YIELD AND MINERAL CONCENTRATIONS OF SOUTHEASTERN UNITED STATES OAT CULTIVARS USED FOR FORAGE

A shift in oat (Avena sativa L.) production from grain to forage (hay and grazing) is occurring in the southeastern USA. However, most available cultivars were developed for improved grain production, rather than forage yield. We field tested several standard and new oat releases over 2 years, using repeated clippings to determine forage yield, nutrient uptake, and the potential to match plant nutrients with cattle mineral dietary needs. There were no differences in total annual forage yield among the tested cultivars within years but there was a difference between years. Forage tissue phosphorus (P), magnesium (Mg), and calcium (Ca) were sufficient, potassium (K), sulfur (S), and manganese (Mn) were excessive, and iron (Fe), copper (Cu), and zinc (Zn) were occasionally or frequently deficient to meet daily cattle dietary mineral needs. Sulfur, Cu, Fe, Zn, and Mn may be the most challenging to regulate in U.S. Coastal Plain soils at concentrations that satisfy both, oat and cattle nutritional requirements.     

Effects of pasture‐applied biosolids on forage and soil concentrations over a grazing season in north Florida. I. macrominerals,crude protein,and in vitro digestibility

Abstract

The rationale for this experiment was to determine forage nutrient concentrations as affected by biosolids fertilization. We studied the effects of single applications of two exceptional quality biosolids to bahiagrass (Paspalum notatum) pasture with regard to satisfying beef cattle nutrient requirements. Twenty‐five 0.8‐ha pastures were divided into five blocks. Two biosolids were applied as normal and double agronomic rates. The control plot received NH₄NO₃. Forages were analyzed for calcium (Ca), phosphorus (P), magnesium (Mg), potassium (K), sodium (Na), crude protein (CP), and in vitro organic matter digestibility (IVOMD), and soils were analyzed for Mehlich I extractable Ca, P, Mg, and K. Single (agronomic or twice this) applications of biosolids to pastures had little effect on Ca, P, Na, and K forage concentrations, but forage Mg was elevated in several treatments late in the season. Crude protein concentrations were elevated above the control for all biosolids treatments late in the season, whereas only small differences were observed at early sampling times. Trends were similar for IVOMD. In general, all treatments were associated with soils with adequate Ca, P, and Mg concentrations, while soil K was uniformly low. In relation to grazing beef cattle requirements, all treatments resulted in generally adequate forage levels of Ca, P, Mg, K, CP, and IVOMD, however, Na (<0.06%) was deficient.     

Management options to decrease phosphorus and sediment losses from irrigated cropland grazed by cattle and sheep

In southern New Zealand, grazing of forage crops is common practice to satisfy feed requirements of animals in winter when pasture growth is limited. This practice has been shown to cause soil physical damage and increased loss of surface water contaminants sediment and phosphorus (P) to water bodies. Strategies to mitigate the loss of sediment and P were trialled on a Pallic soil type (Aeric Fragiaquept) in the North Otago Rolling Downlands of New Zealand. All sites were irrigated and measurements were made of losses in overland and sub‐surface flow from intensive cattle or sheep grazed, winter forage crops, and sheep grazed pasture. Two mitigations (restricted grazing of crop to three hours and the application of aluminium sulphate) were assessed for their potential to decrease contaminant loss from cropland. Volumes of surface runoff and loss of total P, filterable reactive P and sediment showed significant differences (P < 0.05) between the control treatments (i.e. no mitigation) with cattle crop (88 mm surface runoff) > sheep crop (67 mm) > sheep pasture (33 mm). The contribution of irrigation water to overland flow water, as a result of saturation‐excess conditions, varied between treatments with more loss under cattle crop (20% of total) compared with sheep crop (15%) and sheep pasture (11%). These differences are probably an effect of soil physical condition and highlight the importance of accurate irrigation scheduling to keep soil moisture below field capacity. Restricted winter grazing and alum application after grazing significantly (P < 0.05) decreased P losses in surface runoff under cattle (from 1.4 to 0.9 kg P/ha) and sheep (from 1.0 to 0.7 kg/P/ha) grazed crop plots by about 30%. In cattle grazed plots, restricted grazing also decreased suspended sediments (SS) by 60%. The use of restricted grazing is suggested as a means of decreasing P and SS loss from grazed winter forage crops. The use of alum shows some promise for decreasing P losses, but requires further work to determine its long‐term effectiveness and use in other soils and management regimes.     

Spatial distribution of soil carbon in pastures with cow-calf operation: effects of slope aspect and slope position

Background, aim, and scope  

The rate at which soil carbon (C) accumulates in terrestrial beef agro-ecosystem is uncertain, as are the mechanisms responsible for the current C sink. Broad knowledge of cattle movement in pasture situations is critical to understanding their impact on agro-ecosystems. Movement of free-ranging cattle varies due to spatial arrangement of forage resources within pastures and the proximity of water, mineral feeders, and shades to grazing sites. The effects of slope aspect (SA) and slope position (SP) on nutrient dynamics in pastures are not well understood. Few studies have been made of soil-vegetation and soil-landscape relationships along an elevation gradient in tropical and subtropical regions. Current literature suggests no clear general relationships between grazing management and nutrient cycling. Early study reported no effect of grazing on soils nutrients, while other studies determined increases in soil nutrients due to grazing. We hypothesize that SA and SP could be of relative importance in controlling spatial variability of soil organic carbon (SOC). This study addressed the effects of SA and SP on the spatial distribution of SOC in forage-based pastures with cow-calf operation in subtropical region of southeastern USA.     

Applicability of Different Indices to Evaluate Nutrient Status of Winter Wheat in the Organic System

Nitrogen (N), phosphorus (P), and potassium (K) nutrient status of two winter wheat cultivars (Kobra and Juma) in the organic crop production system was compared with integrated and conventional systems. This research was conducted between 1998 and 2000 at the Experimental Station in Osiny (Lublin province, Poland) on a grey-brown podzolic soil. To determine N, P, and K contents shoot samples of wheat were taken at the shooting and earing growth stages. Measurements of chlorophyll content were performed with a chlorophyll meter (SPAD) to estimate N nutrient status. Four different methods [Nitrogen Nutrient Index (NNI), Soil Plant Analysis Development (SPAD), Diagnostic Recommendation Integrated System (DRIS), and Sufficiency Range (SR)] of nutrient status evaluation were compared. Nitrogen (N) and potassium (K) nutrient status of wheat cultivated in the organic system was lower compared with the other farming systems. Assuring sufficient supply of nitrogen to cereals under the conditions of organic farming is particularly difficult in early growth stages. In the integrated and conventional systems wheat was sufficiently supplied with NPK. Kobra cv. proved to be more adapted to the organic system. Results indicate that classical nutrient status indices are of lesser use for organic farming.     

Co-inoculation of potassium solubilizing and nitrogen fixing bacteria on solubilization of waste mica and their effect on growth promotion and nutrient acquisition by a forage crop

Waste mica, a potassium-bearing mineral, is a by-product of mica industry; however, its potassium (K)-supplying capacity for crop production is not well understood. A greenhouse trial was made to study the effect of co-inoculation of potassium solubilizing (Bacillus mucilaginosus) and nitrogen (N) fixing (Azotobacter chroococcum A-41) bacteria on solubilization of waste mica (a potassium-bearing mineral) and their effects on growth promotion and nutrient uptake by a forage crop of sudan grass (Sorghum vulgare Pers.) in a Typic Haplustalf. Results revealed that significantly higher biomass accumulation and nutrient acquisition were obtained in all the pots treated with mica and/or bacterial strain as compared to control. Data indicated that co-inoculation of waste mica with B. mucilaginosus and A. chroococcum A-41 resulted in highest biomass production and nutrient acquisition. Co-inoculation of bacterial strains maintained consistently highest amounts of available K and N in soils even at 150 days of crop growth than other treatments. B. mucilaginosus strain was more effective and potent K solubilizer than A. chroococcum A-41. Thus, co-inoculation of potassium solubilizing and nitrogen fixing bacteria to waste mica could be a promising and alternative option for utilizing this potent source as K fertilizer to crops and maintaining greater nutrients availability in soil. Further studies are necessary to see the effects of these bacterial strains on mobilization of potassium-bearing minerals under field conditions.     

Nitrogen and mineral composition of autumn‐grazed pasture

Abstract

Grazing management in autumn can influence the botanical composition and productivity of a sward. Cycling of nutrients as a result of grazing livestock activity and variable canopy growth rates may influence mineral nutrient supply and demand in a dynamic canopy. An experiment was conducted to determine the influence of autumn grazing practices on the growth and composition, including minerals in terms of ruminant requirements, of a grass/legume sward. Paddocks were established and three replicates grazed by growing lambs for 30‐, 60‐, or 90‐d intervals beginning in late summer. Herbage samples were collected at the beginning of the grazing interval and at the end of each interval (closing date). Herbage mass, and nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg), calcium (Ca), and sulfur (S), as well as copper (Cu) and zinc (Zn) were examined in terms of the influence of sampling date, closing date, year, and the interaction of these factors from stockpiled and grazed canopies. Soil mineral composition was determined as well. Concentrations of all minerals declined with increasing soil depth and P, Na, Mg, and Ca increased in soil over the course of the experiment. Soil N concentration was reflected in the pattern of herbage growth in autumn. In general, closing date had no influence on herbage mineral composition and concentrations were within the recommended levels for a range of livestock. Phosphorus was the exception and concentrations in herbage were low in terms of requirements for high producing livestock such as lactating dairy cattle. Uptake or mineral reallocation within the plant remained constant during the autumn growth interval, since mineral yields were stable as growth rates declined in 1991 and increased when growth rates were stable in 1992. Mineral related nutritional problems in grazed mixed‐species pasture, would most likely be a function of mineral bioavailability or interactions, rather than low concentrations in the herbage.     

The effect of sodium on growth and potassium deficiency symptoms in water convolvulus (Ipomea aquatica,Forsk.)

Water convolvulus, Ipomea aquatica Forsk., was grown in nutrient solution with three concentrations of sodium and potassium, each ranging from deficient to sufficient. All other nutrients were supplied in adequate quantities. Both potassium and sodium increased plant growth, however, the response to sodium was greatest when potassium was deficient. Evidence of a sodium response makes the accepted practice of balancing potassium with sodium in solution culture studies most questionable. Sodium should not be considered a non‐nutrient in water convolvulus.     

稻-麦轮作体系不同施肥模式对氮肥利用效率和土壤有效养分平衡的影响

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

Effects of different organic materials on forage yield and nutrient uptake of silage maize (Zea mays L.)

The use of organic materials as a source of nutrients on agricultural lands ameliorates soil physical properties as well as being an environmentally friendly way of disposing of their wastes. This study was conducted to determine effects of three organic materials (poultry litter, cattle manure, leonardite) on yield and nutrient uptake of silage maize. Poultry litter and cattle manure were applied based on phosphorus (P) or nitrogen (N) requirements of the crop whereas leonardite was applied only one dose (500 kg ha^?1) and also combined with three inorganic fertilizer doses (100%, 75%, 50% of recommended inorganic fertilizer dose). According to the results, the highest green herbage yield and nutrient uptake values were observed in LEO-100 whereas N-based treatments significantly decreased yield and nutrient uptake of silage maize. The use of organic materials as a combination with inorganic fertilizer in silage maize cultivation is highly beneficial for sustainable forage production.     

Nutrients in the West African Sudano-Sahelian zone: Losses,transfers and role of external inputs

Crop growth on acid sandy soils of the Sudano-Sahelian zone is primarily limited by the low amounts of organic matter and available mineral nutrients in the topsoil. The shortening of fallow periods with population growth, the exploitation of fire wood, spatial nutrient transfers by wind and water and net nutrient exports with crop yields in the order of 15 kg nitrogen (N) 2 kg phosphorus (P) and 15 kg potassium (K) ha⁻¹ yr⁻¹ for traditional fields planted to pearl millet (Pennisetum glaucum L.) in the southern Sahel have exhausted these resources. Large productivity declines in the prevailing agro-pastoral systems are the consequence. Data are presented to show bow nutrient exports at the level of individual fields, through grain yields and biomass removal as forage, firewood, construction material, and also through run-off, wind and water erosion, leaching and volatilisation, are either losses for the ecosystem or sources of nutrients transferred within the ecosystem. Livestock is a vector of nutrients from rangelands to manured fields through forage intake and excretion and helps to shortcut nutrient cycles, but it is also a net consumer of organic matter and minerals. Through the effects of trampling on the soil and of grazing on the vegetation composition and production, livestock also indirectly affects the cycling and transfer of nutrients. Net nutrient inputs by heavy rains causing overland flow, dust deposition and through biological nitrogen fixation, are also unequally distributed and thus aggravate the fertility gradient from large nutrient ‘source’ areas such as rangelands to small ‘sink’ areas such as fallows, low lands, temporary lakes and river benches. At a finer resolution, shrubs and trees with their alternating periods of nutrient storage and recycling in leaves and wood, micro-depressions, termite mounts and ant nests become localised points of nutrient concentration and high crop productivity. To balance losses of nutrients in these integrated systems and to obtain sustainable increases in production, external inputs of nutrients are necessary. These may be introduced by two different pathways, either via mineral fertilisers applied to croplands or via externally produced supplements fed to livestock. These pathways are complementary and each one has direct effects on the other. Fertiliser application to croplands affect livestock through the increase in available forage and crop residue feed, whereas feed supplementation affects crop production through higher amounts and better quality of manure. The adoption of either strategy by farmers requires a high nutrient use efficiency at low cost. Data from regional field trials revealed increases in total dry matter (TDM) of cereals with broadcast annual P application at 13 kg ha⁻¹ ranging across three years from 19 to 88% for rockphosphate and from 34 to 102% for single superphosphate (SSP). Still, a low-external input approach seemed more advantageous to farmers. The placement of NPK fertiliser at 4 kg P ha⁻¹ with the seed at or shortly after planting caused average TDM increases of 70% for millet, sorghum, maize, cowpea and groundnut and showed an up to three-fold higher phosphorus use efficiency than broadcast P. On the other hand, late dry season supplementation of grazing steers with millet bran not only decreased animal weight losses but also increased N and P concentrations in the faeces. The larger nutrient concentrations in the manure increased millet grain yield by 28% and stover yield by 21% on a field manured at a rate of 3 t DM ha⁻¹. However, even with such approaches the current trends of declining soil productivity can only be reversed, if local policy makers are willing to support agricultural change through better terms of trade for agricultural products.     

Chromosome and genome composition of a <Emphasis Type="Italic">Triticum</Emphasis> × <Emphasis Type="Italic">Thinopyrum</Emphasis> hybrid by classical and molecular cytogenetic techniques

Triticum–Thinopyrum amphiploids arose from the need to obtain forage grasses highly resistant to pest, drought, soil salinity and frost and they can be used as efficient bridges to transfer desired genes from wheatgrass species to wheat. One of them is trigopiro SH16 INTA, it was introduced in Argentina in 1947 but its genomic composition was unknown. The aim of this work was to determine the chromosome number and genomic and chromosome composition of trigopiro SH16 INTA in order to use it in breeding programs. The simultaneous use of the in situ hybridization technique with different probes (genomic DNA of Th. ponticum (Podp.) Barkworth et D.R. Dewey, pSc119.2 and pAs1) allowed us to conclude that the chromosome number of trigopiro SH16 is 2n = 42 and the genome composition would be: 14 chromosomes of the B genome, the 2D and 4D chromosome pairs of wheat, 14 chromosomes of the J genome of Thinopyrum and the remaining chromosomes probably belong to the A genome of wheat.     

Influence of aggregate size on phosphorus loss and ryegrass yield in a soil cultivated intermittently

Intermittent cultivation for forage cropping and subsequent grazing by dairy cattle during winter is practiced in southern New Zealand to protect remaining pastures from poaching damage by cattle. However, this practice may degrade soil aggregate structure affecting pasture yield and nutrient loss. A study was conducted to determine the ability of different aggregate sizes to supply phosphorus (P) to ryegrass in a soil used for winter forage cropping and grazed by dairy cattle 2 out of 7 years. Over 35 weeks ryegrass was grown in pots containing one of six wet‐sieved soil aggregate size classes and leached every 2 weeks. Soil analyses included water soluble P, inorganic and organic P fractions, and P in leachate. Results showed that organic P was preferentially lost in leachate or mineralized and used by ryegrass with decreasing aggregate size, although this did not affect yield. Ryegrass yield was best correlated with bicarbonate extractable P in aggregates, and P loss with water soluble inorganic P after minimum disturbance. These findings suggest that although intermittent cultivation did not affect yield, if this practice decreases aggregate size in the future, it may increase the risk of P loss.     

红壤地区草-牛-沼生态系统中养分循环利用的研究

在中度熟化的红壤岗地上采取种植黑麦草和玉米饲喂肉牛,牛粪尿沼气发酵后的沼肥与化肥配施养草的方式,并以单施化肥养草喂牛的方式为对照,进行2年试验研究草-牛-沼生态系统中的养分循环。结果表明,沼肥与化肥配施处理玉米植株的产量和养分积累量都高于单施化肥处理,而黑麦草产量和养分积累量都稍低于单施化肥处理,但由于配施沼肥可节省一半的化肥投入,其效益都很显著。牛对不同施肥处理同种饲草中养分的消化率差异不显著,牛粪尿对养分的回收率也差异不明显,但不同种或同种而收获期不同的饲草消化率和回收率都差异明显。牛粪尿经沼气发酵后回收的养分量可节约饲草生产中近一半的化肥投入。且沼肥施用后土壤肥力得以保护和改善,为后续的饲草生产提供了较好的土壤条件,从而有利于养分循环利用。     

不同水稻灌溉模式和氮肥减量对还田麦秸腐解特性及土壤养分的影响

为了探讨不同水稻灌溉模式和氮肥减量对还田小麦秸秆腐解特性及土壤养分的影响，通过田间试验，设置了水稻灌溉模式（常规灌溉，W1；干湿交替灌溉，W2）和施氮水平（不施氮，N0；常量施氮，N1；减量20%施氮，N2）处理，采用尼龙网袋法研究了不同处理下小麦秸秆腐解动态、养分释放规律及土壤养分含量。结果表明，干湿交替灌溉和氮肥施用均可促进还田小麦秸秆的腐解，减量20%施氮处理小麦秸秆累积腐解率低于常量施氮处理。相同施氮水平下，干湿交替灌溉模式小麦秸秆碳与氮磷钾累积释放率高于常规灌溉模式；与常量施氮相比，减量20%施氮处理小麦秸秆碳与氮磷钾累积释放率降低。干湿交替灌溉和施氮使土壤有机质、全氮、碱解氮和有效磷含量提高，而减量20%施氮对土壤养分含量的影响较小。综上可见，干湿交替灌溉和氮肥施用促进了还田小麦秸秆腐解和养分释放，有利于土壤养分提升；而减量20%施氮对小麦秸秆腐解与养分释放以及土壤养分无明显影响。     

Broiler Litter as a Sole Nutrient Source for Cotton: Nitrogen,Phosphorus, Potassium,Calcium, and Magnesium Concentrations in Plant Parts

Abstract

The ability of poultry litter to support plant growth by supplying essential plant nutrients in the absence of other sources of the nutrients has not been studied thoroughly. The objectives of this research were to (1) determine the ability of poultry litter, as the sole nutrient source, to provide macronutrients and support growth of cotton (Gossypium hirsutum L.) (2) evaluate the distribution of these nutrients within the different plant parts, and (3) estimate the efficiency with which these nutrients are extracted by cotton. The research was conducted in plastic containers filled with a 2:1 (v/v) sand:vermiculite growing mix under greenhouse conditions. The treatments included broiler litter rates of 0, 30, 60, 90, or 120 g pot^?1 with or without supplemental Hoagland's nutrient solution. Broiler litter supplied adequate amounts of the macronutrients nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg) and supported normal growth of cotton. Tissue nutrient analysis showed that the concentration of N, P, K, and Mg in the upper mainstem leaves was within published sufficiency ranges for cotton growth. Evaluation of the N distribution indicated that the cotton plant partitions N to reproductive parts when faced with deficiency of this nutrient and favors allocating N to new leaf growth once the requirement for reproductive growth is met. The partitioning of P was similar to that of N but less distinct. Cotton extracted Mg and K with greater efficiency (up to 58%) than the other nutrients and stored these nutrients in older leaves. The extraction efficiency of N ranged between 21% at 120 g pot^?1 litter and 27% at 30 g pot^?1 litter. Phosphorus was the most poorly extracted nutrient, with only 16% of the total applied P extracted when 30 g pot^?1 litter was applied and only 6% extracted at the higher litter rates. This suggests that the same problem of P buildup that has been reported in soils under pasture may also occur when poultry litter is repeatedly applied to the same soil planted to cotton. These results show that broiler litter not only supplied enough N but also supplied the four other macronutrients (P, K, Ca, and Mg) in amounts sufficient to support normal cotton growth. This research implies that poultry litter can effectively substitute for several fertilizers to meet crop macronutrient (N, P, K, Ca, and Mg) needs in soils deficient in any or all of these nutrients.     

Mineral concentrations of forages and soils in Benue State,Nigeria. I. Macrominerals and forage in vitro organic matter digestibility and crude protein concentrations

Abstract

Macromineral composition of different forage species and soils and forage in vitro organic matter digestibility (IVOMD) and crude protein concentrations in three agricultural zones of Benue State were studied. The zones consisted of Tiv zone (Zone A), Igala zone (Zone B), and Idoma zone (Zone C), each of which was made up of three sites. Site I was Fulani cattle migration routes across the state, site II represented grazing sites within home proximity, and site III were grazing reserves. Grazing animals were followed and forages corresponding to that consumed by them, and the corresponding soil samples were collected during the peak of the dry season (December‐January) and analyzed for nutrient composition. Forage IVOMD ranged from 21% to 79%, with values obtained in grass being lowest due to pronounced overmaturity. Only 10% of forage samples (exclusively from grasses), showed protein levels below the critical value of 7%. Most forage samples, as well as their corresponding soil samples were sufficient in calcium (Ca), magnesium (Mg), and potassium (K) concentrations. Soil concentrations of Ca, Mg, and K were particularly high compared to critical requirements in all the zones studied. Approximately 94% and 76% of forages were deficient in phosphorus (P) and sodium (Na), respectively, and the deficiencies were similar in all classes of forage and sites of study for each of the zones investigated. Results of forage‐soil relationships indicated low and nonexisting correlations; therefore soil analyzes are not of great importance in the assessment of available macromineral supplies to grazing livestock. The macrominerals most needed for supplementation of grazing livestock during the dry season are P, Na, and K.     

Comparisons of Composts with Low or High Nutrient Status for Growth of Plants in Containers

Abstract

Composts may be incorporated into container mixes for several purposes, including to supply nutrients, add organic matter, or suppress plant diseases. The objective of this research was to assess the nutritional benefits of two composts derived in common from composted chicken manure and used in formulation of container media for growth of tomato (Lycopersicon esculentum Mill.). The composts differed in extractable and total plant nutrients so that one of the composts was considered a nutrient‐rich material and the other a nutrient‐poor material. Media were formulated from soil or peat with the composts added in a progressive array of concentrations from a medium with no compost addition to a medium that was all compost. Half of the media were treated with a water‐soluble, complete fertilizer and half were left unfertilized. Optimum growth occurred in media in which compost did not exceed 25% of the volume. The beneficial effects of the composts on plant growth were associated with increased supply of nutrients for the plants. The suppressive effects were attributed to restricted accumulation of nutrients with the nutrient‐poor compost and to excessive potassium supply and accumulation with the nutrient‐rich compost. Fertilization was beneficial in increasing plant growth with the nutrient‐rich compost and was essential for plant growth with the nutrient‐poor compost. The research demonstrated that composts can be used in formulation of media for container growth of plants.     

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

Abstract

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

北方褐土区冬小麦养分平衡施肥参数研究

【目的】利用养分平衡法原理,研究各养分平衡施肥参数,建立以土壤有效养分测定为基础的我国褐土冬小麦测土推荐施肥指标体系,以简捷快速、科学合理地指导我国北方褐土区冬小麦的施肥与生产。【方法】通过对多年多点小麦肥效试验结果的分析,分别计算出小麦单位产量养分吸收量、土壤有效养分校正系数、肥料当季利用率等养分平衡施肥参数,主要研究土壤环境、产量水平等因素对土壤有效养分校正系数和肥料利用率的影响及变化规律。【结果】冬小麦每百千克小麦产量养分吸收量在一个相对稳定的范围内变化,因此忽略其变化将其定为常数,即氮(N)、磷(P2O5)和钾(K2O)分别为3 kg、1.2 kg和2.8 kg。土壤有效养分校正系数与土壤有效养分含量之间呈显著幂指数负相关关系。在不同的产量水平下,肥料养分当季利用率与土壤有效养分含量之间呈显著对数负相关关系。在此基础上,建立了以养分平衡原理为依据、土壤有效养分测定为基础的我国褐土冬小麦测土推荐施肥指标体系。【结论】由于养分平衡模型的作物推荐施肥量是根据目标产量需肥量与土壤供肥量之差来计算的,在利用该模型进行施肥推荐时,研究的关键点应该是如何准确确定模型中土壤有效养分校正系数和肥料当季利用率等参数,以便得到广泛地推广应用。在北方褐土区建立了以养分平衡原理为依据,土壤肥力测定为基础,具有氮、磷和钾全定量特性的小麦测土推荐施肥体系。