Nutrient Release Patterns Research Articles

降水变化和氮沉降对荒漠草原两种多年生禾草凋落物分解的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 降水变化和氮沉降对荒漠草原两种多年生禾草凋落物分解的影响 DOI: 10.5846/stxb202103230769 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金（31560156，31860136）；内蒙古自治区自然科学基金（2017MS0350） Effects of precipitation and nitrogen deposition on litter decomposition of two perennial grasses in a desert steppe Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:凋落物分解是陆地生态系统养分循环的重要过程，在生物地球化学循环过程中发挥着重要作用。全球变化是影响凋落物分解的重要因子，其对生态系统养分循环的影响存在诸多不确定性。研究荒漠草原凋落物分解对氮沉降和降水变化及其二者交互作用的响应，是揭示这些不确定性、保护草原生态系统结构和功能的科学基础。以内蒙古四子王旗短花针茅荒漠草原为研究对象，选取建群种短花针茅和优势种无芒隐子草两种植物凋落物，开展为期4年的长期分解实验，探究两种植物凋落物分解特征及养分释放规律。实验采用裂区设计，主区为自然降水（C）、增雨30%（W）和减雨30%（R）3个水分梯度，副区为0（N0）、30（N30）、50（N50）和100（N100） kg hm-2 a-1 4个氮素梯度。结果表明：（1）增雨和氮沉降促进荒漠草原凋落物分解，减雨反之，降水对两种凋落物影响具有差异，而氮沉降的作用不依赖于物种；（2）氮沉降缩短凋落物分解周期5.12%-14.82%，增雨与氮沉降交互缩短凋落物分解周期3.69%-28.75%；（3）降水始终有利于凋落物中碳、纤维素和木质素释放，而分解后期氮沉降对其影响不显著，凋落物分解后期主要受木质素分解速率控制。综上所述，影响荒漠草原凋落物分解的主要因素为降水，其次是氮素，二者对凋落物分解具有协同作用。 Abstract:Abstract:Litter decomposition is an important process of ecosystem nutrient cycling, which plays an important role in biogeochemical cycling. Global change is an important factor affecting litter decomposition, but there are many uncertainties in its impact on ecosystem nutrient cycling. Studies on the response and feedback of litter decomposition of desert steppe to the increased nitrogen deposition and precipitation change will provide the scientific basis for revealing these uncertainties and protecting the structure and function of grassland ecosystem. In this study, taking S. breviflora desert steppe in Siziwang Banner, Inner Mongolia as the research object, two kinds of plant litter, the dominant species S. breviflora and C. songorica, were selected to carry out a 4-year decomposition experiment, to explore the litter decomposition characteristics and nutrient release patterns of the two kinds of plants. The experiment used split-pot design, with precipitation as the whole-plot factor and N as the split-pot factor. Precipitation treatments include addition 30% (W), removal 30% (R), and ambient precipitation(C). Nitrogen was added at 0 (N0), 30 (N30), 50 (N50) and 100 (N100) kg hm-2 a-1. The results show that:(1) Increased precipitation and nitrogen deposition promoted litter decomposition in the desert steppe. Furthermore, the precipitation effects were different between the two kinds of litter, while the effect of nitrogen deposition does not depend on species; (2) Nitrogen deposition shortened the litter decomposition duration by 5.12%-14.82%, and the interaction between precipitation enhancement and nitrogen deposition shortened the litter decomposition duration by 3.69%-28.75%; (3) Precipitation was always beneficial to the release of carbon, cellulose and lignin from litter, but nitrogen deposition had no significant effect on it in the later stage of litter decomposition, and the late stage of litter decomposition is mainly controlled by the decomposition rate of lignin. In conclusion, the main factor affecting the decomposition of litter in the desert steppe is precipitation, followed by nitrogen, and the two factors have a synergistic effect on decomposition of litter. 参考文献 相似文献 引证文献

Production of bacterial cellulose nanocrystals via enzymatic hydrolysis and evaluation of their coating on alginate particles formed by ionotropic gelation

This study aimed to obtain the bacterial cellulose nanocrystals (CNC) by enzymatic hydrolysis and verify the CNC application as coating material in alginate particles. Therefore, the production of CNC was carried out through two enzymatic hydrolysis methods involving a time period of 48 and 72 h. 0.35 mg of dry mass of cellulose was produced approximately 1.6 × 1011 CNC/mL. The CNC obtained by enzymatic hydrolysis at 72 h (Method II) was applied to cover the alginate particles, obtained by ionotropic gelation. The CNC Zeta potential value was about +15 mV and for alginate particles -26.46 ± 1.48 mV. These results confirmed the application of CNC as coating material for alginate particles. It brings an incremental contribution to the knowledge advancement in the pharmaceutical and food area, allowing the engineering of systems to use a mixed composition of nanobiomaterials to modify the release pattern of drugs, macromolecule, nutrients, stabilizers and target specific drug release.

​Nutrient Release Pattern of a Fortified Manure Disc and its Implication on Yield of Tomato in Sandy Soils

Background: Development of fortified organic formulations using various organic sources and fertilizers for soil application will ensure efficient nutrient management in homestead vegetable production systems. Fortified organic formulations will help in preventing nutrient leaching also. Hence, the present study has been undertaken during 2019-20 to develop low cost fortified organic manure discs using various biodegradable agro waste materials and NPK fertilizers and to study its effect on growth and yield of tomato in sandy soils of Kerala. Methods: A fortified manure disc was developed by combining local biodegradable agro waste materials with conventional NPK fertilizers. Organic manures like rice husk ash, cow dung, rice husk, coirpith compost, vermicompost, neem cake and clay were used to develop the manure disc. The combination of organic manures was fortified with fertilizers at various proportions of manure: fertilizer viz., 1:1, 2:1, 0.5:1 and manure alone and used for incubation for a period of two months to study the nutrient release pattern of N, P and K.The 2:1(manure: fertilizer) formulation was selected based on the highest peak of nutrient availability of N, P and K even after 2 months. Effect of fortified manure disc was evaluated by using tomato variety Anagha as test crop in a pot culture experiment. Result: Growth, yield and quality of tomato increased significantly due to the application of fortified manure disc. The highest yield per plant of 0.97 kg was recorded for T8 (50% recommended dose fortified manure disc in 2 splits) and lowest yield was recorded for T9 (Manure alone). The fortified manure disc had a significant influence on nutrient use efficiency also. The highest NUE of 45.5% was recorded in treatment T8 (50% fertilizer fortified discs in 2 splits). Study revealed that fortified manure disc is a promising technology to reduce nutrient leaching and enhancing the nutrient use efficiency in sandy soils. Fifty percentage reduction in the recommended dose of NPK fertilizers were achieved by fortifying the manure disc with fertilizers.Thus the cost of fertilizers and fertilizer load per unit area can be reduced by the application of fortified manure disc which will act as slow release fertilizer.

Physicochemical and Nutrient Release Characteristics of a Thermochemical Organic Fertilizer Produced from Degradable Solid Waste and Its Effect on Productivity of Banana

ABSTRACT Physicochemical characterization and a 300-day soil incubation was conducted to study the effect of a thermochemical organic fertilizer (TOF) produced from biowaste through rapid thermochemical processing technology on soil properties and nutrient release pattern at the Kerala Agricultural University, India. A field experiment to study the effect of TOF on the growth and yield of banana (Nendran) was conducted. The physicochemical properties of TOF were conforming to prescribed quality standards. The TOF imparted moderation of acidity, lower soluble salts and a steady and constant release pattern of organic carbon on incubation. Mineralized nitrogen dynamics was superior in TOF combined with Plant Growth Promoting Rhizobacteria, characterized by a 120-day cycle of net nitrogen mineralization on 10 days and a net immobilization on 20 days. Highest P mineralization was recorded at 150 days with a phase of total immobilization from 180 to 240 days. Mineralization and immobilization up to 60 days, marked by a steady release of potassium followed by a progressive mineralization up to 240 days was evident. The TOF based treatments proved to be superior in plant height, number of leaves, pseudostem girth, bunch yield and dry matter production in banana as compared to farmyard manure – based treatments.

A performance evaluation study of nano-biochar as a potential slow-release nano-fertilizer from wheat straw residue for sustainable agriculture

Agro-Wastes are identified as to manufacture potential valuable organic biochar fertilizer product economically while also managing the waste. Biochar (BC) produced from agriculture waste is helps to improve the soil because of its neutral pH, addition of organic carbon to the soil and lower salt index values. This study focused on the development of nano-biochar into a more enhanced biochar product where it was checked whether the biochar derived from wheat straw can absorb nutrients and then act as support matter for releasing micro-nutrients and macro-nutrients for the plants on slow liberation basis. Wheat biochar (WBC) and wheat nano-biochar (WBNC) were synthesized by pyrolysis at two different temperatures and nutrients were fused into the WBC via impregnation technique. Physical parameters such as Proximate, Ultimate analysis & other were also studied and inspected by standard control procedures. Studies were also carried out on water retention (WR), water absorbance (WA), swelling ratio (SR) and equilibrium water content (EWC) for all samples; data was collected and compared for the better sample. Slow-release studies performed portrayed the release pattern of nutrients for prolonged periods, which are very important for the plant growth, yield and productivity. Overall, the experimental results displayed that BNC produced at 350 °C showed promising features of (SI:0.05, SR: 3.67, WA:64%, EWC:78.6%, FC:53.05% and pH:7.22), is a good substance however the nano-biochar has improved results; environmental friendly & could be utilized as a potential fertilizer on slow release for sustainable and green agriculture application.

Mineralization and nutrient release pattern of vermicast-sawdust mixed media with or without addition of Trichoderma viride.

A combination of vermicast and sawdust mixed medium is commonly used in horticulture, but the added benefit of microbial inoculation and mechanism of nutrient availability are unknown. This study was done to determine nutrient mineralization and nutrient release patterns of different combinations or a mix of vermicast-sawdust growing media amended with or without Trichoderma viride (105 spores/g). The mixed-media treatments were (1) 80% vermicast+20% sawdust; (2) 60% vermicast+40% sawdust; (3) 40% vermicast+60% sawdust; (4) 20% vermicast+80% sawdust; and (5) sawdust alone (control). Total dissolved solids, electric conductivity and salinity increased with each sampling time following submergence in deionized. Nutrients released from media without T. viride were significantly higher than the corresponding media with added T. viride. Overall, the starting total nitrogen of the different media did not change during the incubation period, but nitrate-nitrogen was reduced to a negligible amount by the end of day 30 of incubation. A repeated measures analysis showed a significant effect of Time*T. viride*Treatment on total dissolved solids. Redundancy analysis demonstrated a positive and strong association between media composed of ≥40% vermicast and ≤60% sawdust with or without T. viride and mineral nutrients released, electrical conductivity, total dissolved solids and salinity. These findings suggest that fast-growing plants may benefit from 40% to 60% vermicast added to 40% to 60% sawdust without T. viride while slow-growing plants can benefit from the same mixed medium combined with the addition of T. viride. Further investigation is underway to assess microbial dynamics in the mixed media and their influence on plant growth.

Development of Organic Briquettes from Slaughterhouse Waste as Nutrient Source for Plant Growth

A study was conducted to develop organic briquettes using biomass originating from slaughterhouse wastes and to investigate its potential as a nutrient source for plant growth. Dried rumen contents were mixed with fresh blood collected after bleeding of animals in different proportions and dried using tray drier. The dried rumen content-blood (RB) mixture was further mixed with commercially available coir pith in 12 different proportions. The rumen content-blood-coir pith (RBC) mixture was formed into briquettes using a hydraulic biomass briquetting machine. Each organic briquette was 5 cm in diameter and had an average weight of 30–40 g. The treatments were analyzed for pH, moisture content, electrical conductivity (EC), organic carbon (OC), total nitrogen, carbon: nitrogen ratio, total phosphorus and total potassium. Organic briquette having rumen content with 100% blood and 80% coir pith (T10) recorded the highest total nitrogen, total phosphorus and total potassium content. The treatments for plant growth studies were selected based on the criteria that each treatment had highest values for at least two of the three primary nutrients of nitrogen, phosphorus and potassium. The treatments T5, T7, T8, T10 and T12 were selected for plant growth studies. Pot experiment using selected briquettes was carried out to determine the effect of selected briquettes on growth parameters and yield attributes of okra (Abelmoschus esculentus). Nutrient release pattern of the selected organic briquettes was also studied. The best desirable growth parameters and yield attributes of okra was observed in T10. Availability of nutrients in the medium were relatively less during first 2 months of planting (MAP), however, it significantly increased between 3 and 4 MAP, which resulted in better plant growth and fruit yield. The study showed that there is great potential for development of organic briquettes using slaughter house wastes as an eco-friendly process, which are compact, easy to transport and market, and ideal for grow bag cultivation and garden nurseries.Graphic Abstract

Balanced fertilization for increasing and sustaining fruit quality and productivity-A Review

Balance nutrient management is an approach to soil health management that combines organic and mineral methods of soil fertilization with physical and biological measures for soil and water conservation. The indiscriminate use of chemical pesticides along with improper nutrient management is deleterious to the plant and soil health, environment and human being who consume them. It also causes soil health deterioration and disturbs the soil microorganisms. Due to these practices, the plants also become susceptible to several biotic and abiotic stresses. The quality attributes of different fruits are badly affected due to indiscriminate application of inorganic agro-chemicals which results in quality deterioration with less consumer preference and low returns to the growers. Thus, adequate mineral nutrition is a pre-harvest factor affecting fruit quality. Therefore, it is a holistic approach based on usage of all possible sources of plant nutrients in an integrated manner is considered as alternative source to maintain soil fertility and plant nutrient supply for sustaining the desired crop productivity. Due to huge distinction in the nutrient use efficiency of perennial fruit crops, their nutrient management- based production system is characteristically intricate to understand. Integrated plant nutrient management aims to optimize the condition of the soil, with regard to its physical, chemical, biological and hydrological properties, for the purpose of enhancing farm productivity, whilst minimizing land degradation. There are studies that integrated nutrient management provide tangible benefits in terms of higher yields, but simultaneously and almost imperceptibly conserve the soil resource itself along with produce quality. The replenishment of soil nutrients lost by leaching and/or removed in harvested products through an integrated plant nutrition management approach that optimizes the benefits from all possible on- and off-farm sources of plant nutrients. The review on balanced fertilization on a variety of fruit crops revealed similar combinations. These observations provided a countrywide database that INM module which consists of nutrient sources having three-tier nutrient release pattern, has far reaching consequences on soil and plant health translating into real guard production sustainability, nearer to climate resilient fruit crops.

Fertilizer values of composts as affected by plant materials and composting duration on maize (Zea mays) performance

Chemical properties and nutrient release pattern from compost are influenced by composted plant materials (CPM) and duration of composting (DC). The following plant materials; guinea grass (GGC), tridax weed (TWC), siam weed (SWC) and maize stover (MSC) were composted with cow dung. Pot and field experiments were carried out to evaluate the effect of these CPM on growth yield performance of maize, and the properties of soil after harvest. The pot trial was a 4 × 5 factorial experiment laid out in a completely randomized design (CRD) with three replicates while the field experiment was a 4 × 3 factorial arranged in a randomized complete block design (RCBD), replicated three times. Data collected on initial and soil properties after harvest, growth, dry matter yield (DMY), nutrient uptake and yield of maize were subjected to analysis of variance and means separated using Duncan Multiple Range Test. Results showed that MSC compost had the highest N content while GGC had the highest K. Phosphorus (P) content was similar for all the CPMs. Results of pot experiment showed that maize growth was higher (p ≤ 0.05) with GGC, TWC and MSC of 3, 4 and 5 months DC. The DMY and P-uptake increased with increasing DC. On field trial, plants height was similar for all the CPM that received MSC and GGC gave similar highest DMY which were significantly higher than TWC and SWC. MSC gave the highest N-uptake while GGC treated plant had the highest P and K uptake. Grain yield was significantly higher for MSC (1.80 t ha–1) than SWC and Control but similar to GGC (1.37 t ha–1) and TWC (1.18 t ha–1). Compost application at 20 t ha–1 significantly increased cob weight, N and K uptake of maize compared to control. Application of CPM improved final soil available P which increased with DC and rate of application of different CPM. Therefore, CPM and DC have great potentials in influencing compost quality and should be considered in formulating compost fertilizer in organic farming.

How nutrient rich are decaying cocoa pod husks? The kinetics of nutrient leaching

AimRecycling of cocoa pod husks has potential to contribute to mineral nutrition of cocoa. Yet little is known of the nutrient content and nutrient release patterns from the husks. The potassium (K) rich husks are usually left in heaps in cocoa plantations in Africa. We aimed to understand and quantify release patterns of K and other nutrients from husks under varying rainfall regimes and assessed the effects of partial decomposition and inundation on nutrient leaching rates.MethodsWe incubated chunks of cocoa pod husks to assess decomposition rates and we measured nutrient leaching rates from two sets of husk chunks: one set was placed in tubes that were submitted to simulated scheduled rainfall events while the second set was continuously inundated in beakers.ResultsDecomposition of husks followed a second-order exponential curve (k: 0.09 day−1; ageing constant: 0.43). Nutrient losses recorded within 25 days were larger and more variable for K (33%) than for other macronutrients released in this order: Mg > Ca ≈ P > N (less than 15%). Potassium leaching was mainly driven by rainfall frequency (P < 0.05) and reinforced by intense rainfall, especially at lower frequency. Under water-saturated conditions, 11% of K was leached out within 48 h from fresh husks compared with 92% from partially decayed husks.ConclusionSome initial decomposition of cocoa pod husks is required to expose K to intense leaching. As decomposition progresses, abundant K losses are to be expected under frequent and/or intense rainfall events.

Density manipulation and pruning on fine root production and decomposition dynamics in a mature Acacia mangium Willd. stand in Kerala, India

Fine roots play a major role in water and mineral uptake and nutrient cycling in woody perennial-based ecosystems. Just as other biomass components, stand density manipulation and tree pruning may influence fine root production (FRP) and its decomposition dynamics. However, quantitative information on FRP and its turnover under different density and pruning regimes are meagre for most tropical trees. A field study was conducted to characterize FRP and associated nutrient release under varying stand density and pruning regimes in a 12-year-old Acacia mangium stand in Kerala, India. Soil ingrowth core method was employed for quantifying FRP and sequential core method for estimating standing fine root biomass. Annual FRP estimates were 5.78, 5.39, 3.74, and 3.38 Mg ha–1 for the 5000, 2500, 1250 and 625 trees ha−1 treatments, respectively. Allometric models based on tree diameter and basal area gave a good fit for annual FRP. Fine root turnover rates ranged from 2.81 to 3.16 yr−1, which however, was not influenced by stand density. Carbon stocks ranged from 1.36 to 2.39 Mg ha−1 with highest FRP during rainy season and lowest during the dry period. The litterbag study using nylon mesh bags indicated that annual fine root mass loss ranged from 76.2 (5000 trees ha−1) to 96.8% (625 trees ha−1). Tree pruning had only modest effects on tree growth, FRP, and carbon and nutrient release patterns. The study highlights the importance of stand density manipulation in altering A. mangium FRP, soil carbon and mineral nutrient dynamics.

Leaf litter decomposition and nutrient release of three selected agroforestry tree species

Investigation was carried out on leaf litter decomposition and nutrient content of three agroforestry species—Annona muricata L., Senna siamea (Lam.) and Cola nitida (Vent.) using litterbag technique. Oven-dry leaf litters of each species were put in 432 litterbags of 23 g each. These were divided into two sets with one placed on the soil surface (SSP) and another, soil incorporated (SIP). Initial nutrient content (INC), decay constant, half- and full-lives (weeks) were determined. Decomposition rates, nutrient release patterns (NRP) and litter quality were measured fortnightly for 24 weeks after litter placement (WALP). Data collected were subjected to descriptive statistics and ANOVA at α0.05. The INC was significantly different among the species. N concentration decreased from C. nitida A. muricataS. siamea. P was significantly higher in S. siamea (0.38%) than C. nitida (0.22%) and A. muricata (0.32%). Decay constant was highest (0.005) in C. nitida under SIP. Highest half-life (49.5 weeks) and full-life (178.57 weeks) were recorded in S. siamea and C. nitida; and S. siamea and C. nitida under SSP. After 24 weeks, C. nitida had the highest decomposition rate, 5.97 ± 0.0 under SIP. NRP showed that A. muricata and S. siamea had the highest P (0.17%) and cellulose (28.2%) at 24 WALP under SIP. Lignin concentration at 24 WALP was highest in S. siamea (4.35%) and least in C. nitida (0.43%). Decomposition trend and nutrient release pattern from the leaf litters of selected agroforestry species indicated the potential of these leaf litters to offer nutrients on a sustainable basis in an agroforestry system.

Application of Gliricidia sepium Tree Leaves and Nitrogen Fertilizer to Improve Tomato Production and Soil Properties

Excess use of agrochemicals for intensive cultivation affects crop quality and destroys agro-ecosystems, and eventually creates health hazards. The study aims to investigate the effect of Gliricidia sepium (GS) tree leaf as suitable green manures for supplementing nutrient supply along with nitrogen (N) fertilizer to produce quality tomato and soil fertility improvement. A field experiment was conducted at the Bangabandhu Sheikh Mujibur Rahman Agricultural University, Bangladesh, from November 2016 to March 2017. The experiment was laid out in a randomized complete block design (two factors) with three replications. There were nine treatment combinations with three levels of GS tree leaves (5, 10 and 15 t ha−1) and three doses of N (0, 50 and 100% of the recommended dose of fertilizer). The highest tomato yield was recorded in GS15×N100 treatment combination, which was 41.68% higher compared to the control treatment. Decreasing C: N ratio in increasing dose of GS and N treated plot indicated the quality of tree leaves that ensures faster decomposition and high nutrient release pattern of this species. Increasing rate of soil pH and cation exchange capacity (CEC) in different treatments as compared to initial soil showed soil fertility improvement. Overall, the results indicated that quality tomato could be grown successfully by the application of G. sepium tree leaves along with an appropriate amount of N fertilizer.&#x0D; Ann. Bangladesh Agric. (2020) 24(1) : 77-87

Decomposition and nutrient mineralisation of leaf litter in smallholder cocoa agroforests: a comparison of organic and conventional farms in Ghana

PurposeAlthough litter decomposition and nutrient release patterns have been studied in cocoa agroforestry systems in general, studies focusing on organic and conventional cocoa systems are lacking which is critical as organic farms are particularly dependent on nutrient returns from decomposing litter.Materials and methodsDynamics in leaf litter decomposition and the mineralisation of macro- and micro-nutrients in organic and conventional cocoa agroforestry systems were studied using the litterbag technique for 12 months.ResultsThe average monthly mass loss was more than two times higher on organic farms (9.2–14.4 g month−1) compared to conventional farms (4.2–7.3 g month−1) in the first five months. The annual rate of decomposition (k) was higher on organic farms (1.9) compared to conventional systems (1.4). The time required for 50% (t50) and 99% (t99) decomposition of leaf litter was both lower on organic farms (t50 = 0.4 years, t99 = 2.6 years) than conventional farms (t50 = 0.5 years, t99 = 3.5 years). The estimated k values for macro- and micro-nutrients on organic cocoa systems ranged from 2.3 for calcium to 4.5 for potassium compared to 1.6 (Ca) to 2.8 (K) on conventional farms. The k values of all nutrients (except nitrogen and phosphorus) were significantly greater on organic farms than conventional systems. The estimated k values for both litter decomposition and nutrient mineralisation correlated with soil pH and moisture content, but not initial litter chemistry.ConclusionsOrganic management of smallholder cocoa agroforestry systems enhanced leaf litter decomposition and nutrient mineralisation through improved soil conditions. Thus, organic management of cocoa agroforestry systems may contribute to sustainable cocoa production in smallholder systems through enhanced nutrient return from litter decomposition.

Understanding the Role of Litter Decomposition in Restoration of Fly Ash Ecosystem.

Plant species possess a huge potential in restoration of fly ash ecosystem. Litter deposition and its decomposition in the ash deposited sites are two important processes of the fly ash ecosystem. In order to identify the biological potential of a plant species to aid restoration of fly ash deposited sites, it is needed to assess leaf litter decomposition as well as nutrient release pattern. In the present investigation, we studied the leaf litter decomposition of the plant species (Leucaena leucocephala, Pithecellobium dolce and Prosopis juliflora) and mix plantation in the fly ash ecosystem. The litter bag experiment was conducted in the area of plantation on the fly ash deposited site during a period of 365days. Percentage of C and N was higher in L. leucocephala > P. dolce >Mix Plantation > P. juliflora while C/N ratio was higher in P. juliflora >Mix Plantation > L. leucocephala > P. dolce. L. leucocephala and P. dolce showed relatively fast decomposition rates (k = 1.27, 1.17), respectively while mix plantation (k = 0.82) and P. juliflora (k = 0.73) exhibited relatively slower decomposition rates. Thus, we noted that the decomposition rate of L. leucocephala was greater than the other selected species. This shows that the species having faster decomposition rate and nutrient release could be a factual choice for rehabilitation of fly ash deposited sites.

Spatial and Temporal Distribution of Cattle Dung and Nutrient Cycling in Integrated Crop–Livestock Systems

Residue decomposition from cattle dung is crucial in the nutrient cycling process in Integrated Crop–Livestock Systems (ICLS). It also involves the impact of the presence of trees exerted on excreta distribution, as well as nutrient cycling. The objectives of this research included (i) mapping the distribution of cattle dung in two ICLS, i.e., with and without trees, CLT and CL, respectively, and (ii) quantification of dry matter decomposition and nutrient release (nitrogen—N, phosphorus—P, potassium—K, and sulphur—S) from cattle dung in both systems. The cattle dung excluded boxes were set out from July 2018 to October 2018 (pasture phase), and retrieved after 1, 7, 14, 21, 28, 56 and 84 days (during the grazing period). The initial concentrations of N (~19 g kg−1), P (~9 g kg−1), K (~16 g kg−1), and S (~8 g kg−1) in the cattle dung showed no differences. The total N, P, K and S released from the cattle dung residues were less in the CLT system (2.2 kg ha−1 of N; 0.7 kg ha−1 of P; 2.2 kg ha−1 of K and 0.6 kg ha−1 of S), compared to the CL (4.2 kg ha−1 of N; 1.4 kg ha−1 of P; 3.6 kg ha−1 of K and 1.1 kg ha−1 of S). Lesser quantities of cattle dung were observed in the CLT (1810) compared to the CL (2652), caused by the lower stocking rate, on average, in this system (721 in the CL vs. 393 kg ha−1 in the CLT) because of the reduced amount of pasture in the CLT systems (−41%), probably due to light reduction (−42%). The density of the excreta was determined using the Thiessen polygon area. The CL system revealed a higher concentration of faeces at locations near the water points, gate and fences. The CLT affects the spatial distribution of the dung, causing uniformity. Therefore, these results strengthen the need to understand the nutrient release patterns from cattle dung to progress fertilisation management.

Effect of wood vinegar on the nutrient release of Zn and Fe in a sodic soil

The use of ZnSO4 and FeSO4 either alone or in combination with wood vinegar is incubated to 60 days and it was compared in the present investigation with an aim to increase the nutrient release pattern of micronutrients viz, Fe and Zn under sodic soil conditions. An incubation experiment was conducted during 2019 in ADAC & RI, Trichy, Tamil Nadu. The incubation experiment comprised of 12 treatments replicated twice in a completely randomized design. The treatments included recommended dose of FeSO4 and ZnSO4 alone and their combination and their combination with three levels of wood vinegar viz., 50, 100 and 150 ml/l applied as as spot drenching (SD). Incubated soil sample were analysed for DTPA Zn and Fe at different intervals (0, 15, 30 45 and 60 DAI). The results of the investigation revealed significant differences in wood vinegar release of DTPA Zn and Fe among the treatments in comparison with the ZnSO4 and FeSO4 either alone or in combination of ZnSO4 and FeSO4. Among the treatments, During 0th day of incubation (DAI), the treatment T12 receiving the recommended dose of both ZnSO4 and FeSO4 along with wood vinegar (WV) @ 150 ml/l as spot drenching recorded significantly higher value of available Zn content (46.68 mg kg-1). The lowest value was recorded in the treatment T1 (6.72 mg kg-1) which received recommended dose of FeSO4 alone. At 0th day of incubation (DAI), the treatment receiving recommended dose of ZnSO4 alone (T2) recorded the lowest DTPA Fe (7.32mg kg-1) while the highest value(48.28 mg kg-1) was recorded in the treatment receiving recommended dose FeSO₄ @ 50 kg /ha along with WV @150 ml/l (T6). Therefore, incorporation of wood vinegar increased the effectiveness of Fe and Zn in sodic soils. The release of DTPA Zn and Fe attained peak at 15 DAI and declined thereafter up to 60 DAI. The experiment received that the DTPA Zn and Fe which contributes to available Zn and Fe considerably increased under wood vinegar drenching in sodic soil.

Nutrient Release Pattern and Greenhouse-Grown Swiss Chard Response to Biochar Inoculated with Vermicast

A study was performed to assess nutrient release from biochar inoculated with solid vermicast (SVB), vermicast tea (VTB), deionized water (DWB), uninoculated biochar (Bioc), and Promix-BX (Pro-BX). The growth response of Swiss chard (Beta vulgaris subsp. vulgaris) cv. Rhubarb chard was also assessed. Comparatively, nutrients were released slowly from treatments SVB and VTB compared to the other treatments. The rate of nutrient release determined by total dissolved solids and electric conductivity from the Pro-BX was the highest. The trend for the plant growth components, total leaf surface area and leaf fresh weight at first harvest, was Pro-BX &gt; Bioc &gt; DWB = SVB &gt; VTB. The only treatment that increased total leaf area and leaf fresh weight at the second harvest by approximately 1.02- and 1.88-fold was VTB. Leaf fresh weight was significantly reduced by approximately 0.33-fold for DWB, 0.28-fold for Bioc, and 0.70-fold for Pro-BX but was not altered by SVB at the second harvest as compared to the first harvest. A 2-dimensional principal component analysis (PCA) biplot confirmed that treatment Pro-BX increased plant growth components at the first harvest only. The locations of SVB and VTB on the PCA biplot confirmed their efficacies, which led to increases in the plant growth components at the second harvest. Overall, the VTB adsorbed more nutrients onto its surface that were slowly released to enhance the Swiss chard cv. Rhubarb chard plant growth at the second harvest. Further studies should consider microbial activities.

Effect of different biochars on soil moisture retention and nutrient release pattern

Soil incubation study in pots was carried out to study the effect of three different biochars on soil moisture retention percentage. The treatments involve three doses of maize biochar (MB), cotton biochar (CB) and prosopis biochar (PB) @ 2.0 t ha-1 (2T), 3.0 t ha-1 (3T) and 4.0 t ha-1 (4T), respectively besides a control and Farm Yard Manure @ 12.5 t ha-1. Significantly higher moisture per cent was noted in treatments of higher doses of all the biochars in second and third day of incubation. The significant increase in moisture per cent was noted in PB 4 T incubated pot, which was followed by CB 4T. The reduction in moisture per cent was noted with lower doses of biochar irrespective of source. Results of another incubation study with different biochars with varied doses, to find out nutrient release pattern revealed that the available N, P and K was higher at the start of incubation in control, where as in later days of incubation N, P and K availability was higher in Prosopis Biochar 4T after 70 days of incubation which was followed by cotton biochar 4T.

Effects of trees and nitrogen supply on macronutrient cycling in integrated crop–livestock systems

AbstractResidue decomposition from pastures and crops plays an important role in nutrient cycling in integrated crop–livestock systems (ICLS). The objective of this research was to quantify dry matter decomposition and nutrient release—nitrogen, phosphorus, and potassium (N, P, and K, respectively), the most commonly required nutrients in tropical and subtropical agriculture—from pasture and soybean (Glycine max) residues of stocking and crop seasons in two ICLS (with and without trees, CLT and CL, respectively) and two N fertilization levels (90 vs. 180 kg N ha−1, N90 and N180, respectively, applied during the pasture phase). Litter bag incubations were set out in the December 2014 (soybean phase) and May 2015 (pasture phase), and retrieved after 7, 15, 30, 60, 90, and 120 d in each season. The total N, P, and K released from the pasture or soybean residues were related to the initial quantity of plant residues, which was reduced in the CLT systems, mostly for pasture residue (−60%), probably due to light reduction (−55%), rather than changes in litter quality and dynamics. Significant amounts of N (∼57 kg ha−1), P (∼11 kg ha−1), and K (∼58 kg ha−1) were cycled, particularly in CL and N180 treatments. The quantities of K released from pasture residues were enough to restore the quantity of K exported by soybean grains. Therefore, results reinforce the need to understand nutrient release patterns from residues to improve fertilization management.