落结构影响较小。     

稻-麦轮作体系不同施肥模式对氮肥利用效率和土壤有效养分平衡的影响

土壤肥力和养分利用效率是保障可持续粮食生产的基础。通过田间试验研究了稻—麦轮作体系下不同施肥模式氮肥利用效率和土壤有效养分的变化,结果表明:在减少养分总投入量的条件下,有机肥部分替代化肥处理(RF-OM和RF-S处理)水稻地上部总生物量显著高于LRF处理(P<0.05),与FP处理差异不大;小麦秸秆生物量与FP和LRF处理差异均不显著,籽粒生物量及地上部总生物量与LRF处理相差不大。水稻收获期RF-OM处理地上部主要器官含氮量与LRF处理差异不显著,氮素积累总量显著高于LRF处理(P<0.05);小麦收获期RF-OM和RF-S处理秸秆、籽粒含氮量和氮素积累量与LRF处理均无显著差异。收获期RF-OM和RF-S处理水稻糙米和稻壳、小麦秸秆和籽粒含磷量及磷素积累量与FP和LRF处理差异都不大;水稻秸秆、稻壳及小麦秸秆含钾量和钾素积累量均显著高于FP和LRF处理(P<0.05)。有机肥部分替代化肥处理水稻、小麦氮肥农学利用率、氮肥表观回收率和氮肥偏生产力与FP和LRF处理相比均显著提高(P<0.05),氮素籽粒生产效率也高于FP和LRF处理,甚至达到显著水平(P<0.05)。试验表明,水稻、小麦收获期增钾处理(RF-OM和RF-S处理)土壤速效钾、缓效钾含量显著高于FP和LRF处理(P<0.05),水稻收获期土壤碱解氮和小麦收获期土壤有效磷含量与LRF处理差异不大,同时,经1个稻—麦轮作周期后,4个施肥处理土壤有效养分(碱解氮、有效磷、速效钾、缓效钾)含量均高于供试土壤。有机肥部分替代化肥能显著提高稻麦氮肥利用效率,有利于土壤有效养分平衡,并显著提高土壤速效钾和缓效钾养分含量,是适宜的稻麦化肥减量和稳产增效施用技术。     

有机无机肥配施对双季稻田土壤养分利用与渗漏淋失的影响

采用田间小区试验,研究稻草、猪粪、猪粪堆肥或沼渣沼液与化肥配施对双季稻田土壤养分利用与渗漏淋失的影响。结果表明,有机肥与化肥配施有利于提高稻田土壤中N、P、K养分和有机质含量,降低稻田渗漏液中TN、TP、NH4+-N、NO3--N浓度,促进水稻养分吸收与利用。其中,以20%的猪粪堆肥氮与化肥配施效果较好,与施纯化肥相比,1年后土壤中全氮、全磷、全钾和有机质含量分别提高了2.59%,0.87%,0.15%和21.45%,碱解氮、速效磷、速效钾含量分别提高3.31%,3.22%和12.24%;氮、磷、钾肥料利用率分别提高5.22%,0.55%,3.50%;水稻地上部氮、磷、钾养分累积量分别提高7.83,0.33,3.14g/kg;水稻生长期稻田渗漏液中TN、TP、NH4+-N、NO3--N浓度明显降低;早稻增产19.65%,晚稻无明显减产。     

Application rate and composting method affect the immediate and residual manure fertilizer value in a maize–rice–rice–maize cropping sequence on a degraded soil in northern Vietnam

A field experiment was carried out in northern Vietnam to investigate the effects of adding different additives [rice (Oriza sativa L.) straw only, or rice straw with added lime, superphosphate (SSP), urea or a mixture of selected microorganism species] on nitrogen (N) losses and nutrient concentrations in manure composts. The composts and fresh manure were applied to a three-crop per year sequence (maize–rice–rice) on a degraded soil (Plinthic Acrisol/Plinthaquult) to investigate the effects of manure type on crop yield, N uptake and fertilizer value. Total N losses during composting with SSP were 20% of initial total N, while with other additives they were 30–35%. With SSP as a compost additive, 65–85% of the initial ammonium-N (NH₄-N) in the manure remained in the compost compared with 25% for microorganisms and 30% for lime. Nitrogen uptake efficiency (NUE) of fresh manure was lower than that of composted manure when applied to maize (Zea mays L.), but higher when applied to rice (Oriza sativa L.). The NUE of compost with SSP was generally higher than that of compost with straw only and lime. The mineral fertilizer equivalent (MFE) of manure types for maize decreased in the order: manure composted with SSP?>?manure composted with straw only and fresh manure?>?manure composted with lime. For rice, the corresponding order was: fresh manure?>?manure composted with SSP/microorganisms/urea?>?manure composted with lime/with straw alone. The MFE was higher when 5 tons manure ha^?1 were applied than when 10 tons manure ha^?1 were applied throughout the crop sequence. The residual effect of composted manures (determined in a fourth crop, with no manure applied) was generally 50% higher than that of fresh manure after one year of manure and compost application. Thus, addition of SSP during composting improved the field fertilizer value of composted pig manure the most.     

Nitrous oxide emission,global warming potential,and denitrifier abundances as affected by long-term fertilization on Mollisols of Northeastern China

ABSTRACT

A long-term field experiment was performed to assess the effects of fertilization regimes on greenhouse gas emissions, soil properties, soil denitrifies, and maize (Zea mays) grain yield on Mollisols of Northeastern China. Chemical nitrogen (N), phosphorus (P), and potassium (K) fertilizers plus pig manure (MNPK) treatment significantly increased soil N₂O emissions by 29.9–226.4% and global warming potential (GWP) by 29.8–230.7% compared to unfertilized control (CK), chemical N fertilizer only (N), chemical N, P, and K fertilizers (NPK) and chemical N, P, and K fertilizers plus corn straw (SNPK) treatments. However, the MNPK treatment yielded similar greenhouse gas intensity (GHGI) as compared with other treatments, mainly due to higher maize grain yield. There were also higher gene copy numbers of nirK, nirS, and nosZ in topsoil (0–20 cm depth) under MNPK treatment. Automatic linear modeling analysis indicated that main factors influencing soil N₂O emissions were soil organic carbon (SOC), NO₃^? content, and nirK gene abundance. Although the application of chemical fertilizers plus organic manure increases N₂O emissions due to higher N and C availability and nirK gene activity in the soil, this is still a promising fertilizer management due to its notable enhancement of maize grain yield and SOC content.     

Changes in Biological Properties in Soil Amended with Rock Phosphate and Waste Mica Enriched Compost using Biological Amendments and Chemical Fertilizers Under Wheat-Soybean Rotation

The main aim of this research work is to prepare an enriched compost using rice straw mixed with rock phosphate, waste mica and Aspergillus awamori and to study their effect on changes in microbial properties in soils with and without chemical fertilizers under wheat-soybean rotation. Data revealed that significant increase in microbial biomass carbon (MBC), dehydrogenase activity, phosphatase activities, and microbial biomass phosphorus (MBP) in soil were maintained in enriched compost than ordinary compost after both the crops. Significant increase in MBC, dehydrogenase activity, phosphatase activities, and MBP were found in surface soil. The maximum microbial activities were observed in the treatment receiving 50% recommended dose of fertilizer (RDF) + enriched compost at 5 t ha^?1 indicating that integrated use of chemical fertilizers and enriched compost significantly improved the biological properties of soil under wheat–soybean rotation thereby enhanced soil fertility and crop production.     

Soil nutrient status and yield of rice as affected by long-term integrated use of organic and inorganic fertilizers

Nutrient balance is the key component to increase crop yields. Excess and imbalanced use of nutrients has caused nutrient mining from the soil and deteriorated crop productivity and ultimately soil health. Replenishment of these nutrients has a direct impact on soil health and crop productivity. Based on this fact, the present research was conducted to determine the effects of long-term integrated use of organic and inorganic fertilizers on soil nutrient status and yield (grain and straw) in rice. Different combinations of inorganic nitrogen (N) and organic sources (sewage sludge and compost) were applied to the soil. Data revealed that application of mineral NPK in combination with 50% N through compost significantly increased the organic matter content (0.36%), available phosphorus (16.50 kg/ha) and available potassium content (239.80 kg/ha) in soil. The maximum available N (225.12 kg/ha) was found by the substitution of 50% N through sewage sludge. This improvement in soil nutrient status through combined use of organic and inorganic fertilizers produced significant increase in grain and straw yield as compared to inorganic fertilizers alone. Maximum grain (6.96 t/ha) and straw (8.56 t/ha) yields were found in treatment having substitution of 50% N (recommended) through compost @10t/ha. Also, a significant positive correlation was found between soil nutrients and straw and grain yield in rice. Thus the study demonstrated that substitution of 50% inorganic N through compost will be a good alternative for improving soil fertility.     

不同原料生物炭对氮、磷、钾的吸附和解吸特性

【目的】通过三种不同原料生物炭 (玉米秆炭、稻壳炭、稻秆炭) 对氮、磷、钾的吸附解吸试验,了解不同材料来源的生物炭对无机养分的吸附和解吸特征,为将其作为添加物来调节有机肥的性质提供参考。【方法】在pH 6.75 ± 0.25、25℃下,采用Langmuir和Freundlich方程对三种不同原料生物炭 (玉米秆炭、稻壳炭、稻秆炭) 氮、磷、钾的等温吸附进行拟合。对吸附养分后的生物炭进行连续5次解吸,前4次采用水浸提,第5次浸提采用1 mol/L KCl浸提氮,0.5 mol/L的NaHCO₃浸提磷,1 mol/L的CH₃COONH₄浸提钾。【结果】1) Langmuir和Freundlich方程均可用来拟合生物炭对氮、磷、钾的等温吸附,Langmuir方程对氮、磷的吸附拟合较好,Freundlich方程对钾的吸附拟合较好。对不同原材料而言,稻秆炭对氮、磷、钾的吸附性能均较好,其最大吸附量q_m分别为 (2.44 ± 0.15) mg/g、(2.91 ± 0.12) mg/g和 (4.97 ± 0.22) mg/g。2) 不同原材料生物炭对氮、磷、钾的单次解吸率和总解吸率具有一定的差异。生物炭对阳离子 (铵根离子和钾离子) 的最大吸附量受阳离子交换量和酸性官能团的数量以及pH_pzc影响,对磷酸根的最大吸附量主要与阳离子交换量和碱性官能团的数量有关。【结论】所试三种生物炭对氮、磷、钾的吸附存在单分子层吸附和多分子层吸附,在单次解吸率和总解吸率上不同原料生物炭存在一定的差异性。在生物炭对氮和钾吸附的总量上,物理性吸附的贡献高于化学吸附;对磷的吸附总量上,化学吸附的贡献高于物理吸附。三种生物炭对氮、磷、钾的固储和缓释能力具有一定的差异,稻秆炭的保肥供肥能力优于玉米秆炭和稻壳炭。     

西湖平原区连续13年定位施肥对麦、稻产量及土壤肥力的影响

以浙江省水网平原水稻主产区土壤为对象,通过定位试验,研究了连续13年的不同施肥处理对麦稻产量、土壤养分状况和物理性状的影响。结果表明,化肥配施有机肥可显著提高麦、稻产量; 不同施肥处理的长期定位试验土壤有机质含量和全氮均呈上升趋势,增幅依次为: 栏肥+NPK秸秆+NPKNPK秸秆栏肥CK处理; 土壤碱解氮和速效磷也呈增加趋势,以栏肥+NPK处理的增幅最为明显。土壤物理性状的分析表明,长期施肥均能明显增加土壤水稳性团粒含量和土壤孔隙度。经土壤养分平衡分析,栏肥+NPK、秸秆+NPK和NPK处理的氮和磷呈现盈余,秸秆和CK处理氮和磷亏缺; 栏肥+NPK和秸秆+NPK处理钾基本平衡,NPK、秸秆、栏肥和CK处理钾严重亏缺。长期定位试验进一步证明有机肥与氮、磷、钾化肥长期配合施用可实现当地农作物持续稳产,农田施肥管理要注意适当减少氮、磷投入,增加钾肥施用量,保持农田土壤养分平衡。     

Soil aggregation and distribution of carbon and nitrogen in different fractions under long-term application of compost in rice–wheat system

Soil organic matter improves the physical, chemical and biological properties of soil, and crop residue recycling is an important factor influencing soil organic matter levels. We studied the impact of continuous application of rice straw compost either alone or in conjunction with inorganic fertilizers on aggregate stability and distribution of carbon (C) and nitrogen (N) in different aggregate fractions after 10 cycles of rice–wheat cropping on a sandy loam soil at Punjab Agricultural University research farm, Ludhiana, India. Changes in water stable aggregates (WSA), mean weight diameter (MWD), aggregate-associated C and N, total soil C and N, relative to control and inorganically fertilized soil were measured. Total WSA were significantly (p = 0.05) higher for soils when rice straw compost either alone or in combination with inorganic fertilizers was applied as compared to control. The application of rice straw compost either alone or in combination with inorganic fertilizers increased the macroaggregate size fractions except for 0.25–0.50 mm fraction. The MWD was significantly (p = 0.05) higher in plots receiving rice straw compost either alone at 8 tonnes ha⁻¹ (0.51 mm at wheat harvest and 0.41 mm at rice harvest) or at 2 tonnes ha⁻¹ in combination with inorganic fertilizers (0.43 and 0.38 mm) as compared to control (0.34 and 0.33 mm) or inorganically fertilized plots (0.33 and 0.31 mm). The macroaggregates had higher C and N density compared to microaggregates. Application of rice straw compost at 2 tonnes ha⁻¹ along with inorganic fertilizers (IN + 2RSC) increased C and N concentration significantly over control. The C and N concentration increased further when rice straw compost at 8 tonnes ha⁻¹ (8RSC) was added. It is concluded that soils can be rehabilitated and can sustain the soil C and N levels with the continuous application of rice straw compost either alone or in combination with inorganic fertilizers. This will also help in controlling the rising levels of atmospheric carbon dioxide.     

长期不同施肥红壤磷素特征和流失风险研究

为探索长期施肥对红壤磷素吸附固持的影响,分析不同施肥土壤磷流失风险及影响因素。在南方丘陵区红壤上开展了持续25年的长期定位试验,处理包括:不施肥(CK)、施氮肥(N)、施磷肥(P)、施钾肥(K)、施氮磷钾肥(NPK1)、施2倍量氮磷钾肥(NPK2)、单施有机肥(OM)和氮磷钾配施有机肥(MNPK)。研究了不同施肥下土壤全磷、Olsen-P、Mehlich1-P、CaCl2-P含量及磷吸持指数(PSI)、磷饱和度(DPS)的变化,探讨不同施肥处理土壤对磷的吸附和解吸特征,并分析了土壤磷指标与土壤有机碳、pH、CEC之间的关系。结果表明:长期施用化学磷肥有利于补充土壤磷素,特别是土壤全磷,并使Olesn-P和Mehlich 1-P有增加趋势,而对CaCl2-P影响不显著;施用化肥对DPS影响不显著,单施磷会降低PSI,低量氮磷钾提高了PSI,高量氮磷钾处理与对照差异不显著;长期施用有机肥(猪粪)土壤全磷增加,而Olsen-P、Mehlich 1-P和CaCl2-P则大幅累积, PSI显著降低, DPS显著增加。长期施用化肥处理土壤对新添加磷的吸附较强,长期施用有机肥降低了土壤对新添加磷的吸附;土壤全磷、Olsen-P、Mehlich1-P、CaCl2-P、PSI、DPS及最大吸附容量(Qm)与土壤pH、CEC、土壤总有机碳(TSOC)、土壤水溶性有机碳[冷水提取水溶性有机碳(CWSOC)和热水提取水溶性有机碳(HWSOC)]间相关性较高;土壤磷指标和土壤有机碳、pH、CEC指标之间存在典型相关关系,第1对和第2对典型变量的典型相关系数分别为0.997和0.951,达显著水平。研究表明,施用有机肥是调节土壤磷的供给和保持的重要措施,土壤水溶性有机碳和pH可能是反映红壤磷素供应和流失的关键指标。     

长期秸秆还田下土壤铵态氮的吸附解吸特征

【目的】研究长期秸秆还田对不同轮作区域耕层和亚耕层的土壤铵态氮 (NH₄+) 的吸附、解吸特征差异,通过 Langmuir 等温吸附方程拟合得到 NH₄+ 最大吸附量 (q_max) 和吸附系数 (b),分析长期秸秆还田对不同土壤 NH₄+ 的吸附、解吸特征差异及影响因素。 【方法】2015 年 10 月水稻收获后,在湖南望城 (稻–稻轮作)、江西进贤 (稻–稻轮作)、重庆北碚 (稻–麦轮作) 三个长期定位试验点 (25 年) 采集不施肥 (CK)、长期施用化肥 (NPK) 和长期秸秆还田配施化肥 (NPKS) 三个处理、0—20 cm 和 20—40 cm 两个土层的土样,进行土壤 NH₄+ 的吸附–解吸室内试验,吸附试验为添加不同浓度的 NH₄Cl 溶液振荡、离心后,测定滤液 NH₄+ 浓度;解吸试验采用吸附试验后的土壤样品,经无水乙醇淋洗至无 NH₄+ 后,再加入 0.01 mol/L 的 KCl 溶液振荡、离心后测定滤液 NH₄+ 浓度。 【结果】长期秸秆还田对不同试验点土壤 NH₄+ 吸附–解吸特征的影响差异较大。处理间的差异主要表现在耕层土壤。当平衡溶液 NH₄+ 浓度 < 400 mg/L 时,不同试验点耕层和亚耕层处理间差异均不明显;当平衡溶液浓度 > 400 mg/L 时,处理间耕层土壤对 NH₄+ 吸附表现出差异,其中望城试验点土壤对 NH₄+ 的吸附表现为 CK > NPK > NPKS,北碚试验点则表现为 CK > NPKS > NPK,且北碚试验点的紫色土对 NH₄+ 的吸附显著高于望城和进贤试验点的红壤性水稻土。进贤试验点不同处理间差异不明显,且土壤对 NH₄+ 的吸附量最低。 通过相关性分析发现,q_max和土壤 pH、阳离子交换量 CEC 呈显著正相关,而与土壤有机质和全氮含量呈显著负相关;b 与土壤性质的相关性与q_max 则相反。从土壤对 NH₄+ 的解吸曲线来看,耕层和亚耕层土壤对 NH₄+ 的解吸在各试验点不同处理间均表现为差异不显著,其中望城和进贤试验点的红壤性水稻土 NH₄+ 的最大解吸量高于其吸附量,而北碚试验点的紫色土 NH₄+ 的最大解吸量 (541.89～742.38 mg/kg) 则远低于其吸附量 (1003.83～2014.79 mg/kg)。 【结论】长期秸秆还田对不同土壤 NH₄+ 的吸附–解吸作用影响不同,对于土壤吸附位点较多且钾离子含量丰富的紫色土而言,长期秸秆还田有利于土壤对氮的吸附;而对于土壤偏酸性的红壤性水稻土而言,长期秸秆还田则可能因为增加了土壤有机质含量而减少了土壤对铵态氮的吸附位点,从而降低了土壤对氮的吸附保持能力。     

氮肥减量施生物炭对水稻产量和养分利用的影响

为解决水稻生产过度依赖化肥及其环境和高效利用问题,探讨贵州黄壤稻田科学施用生物炭。在贵州省思南县典型黄壤稻田开展氮肥不减量(T0)和氮肥减10%施2.5 t/hm²(T1),氮肥减20%施5.0 t/hm²(T2),氮肥减30%施7.5 t/hm²(T3),氮肥减40%施10.0 t/hm²生物炭(T4)和不施肥对照(CK)共6个处理3次重复田间小区随机区组试验,研究了氮肥减量施生物炭对水稻产量、产量构成和氮磷钾养分吸收利用的影响。结果表明,氮肥减量施生物炭显著影响贵州黄壤稻田水稻产量、产量构成、地上部氮磷钾积累量和利用效率。水稻产量和氮磷钾积累量随氮肥减量和生物炭用量增加先增大后减小。2019年、2020年和2021年水稻实际产量和理论产量均分别以T2、T3和T2最高,较T0分别显著增产16.04%,17.94%和14.73%以及55.72%,64.08%和118.91%,水稻籽粒N、P₂O₅和K₂O积累量、偏生产力、农学效率、表观利用率和收获指数均较高,是较好的氮肥减量施生物炭处理。产量—施生物炭量回归方程和极值分析表明,2019年、2020年和2021年氮肥分别减量21.76%,24.60%和19.00%(即32.64,36.90,28.50 kg/hm²)施生物炭量5.44,6.15,4.75 t/hm²时水稻产量最高(分别为7.80,8.57,8.03 t/hm²),较T0分别增产22.52%,18.78%和13.74%。氮肥减量施生物炭显著提高氮磷钾化肥利用率,但导致化肥+生物炭磷和钾利用率降低,因此,贵州黄壤稻田施生物炭时应氮磷钾化肥同步减量,降低比例以氮磷钾减量19.00%~24.60%,施生物炭5.00~6.25 t/hm²为宜。研究结果对指导贵州黄壤稻田氮磷钾化肥减量和施生物炭具有重要指导意义。     

水稻秸秆堆沤肥对优质水稻产量及质量的影响

以不施肥为对照,设习惯性分阶段施用化肥、一次性施用化肥、施用一般有机肥及一次性单施不同用量的水稻秸秆堆沤肥或与不同比例化肥配施的12个处理,以水稻产量及质量为主要指标,探索以水稻秸秆堆沤肥种植优质水稻的适宜措施、规律及用量。结果表明,试验组各处理的稻谷产量及稻米垩白度、蛋白质含量、食味值存在较大差异,大小范围分别为5 560～9 460 kg/hm~2、1.57%～2.23%、8.11%～10.06%、64.56～73.24,水稻秸秆堆沤肥各处理的稻米外观、营养、蒸煮、食味等品质较好;其中50%水稻秸秆堆沤肥+25%化肥处理产量达8 705 kg/hm~2并与习惯分阶段施用化肥及施用一般有机肥处理接近,稻米垩白度1.84%、蛋白质含量8.54%,食味值最佳,其它稻米外观、蒸煮等品质亦适宜。说明水稻秸秆堆沤肥供养分能力强,并具有与化肥配施良好,提高养分利用率及肥料减量,提高稻米食味等作用,可作为优质水稻种植的重要肥源之一。     

Rice straw biochar amended soil improves wheat productivity and accumulated phosphorus in grain

Abstract

Biochar is a pyrolyzed biomass produced under limited oxygen or oxygen absent conditions. Few investigations have been conducted to determine the combined effect of biochar with chemical fertilizer on growth, yield and nutrient distribution pattern in root, shoot and grain in wheat as well as changes in soil physiochemical properties. This research was designed to study the combined effect of chemical fertilizer and rice straw-derived biochar on soil physio-chemical properties, growth, yield and nutrient distribution pattern within wheat plant tissue and grain. Results showed that rice straw biochar caused a significant decrease in soil pH and increase in soil organic matter as well as nutrients like total nitrogen (TN), potassium (K), magnesium (Mg) and boron (B) due to incubation. Result also showed that root biomass and straw did not differ between Bangladesh Agricultural Research Council (BARC) and ½ BARC?+?rice straw biochar treatment. Similarly, thousand grain weight and grain yield did not differ between the same treatments. The phosphorus concentration in wheat grain was highest in ½ BARC?+?rice straw biochar as compared to other treatments. The use of rice straw biochar in addition to the chemical fertilizers in wheat production systems is an economically feasible and practical nutrient management practice. Our findings urged that reduction of chemical fertilizer application is possible with supplementation of rice straw biochar.     

不同生物质炭对棕壤中磷素吸附解吸的影响

为了减少土壤磷素流失,提高磷肥利用效率,探究不同生物炭对棕壤中磷素吸附解吸行为的影响规律,以水稻秸秆、玉米秸秆和花生壳为原材料,利用限氧升温炭化法制备生物炭,通过批量吸附实验研究了生物炭种类和生物炭添加量对棕壤磷吸附解吸的影响。结果表明：水稻秸秆生物炭在添加量为0.4%时显著提高棕壤对磷的吸附量,花生壳生物炭和玉米秸秆生物炭则显著降低棕壤对磷的吸附量；等温吸附曲线表明,不同生物炭均未改变等温吸附曲线的变化趋势,均可用Langmuir方程和 Freundlich 方程进行描述(R²>0.93),其中 Langmuir 方程拟合效果更好,不同处理对磷的理论吸附量大小顺序为：水稻秸秆生物炭+棕壤>棕壤>花生壳生物炭+棕壤>玉米秸秆生物炭+棕壤；吸附动力学实验表明,不同生物炭均未改变磷吸附动力学曲线的变化趋势,在所有动力学模型中,准二级动力学模型最适合描述土壤对磷的吸附行为(R²>0.99),其次为准一级动力模型(R²>0.99)和Elovich动力学模型(R²>0.88)；三种生物炭均显著促进棕壤对磷的解吸,当生物炭添加量为≥0.2%时,水稻秸秆生物炭、玉米秸秆生物炭和花生壳生物炭,分别可提高棕壤对磷的解析率50%、70%和90%以上。由此可见,不同生物炭可提高棕壤对磷素的供应和利用,水稻秸秆生物炭在减少棕壤磷素流失、保护生态环境方面具有更大的应用价值。