Turkey Manure Ash Effects on Alfalfa Yield,Tissue Elemental Composition,and Chemical Soil Properties

A power plant that utilizes turkey manure as fuel to produce energy was built in Benson, Minnesota, and started full energy production in 2007. The plant was built to meet legislative requirements governing the use of renewable sources to generate energy in Minnesota. Although the use of turkey manure as biofuel generates energy, it also results in turkey manure ash (TMA) as a by‐product that contains phosphorus (P), potassium (K), sulfur (S), and zinc (Z) as well as other essential and nonessential elements. A 2‐year study was conducted to compare TMA with triple‐superphosphate and potassium chloride fertilizers as a source of nutrients for alfalfa (Medicago sativa) at three locations: Lamberton, Morris, and Appleton, Minnesota. The soils at Lamberton and Appleton were acidic with P and K concentrations ranging from medium‐high to very high, whereas the soil at Morris was alkaline with high concentrations of P and K. The experiment consisted of a control (0 P and 0 K) and annual and split applications of TMA and fertilizer. Annual TMA and fertilizer rates were 84 kg P₂O₅ ha^?1, 118 kg K₂O ha^?1, and 34 kg S ha^?1. Split rates were 42/42 kg P₂O₅ ha^?1, 59/59 kg K₂O ha^?1, and 17/17 kg S ha^?1. However, because of an overestimation of citrate‐soluble P in 2005 for the TMA, the total amount of available P applied with the TMA for the 2‐year study was 168 kg P₂O₅ ha^?1 compared with 286 kg P₂O₅ ha^?1 for the fertilizer. In the first year, fertilizer resulted in greater alfalfa biomass yield than TMA and the control, whereas in the second year, alfalfa yields with TMA and fertilizer were similar and both more than the control. In 2005, TMA resulted in more copper (Cu) and S tissue concentrations than the fertilizer. In 2006, application of both sources increased tissue P and S concentrations compared with the control. The TMA increased tissue Cu concentration and Zn plant uptake compared with fertilizer. Bray P1–extractable soil P concentrations were less with TMA and control treatments than with the fertilizer treatments. Ammonium acetate–extractable soil sodium (Na) concentrations were greater with TMA than with fertilizer and the control. By the second year, both ash and fertilizer treatments resulted in more K uptake than the untreated control with no difference in K uptake between the two sources or time of application. Both sources were effective in increasing P uptake compared with the untreated control. TMA was shown to be an effective source of nutrients for alfalfa production.     

Changes in Soil pH and Extractable Phosphorus Following Application of Turkey Manure Incinerator Ash and Triple Superphosphate

During the incineration of turkey manure, a wide variety and concentration of nutrients are conserved in the turkey manure ash (TMA). In particular, the high concentration of citrate-soluble phosphorus (P) (43 g kg^?1) may make it a suitable P source for crop production. The ash is alkaline with a pH of 12.2. We conducted a soil incubation study using a low-P soil with a pH of 6.2 to evaluate the effects of TMA on soil pH and extractable P. Two TMA rates, based on citrate-soluble P (10.9 and 21.9 mg kg^?1), were compared with equivalent rates of triple superphosphate (TSP). In addition, a 0-P control was included. At the rates tested, TMA slightly increased soil pH, but this increase would be of minor agronomic importance. At equivalent P rates, changes in water-soluble P (WSP) concentrations with TMA and TSP were similar. Changes in iron-oxide-strip–extractable P (FeO P) and Bray 1 P concentrations were greater with TMA than with TSP. In contrast, changes in Olsen P concentrations were greater with TSP than with TMA for up to 32 days. For TMA, the ability of the tests to extract P was ranked, from highest to lowest, as Bray 1 P > FeO P > Olsen P > WSP, and for TSP they were ranked Bray 1 P ≥ Olsen P ≥ FeO P > WSP. However, the Bray 1 P and FeO P tests tended to overestimate plant-available P because they measured more citrate-soluble P than that added with TMA. We conclude that TMA can be used as a P source for crop production and that the Olsen test may provide a better estimate of plant-available P in TMA-amended soil.     

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.     

Utilizing Composted Beef Cattle Manure and Slaughterhouse Waste as Nitrogen and Phosphorus Fertilizers for Calcareous Soil

Effectively utilizing composts requires that their nitrogen (N) and phosphorus (P) contents be used as fertilizer, but how this is best accomplished is not fully understood. The authors' objective was to quantify N and P availability of a calcareous clay loam soil receiving composts derived from four contrasting beef cattle feedlot feedstocks applied at 50, 150, and 450 mg total P kg^?1 and supplemented twice with fertilizer N for a 42-week greenhouse plant bioassay. Three composted manures from beef cattle fed distinct diets and a composted mix of slaughterhouse and construction waste were applied. Inorganically fertilized and non-amended soils were included as controls. Canola (Brassica napus L.) and pea (Pisum sativum L.) were grown in pots containing 1.5 kg air-dried soil for six alternating 7-week cycles. Soils amended with composted manure from beef cattle fed typical finishing diets had the lowest apparent N recovery (31%) and the greatest soil nitrate after 42 weeks (25 mg N kg^?1). Phosphorus availability was greater with composted manure from beef cattle fed distillers' dried grains than composted manure from beef cattle fed typical finishing diets and a composted mixture of slaughterhouse and construction waste. Apparent P recovery (66%) was greatest from composted manure of beef cattle fed corn (Zea mays L.) distillers' dried grains applied at 50 mg total P kg^?1. Composted manure from beef cattle fed distillers' dried grains had greater P availability than conventional composted beef cattle feedlot manure. Overall, performance of the composted mixture of slaughterhouse and construction waste was similar to the composted beef cattle manures.     

Potassium fertilization and soil diagnostic criteria for forage corn (Zea mays L.) production contributing to lower potassium input in regional fertilizer recommendation

Abstract

Effective soil diagnostic criteria for exchangeable potassium (Ex-K) combined with inorganic potassium (K) application rates were developed to lower K input in forage corn (Zea mays L.) production using experimental fields with different application rates and histories of cattle manure compost. Two corn varieties, ‘Cecilia’ as a low K uptake variety and ‘Yumechikara’ as a high K uptake variety, were selected from among 20 varieties and tested to make diagnostic criteria for K fertilization applicable to varieties with different K uptakes. The K uptakes increased from 96 to 303 kg K ha^?1 for ‘Cecilia’ and from 123 to 411 kg K ha^?1 for ‘Yumechikara’ with increasing Ex-K content on a dry soil basis from 0.11 to 0.92 g kg^?1 with no inorganic K fertilizer application. The K uptake by corn for achieving the target dry matter yield of 18 Mg ha^?1 was estimated to be approximately 200 kg K ha^?1 in common between the two varieties. Yields of both varieties achieved the target yield at an Ex-K content of approximately 0.30 g kg^?1 with no K fertilization, although ‘Yumechikara’ reached the target yield at a lower Ex-K content. At the low Ex-K content of 0.1 g kg^?1, inorganic K fertilizer application at 83 kg K ha^?1 was needed to gain the target yield, and apparent K recovery rate for K fertilizer was calculated to be 70% for both varieties. The K uptakes for gaining the target yield by the K fertilization were lower than that by soil K supply. Based on these results, diagnostic criteria of Ex-K and inorganic K application rates were set up as follows: at an Ex-K content of < 0.15 g kg^?1, inorganic K fertilizer is applied at 83 kg K ha^?1 (100 kg ha^?1 as potassium oxide (K₂O) equivalent); at an Ex-K content of 0.15–0.30 g kg^?1, the application rate is reduced to 33 kg K ha^?1 (40 kg K₂O ha^?1); at an Ex-K content of ≥ 0.30 g kg^?1, inorganic K fertilizer is not applied because of sufficient K in the soil. Additionally, we propose that cattle manure compost be used to supplement soil K fertility.     

Assessing the Effect of Phosphorus Fertilizer Levels on Soil Phosphorus Fractionation in Rhizosphere and Non-Rhizosphere Soils of Wheat

This study evaluated the effects of phosphorus (P) fertilizer levels on inorganic P fractions. Wheat cultivars (Azadi and Marvdasht) were grown in the soils amended with the four rates of P fertilizer levels (no fertilizer, 10, 15, and 25 mg available P kg^?1 soil). Soils were sampled from rhizosphere and non-rhizosphere areas after 6 weeks. The mean of all P fractions was significantly different in various P fertilizer levels. The smallest and the largest amounts of all P fractions were observed in the soil with no P and in 25 mg kg^?1 soil P level, respectively. The Azadi cultivar, as P-efficient, showed the smallest increase in soil P fractions with increasing soil P levels. The means of all P fractions except Al-phosphates (Al-P) were significantly higher in non-rhizosphere soil. There were differences between these cultivars associated with the more inaccessible fractions at the 15 mg P kg^?1 soil level.     

Soil Phosphorus Management Based on the Agronomic Critical Value of Olsen P

Fertilizer phosphorus (P) is generally added to agricultural soils to meet the needs of crop production. In this study, the crop yield and soil Olsen P were measured every year (5–18 years) at 16 winter wheat (Triticum aestivum L.) –maize (Zea mays L.) crop rotation sites in cinnamon soil (Luvisols in FAO system). The mean agronomic critical value of Olsen P for maize was 14.2 mg kg^?1 and for winter wheat was 14.4 mg kg^?1 when using the Liner-plateau and Mitscherlich models. The change in soil Olsen P was positively linearly correlated with the P budget (P < 0.01), and an increase of 4.70 mg kg^?1 in soil Olsen P for each 100 kg ha^?1 of P budget in the 0–20 cm soil layer. A model of P fertilizer recommendation rate that integrated values of the change in soil Olsen P in response to P budget and the agronomic critical value of Olsen P was used, in order to adjust current levels of soil Olsen P to the agronomic critical value at the experimental sites over the next 5 years, P fertilizer application rate should be in the range of 0–87.5 kg P ha^?1.     

Effects of zinc fungicides and different zinc fertilizer application methods on soluble and total zinc in potato plant shoots

Abstract

The experiment was carried out to evaluate the effects of fungicides [with or without zinc (Zn)] and different Zn fertilizer application methods (no fertilizer; soil application; shoot application; soil plus shoot application) on the soluble and total Zn in the dry matter of potato shoots. Zinc fertilizer was applied to the shoots at 20 and 45 days after plant emergence (DAE), immediately before plant sampling. At 25 DAE, Zn fungicide increased soluble and total Zn in the fourth leaf. The same occurred, at 45 DAE, with the Zn fertilizer applied to the shoots. It were not observed significant increases on both soluble and total Zn contents in the fourth leaf of plants that received soil Zn fertilization. Even in the leaves with 262 mg Zn kg^‐1, there was no phytotoxicity symptoms. The total Zn concentration at 20 DAE was the best index correlated to potato tuber yield reaching 50.9 mg Zn kg^‐1 in the fourth leaf of plants at the highest marketable tuber yield treatment. Plant nutrient element contents [phosphorus (P), calcium (Ca), magnesium (Mg), copper (Cu), iron (Fe), and manganese (Mn)] were not affected by the treatments.     

Simultaneous Dynamics and Kinetics of Soil Phosphorus Under Different Fertilizer Systems During Two-Growth Seasons of Maize

This study investigated phosphorus (P) dynamics and kinetics in calcareous soil under inorganic, organic, and integrated (inorganic+organic) fertilizer systems during two growing seasons of maize in two soil depths (0–0.15 and 0.15–0.30 m). A field experiment was conducted with 150, 300, and 400 kg ha^?1 triple superphosphate (TSP), 7.5 and 15.0 ton ha^?1 (on dry matter basis) farmyard manure (FYM), and integrated systems. In order to analyze Olsen P, soil samples were collected in 30-day-intervals after planting. The results showed that at the end of the two growing seasons of maize, the lowest magnitudes of Olsen P_0–0.15 m were 6.0, 6.8, 7.4, and 7.6 mg kg^?1 for the control, 7.5 FYM, 15 FYM, and 150 TSP, respectively. The highest magnitudes of Olsen P_0–0.15 m were 12.4, 11.5, 11.4, and 11.1 mg kg^?1 for 300 TSP+15 FYM, 400 TSP+7.5 FYM, 400 TSP+15 FYM, and 300 TSP+7.5 FYM, respectively. The same trends were observed for Olsen P_{0.15–0.30 m}. Heterogeneous diffusion model demonstrated that Elovich equation could best describe the experimental data (mean; R² = 0.98, SE = 0.29). The highest P supply rates (PSR) were 4.73, 3.91, and 3.86 mg kg^?1day^?1 (days after application) for 400 TSP, 400 TSP+15 FYM, and 300 TSP, respectively. The models of P supply capacity of soil could estimate P supply of soil under different fertilizer systems (R² = 0.84–0.95). The present study improved the understanding of the capacity and rate of P supply by considering P uptake by grain maize. Fertilizer recommendations depend on the accessibility of fertilizer types suggested to help choose the best fertilizer systems.     

不同磷源对设施菜田土壤速效磷及其淋溶阈值的影响

土壤中磷的移动性不仅取决于磷的数量且与磷肥形态有关。了解不同磷源（有机肥和化肥）对设施菜田土壤磷素的影响对于指导科学施肥和面源污染防治至关重要。本文选取河北省饶阳县3种不同磷含量的农田土壤（未种植过蔬菜的土壤、种植蔬菜30年的塑料大棚土壤和种植蔬菜4年的日光温室土壤）为研究对象,采用室内培养试验和数学模型模拟方法研究有机无机磷源对设施菜田土壤磷素的影响,确定无机肥和有机肥源土壤磷素淋溶的环境阈值。结果表明添加有机肥和无机磷肥都会显著增加3种不同种植年限设施菜田土壤速效磷（Olsen-P）和氯化钙磷（CaCl₂-P）含量,但增加速度不同。对于未种植过蔬菜的低磷对照土壤,磷投入量高于50 mg·kg^-1（干土）后,无机肥比有机肥显著提高了土壤Olsen-P含量。对于已种植蔬菜30年的塑料大棚土壤,高磷投入时[300 mg·kg^-1（干土）和600 mg·kg^-1（干土）],无机肥比有机肥显著提高了土壤Olsen-P含量,低于此磷投入量时有机肥和无机肥处理之间没有显著差异。3种不同农田土壤CaCl₂-P的含量所有处理均表现出无机肥显著高于有机肥处理,尤其是在高磷量[>300 mg·kg^-1（干土）]投入时表现更加明显。两段式线性模拟结果表明,设施菜田土壤有机肥源磷素和无机肥源磷素淋溶阈值分别为87.8 mg·kg^-1和198.7 mg·kg^-1。随着土壤Olsen-P的增加,添加无机肥源磷对设施菜田土壤CaCl₂-P含量的增加速率是有机肥源磷的两倍。因此,建议在河北省高磷设施菜田应减少无机磷肥的投入,特别是土壤速效磷高于198.7 mg·kg^-1的设施菜田应禁止使用化学磷肥和有机肥,在土壤速效磷低于198.7 mg·kg^-1的设施菜田应加大有机肥适度替代无机肥技术的推广。     

Effects of Source and Amount of Phosphorus on Sorption Kinetics in the Topsoil of a Highly Weathered Soil

Abstract

Soil chemical and physical reactions involving phosphorus (P) must be understood to predict the risk of P being transported from agricultural land to streams and lakes. The kinetics of P sorption by an Ultisols from West Virginia, USA, receiving P from fertilizers were compared to soils amended with turkey litter. Addition of 6.6 and 13.2 Mg turkey litter ha^?1 increased Bray 1P levels to about the same level as adding 53 and 115 kg P ha^?1, respectively. Phosphorus binding capacity decreased to a greater extent when P was added as fertilizer as compared to turkey litter. For example, P binding maximum was 360 mg P kg^?1 dry soil when soil was amended with 6.6 Mg turkey litter ha^?1 as compared to 260 mg P kg^?1 dry soil when amended with 53 kg P ha^?1. This study demonstrates that the decrease in P‐binding capacity with increasing soil P is less when P is added as turkey litter.     

Nutrient dynamics,dehydrogenase activity,and response of the rice plant to fertilization sources in an acid lateritic soil

Abstract

Rice variety IR 36, grown under flooding, was studied in 1998 to determine the effects of fly ash, organic, and inorganic fertilizers on changes in pH and organic carbon, release of nutrients (NH₄ ⁺-N, Bray's P, and NH₄OAc K), and dehydrogenase activity in an acid lateritic soil at 15-day intervals. Application of fly ash at 10?t?ha^?1 alone did not improve the availability of NH₄ ⁺-N, or P, as well as the rice grain yield. Availability of NH₄ ⁺-N (35.3–36.9?mg?kg^?1), and P (12.3–14.6?mg?kg^?1) at 15 days after transplanting, and rice grain yields (48.0–51.7?g per pot) were similar under the various fertilization sources such as inorganic fertilizer alone, inorganic fertilizer?+?fly ash or inorganic fertilizer?+?green manure?+?fly ash. Mean dehydrogenase activity was the highest (8.47?µg triphenyl formazon g^?1 24?h^?1) under the mixed fertilization treatments with green manure. At the end of the cropping season (75 days after transplanting), pH, organic carbon, and dehydrogenase activity were higher under the mixed fertilization treatments involving green manure by 3, 15 and 154%, respectively, compared with the inorganic fertilizer alone.     

Coffee‐husk biochar application increased AMF root colonization,P accumulation,N2 fixation,and yield of soybean grown in a tropical Nitisol,southwest Ethiopia

Low soil fertility and soil acidity are among the major bottlenecks that limit agricultural productivity in the humid tropics. Soil management systems that enhance soil fertility and biological cycling of nutrients are crucial to sustain soil productivity. This study was, therefore, conducted to determine the effects of coffee‐husk biochar (0, 2.7, 5.4, and 16.2 g biochar kg^?1 soil), rhizobium inoculation (with and without), and P fertilizer application (0 and 9 mg P kg^?1 soil) on arbuscular mycorrhyzal fungi (AMF) root colonization, yield, P accumulation, and N₂ fixation of soybean [Glycine max (L.) Merrill cv. Clark 63‐K] grown in a tropical Nitisol in Ethiopia. ANOVA showed that integrated application of biochar and P fertilizer significantly improved soil chemical properties, P accumulation, and seed yield. Compared to the seed yield of the control (without inoculation, P, and biochar), inoculation, together with 9 and 16.2 g biochar kg^?1 soil gave more than two‐fold increment of seed yield and the highest total P accumulation (4.5 g plant^?1). However, the highest AMF root colonization (80%) was obtained at 16.2 g biochar kg^?1 soil without P and declined with application of 9 mg P kg^?1 soil. The highest total N content (4.2 g plant^?1) and N₂ fixed (4.6 g plant^?1) were obtained with inoculation, 9 mg P kg^?1, and 16.2 g biochar kg^?1 soil. However, the highest %N derived from the atmosphere (%Ndfa) (> 98%) did not significantly change between 5.4 and 16.2 g kg^?1 soil biochar treatments at each level of inoculation and P addition. The improved soil chemical properties, seed yield, P accumulation and N₂ fixation through combined use of biochar and P fertilizer suggest the importance of integrated use of biochar with P fertilizer to ensure that soybean crops are adequately supplied with P for nodulation and N₂‐fixation in tropical acid soils for sustainable soybean production in the long term.     

Long‐term fertilization impacts on corn yields and soil organic matter on a clay‐loam soil in Northeast China

A long‐term fertilization experiment with monoculture corn (Zea mays L.) was established in 1980 on a clay‐loam soil (Black Soil in Chinese Soil Classification and Typic Halpudoll in USDA Soil Taxonomy) at Gongzhuling, Jilin Province, China. The experiment aimed to study the sustainability of grain‐corn production on this soil type with eight different nitrogen (N)‐, phosphorus (P)‐, and potassium (K)–mineral fertilizer combinations and three levels (0, 30, and 60 Mg ha^–1 y^–1) of farmyard manure (FYM). On average, FYM additions produced higher grain yields (7.78 and 8.03 Mg ha^–1) compared to the FYM0 (no farmyard application) treatments (5.67 Mg ha^–1). The application of N fertilizer (solely or in various combinations with P and K) in the FYM0 treatment resulted in substantial grain‐yield increases compared to the FYM0 control treatment (3.56 Mg ha^–1). However, the use of NP or NK did not yield in any significant additional effect on the corn yield compared to the use of N alone. The treatments involving P, K, and PK fertilizers resulted in an average 24% increase in yield over the FYM0 control. Over all FYM treatments, the effect of fertilization on corn yield was NPK > NP = NK = N > PK = P > K = control. Farmyard‐manure additions for 25 y increased soil organic‐matter (SOM) content by 3.8 g kg^–1 (13.6%) in the FYM1 treatments and by 7.8 g kg^–1 (27.8%) in the FYM2 treatments, compared to a 3.2 g kg^–1 decrease (11.4%) in the FYM0 treatments. Overall, the results suggest that mineral fertilizers can maintain high yields, but a combination of mineral fertilizers plus farmyard manure are needed to enhance soil organic‐matter levels in this soil type.     

Einfluß unterschiedlicher Düngung auf pH,N, C und die Gehalte an CAL-extrahierbarem K und P im Boden

Influence of different fertilization on pH, N, C and CAL-extractable K and P in the soil The influence of different fertilization (mineral fertilizer, different kinds and quantities of farmyard manure and biocompost, horn meal) on soil properties was studied during 8 years of cultivation. The plots were planted and harvested as practised under local farming conditions. The pH of the non-fertilized plots decreased from 5.84 to 5.69, while it was increased by fertilization with farmyard manure or biocompost. N_t in the soil was not influenced by different fertilization. C_t was increased by high biocompost application, stayed constant on the other fertilized plots but decreased on the nonfertilized plots from 1.08 to 0.99%. Without fertilization, plant available nutrients were diminished from 7.3 to 4.3 mg P(CAL) 100 g^?1 and from 22.5 to 13.9 mg K(CAL) 100 g^?1. However, if the plots were fertilized with mineral or organic fertilizer, the nutrient content remained on the initial level. Storing farmyard manure under roof or covering with straw or polyethylene sheet did not affect the criteria of soil studied.     

Critical Soil Zinc Deficiency Concentration and Tissue Iron: Zinc Ratio as a Diagnostic Tool for Prediction of Zinc Deficiency in Corn

ABSTRACT

Zinc (Zn) fertilizer application is most economic if based on soil test and plant analysis information. The aim of this study was to determine the soil test [diethylenetrinitrilopentaacetate (DTPA) and ethylenetriaminepentaacetic acid (EDTA) extractable] Zn-critical levels and tissue Fe/Zn ratio for corn (Zea mays L.). A greenhouse experiment with 12 soil series and two Zn fertilizer treatments (0 and 15 mg Zn kg^?1 as zinc sulfate) was conducted. Critical Zn deficiency levels were determined using the Cate-Nelson procedure. Relative corn yield varied from 0.59 to 1.64. Critical deficiency levels based on the Cate-Nelson method were 1.50 and 1.17 mg kg^?1 for DTPA and EDTA-extracted soil Zn, respectively. No accurate critical deficiency level could be established using the shoot Zn concentrations. The critical iron (Fe)/Zn ratio in the corn shoot was 3.9. Values greater than 3.9 indicate hidden Zn deficiency and probable response to applied Zn.     

Potassium fertilization on sandy soils in relation to soil test,crop yield and K-leaching

To study the influence of potassium (K) fertilizer rate on soil test K values, crop yield, and K-leaching in sandy soils, four long-term fertilizer experiments (0–60–120–180 kg K ha^?1 a^?1) were initiated in 1988 in northern Germany on farmers fields. Clay content of the plow layer was about 4%, and organic matter between 2% and 5%. Plant available soil K was estimated with the double lactate (DL) method. Small grain cereals (rye and barley) did not respond to K fertilization in the 7-year period even though the soil test value of the K-0 plots decreased from ca. 90 to ca. 30 mg K_DL kg^?1 within 3 years. This value remained almost constant thereafter. Crop removal (including straw) of 75 kg K ha^?1 a^?1 was therefore apparently supplied from nonexchangeable K fractions. Compared to the optimum, no K application reduced the yield of potato by up to 21%, and that of white sugar yield up to 10%. Maximum potato yield was obtained by annually applying 60 kg K ha^?1 which resulted in a test value of 60 mg K_DL kg^?1 soil. Maximum potato yield was also obtained at 40 mg K_DL kg^?1 soil, however, with a single application of 200 kg K ha^?1. Similar results were obtained with sugar beet. This indicates that for maximum yield, even for K demanding crops, it is not necessary to maintain K_DL values above 40 mg K kg^?1 soil throughout the entire crop rotation. Soil test values increased roughly proportional to the K fertilizer level. About 120 kg fertilizer K ha^?1 a^?1, markedly more than crop K removal, was required to maintain the initial K_DL of 90 mg kg^?1. The K concentration of the soil solution in the top soil measured after harvest was increased exponentially by K fertilizer level and so was K leaching from the plow layer into the rooted subsoil. The leached quantity increased from 22 kg K ha_?1 a_?1 in the plot without K application to 42.79 and 133 kg Kha^?1 a^?1 in plots supplied with 60, 120 and 180 kg K ha^?1 a^?1 respectively. Soil test values around 100 mg K_DL kg^?1 on sandy soils, as often found in the plow layer of farmers fields, lead to K leaching below the root zone that may exceed the critical K concentration of 12 mg K T^?1 for drinking water.     

Soil phosphorus dynamics in a Vertisol as affected by cattle manure and nitrogen fertilization in soybean‐wheat system

Repeated application of phosphorus (P) as superphosphate either alone or in conjunction with cattle manure and fertilizer N may affect the P balance and the forms and distribution of P in soil. During 7 years, we monitored 0.5 M NaHCO₃ extractable P (Olsen‐P) and determined the changes in soil inorganic P (P_i) and organic P (P_o) caused by a yearly dose of 52 kg P ha^—1 as superphosphate and different levels of cattle manure and fertilizer N application in a soybean‐wheat system on Vertisol. In general, the contents of Olsen‐P increased with conjunctive use of cattle manure. However, increasing rate of fertilizer nitrogen (N) reduced the Olsen‐P due to larger P exploitation by crops. The average amount of fertilizer P required to increase Olsen‐P by 1 mg kg^—1 was 10.5 kg ha^—1 without manure and application of 8 t manure reduced it to 8.3 kg ha^—1. Fertilizer P in excess of crop removal accumulated in labile (NaHCO₃‐P_i and P_o) and moderately labile (NaOH‐P_i and P_o) fractions linearly and manure application enhanced accumulation of P_o. The P recovered as sum of different fractions varied from 91.5 to 98.7% of total P (acid digested, P_t). Excess fertilizer P application in presence of manure led to increased levels of Olsen‐P in both topsoil and subsoil. In accordance, the recovery of P_t from the 0—15 cm layer was slightly less than the theoretical P (P added + change in soil P — P removed by crops) confirming that some of the topsoil P may have migrated to the subsoil. The P fractions were significantly correlated with apparent P balance and acted as sink for fertilizer P.     

Phosphorus Management of Lucerne Grown on Calcareous Soil in Turkey

ABSTRACT

Lucerne or alfalfa (Medicago sativa L.) is grown as a forage crop on many livestock farms. In calcareous soils in eastern Turkey, lucerne production requires phosphorus (P) additions as the soils are naturally P deficient. Phosphorus sorption isotherms were used to estimate P fertilizer needs for lucerne grown for two years in a 3-cut system on a calcareous P deficient Aridisol in eastern Anatolia, Erzurum province, Turkey. Annual P applications ranged from 0–1200 kg P ha^?1. The Langmuir two-surface adsorption equation was used to derive the maximum P sorption capacity of unamended soil and to determine soil solution P, maximum buffer capacity (MBC), equilibrium buffer capacity (EBC), and P saturation at the optimum economic P rate (OEPR) for dry matter (DM) production. Soils were tested for Olson P at the onset of the study and after two years of P applications. In both years, tissue was analyzed for P content at flowering prior to first cutting. The OEPR (2-year average) was 754 kg P ha^?1 yr^?1 corresponding with a soil solution P concentration of 0.30 mg L^?1, a DM yield of 8725 kg DM ha^?1, and $528 ha^?1 annual profit. The P content of leaves at flowering increased linearly with P application beyond 100 kg P ha^?1 and was 3.2 g kg^?1 P at the OEPR. The unfertilized soil had an EBC, MBC, P saturation, and X_max of 3304 mL g^?1, 3401 mL g^?1, 6%, and 1086 mL g^?1, respectively, whereas two years of fertilization to the OEPR decreased EBC and MBC to 358 mL g^?1 and 540 mL g^?1, and increased P saturation and Olsen P to 56% and 32 mg kg^?1, respectively. These results suggest a P saturation >50% or Olsen P >30 mg kg^?1 are needed to maintain an optimum soil solution concentration of 0.30 mg L^?1 in this calcareous Aridisol. Similar studies with different soils and initial soil test P levels are needed to conclude if these critical soil test values can be applied across the region.     

Nodulation and nitrogen fixation by arrowleaf clover: Effects of phosphorus and potassium

“Yuchi” arrowleaf clover (Trifolium vesiculosum Sav.) has a potential for high forage productivity with desirable symbiotic nitrogen fixation within most temperate regions. Our objective was to determine the effects of soil fertility on growth, nodulation, nitrogenase and associated enzyme activities of arrowleaf clover. In greenhouse experiments top growth increased with additions of 300 mg K kg^?1 soil with and without 100 mg P kg^?1 soil to a Cumulic Haplustoll (Port silt loam, pH 6.1). Nodule mass without P fertilizer additions increased linearly up to 400 mg K kg^?1 soil. When both P and K fertilizer additions were combined nodule mass increased significantly only up to the 300 mg K addition. However, nodule weight, increased 4-fold with the PK combination treatments. Nitrogenase activity, as measured by C₂H₂ reduction, more than doubled with P additions and increased linearly up to 400 mg K kg^? soil, with and without the P additions. Aspartate amino-transferase (AST) activity of nodule cytosol more than doubled with P additions but increased only with up to 300 mg K without P. Highest AST activities were recorded with the 400 mg K addition when combined with P. Glutamate synthetase (GS) activity increased with up to 300 mg K without P addition, but when combined with P was approximately 3 times higher, increasing linearly to 400 mg K. Differences in glutamate synthetase (GOGAT) activity were not significant with K additions without P, but when combined with P treatments were almost doubled up to the 400 mg K concentrations. Multiple regression for nitrogenase (C₂H₂ red.) as the dependent variable = 5.89 (AST) + 12.79 (GS) + 21.52 (GOGAT) + 13.53 (GDH); R² = 0.92 and C.V. = 15.6%. Nodule cytosol P and K compositions reflected soil treatment levels and combinations. Reciprocal effects of monovalent cations were highly significant, with increased K concentrations reducing Na content; nitrogenase = 0.12 (P) + 0.01(K) + 0.14(Ca) ?0.34 (Na); R² = 0.86 and C.V. = 21.9%.