Crop Nutrient Requirements Research Articles

Estimating nutrient requirements for winter oilseed rape based on QUEFTS analysis

SUMMARYEstimating crop nutrient requirements for winter oilseed rape (Brassica napus L.) is a crucial step in optimizing fertilization to enhance seed yield and improve fertilizer use efficiency. In the present paper, a database composed of 1035 on-farm observations collected from 2005 to 2010 across the major winter oilseed rape production regions in China was used to evaluate internal nutrient efficiencies (kg seed per kg nutrient in plant dry matter); then the Quantitative Evaluation of the Fertility of Tropical Soils (QUEFTS) model for winter oilseed rape was developed to describe the nutrient uptake-yield relationship of oilseed rape over a wide range of environmental conditions and predict the nutrient requirements for a target yield. After excluding observations with low harvest index values, <0·20, and excluding 0·025 of the highest and lowest internal nutrient efficiencies, the minimum and maximum internal nutrient efficiencies were estimated as 13·1 and 31·6 kg seed/kg nitrogen (N), 68·9 and 200·3 kg seed/kg phosphorus (P) and 8·9 and 31·1 kg seed/kg potassium (K), respectively. On the basis of the data settings, the balanced N, P and K uptake at different yield potential levels was calculated using a linear–parabolic–plateau curve with the QUEFTS model. Crop nutrient requirements increased linearly until the yield reached approximately 0·60–0·70 of the potential yield, and 46·0 kg N, 8·0 kg P and 57·1 kg K were found to be needed to produce 1000 kg of seed. The corresponding internal nutrient efficiencies were 21·8, 125·1 and 17·5 kg seed/kg N, P and K, respectively. However, when the target yields approached the yield potential, a decrease in internal nutrient efficiencies was detected in the model. The predicted nutrient requirement values simulated by the QUEFTS model compared well with observed values across a range of conditions. To conclude, the QUEFTS model was shown to be a practical and robust tool for assessing the crop nutrient requirements of winter oilseed rape.

INFLUENCE OF SUSTAINABLE SOURCE OF NUTRIENT ON GROWTH AND YIELD OF SUNFLOWER (HELIANTHUS ANNUS L)

Sunflower is a one of the most important oilseed crop. Production of sunflower with the use of sustainable source of nutrient is cheap as compared with the application of synthetic fertilizers and its quality and soil heath improved by the application of organic chemical (OC) source of nutrient while chemical fertilizers are generally dangers for our environment and soil health. The nutrient requirement of sunflower can easily be carried by the self-made OC source of nutrient through this equation FYM + CaCO3 + H2 O + NO3 → OC (OC source of nutrient) with very low cost, so a farmer can self-made and fulfill nutrient requirement of crop and can obtain higher yield. A field experiment was carried out during 2013 at village Mir Khan Leghari near Agriculture Training Institute Sakrand, district Nawabshah (Sindh). The sunflower variety HO-1 was sown by using randomized complete block design with tree replications. Three levels of self-made OC source of nutrient viz: T1 = 200 kg/ha, T2 = 300 kg/ha, and T3 = 500 kg/ha was used. Regarding to the result maximum plant height, stem girth, number of leaves, head diameter, seed yield (140 cm, 7.60 cm, 16/plant, 15.70 cm, 1580.00 kg/ha, respectively) were recorded in T3 in which high dose (500 kg/ha) of self-made OC source of nutrient were applied. While the minimum plant height 110 cm, stem girth 3.25 cm, leaves per plant 12, head diameter 9.50 cm, seed yield 1300.40 kg/ha were recorded in T1 plot, where low dose (200 kg/ha) of self-made OC source of nutrient were applied in this plot.

Fertilizer Recommendation Philosophies

Farmers receive varying fertilizer recommendations depending on which lab they consult because labs employ different chemical methods and procedures to analyze the samples and subscribe to different fertilizer recommendation philosophies. This 4-page fact sheet explains the main soil-test philosophies, their basis, and their applications, and explains why the Sufficiency Level of Available Nutrient philosophy (SLAN), also called the Crop Nutrient Requirement (CNR), is most likely to be the best to govern fertilizer recommendations in Florida today. Written by George Hochmuth, Rao Mylavarapu, and Ed Hanlon, and published by the UF Department of Soil and Water Science, October 2014. (Photo by George Hochmuth, UF/IFAS)
 SL410/SS623: Fertilizer Recommendation Philosophies (ufl.edu)

Economic and environmental effects of nutrient budgeting strategies in animal excreta treatment

Purpose – The purpose of this paper is to optimize manure allocation through nutrient budgeting strategy to meet crop nutrient requirements under maximizing economic returns and environmental constraints, and then to evaluate the economic and environmental effects of different nutrient budgeting strategies in animal excreta treatment. Design/methodology/approach – In this study, a holistic integrated “ecological-economic” model is developed. It incorporates the systems of animal-crop production and waste treatment is developed for a pilot pig farm in China in order to simulate the economic and environmental effects of several nutrient budgeting strategies in excreta treatment for resource use. Findings – The results reveal nutrient management deficiencies cause some serious environmental problems. The operations including biogas and composting are economically and environmentally efficient methods for manure management through nutrient budgeting strategy in an intensive animal farming with limited access to cropland. The nutrient budgeting strategy of constrained phosphorus, however, creates better environmental effects and brings more income from the waste treatment than the strategy of constrained nitrogen. The current standard of manure application in cropland which emphasizes on crop requirements for nitrogen should be reconsidered. Originality/value – The paper is an original work and its methodology makes a meaningful contribution to understanding the relations between different nutrient budgeting strategies and their economic and environmental effects.

Spatial distribution characteristics of volatile halogenated hydrocarbons in unsaturated zone of Xiaodian sewage irrigation area, Taiyuan, China.

Sewage irrigation is one of the best options to reduce the stress on limited fresh water and to meet the nutrient requirement of crops. Environment pollution caused by volatile halogenated hydrocarbons (VHCs) associated with sewage irrigation has received increasing attention due to the toxicological importance in ecosystem. The aim of this study was to discuss the spatial distribution characteristics of VHCs in unsaturated zone under sewage irrigation and their migration in the environment. Soil samples were collected from XiaoDian district of TaiYuan city and measured for the major VHCs including of chloroform (CHCl3), tetrachloromethane (CCl4), trichloroethylene (C(2)HCl(3)), tetrachloroethylene(C(2)Cl(4)), pentachlorobenzene (C(6)HCl(5)), hexachlorobenzene (C(6)Cl(6)). Results showed that VHCs were accumulated in the unsaturated zone with long-term sewage irrigation. The contents of VHCs in the unsaturated zone of the study area were 34, 2, 3, 1.5, 8.3, 4.8 times higher than the background value respectively. Soils with long-term irrigation of sewage showed higher contents of VHCs than that with short-term irrigation of sewage. Not only the irrigation time, soil physical properties (e.g. soil texture) also played an important role on VHCs accumulation in soil.

Miscanthus × giganteus nutrient concentrations and uptakes in autumn and winter harvests as influenced by soil texture, irrigation and nitrogen fertilization in the Mediterranean

AbstractFertilization has a great impact on GHG emissions and crop nutrient requirements play an important role on the sustainability of cropping systems. In the case of bioenergy production, low concentration of nutrients in the biomass is also required for specific conversion processes (e.g. combustion). In this work, we investigated the influence of soil texture, irrigation and nitrogen fertilization rate on nitrogen, phosphorus and potassium concentrations and uptakes in Miscanthus × giganteus when harvested at two different times: early (autumn) and late (winter). Our results confirmed winter harvest to significantly reduce nutrient removals by as much as 80% compared to autumn. On the other hand, a few attempts have been made to investigate the role of soil texture and irrigation on nutrients in miscanthus biomass, particularly in the Mediterranean. We observed an effect of soil mainly on nutrient concentrations. Similarly, irrigation led to higher nutrient concentrations, while its effect on nutrient uptakes was less straightforward. Overall, the observed differences in miscanthus nutrient uptakes as determined by the crop management (i.e. irrigation and nitrogen fertilization) were highlighted for autumn harvest only, while uptakes in all treatments were lowered to similar values when winter harvest was performed. This study stressed the importance of the time of harvest on nutrient removals regardless of the other management options. Further investigation on the environmental and economic issues should be addressed to support decisions on higher yields‐higher nutrient requirements (early harvest) vs. lower yields‐lower nutrient requirements (late harvest).

Effect of Optimal Daily Fertigation on Migration of Water and Salt in Soil, Root Growth and Fruit Yield of Cucumber (Cucumis sativus L.) in Solar-Greenhouse

Inappropriate and excessive irrigation and fertilization have led to the predominant decline of crop yields, and water and fertilizer use efficiency in intensive vegetable production systems in China. For many vegetables, fertigation can be applied daily according to the actual water and nutrient requirement of crops. A greenhouse study was therefore conducted to investigate the effect of daily fertigation on migration of water and salt in soil, and root growth and fruit yield of cucumber. The treatments included conventional interval fertigation, optimal interval fertigation and optimal daily fertigation. Generally, although soil under the treatment optimal interval fertigation received much lower fertilizers than soil under conventional interval fertigation, the treatment optimal interval fertigation did not statistically decrease the economic yield and fruit nutrition quality of cucumber when compare to conventional interval fertigation. In addition, the treatment optimal interval fertigation effectively avoided inorganic nitrogen accumulation in soil and significantly (P<0.05) increased the partial factor productivity of applied nitrogen by 88% and 209% in the early-spring and autumn-winter seasons, respectively, when compared to conventional interval fertigation. Although soils under the treatments optimal interval fertigation and optimal daily fertigation received the same amount of fertilizers, the treatment optimal daily fertigation maintained the relatively stable water, electrical conductivity and mineral nitrogen levels in surface soils, promoted fine root (<1.5 mm diameter) growth of cucumber, and eventually increased cucumber economic yield by 6.2% and 8.3% and partial factor productivity of applied nitrogen by 55% and 75% in the early-spring and autumn-winter seasons, respectively, when compared to the treatment optimal interval fertigation. These results suggested that optimal daily fertigation is a beneficial practice for improving crop yield and the water and fertilizers use efficiency in solar greenhouse.

Selected Soil Chemical Properties and Fertility Assessment in Some Traditional Irrigation Schemes of the Mpwapwa District, Tanzania

Aims: To find out the status of the major plant nutrients important for plant growth and development in selected areas in Tanzania. Place and Duration of Study: The soil physicochemical properties survey was conducted in Msagali and Chipogolo proposed irrigation schemes, Mpwapwa District, Dodoma Region, in Tanzania during the dry season of 2003. Methodology: Before sampling, the study areas were divided into twenty two (22) pedogeomorphic units or soil types using pedogeomorphic approach. Thirty soil samples were collected from each pedogeomorphic unit at a depth of 0 – 20 cm in a zigzag manner, bulked, homogeneously mixed, and sub-sampled to obtain a representative composite sample. The composite soil samples were sent to Selian Agricultural Research Institute (SARI), Arusha, Tanzania, for analysis of physicochemical characteristics leading to the determination of the soil fertility status by means of these major mineral elements. Results: The results showed variations in fertility status in the selected sites of each scheme. Based on guidelines of soil mineral elements contents established elsewhere, the soils in Msagali had high pH (8.1) and excessive Na (6.1 cmol (+).kg soil) in 30.9% of the total surveyed area (263.5 ha). Crop production in Chipogolo was slightly constrained by sodicity (ESP=9.6%) in 73.1% of the total area (130.3 ha) surveyed and very strongly (ESP =27.9%) in 55.8% of the total surveyed area in Msagali. Total N and Organic Matter (OM) were low, ranging from 0.2 to 1.0g.kg and 2.3 to 11.7g.kg respectively. Available P was rated as low to medium and ranged from 1.01 to 5.13 mg P.kg in all sites (i.e. Original Research Article American Journal of Experimental Agriculture, 4(5): 584-600, 2014 585 Msagali and Chipogolo). Mg were rated as low (1.0 to 3.2 cmol (+).kg soil.) in 26.9% of the area surveyed in Chipogolo and low in 18.4% of the surveyed area in Msagali ranging from 0.6 to 6.5 cmol (+).kg soil. Of the total surveyed area, 63.7% in Chipogolo and 18.4% in Msagali have low Cation Exchange Capacity (CEC) with values <12 cmol.kg. C:N ratio in 63.2% the total area surveyed in Chipogolo was of good quality (i.e. C:N between 8–12) suggesting ideal conditions for plant growth compared with 36.8% of the total study area in Chipogolo and all the studied sites in Msagali. The data have indicated Ca: Mg ratios to be less than the suggested guidelines in 36.8% of the total surveyed area in Chipogolo suggesting that plants would probably respond to the addition of Ca or Mg in such areas. Conclusion: The fertility status and overall information from this study could be used in soil and fertiliser management studies to establish nutrient requirements for different crops grown in these areas.

4R Nutrient Stewardship for Improved Nutrient Use Efficiency

Fertilizers play a significant role in securing the production of food crops around the world. In fact, it is estimated that fertilizers currently support 40-60% of all crop production currently. Meeting future food security targets requires the responsible use of fertilizer nutrients. The 4R Nutrient Stewardship guidelines were developed by the fertilizer industry as a process to guide fertilizer Best Management Practices (BMP) in all regions of the world. This approach was required to address the growing concern that fertilizers are applied indiscriminately to the detriment of the environment. Given that farmers purchase fertilizers at world prices in most regions, and these prices have been steadily increasing over time, most users are very cautious about the rates of nutrients they apply. To avoid unnecessary policy intervention by governments, the fertilizer industry needs to be unified in their promotion of BMPs that support improved nutrient use efficiency and environmental sustainability, while supporting the farmer's profitability. This ultimately comes down to developing appropriate recommendations that match crop nutrient requirements fertilizer additions and minimize nutrient losses from fields. This lead to the 4R Nutrient Stewardship concept, applying the Right Source of nutrients, at the Right Rate, at the Right Time and in the Right Place. Right source means matching the fertilizer to the crop need and soil properties. A major part of source is balance between the various nutrients, a major challenge globally in improving nutrient use efficiency. Finally, some fertilizer products are preferred to others based on the soil properties, like pH. Right rate means matching the fertilizer applied to the crop need – simple as that. However, this is far from being a simple concept when you consider the variations in yield goals, previous crop management, crop residue management, influence of legume crops in rotation, etc. Adding too much fertilizer leads to residual nutrients in the soil and losses to the environment. Ultimately, striking a balance between the crop needs, environmental conditions and the farmers economic situation is required. Right time means making fertilizer nutrients available to the crop when they are needed. Nutrient use efficiency can be increased significantly when their availability is synchronized with crop demand. Split time of application, slow and controlled release fertilizer technology, stabilizers and inhibitors are just a few examples of how fertilizer nutrients can be better timed for efficient crop uptake. Right place means making every effort to keep nutrients where crops can use them. This is an issue which poses the greatest challenge in small holder agricultural systems, where most fertilizer is broadcast applied, and in many cases without incorporation. Research indicates that fertilizer placement can not only improve crop response, but also improve fertilizer use efficiency significantly by lowering nutrient application rates. Adaptation to non-mechanized agriculture have been made in certain regions which clearly support efforts to modify fertilizer placement as a BMP.

Fontes e doses de zinco na nutrição e produção de feijão-comum e mamona em consórcio

The castor oil is taken by the Brazilian government as the main oilseed for biodiesel production. However, this did not happen because of their low levels of income, especially in the Northeast region, Brazil, where it is commonly grown under intercropping system with annual crops such as common bean. Satisfactory yields only be achieved with real knowledge of nutrient requirements of crops intercropping system participants. Therefore, this study aimed to assess the nutritional and agronomic traits of crops common bean and castor intercropping under different sources of zinc rates. The experimental of randomized block in 2 x 5 + 4 factorial in scheme design, with three replications. The treatments consisted of two sources of zinc (zinc oxide = 15% Zn and zinc sulfate = 20% Zn) combined with five rates of zinc (0.0; 1.0; 2.0; 4.0 and 8.0 kg ha-1 Zn in soil) intercropping in common bean and castor, plus additional treatments single system common bean and castor, using a rate of 4.0 kg ha-1 of said sources. It is concluded that fertilization with zinc influenced foliar the phosphorus, calcium, magnesium, manganese content and zinc in these crops in intercropping system, especially zinc sulphate, with the use of zinc sulfate, given its greater solubility compared to zinc oxide. The fertilization with 4.1 and 4.9 kg ha-1of zinc in soil, lead to the greatest yields of beans and castor under intercropping. The system of intercropping common bean and castor was more effective than the single, for different rates of zinc through fertilizer added.

Nitrogen Cycling and Management for Romaine and Crisphead Lettuce Grown on Organic Soils

Lettuce has rapid growth and reaches harvest in 60–70 days in South Florida. This leads to high demands for nitrogen fertilization during the short growing season. A good N fertilization scheme should reduce costs, conserve natural resources, and minimize negative environmental impacts. The keys to using fertilizer efficiently are understanding the crop nutrient requirements to predict fertilizer needs and management as well as knowing the appropriate amounts to apply. Lettuce growers also need to know the nutritional status of the crop through soil and plant tissue testing. This 4-page fact sheet was written by Luis Santos, Alan L. Wright, Yigang Luo, Huangjun Lu, and D. Calvin Odero, and published by the UF Department of Soil and Water Science, September 2013.&#x0D; http://edis.ifas.ufl.edu/ss588

A new sludge-derived organo-mineral fertilizer gives similar crop yields as conventional fertilizers

Sewage sludge, a waste material commonly known as biosolids, has good potential as a valuable agricultural resource, providing that its nutrient imbalances could be overcome. Sewage sludge is rich in phosphorus but low in nitrogen and potassium. Technology exists to supplement sewage sludge with mineral fertilizers, such as urea and muriate of potash as sources of nitrogen and potassium, respectively, to produce an organo-mineral fertilizer with balanced crop nutrient requirements. Here, an experimental plot trial set up in 2008 was established at Broxton, Cheshire, UK, to compare crop yield response for typical crop varieties. Crops included wheat, oilseed rape, barley, beans and forage maize, treated with conventional fertilizer and organo-mineral fertilizer. The organo-mineral fertilizer is a nutrient-balanced sludge-based product produced by drying digested sewage sludge cake at 80 °C in a tumbling evaporator, which produces sludge granules of 3–6 mm in diameter. Analysis was carried out on soil NPK and crop yield. N use efficiency was measured to assess N uptake. Results show that there is no significant difference in crop yield between treatments over the three trial years, with the exception of one crop. This finding demonstrates that the new organo-fertilizer is as efficient as conventional fertilizers. Moreover, levels of heavy metal in soil did not exceed permissible levels. The novelty of this research lies in the fact that it is the first field scale trial of a modified sewage sludge product that has the potential to transform a hitherto waste product into a practical fertilizer product. We conclude that the organo-mineral fertilizer is a promising alternative product for sustainable agriculture.

Effects of Composts from Agroindustrial Wastes on Microbial Activity of a Typic Xerofluvent Soil Under Mediterranean Conditions, SE Turkey

Supplementing the nutrient requirement of crops through organic manures as compost derived from agroindustrial wastes plays a key role in sustaining soil fertility, and crop productivity and reducing use of chemical fertilizers. Therefore, this work was conducted for investigating the effects of addition of oily cumin compost (CC) and oily oregano compost (OC) (these composts were derived from oily cumin and oily oregano wastes of aromatic plant factory) at rates of 40 t ha−1 to identify those potential organic amendments that might improve the quality of an Entisol. Additionally, those effects on the biochemical properties of a Typic xerofluvent soil were compared to chemical fertilization (CF) and also control (CT) during a cotton vegetation period under a Mediterranean climatic condition. Soil biological status was evaluated by measuring the soil microbial biomass carbon (MBC), basal soil respiration (BSR), N-mineralization (Nmin), soil metabolic quotient (qCO2) and soil enzymatic activities (dehydrogenase-DHG, urease-UA, protease-PRO, and alkaline phosphate-ALKPA) in soil samples that were collected on the 19th, 78th and 190th days followed by compost application to the experimental soils. The MBC, BSR and qCO2, as well as soil enzyme activities, increased significantly in the compost-treated soils compared with the CF-treated soil and nontreated soils (CT) with respect mean values. The level of microbial activity of soil applied chemical fertilizer was almost the same to those of control soil. As a result of cumin compost (CC) application 137-1810% increase of the level of microbial activity with respect to the CT and CF, followed by OC, 47-314% occurred at the end of the experiment. Because of this there were no toxic effects caused by composts observed. The application of these composts to the soil resulted in the most increase in DHG activity significantly. The application of CC with a C/N ratio of 23 resulted a more favorable soil biological properties than the application of OC (C/N ratio = 32) during cotton vegetation period (190 days). Results from this study suggest that composted aromatic plant wastes can be used to enhance the soil microbial activity, thereby promoting plant growth.

Sensitivity of Plant and Soil Indices in Evaluating the Long-Term Consequences of Soil Mining from Reserves of Phosphorus, Potassium, and Magnesium

Mineral fertilizer production and distribution in Poland prior to 1991 were subsidized by the state. Demand for low-cost products exceeded substantially their production. During the transformation to market-oriented economy, the subsidy on fertilizers was removed and the demand from agriculture dropped dramatically. In 2008/2009 mineral fertilizer consumption reached only 122 kg nitrogen–phosphorus–potassium (N–P–K) per 1 ha and the N/P/K ratio remained 1:0.3:0.4. This tendency is disturbing because the soils in Poland are commonly acidic and poor in available K and Mg. Nitrogen fertilization and high-yielding crops compound the process of soil depletion. The objective of this article was an evaluation of soil and plant index sensitivity for soil exhaustion from P, K, and Mg. Two factorial experiments were carried on in 2003–2009 in a four-crop rotation: winter rape–winter wheat–maize–spring barley. The first factor was treatment without P, K, or Mg and a control treatment fertilized with all the macronutrients and the second one had five levels of N. For determination of plant fertilizer recommendations, official methods have been used (Egner DL, Schachtschabel). The nutrient requirements of crops were evaluated by determining the concentrations of N, P, K, and Mg in plant dry matter and N status of cereals with the nitrogen nutrition index (NNI) and Soil Plant Analysis Development (SPAD) tests. The soil was depleted for a 7-year period from analyzed macronutrients that led to a decrease of available forms of P, K, and Mg, but only a slight crop reduction. Only maize and rape crops, with high nutritional requirements, responded with a decreased yield pursuant to the lack of long-term fertilization with P, K, and Mg. There was a close correlation between K2O exhaustion and N rates. Soil indices have been more sensitive than plant indices.

Developing a Vegetable Fertility Program Using Organic Amendments and Inorganic Fertilizers

This review integrates information from common organic amendments used in conventional vegetable production, including 1) cover crops (legumes and nonlegumes), 2) compost generated from yard wastes, biosolids, municipal solid waste (MSW), animal manures, and other biodegradable waste by-products, and 3) raw animal manure (with and without bedding). Environmental monitoring has shown elevated nitrate concentration to be widespread in both surface and groundwater, often occurring in regions with concentrated horticultural production. Therefore, the objective of this review was to calculate the nutrient content from organic amendments, since these are not considered nutrient sources. Common organic amendments affect soil bulk density, water-holding capacity, soil structure, soil carbon content, macro- and micronutrients, pH, soluble salts, cation exchange capacity (CEC), and biological properties (microbial biomass). The first step in building a conventional tomato (Solanum lycopersicum) fertility program will be to take a soil sample and send it to a soil laboratory for a nutrient analysis. These results should be compared with the local crop recommendations. Second, select the organic amendments based on local cover crop suitability and availability of compost, raw animal manure, or both. Then, determine the nutrients available from cover crops and other applied organic amendments and use inorganic fertilizer sources to satisfy the crop nutrient requirements not supplied from these other sources.

Fertigation for Vegetables: A Practical Guide for Small Fields

More and more farmers are growing small crops of fruits and vegetables for specialty local markets. They commonly grow several crops at different stages of development at the same time, so they have a variety of produce to sell to customers. This forces farmers to make several fertilizer calculations because of their diverse crop demands, because water and nutrient requirements vary according to the crop and stage of development. This 7-page fact sheet helps growers correctly interpret fertilizer recommendations and calculate accurate fertilizer amounts to be used based on crop nutrient requirements. Written by Jim DeValerio, David Nistler, Robert Hochmuth, and Eric Simonne, and published by the UF Department of Horticultural Sciences, October 2012. HS1206/HS1206: Fertigation for Vegetables: A Practical Guide for Small Fields (ufl.edu)

Potential microbial candidate strains for management of nutrient requirements of crops

Zinc (Zn) and phosphorus (Pi) are essential for optimum plant growth. Upon application, they get fixed in the soil matrix. Application of more than one microbe for each nutrient is often difficult. Azotobacter (31), Azospirillum (38), Bacillus (19) and Pseudomonas (82) strains were isolated from diverse crop production systems and were evaluated for solubilization of ‘Zn’ and ‘Pi’ in vitro from insoluble zinc (ZnO, ZnCO3) and phosphorus [tricalcium phosphate (TCP)], respectively. After 15 days of incubation, 15 strains solubilized zinc and produced >50 cm2 solubilization zone on solid media. In broth culture, with ZnO as zinc source, B116 could release maximum available Zn (13.12 ppm) and with ZnCO3, B118 could release highest available Zn (16.3 ppm). Pseudomonas strain PIII-105 released highest available 'Pi' (14.8 ppm) and solubilization of Zn and Pi corresponded with fall in pH of the medium except in case of B116. Two (2) strains of Azospirillum, 6 strains each of Bacillus and Pseudomonas showed a clearance zone area of >50 cm2with both Zn sources. Similarly, 2 strains each of Azospirillum and Bacillus and 3 strains of Pseudomonas solubilized TCP. Azospirillum strains As-20, As-22; Bacillus strains B113, B118; and Pseudomonas strains P17, P33 and PIII 105 solubilized both Zn and P sources showing their ability to supplement both essential nutrients to plants. Interestingly,Azospirillum is already known to supplement nitrogen also. Key words: Multi-nutrient management, zinc carbonate, zinc oxide, tricalcium phosphate,Pseudomonas, Bacillus, Azospirillum.

수생식물 고사체의 농업적 재활용을 위한 퇴비화 가능성 평가

본 연구는 공시 수생식물체 퇴비화 과정 중 산소 소비량과 소비패턴을 조사하기 위하여 식물이 고사된 11월에 수확한 갈대, 부들, 줄을 사용하여 퇴비화를 제조하였다. 수생식물체별 퇴비화 과정중 산소소비량을 조사한 결과 모든 수생식물의 퇴비화조에서 퇴비화 초기에 누적산소소비량이 급격하게 증가하여 약 15일째에 들어서 누적산소소비량의 증가가 둔화되는 경향이었다. 각각의 수생식물별로 누적산소 소비량은 초기에는 비슷한 소비량을 보이나 부들 > 줄 > 갈대 순으로 나타났다. 수생식물체별 퇴비화 과정중 온도변화는 퇴비화가 진행되면서 초기에 급격하게 증가된 후 서서히 감소되어서 약 <TEX>$30{\sim}40^{\circ}C$</TEX> 정도로 안정화 되었다. 각 수생식물체의 퇴비화에서 최고온도까지 도달하는데 걸린 기간은 갈대 (7일) > 부들 (10일) > 줄 (11일) 순으로 나타났고, 퇴비화조 최고온도는 걸린 기간과 반대로 줄 (<TEX>$72.2^{\circ}C$</TEX>) > 부들(<TEX>$70.2^{\circ}C$</TEX>) > 갈대 (<TEX>$66.5^{\circ}C$</TEX>) 순으로 나타났다. 최고온도 도달시까지 소비된 산소량은 부들 <TEX>$12,485mg\;O_2\;kg^{-1}$</TEX> > 줄 <TEX>$12,400mg\;O_2\;kg^{-1}$</TEX> > 갈대 <TEX>$9,340mg\;O_2\;kg^{-1}$</TEX> 순으로 나타났는데 이는 각각의 식물체별 비중과 통기성에 따른 것으로 판단된다. 본 연구에서 제조한 수생식물을 이용한 퇴비는 유기물함량이 39.5~44.8%로 부산물비료 공정규격의 퇴비의 규격 50% 이상에 미치지 못하였으나 함유할 수 있는 유해 성분(As, Cd, Cu, Cr, Hg, Ni, Pb 및 Zn) 함량이 규격 이하로 적합하였고, 그 밖의 규격에서 염분(NaCl) 함량 0.01%, 수분함량 29.6~35.6% 및 유기물대 질소의 비 27.93~32.94로 퇴비 규격에 적합하였다. To evaluate the possibility of water plant wastes in composting for agricultural recycling, Phragmites communis (PHRCO), Typha orientalis (TYHOR) and Zizania latifolia (ZIZLA) were used as a compost materials. In composting basin, cumulative oxygen consumptions of the compost used by water plant wastes were rapidly increased at the early stage and slightly decreased in around 15 days. Cumulative oxygen consumptions under different water plant wastes were higher in the order of TYHOR > ZIZLA > PHRCO. Temperature changes during composting process were rapidly increased at the early stage and then slowly decreased to <TEX>$30{\sim}40^{\circ}C$</TEX>. The maximum temperatures were higher in the order of ZIZLA (<TEX>$72.2^{\circ}C$</TEX> at 11 days after starting composting) > TYHOR (<TEX>$70.2^{\circ}C$</TEX> at 10 days after starting composting) > PHRCO (<TEX>$66.5^{\circ}C$</TEX> at 7 days after starting composting). Oxygen consumptions at maximum temperature were higher in the order of TYHOR (<TEX>$12,485mg\;O_2\;kg^{-1}$</TEX>) > ZIZLA (<TEX>$12,400mg\;O_2\;kg^{-1}$</TEX>) > PHRCO (<TEX>$9,340mg\;O_2\;kg^{-1}$</TEX>). Organic matter contents, moisture contents and OM/N rates in the compost ranged 39.5~44.8%, 29.6~35.6% and 27.9~32.9, respectively. Considering that water plant waste can supply some of the nutrient requirements of crops and is a valuable fertilizer.

Calcium, Magnesium, Sodium, and Potassium Release during Decomposition of Some Organic Residues

The use of organic residues might be appropriate in maintaining long-term nutrient requirements of crops. We investigated under laboratory conditions the dynamics of calcium (Ca2+), magnesium (Mg2+), sodium (Na+), and potassium (K+) release during decomposition of eight plant residues and two manures over 12 weeks of incubation at 25 ○C. During the processes of decomposition, these nutrients were extracted by 0.1 M sulfuric acid (H2SO4). The release rate of nutrients for residues was best estimated by the exponential model. There were differences in the rates at which release took place between residues and nutrients. In general, release patterns of nutrients with time for all residues were similar in shape, and two regions could be distinguished: a first one during the first 4 weeks of incubation, corresponding to faster release of nutrients, and a second for longer incubation times (weeks 5–12), when the release of nutrients was slower. A 71% loss of K+ was found after 1 week for vegetable waste and only 43% loss of Na+ for rape. Generally, based on release rate (% week–1), nutrient release from residues was in the order K+ (–0.363) > Na+ (–0.344) > Mg2+ (–0.327) > Ca2+ (–0.280). The release rate of nutrients was significantly correlated with their residue content. Our results suggest that the use of organic residues as a source for short- and long-term nutrients supply for crops should be encouraged. The quick release of K+ and Na+ may pose a high risk of K+ and Na+ losses in sandy soils with low cation exchange capacity.

Pollution of the Natural Environment in Intensive Cultures Under Greenhouses

Pollution of the Natural Environment in Intensive Cultures Under GreenhousesThe last two decades have brought a significant modernization in methods of cultivation in greenhouses. Soilless cultures, isolated from soils, have become a common practice, similarly as fertigation (fertilization + irrigation) installations, although most of them are applied in the open system (with no recirculation), where excess nutrient solution is removed straight to soil. This situation was the reason why it was decided to conduct studies, extended over a period of many years, on the estimation of environmental pollution caused by discharged drainage waters containing mineral fertilizers in economically important cultures in Poland (anthurium, tomato, cucumber). On the basis of the chemical composition of drainage waters and amounts of nutrient solution spillway from culture beds data were estimated concerning pollution of the soil medium by the nutrient solution. The level of pollution was dependent on nutrient requirements of crops and the length of the vegetation period. The highest environmental pollution is caused by intensive tomato growing (in kg·month·ha-1): N-NO3(up to 245), K (up to 402), Ca (up to 145) and S-SO4(up to 102). A lesser threat is posed by metal microelements: Fe (up to 2.69), Mn (up to 0.19), Zn (up to 0.52) and Cu (up to 0.09). Lower contamination of the natural environment is generated in cultures with lower nutrient requirements (anthurium) and in the case of culture on organic substrates. With an increase in ecological awareness of producers recirculation systems should be implemented in the production practice, in which drainage waters do not migrate directly to soil, but are repeatedly used to feed crops.