Effects of long-term treatments of different organic fertilizers complemented with chemical N fertilizer on the chemical and biological properties of soils

Continuous cultivation has been known to decrease soil organic matter content. Application of organic matter to cultivated soil is an important practice from the point of view of maintaining an adequate amount of soil organic matter. Soil organic matter content significantly affects soil microbial activity, which is an important index of soil quality. In this study, a field experiment was conducted to examine the long-term effects of different kinds of organic matter in combination with inorganic nitrogen (N) fertilizer on chemical and biological properties of soils. There were seven treatments, namely (1) CK (without fertilization), (2) Chem-N (applying chemical N fertilizer only), (3) Comp (applying compost with the same rate of N as the Chem-N treatment), (4) Comp + l/3 N (applying compost complemented with 33% of the chemical N fertilizer of the Chem-N treatment), (5) Comp + 2/3 N (applying compost complemented with 66% of the chemical N fertilizer of the Chem-N treatment), (6) GM + 1/3 N (applying green manure complemented with 33% of the chemical N fertilizer of the Chem-N treatment) and (7) Peat + 1/3 N (applying peat complemented with 33% of the chemical N fertilizer of the Chem-N treatment). After continuous treatment for 12 years and with cultivation of 24 crops on the same area, soils were sampled for analyses of chemical and biological properties, enzymatic activities and phospholipid fatty acid (PLFA) profiles. The results showed that compared with CK and Chem-N treatments, applications of compost and peat increased soil organic carbon (SOC) content and altered microbial activities and microbial community structure. However, application of green manure for 12 years had no effect on SOC content. Both microbial activities and PLFA profiles were clearly dependent on the characteristics of the applied organic amendments. In summary, a peat application led to the highest increase in SOC content compared to compost and green manure; however, compost-treated soil had a higher microbial population and higher microbial and enzyme activities, while the effects of both green manure and chemical N fertilizer on soil properties were similar.     

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.     

Plant and Soil Responses to the Combined Application of Organic Amendments and Inorganic Fertilizers in Degraded Sodic Soils of Indo-Gangetic Plains

ABSTRACT

Soil degradation due to salinization and sodication is the paramount threat in Indo-Gangetic plains. The studies on reclamation and management of such soils can provide a pragmatic solution for improving fertility and productivity of these soils. Lack of organic matter and poor availability of nutrients are the major factors for low productivity of sodic soils. Rice-wheat is a major cropping system in Indo-Gangetic alluvial plain region even in reclaimed sodic soils and farmers used inorganic fertilizers only to get higher yields. In this study, we used different organic sources of amendments in conjunction with different nitrogen (N) doses supplied through inorganic fertilizers to investigate the combined effect of organic and inorganic amendments on soil fertility and the productivity of rice- wheat system in sodic soils. Salt tolerant varieties of rice and wheat were grown in sodic soil (pH: 9.30, EC: 1.12 dSm^?1 and exchangeable sodium percentage, ESP: 52) during 2014–15 to 2016–17 in a field experiment with 13 treatment combinations of organic and inorganic amendments (T₁- (control) 100% of recommended dose of N (RDN), T₂-municipal solid waste compost (MSWC) @10 t ha^?1 + 50%RDN, T₃- MSWC @10 t ha^?1 + 75% RDN,T₄- MSWC @10 t ha^?1 + 100%RDN, T₅-Vermicompost (VC) @10 t ha^?1 + 50% RDN, T₆- VC @10 t ha^?1 + 75% RDN, T₇-VC@10 t ha^?1 + 100% RDN, T₈- Farm yard manure (FYM) @ 10 t ha^?1 + 50% RDN,T₉- FYM@10 t ha^?1 + 75%RDN, T₁₀- FYM@10 t ha^?1 + 100% RDN, T₁₁-Pressmud (PM) @10 t ha^?1 + 50% RDN, T₁₂-PM@10 t ha^?1 + 75%RDN, and T₁₃- PM @ 10 t ha^?1 + 100% RDN). Use of organic amendments supplemented with reduced dose of N through inorganic fertilizer has significantly improved soil bio-physical and chemical properties. Application of VC@10 t ha^?1 + 100% RDN (T₇) decreased soil bulk density, pH, EC, ESP and Na content to 2.0, 4.2, 26.5, 42.8, and 56.6% respectively and increased soil organic carbon by 34.6% over control (T₁). Soil fertility in terms of available N, P, K, Ca, and Mg increased by 20.5, 33.0, 36.4, and 44%, respectively, over control (T₁). Soil microbial biomass carbon, nitrogen, and phosphorus also improved significantly due to combined use of organic amendments and inorganic fertilizers over the only use of inorganic fertilizers. Decreasing in soil sodicity and increasing soil fertility showed significant increase (P < 0.05) in crop growth, growth indices, and grain yields of rice and wheat. The study revealed that combined use of VC or MSW compost @10 t ha^?1 in conjunction with 75% RDN through inorganic fertilizers in sodic soils proved sustainable technology for restoration of degraded sodic soils and improving crop productivity.     

Effects of organic fertilizers on yam productivity and some soil properties of a nutrient-depleted tropical Alfisol

Field experiments were conducted at Owo, southwest Nigeria to select organic fertilizer treatments most suitable for sustaining high soil fertility and yam productivity on a nutrient-depleted tropical Alfisol. Eight organic fertilizer treatments were applied at 20 t ha^?1 with a reference treatment inorganic fertilizer (NPK 15–15–15) at 400 kg ha^?1 and natural soil fertility (control), laid out in a randomized complete block design with three replications. Results showed that organic fertilizers significantly increased (p = 0.05) tuber weight and growth of yam, soil and leaf N, P, K, Ca and Mg, soil pH and organic C concentrations compared with the NSF (control). The oil palm bunch ash + poultry manure treatment increased tuber weight, vine length, number of leaves and leaf area of yam by 66, 25, 21 and 52%, respectively, compared with inorganic fertilizer (NPK) and 37, 22, 19 and 44%, respectively, compared with poultry manure alone. Sole or mixed forms of organic fertilizers showed significant improvement in soil physical conditions compared with IF (NPK) and NSF (control). Synergistic use of oil palm bunch ash + poultry manure at 10 t ha^?1 each was most effective for sustainable management of soils and for improving agronomic productivity of yam.     

Effects of Inorganic and Organic Fertilizers on Soil CO2 Efflux and Labile Organic Carbon Pools in an Intensively Managed Moso Bamboo (Phyllostachys pubescens) Plantation in Subtropical China

Impact of combined application of inorganic and organic fertilizers on soil carbon dioxide (CO₂) emission is poorly understood. We investigated the effects of inorganic fertilizer (IF), organic fertilizer (OF), and a mixture of organic and inorganic fertilizers (OIF) applications on the dynamics of soil CO₂ efflux in intensively managed Moso bamboo plantations. Soil CO₂ efflux and concentrations of water soluble organic C (WSOC) and microbial biomass C (MBC) in the IF treatment were higher than those in the control but lower than those in the OF and OIF treatments. Both OF and OIF treatments increased the SOC stock. Strong exponential relationships (p < 0.01) between soil temperature and CO₂ efflux were observed in all treatments. Soil CO₂ efflux in all four treatments was correlated with WSOC (p < 0.05) but not with MBC. We concluded the combined approach can possibly contribute to increasing the level of SOC stock in intensively managed plantations.     

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.     

Nutrient Mineralization from Nitrogen- and Phosphorus-Enriched Poultry Manure Compost in an Ultisol

The combination of inorganic fertilizers and compost is a technique aimed at improving crop growth and maintaining soil health. Understanding the rate of nutrient release from enriched compost is important for effective nutrient management. A laboratory incubation study was conducted for 112 days to study the nutrient mineralization pattern of poultry manure compost enriched with inorganic nitrogen (N) and phosphorus (P) fertilizer nutrients in an Ultisol. Compost applied at the rate of either 5 or 10 g kg^?1 was blended with N (50 kg N ha^?1) and P (30 kg P ha^?1). Carbon dioxide evolution and N and P mineralization were measured fortnightly. The bacterial and fungal populations were determined at the mid and end of the experiment. The combination of compost and inorganic N and P increased carbon (C) and P mineralization by 4?8% and 56?289%, respectively, over the application of either compost or inorganic N and P. However, P addition influenced the amount of C mineralized. Inorganic N and P, on the other hand, were better at increasing N mineralization than compost blended with inorganic N and P over a short time. The addition of compost stimulated bacterial and actinomycete populations, while fungal populations were unaffected. Actinomycetes and bacteria had similar and higher relationship trend with C (R² = 0.24) and P (R² = 0.47) mineralization and were key determinants in nutrient mineralization from compost in this Ultisol. Integrating compost with inorganic fertilizers improves nutrient availability through the growth and activities of beneficial microorganisms.     

A Correlation of Rapid Cardy Meter Sap Test and ICP Spectrometry of Dry Tissue for Measuring Potassium (K+) Concentrations in Pak Choi (Brassica Rapa Chinensis Group)

Nutritional status of vegetable crops is often monitored by analysis of dried plant tissues, which is costly and often time consuming. Two greenhouse trials were conducted, at the University of Hawaii at Manoa, Magoon facilities, to evaluate the portable cardy ion meter (CIM) in determining potassium (K⁺) status in fresh petiole sap of pak choi as compared with standard laboratory methods. In the first greenhouse trial, three algae species (Gracilaria salicornia, Kappaphycus alvarezii, and Eucheuma denticulatum) were used to apply five rates of K⁺ (0, 84, 168,252, and 336 kg.ha^?1). The pak choi was directly seeded into 4 L pots and was grown in peat moss. In the second greenhouse trial, K+ was provided through Eucheuma denticulatum and potassium nitrate (KNO₃) at five rates (0,112, 168, 224, 280, and 336 kg.ha^?1) in peat moss and soil media. At harvest, K⁺ concentrations in fresh petiole sap were analyzed immediately with CIM and the dried samples were analyzed by inductively coupled plasma spectroscopy (ICP) measurement. The results showed increase in leaf K+ content at higher rates and the maximum concentration of leaf K⁺ at 4500–5300 mg/L for sap and 8–9% for tissue was obtained when K⁺ was provided between 224 and 284 kg.ha^?1. There was a close correlation between the CIM readings and the ICP method (r = 0.8048 and 0.8314) from the first and second GH results, respectively. The results suggest that the CIM could be used for the rapid monitoring of the relative K⁺ status of plants. The data further suggested 4500–5000 mg K/L for fresh petiole sap and 7.5% K⁺ in tissue as critical levels for K⁺ concentration in pak choi.     

土壤中可溶性氮和pH对有机肥和化肥的短期响应

通过温室盆栽试验,施用猪粪堆肥(PC)、污泥堆肥(SC)、菜籽饼肥(CM)和无机化肥(IF)后,对土壤pH值和不同形态氮素的短期响应进行研究,探讨土壤可溶性无机氮、有机氮及土壤pH值之间的相互关系。结果表明,CM,PC和IF处理的pH值都呈现先快速下降后缓慢回升的趋势,但PC处理下降幅度较小;而SC处理和不施肥对照(CK)处理的pH值基本不变;不同施肥处理均提高了土壤中氮素水平,3种有机肥中以CM处理最显著地提高了土壤中总可溶性氮(TDN)、NH4+-N、NO3--N和可溶性有机氮(DON)浓度,PC处理的次之,SC处理的最弱,而IF处理与CM处理提高幅度相似。不同施肥处理中土壤可溶性氮表现出不同的短期响应,IF处理和CM处理的TDN分别经过11,13d的稳定期后迅速上升到一个较高的水平,至31d开始下降;PC处理和SC处理未出现突然升高的现象,而是前20d较稳定在一定的范围内波动,之后缓慢下降,总体与对照趋势一致。不同处理土壤中NH4+-N均呈下降趋势;IF处理、CM处理的NO3--N呈增加趋势,PC处理的呈先增加后降低趋势,而SC处理的呈缓慢下降趋势,结果说明不同有机肥在土壤中的转化存在明显的差异。相关性分析显示,CM处理、IF处理的土壤pH值与NH4+-N呈极显著正相关,而与NO3--N呈极显著负相关;除PC处理外,其他处理的DON含量与TDN具有显著正相关性,而PC处理的DON同时与NH4+-N、NO3--N呈显著负相关。     

Fortified cassava peel compost amendment for Amaranthus: Influence on plant growth,nutrients uptake and on soil nutrient changes

Nutrient supply through organic sources usually requires fortification for timely and optimum release of plant nutrients to achieve optimum crop performance. A pot experiment was conducted in a screen house to determine the optimum rate of cassava peel compost (CPC) fortification that supports optimum Amaranthus (Amaranthus cruentus L.) plant nutrient contents and residual soil nutrient contents. A compost of cassava peel and poultry manure was applied at 2.5; 5.0 and 7.5 t ha^?1each complemented with either 25 or 50 kg nitrogen (N), using nitrogen, phosphorus and potassium (NPK) 20-10-10 at 2 weeks before sowing Amaranthus. An unfertilized treatment served as control. Seeds were sown in plastic containers with a surface diameter of 24 cm filled with 5 kg soil, with a drain underneath. Seedlings were thinned to 4 plants/pot 2 weeks after planting. Plants were harvested at 5 weeks by ratooning and plant re-growth also harvested after 5 weeks. Soil pH was lower with high rates of 5.0 and 7.5 t ha^?1 CPC while the organic matter content was increased with increased CPC rate. Soil N was reduced but reflected in increased plant shoot and root N, with compost application. Soil P was generally increased but was not reflected in plant contents. Soil K contents were reduced and were reflected in increased plant contents. Application of 2.5 t ha^?1 CPC, fortified with either 25 or 50 kg N ha^?1 gave the optimum Amaranthus shoot nutrient contents with optimum residual soil nutrient contents.     

Effective Nutrient Sources for Plant Growth on Bauxite Residue

We conducted a field experiment to evaluate alternatives to poultry manure, the normal fertilizer used for growing dust control crops and native vegetation on bauxite residue sand. We compared plant growth, nutrient uptake and residue properties after applications of poultry manure, compost, composted poultry manure and inorganic fertilizer. The compost used was prepared from green waste treated with piggery waste. Plant growth was poor under the compost and composted poultry manure treatments, which produced 0.69 and 1.11 t ha^{? 1} of above ground biomass, respectively. This compared with 2.43 t ha^{? 1} from the inorganic fertilizer treatment which had a similar biomass to the poultry manure treatment (3.00 t ha^{? 1}). All treatments, including poultry manure, had low foliar concentrations of some nutrients, with low levels of N, P, K, Mg, Cu and Zn found in most treatments. Of the two treatments which gave effective dust control (inorganic fertilizer and poultry manure) the most economical was inorganic fertilizer which cost A$1227 ha^{? 1}. The high application rate of the poultry manure made it the most expensive fertilizer treatment at a cost of A$1650 ha^{? 1}. There appeared to be no long-term benefit of using organic amendments, as organic fertilizers did not improve residue conditions (organic matter content, pH, electrical conductivity, activity of Na⁺ ions) compared with the inorganic fertilizer. It was concluded that inorganic fertilizer could provide a suitable, cost-effective alternative to poultry manure for growth of dust control crops, with further research required to address low levels of some nutrients.     

Distribution and Speciation of Chromium and Cadmium in an Organic and Inorganic Fertilized Chernozem

Fertilizers are widely applied in agricultural practice to improve crop yield and quality. However, they can also alter the behavior of soil pollutants. A field experiment was conducted on a chernozem in Heilongjiang Province, China. Various proportions of inorganic nitrogen (N), phosphorus (P), and organic (manure) fertilizers were applied. Soil samples were collected four times over 2 years, and the total concentrations and speciation of chromium (Cr) and cadmium (Cd) were analyzed. Inorganic fertilizer addition had little effect on the total concentration of Cr and Cd, while organic fertilizer addition reduced the total concentrations of both Cr and Cd. Inorganic fertilizers increased the concentration of Cr in the exchangeable form, but decreased that of the residual form (P < 0.05). Addition of inorganic or organic fertilizer alone decreased concentrations of exchangeable Cd (P < 0.05), but the combination of inorganic and organic fertilizers had the opposite effect. High concentration of total Cd exceeding the upper limits of the Environmental Quality Standard for Soils proposed by the Ministry of Environmental Protection of China could result in an environmental risk, and fertilizer application could lower that risk. Results of risk assessment code calculated as the percentage of the sum of metal concentrations in the exchangeable and carbonate-associated form in total metal concentration showed that Cr and Cd risks were lowered when organic fertilizer was applied alone or in combination with inorganic fertilizers. Our study highlighted that organic fertilizer should be applied alone or in combination with inorganic fertilizers to lower the environmental risks of Cr and Cd pollution in the chernozem.     

Changes in the soil C and N contents,C decomposition and N mineralization potentials in a rice paddy after long-term application of inorganic fertilizers and organic matter

A long-term experiment on combined inorganic fertilizers and organic matter in paddy rice (Oryza sativa L.) cultivation began in May 1982 in Yamagata, northeastern Japan. In 2012, after the 31^st harvest, soil samples were collected from five fertilizer treatments [(1) PK, (2) NPK, (3) NPK + 6 Mg ha^?1 rice straw (RS), (4) NPK + 10 Mg ha^?1 rice straw compost (CM1), and (5) NPK + 30 Mg ha^?1 rice straw compost (CM3)], at five soil depths (0–5, 5–10, 10–15, 15–20 and 20–25 cm), to assess the changes in soil organic carbon (SOC) content and carbon (C) decomposition potential, total nitrogen (TN) content and nitrogen (N) mineralization potential resulting from long-term organic matter addition. The C decomposition potential was assessed based on the methane (CH₄) and carbon dioxide (CO₂) produced, while the N mineralization potential was determined from the potassium chloride (KCl)-extractable ammonium-nitrogen (NH₄⁺-N), after 2, 4, 6 and 8 weeks of anaerobic incubation at 30°C in the laboratory. Compared to NPK treatment, SOC in the total 0–25 cm layer increased by 67.3, 21.0 and10.8%, and TN increased by 64.2, 19.7 and 10.6%, in CM3, RS and CM1, respectively, and SOC and TN showed a slight reduction in the PK treatment by 5.2 and 5.7%, respectively. Applying rice straw compost (10 Mg ha^?1) instead of rice straw (6 Mg ha^?1) to rice paddies reduced methane production by about 19% after the soils were measured under 8 weeks of anaerobic incubation at 30°C. Soil carbon decomposition potential (Co) and nitrogen mineralization potential (No) were highly correlated with the SOC and TN contents. The mean ratio of Co/No was 4.49, lower than the mean ratio of SOC/TN (13.49) for all treatments, which indicated that the easily decomposed organic matter was from soil microbial biomass and soil proteins.     

有机无机肥配施对麦-稻轮作系统土壤微生物学特性的影响

采用盆栽试验研究了不同比例有机无机肥配施对连续4茬麦-稻轮作后土壤微生物学特性的影响。结果表明,与对照相比,单施化肥处理促进了土壤微生物生物量碳、氮和微生物熵的增加,提高了土壤蔗糖酶、蛋白酶、脲酶活性,降低了过氧化氢酶活性,提高了放线菌的数量,但对土壤细菌、真菌数量的影响不明显;有机无机肥配施处理的土壤微生物生物量碳、微生物生物量氮、微生物熵、土壤酶活性及3大类土壤微生物数量显著高于单施化肥及对照处理;土壤微生物生物量碳、微生物生物量氮、微生物熵和3大类微生物数量随着有机肥配施比例的提高而增加,以配施30%有机肥处理的最高;土壤酶活性综合指数以配施20%有机肥处理的最高。可见,化肥配施有机肥特别是配施中高量有机肥更有利于改善土壤微生物学特性,提高土壤生产能力。     

Soil Organic Carbon Sequestration by Long-Term Application of Manures Prepared from Trianthema portulacastrurm Linn

ABSTRACT

A 6-year field experiment was conducted at Maharashtra, India, from 2011 to 2017 on a silty clay soil, to study the impact of organic manure prepared from common weed Trianthema portulacastrurm Linn. on soybean-fodder maize crop system and soil organic carbon (SOC) sequestration. Organic manures were prepared from Trianthema as compost, vermicompost, dry leaf powder and were compared with application of Farm Yard Manure (FYM), chemical fertilizer treatment (NPK), and control. All treatments were repeated to same earlier treated plots every year for subsequent 6 years. Soil samples were analyzed before experiment and after harvesting of crops at the end of 6 years. All organic manures prepared from Trianthema and FYM increased SOC, nitrogen, phosphorus, and potassium content in the soil as compared to chemical fertilizer treatment and control. The overall increase in SOC content in the 0–60-cm soil depth in vermicompost treatment was 3.51 Mg C ha^?1 as compared to control at the end of this 6 years experiment at the carbon sequestration rate of 585 kg ha^?1 year^?1. Preparation and use of different manures from Trianthema will increase the carbon sequestration in soil, a measure to mitigate global warming.     

不同施肥措施对洞庭湖区旱地肥力及作物产量的影响

应用长期定位试验方法,研究了洞庭湖区非粮食作物棉花-油菜轮作下,农民习惯施肥(TF)、配方施肥(NPK)及有机肥和化肥不同配比模式[有机肥来源氮占配方肥总氮量的50%(50%OM)、30%(30%OM)和10%(10%OM)]的作物产量和土壤养分的变化,以期为相应作物种植制度下的合理施肥提供参考。研究结果表明:在本试验施肥量及有机无机肥配比下,有机肥和化肥配施显著提高了棉花和油菜的产量,且以50%OM处理产量最高,各处理产量的顺序为50%OM30%OM10%OMNPKTFCK(不施肥对照);当有机氮施用量占总氮量的50%时(50%OM处理),棉花和油菜产量分别比NPK处理高24.52%、29.57%,比习惯施肥(TF)处理分别高46.03%和49.07%。同时,施用有机肥各处理作物产量的年际变化均不到20%,明显小于NPK、TF和CK处理,即施用有机肥不仅能促进旱地作物高产,同时也能保证其稳产。有机肥与化肥配施能增加土壤有机质、全氮、碱解氮和速效钾含量,且以50%OM处理效果最好,与试验前比较的增加幅度分别达57.5%、38.2%、65.1%和48.1%;土壤有效磷含量有随施入磷素量的增加而增加趋势;而CK处理土壤有机质和养分含量则均呈逐年下降的趋势。各处理土壤有机质和养分含量(Y)随试验年限(X)的变化均可用方程式Y=a X+b来表示。在洞庭湖区肥力较高的旱地土壤中,合理的有机肥和化肥施用比例对保障非粮作物高产稳产和耕地地力提升尤为重要,且本试验条件下当有机肥来源氮占总施氮量的50%时能获得最佳效果。     

Soil nutrient dynamics,growth and yield of green maize and vegetable cowpea with organic-based fertilization

The growth and yield performance of green maize (Zea mays), followed by a late-season vegetable cowpea (Vigna unguiculata), was assessed with two rates of three different types of organic-based fertilizers (OBFs) fortified with an inorganic nutrient source. There was also an inorganic fertilizer treatment of NPK 20–10–10 applied at 300 kg ha^?1 and a no-fertilizer control treatment. Maize growth was affected by fertilizer type and rate. Organic fertilizer, applied at 5 t ha^?1, 3 weeks before maize released enough nutrients to have comparable growth as inorganic fertilizer. Applying the OBF at 2.5 t ha^?1 was inadequate to give comparable growth. Application of fortified OBF with total nitrogen content higher than 2.4% N at 5.0 t ha^?1 gave maize grain yields comparable with NPK fertilizer. Cowpea yields following early-season maize were highest with DPW + NPK. They were significantly lower with 2.5 t ha^?1 of the OBFs. Application of the IAR&T-OBF (OBF made by Institute of Agricultural Research and Training) and decomposed poultry waste (DPW) + NPK at 5.0 t ha^?1 gave comparable seed yields significantly higher than OYO-OBF (OBF made by Oyo State Government of Nigeria). NPK fertilizer application supported early-season maize cultivation, but it was not adequate to support the following cowpea. OBF should have nitrogen content up to 2.4% and applied at 5.0 t ha^?1 to support an early-season maize cultivation with a late-season cowpea.     

Corn biomass,uptake and fractionation of soil phosphorus in five soils amended with organic wastes as P fertilizers

Abstract

Sustainable food production includes mitigating environmental pollution and avoiding unnecessary use of non-renewable mineral phosphate resources. Efficient phosphorus (P) utilization from organic wastes is crucial for alternative P sources to be adopted as fertilizers. There must be predictable plant responses in terms of P uptake and plant growth. An 18-week pot experiment was conducted to assess corn (Zea mays L.) plant growth, P uptake, soil test P and P fractionation in response to application of organic P fertilizer versus inorganic P fertilizer in five soils. Fertilizers were applied at a single P rate using: mono-ammonium phosphate, anaerobically digested dairy manure, composted chicken manure, vegetable compost and a no-P control. Five soils used varied in soil texture and pH. Corn biomass and tissue P concentrations were different among P fertilizers in two soils (Warden and Quincy), with greater shoot biomass for composted chicken manure and higher tissue P concentration for MAP. Plant dry biomass ranged from highest to lowest with fertilizer treatment as follows: composted chicken manure?>?AD dairy?=?MAP?=?no-P control?=?vegetable compost. Soil test P was higher in soils with any P fertilizer treatment versus the no-P control. The loosely bound and soluble P (2.7?mg P kg^?1) accounted for the smallest pool of inorganic P fractions, followed by iron bound P (13.7?mg P kg^?1), aluminum bound P (43.4?mg P kg^?1) and reductant soluble P (67.9?mg P kg^?1) while calcium bound P (584.6?mg P kg^?1) represented the largest pool of inorganic P.     

Effect of nitrogen sources on the yield of common bean (Phaseolus vulgaris) in western Kenya

Depletion of soil nutrients due to continuous cultivation without adequate external fertilization is one of the challenges facing many smallholder farmers in western Kenya. This study was conducted to assess the effects of organic (water hyacinth compost), inorganic (urea) nitrogen (N) sources, and commercial Rhizobia inoculant on the yield of common bean (Phaseolus vulgaris) for two consecutive seasons in the short rains (2013) and long rains (2014). The experiments were laid out in a randomized complete block design and replicated four times. Triple superphosphate was applied to all treatments except those with compost to ensure that the soil had adequate phosphorus (P). Yellow and Rose coco bean varieties grown with urea and inoculated with commercial Rhizobia inoculant gave significantly higher yield of 382 kg ha^?1 and 341 kg ha^?1, respectively in the short rains (SR) season. In the long rains (LR) season bean yield was high in water hyacinth compost (1526 kg ha^?1) and control with non-limiting P (1300 kg ha^?1) treatments. Commercial Rhizobia inoculant did not significantly increase in yield in the SR and LR seasons. There was no significant influence on soil properties after two seasons of continuous cultivation of common bean and application of organic and inorganic fertilizers. These results demonstrate that water hyacinth compost improved bean yield in the LR season. However, longer field testing and economic analysis are required for it to be recommended as a substitute for inorganic N source among smallholder farmers.     

几种有机和无机氮肥对草莓生长及其氮素吸收分配影响的差异

通过不同生育时期植株各部位的氮素分析,研究了不同商品有机肥和有机无机复混肥对大田草莓(FragariaAnanassa.c.v.Dutch.)植株生长及氮素吸收分配的影响。结果表明,施用不同肥料品种均可促进植物氮素吸收,提高氮素积累速率,促进氮素向果实中分配。在施等量氮素养分条件下,草莓器官的氮素吸收状况对不同氮肥品种反应不一。尽管无机肥处理的氮素积累速率和地上部全氮含量较高,但施用商品有机肥较无机氮肥或有机无机复混肥更能促进草莓生长发育和草莓果实产量的增加,说明无机氮不宜作为草莓基肥一次性施用。结果还表明,施肥处理氮素的日均积累量平均为10.8.mg/plant,而不施肥处理仅为5.1.mg/plant。在果实采收末期,不同处理草莓各器官的氮素分配趋势为果实茎和叶柄叶片根系。施用纯有机肥(OFA和OFB),果实中吸收的氮素超过植株吸收总量的一半,分别占53.5%和51.7%,无机氮肥处理(UN)和有机无机复混肥处理(OIF)的果实氮素分配率分别只有46.1%和39.8%。