Inorganic Nutrient Sources Research Articles

Differential effect of coal combustion products on the bioavailability of phosphorus between inorganic and organic nutrient sources

In farming systems, all the applied phosphorus (P) is not available to plants because they are either adsorbed in soil or lost to the environment through leaching or runoff. The effect of coal combustion products (CCPs) for enhancing the bioavailability of applied phosphorus (P) in soil was examined separately for inorganic (KH2PO4 – PP) and organic (poultry manure – PM) P treatments, where fluidised bed combustion (FBC) ash emerged as the most effective amendment. Greenhouse study was conducted by growing mustard plants on FBC amended soils under leaching and non-leaching setups. The FBC increased the biomass yield for organic P treatments in the first crop and increased for both inorganic and organic P in the second cropping. The increase in cumulative yield was highest in leached PP and unleached PM treatments. Field experiment assessed the effectiveness of FBC on inorganic (single super phosphate – SSP) and organic P (biosolids – BS) uptake by mustard and sunflower plants. In the first cropping, the yield was higher in crops treated with SSP alone. In the second crop, yields were higher in the presence than absence of FBC, as reflected by the high relative agronomic effectiveness (RAE) exhibited by BS+FBC (462%) combination. Overall, FBC used in these experiments enhanced bioavailability of P in soil through adsorption and mineralisation of inorganic and organic P, respectively as evident from phosphatase activity and Olsen P relationship. Hence the differential effect of CCPs has not only decreased the loss of applied P (from inorganic and organic sources) to the environment, but also enhanced the P bioavailability in the soil. Among the three CCPs used in the preliminary experiments, FBC proved to perform better than the other two and hence can be recommended for agricultural and environmental applications targeting P issues.

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

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

Role of Organic and Inorganic Nutrient Sources in Improving Wheat Crop Production

Abstract Effects of organic manures on grain yield and yield components of wheat (Triticum aestivum L.) cultivar Minthar-03 were studied at (RARI) Regional Agricultural Research Institute Bahawalpur, Pakistan, during 2010-2011 seasons in chemistry division. The present study have six treatments i.e. control, NPK=150-120-60 kg/ha, control, NPK= 150-120-60 kg/acre, NPK+ poultry manure 50 kg /acre, NPK + press mud 500 kg/acre, NPK + city compost 300 kg/acre, NPK + humic acid 4 kg/acre. Combinations of NPK + PM 50 kg/ha having high plant height (102.53) while number of (343) tillers/m2 was obtained high in combination with NPK + city compost 300 kg/ha which was at par with combination (NPK + press mud 500 kg/acre) having plant height 100.90. spike length, number of grains /spike, 1000 grains weight, grain yield t/ha was 13.35 cm, 61.85, 40.60 grams and 3.14 t/ha respectively obtained in treatment (NPK + press mud 500 kg/acre). While minimum amount of plant height (94.80), number of tillers/m2 (223), spike length (10.35 cm), number of grains/spike (43.43), 1000 grains weight (35.33g), grain yield t/ha (38.41) was found in control where no dose of organic and inorganic fertilizer were applied.

Response of bacterial community structure and function to experimental rainwater additions in a coastal eutrophic embayment

Although recognized as a potentially important source of both inorganic and organic nutrients, the impact of rainwater on microbial populations from marine planktonic systems has been poorly assessed. The effect of rainwater additions on bacterioplankton metabolism and community composition was evaluated in microcosm experiments enclosing natural marine plankton populations from the Ría de Vigo (NW Spain). The experiments were conducted during three different seasons (spring, autumn and winter) using rainwater collected at three different locations: marine, urban and rural sites. Bacterial abundance and production significantly increased up to 1.3 and 1.8-fold, respectively, after urban rainwater additions in spring, when ambient nutrient concentration was very low. Overall, the increments in bacterial production were higher than those in bacterial respiration, which implies that a higher proportion of carbon consumed by bacteria would be available to higher trophic levels. The response of the different bacterial groups to distinct rainwater types differed between seasons. The most responsive bacterial groups were Betaproteobacteria which significantly increased their abundance after urban (in spring and winter) and marine (in spring) rainwater additions, and Bacteroidetes which positively responded to all rainwater treatments in spring and to urban rainwater in autumn. Gammaproteobacteria and Roseobacter responded only to urban (in spring) and marine (in winter) rainwater treatment, respectively. The responses to rainwater additions were moderate and transient, and the resulting bacterial community structure was not importantly altered.

Relative effectiveness of organic and inorganic nutrient sources in improving yield, seed quality and nutrient uptake of canola

The proper use of organic and inorganic nutrient sources is important to sustain high levels of crop production, while maintaining or enhancing soil and environmental quality. A 4-year (2009 to 2012) field experiment was established in spring 2009 on a Gray Luvisol (Typic Haplocryalf) loam soil at Star City, Saskatchewan, Canada, to determine the effectiveness of organic/biological (compost, wood ash [fine and granular], alfalfa pellets, distiller grain, thin stillage, glycerol, fish food additive, Penicillium bilaiae), inorganic/mineral (granular-gypsum, rapid release elemental S [RRES], rock phosphate [granular and fine]) and chemical/synthetic (granular-ammonium nitrate, triple super phosphate and potassium sulphate) nutrient sources (amendments/chemicals) in improving seed yield, straw yield, seed quality and nutrient uptake (N, P, K and S) in seed + straw of canola. Combined application of N, P and S chemical fertilizers (NPS) produced considerably greater seed yield, straw yield and nutrient uptake of canola compared to the unamended control in all four years. In treatments receiving only organic amendments, thin stillage produced the greatest seed yield, straw yield and nutrient uptake in all years, and it was similar to the NPS balanced fertilizer treatment, while fish food additive and distiller grain dry of wheat in 2009, 2011 and 2012, distiller grain dry of corn in 2009 and 2012, and compost and alfalfa pellets in 2011 and 2012 produced significantly greater seed yield, straw yield and nutrient uptake, when compared to the control. In treatments where chemical fertilizers were also applied, in addition to organic amendments, ap- plication of N fertilizer increased seed yield, straw yield and nutrient uptake substantially when combined with wood ash fine in 2009, 2010, 2011 and 2012, wood ash granular in 2009, 2011 and 2012, and glycerol in 2009 and 2012 (moderate increase in 2012). In the chemical fertilizer treatments, there was a reduction in seed yield, straw yield and nutrient uptake of canola when only N fertilizer was applied compared to the control (significant in 2010 and 2011). Application of P along with N (NP) increased seed yield, straw yield and nutrient uptake of canola compared to N alone treatment, but was less than the NPS treatment in all years. Application of S along with N (NS) increased seed yield, straw yield and nutrient uptake of canola further compared to the NP treatment, but it was still lower than the NPS treatment in 2010 and 2011. In treatments receiving inorganic/mineral amendments in addition to chemical fertilizers, application of N + P fertilizers substantially increased seed yield, straw yield and nutrient uptake in treatments receiving gypsum and RRES in 2009, 2010, 2011 and 2012. This suggests the potential of gypsum and RRES in preventing S deficiency in organic crops when grown on S-deficient soils, provided other nutrients are not limiting in the soil for crop growth. Seed yield, straw yield and nutrient uptake with application of N and S fertilizers in combination with rock phosphate and/or Penicillium bilaiae were similar to N + S treatment in most cases, except in 2011 when application of finely-ground or powder rock phosphate in a combination with N + S produced significantly greater yield and nutrient uptake than N + S with granular rock phosphate. This suggests little contribution of rock phosphate and/or Penicillium bilaiae in improving yield and nutrient uptake of canola, and improves the performance of fine rock phosphate only evident in the third growing season in 2011, after three consecutive applications, but not in 2012. In conclusion, some organic amendments showed potential for improvement in organic crop production, and in some other cases highest yield and nutrient uptake were produced

Improving Yield and Nutrient Status of Rejuvenated Guava Orchard by Integrated Nutrient Management Under Semi-Arid Conditions

An investigation was carried out during 2010–11 to study the effect of integrated nutrients management after rejuvenating more than 25 years old guava orchard planted at 6x6 m apart under semiarid conditions of eastern Rajasthan. The results revealed that almost all treatments with combined application of organic and inorganic sources of nutrients had significantly increased the fruits yield of guava, soil dehydrogenase activity, NPK content of leaf, fruit and soil over control (only recommended dose of NPK i.e. 500:200:500 g/plant-T1). Among different treatments, application of 2/3 of T1+25 kg FYM+250g Azospirillum +250g Azotobacter/plant (T11) significantly increased the number of fruits/plant (138.33), yield/plant (15.03 kg) and yield/ha (4.18 t) on pooled basis. The soil dehydrogenase activity both at 30 days (3.854 4.040 μg TPF g−1 ha−1) and 60 days (8.022 μg TPF g−1 ha−1) was also higher in this treatment (T11). The leaf N content (2.008%) was higher in T15-(2/3 of T1+5 kg vermicompost + 250g Azospirillum + 250g Azotobacter/plant) while P (0.311%) and K (1.833%) content were higher in T11. The trend of NPK content at harvest was same in the fruit sample also. The available soil N and k content did not make significant impact within two years of experimentation but P content varied significantly with the combined application of various organic and inorganic sources. From the present investigation it is concluded that with the application of 2/3 quantity of recommended dose of fertilizers i.e. 500:200:250 g NPK +25 kg FYM+250g Azospirillum +250g Azotobacter/plant (T11) in rejuvenated guava orchard of cultivar Sardar not only 20% higher fruit yield can be harvested but better plant and soil health can be maintained.

Environmental dynamics as a structuring factor for microbial carbon utilization in a subtropical coastal lagoon.

Laguna de Rocha belongs to a series of shallow coastal lagoons located along South America. It is periodically connected to the sea through a sand bar, exhibiting a hydrological cycle where physicochemical and biological gradients are rapidly established and destroyed. Its most frequent state is the separation of a Northern zone with low salinity, high turbidity and nutrient load, and extensive macrophyte growth, and a Southern zone with higher salinity and light penetration, and low nutrient content and macrophyte biomass. This zonation is reflected in microbial assemblages with contrasting abundance, activity, and community composition. The physicochemical conditions exerted a strong influence on community composition, and transplanted assemblages rapidly transformed to resembling the community of the recipient environment. Moreover, the major bacterial groups responded differently to their passage between the zones, being either stimulated or inhibited by the environmental changes, and exhibiting contrasting sensitivities to gradients. Addition of allochthonous carbon sources induced pronounced shifts in the bacterial communities, which in turn affected the microbial trophic web by stimulating heterotrophic flagellates and virus production. By contrast, addition of organic and inorganic nutrient sources (P or N) did not have significant effects. Altogether, our results suggest that (i) the planktonic microbial assemblage of this lagoon is predominantly carbon-limited, (ii) different bacterial groups cope differently with this constraint, and (iii) the hydrological cycle of the lagoon plays a key role for the alleviation or aggravation of bacterial carbon limitation. Based on these findings we propose a model of how hydrology affects the composition of bacterioplankton and of carbon processing in Laguna de Rocha. This might serve as a starting hypothesis for further studies about the microbial ecology of this lagoon, and of comparable transitional systems.

Vermicompost Substitution Influences Shelf Life and Fruit Quality of Tomato (Lycopersicon esculentum Mill.)

The growing awareness on health makes consumer more concerned for food quality and safety. In tomato, the nutrient content, texture, colour and nitrate level mostly determines the degree of acceptability of ripe fruit. The present study was aimed to assess the influence of different nutrient sources on shelf life and important quality attributes of tomato. The field experiment was conducted during 2005-06 and 2006-07 with 14 different treatments by combining inorganic and organic sources of nutrients in presence and absence of microbial amendment. The pooled analysis revealed that the shelf life, total soluble solids, total sugar, vitamin A and vitamin C contents were significantly influenced by the application of different sources of nutrients. Also, substitution of 25% inorganic nitrogen with manure along with microbial amendment influenced shelf life and nutritional qualities of tomato. Within the 75% inorganic fertilizer treatment combination, quality attributes were correlated with the type and amount of the organic manure applied. Higher levels of vermicompost resulted in better growth medium compared to higher levels of farmyard manure. Within the vermicompost treated plots, inoculation with microbial amendment gave better results than the uninoculated treatments. The fruit nitrate content was also reduced upon the application of 75% of recommended inorganic fertilizer combination as compared to 100% inorganic fertilizer treatment combination.

Effect of IPNS on Yield Attributes of Maize (Zea maysL.) Intercropped with Black Gram (Vigna mungo(L.) Hepper)

An experiment was carried out to study the response of integrated nutrient supply (IPNS) on yield traits of maize e.g., total number of cobs in net plot, cob weight (q ha−1), number of rows/cob, number of grains/row, number of grains/cob and 1000 grain weight on average basis ranged from 57.07 to 71.67 thousand ha−1, 38.85 to 60.62 q ha−1, 13.47 to 17.16, 32.70 to 35.07, 415.29 to 566.93 and 170.70 to 224.86 g, respectively. The values of these parameters recorded highest under treatment T3 (FYM + Chem.) which were at par with T8 (Azotobacter + Rhizobium + PSB + FYM + Chem.) and these were significantly superior to rest of the treatments during both the years of study. Grain yield 33.13 to 52.56 q ha−1, stover yield 40.32 to 60.76 q ha−1, total biological yield 73.44 to 113.32 q ha−1, grain: strover ratio and harvest index of maize on an average ranged from 0.82 to 0.87 and 45.11 to 46.38%, respectively. In these parameters, significant increase was recorded in the treatments received organic, inorganic and bio-fertilizer sources of nutrients in combined form.

Organic fertilization: An alternative to produce jalapeñ o pepper under greenhouse conditions

The experiment was conducted during fall-winter seasons of years 2011-2012 to determine the effects of vermicompost tea (VCT) on growth and productivity of ?Hechicero? jalapen o pepper plants grown under organic and synthetic fertilization in greenhouse. Five different fertilization forms were applied to plants [F1 = sand + inorganic nutrient solution (control group); F2 = sand + VCT on concentration of 10%; F3 = mixture of sand + compost (ratio 1:1; v:v) + VCT on concentration of 2.5%; F4 = mixture of sand + vermicompost (ratio 1:1; v:v) + VCT on concentration of 2.5% y F5 = mixture of sand + compost + vermicompost (ratio 2:1:1; v:v:v) + VCT on concentration of 2.5%]. Treatments F4 and F5 showed an increased yield of 70 and 45% with regard to the yield obtained with F1; the F1 and F2 yields were not statistically different at the 0.05 significance level. The fruit length and the pericarp thickness were increased until 7.55 and 7.01% in F5, respectively. These results suggest that, since there were differences in yield when using the organic and inorganic nutrient source VCT combined with mixtures of sand + compost + vermicompost may be considered a successful alternative fertilizer for organic jalapen o pepper production in greenhouse.

USEING ALGAL ORGANIC FERTILIZERS

<p>Algae have been explored as inorganic nutrient sources, human and animal food and biochemical products. Several beaches in the northeastern state of Alagoas, Brazil, frequently experience large amounts of algal drifts, representing a huge amount of biomass that could be used as an organic fertilizer for coastal farmers. The purpose of this study was to observe the growth and development of lettuce grown using algal with organic fertilizers. The lettuce was grown in the following conditions: controlled, soil neither algal powder nor cattle manure, soil plus 5% of algal powder, and soil plus 5% of cattle manure. The lettuce plantlets were transferred to a substrate and harvested with after 60 days. The fresh and dry mass, shoot and root length of the lettuce plants, and the mineral nutrient content of the algae fertilizer were evaluated as parameters Algae fertilizers have low levels of phosphorus and but have suitable levels of other mineral nutrients when compared to other organic fertilizers. Algal fertilizers induced a similar growth response in lettuce plants compared to cattle manure. Overall, this data lets us conclude that algal drifts, with the addition of phosphorus and potassium, might be a good resource as an organic fertilizer.</p><p> </p>

An overview of soil fertility management, maintenance, and productivity in Kenya

Soil fertility-related issues are a major concern to Kenya. For more than a decade, the country has experienced a declining trend in agricultural production as exemplified by low yields of major crops. Crop yields of no inputs declined by over 70% in 11 years. Continuous cropping without fertilizer caused declines in soil organic carbon and microbial biomass size and activity compared to farmyard manure alone or in combination with inorganic fertilizer. In fertilizer trials throughout the country, nitrogen (N) and phosphorus (P) were deficient in 57% and 26% of the sites, respectively. With declining productivity and soil nutrient depletion, many farmers have taken the initiative to improve the situation by use of both inorganic and organic nutrient sources such as manures, composts and traditional fallows where possible. There is strong evidence that application of fertilizer increases crop production, especially for maize. Among the bio-physical factors, a soil fertility decline remains the single most important constraint to food security in this region. After soil moisture stress, low soil fertility is the most important constraint limiting crop productivity in sub-Saharan Africa.

Waste Streams from Methane Digesters: Exporting Nutrients through Turfgrass and Forage Production Systems

Similar to manure, residual manure solids (MS) from methane digesters require cropping systems and management practices that optimize nutrient export to prevent large increases in soil P levels. The objectives were to compare forage and turfgrass sod production systems with respect to effects of MS management practices on soil properties and crop productivity and to compare mass balance of N and P on field scale. A 2‐yr field experiment was conducted on a fine sandy loam soil receiving MS to compare nutrient imports, forms in soil, and export by Tifton 85 bermudagrass (Cynodon spp.) grown for forage and Tifway bermudagrass [C. dactylon (L.) Pers. × C. transvaalensis (Burtt‐Davy)] grown for turfgrass sod. Five soil treatments for each crop included MS with and without Alum topdressed (250 kg total phosphorus [TP] ha−1) annually or a single application of MS (500 kg TP ha−1) incorporated compared to soil without MS. One harvest of Tifway sod removed 2.7 times more total nitrogen (TN) and 2.8 times more TP than three harvests of Tifton 85 forage biomass during the first year of production. Greater biomass production and nutrient uptake by Tifton 85 forage during the second production season reduced the difference in nutrient export between Tifton 85 and Tifway sod. Turfgrass sod production systems can be used by producers to increase export of MS applied nutrients compared to forage production and enable waste streams from methane digesters to be recycled.

Rapid transformation of inorganic to organic and plant-available phosphorous in soils of a glacier forefield

Chemical weathering of rocks or sediments is extremely important for the generation of soils, for the evolution of landscape, and as a main source of inorganic nutrients for plant growth and therefore for life. Temporal trends in weathering mechanisms, plant succession and nutrients availability in cold environments can be successfully studied in soil chronosequences along a glacier forefield. In the present paper, this was carried out in the pro-glacial area of Morteratsch. Different forms of phosphorous in the soil, stream and spring water chemistry were investigated. Apatite constitutes the main source of P, but it occurs only as a minor accessory mineral phase in the granitic/gneiss parent material. The identification of apatite was performed using SEM-EDX and cathodoluminescence. Water chemistry data indicated some calcite dissolution at the earliest phase of exposure, pyrite and — on older surfaces increasingly — feldspar weathering. Apatite also seemed to contribute to Ca which is leached from the soils. The concentrations of dissolved P in the stream and spring waters were, however, extremely low (only a few μg P/l). In the topsoil, the total stocks of P showed a slight decrease with time. Losses were rather difficult to detect even though the water fluxes through the soils and discharges are relatively high. Soil organic P is almost identical to the EDTA-extractable fraction. In an 11.5ky-old soil outside the glacier forefield the concentration and proportions of organic P, EDTA-extractable P and inorganic P forms did not differ that much from the oldest soils (max. 150years) of the glacier forefield. In the bulk soil, about 78% of total P was transformed into an organic form (40% already after 150years) and, in the fine earth, about 81% (40–70% after about 150years of soil evolution). Thus the P transformation reactions are shown to be very rapid, occur predominantly in the early phase of soil formation, and could be best described by an exponential decay model.

Organic manure supplementation effects on rice–pulse cropping system productivity

The effects of organic manure supplementation on rice–pulse cropping system productivity were studied. Three pulses, viz., blackgram, greengram and pea were grown after rice on the same plots to explore the feasibility of growing second crops with carry-over residual soil moisture and residual soil fertility. The study revealed that during the rainy season, 30%–35% higher rice grain yield was obtained when both inorganic and organic sources of nutrients were applied compared with the full dose of inorganic fertilizer, and the rice grain yield was 65%–78% higher than obtained following farmers’ practices. In the post-rainy season, pea crop recorded the highest grain yield of 490 kg ha-1 under the treatment combination of Sesbania and inorganic fertilizer. Organic carbon, and available N, P, K also enhanced yield by 20%–29%, 5.0%–29.4% to 7.9%–39.9% and 22.4%–60.3%, respectively when 25% N was applied through different organic sources of nutrients (green manure/press mud/farmyard manure).

Composition of inorganic and organic nutrient sources influences phytoplankton community structure in the New River Estuary, North Carolina

The New River Estuary, NC, is a nutrient-sensitive, eutrophic water body that is prone to harmful algal blooms. High annual loading from the watershed of varying nutrient forms, including inorganic phosphorus and inorganic and organic nitrogen, may be linked to the persistence of algal blooms in the estuary. In order to evaluate phytoplankton response to nutrient inputs, a series of in situ nutrient addition experiments were carried out during June 2010 to July 2011 on water from an estuarine site known to support algal blooms. Estuarine water was enriched with nutrients consisting of individual and combined sources of dissolved inorganic nitrogen, orthophosphate, urea, and a natural dissolved organic nitrogen (DON) addition derived from upstream New River water. The combined inorganic N and P addition most frequently stimulated phytoplankton biomass production as total chlorophyll a. The responses of diagnostic (of major algal groups) photopigments were also evaluated. Significant increases in peridinin (dinoflagellates), chlorophyll b (chlorophytes), and myxoxanthophyll (cyanobacteria) were most frequently promoted by additions containing riverine DON. Significant increases in zeaxanthin (cyanobacteria) were more frequently promoted by inorganic nitrogen additions, while increases in fucoxanthin (diatoms) and alloxanthin (cryptophytes) were not promoted consistently by any one nutrient treatment. Evaluating the impact of varying nutrient forms on phytoplankton community dynamics is necessary in order to develop strategies to avoid long-term changes in community structure and larger-scale changes in ecosystem condition.

Enhancement of head yield and quality of cabbage (Brassica oleracea) by combining different sources of nutrients

The present study was aimed to study on influence of different nutrient sources on important quality attributes of cabbage cv. Golden Acre. The field experiment was conducted during 2005–06 and 2006–07 with 14 different treatments by combining inorganic and different organic sources of plant nutrients. The marketable cabbage heads from different treatments were studied for yield and different quality attributes. The pooled result revealed that cabbage head yield and its shelf life, TSS, vitamin A and vitamin C contents were significantly influenced by the application of different sources of nutrients. Vermicompost emerged as better organic nutrient source over farmyard manure. Inoculation with Azophos, a commercial biofertilizer preparation containing the Azotobacter and phosphate-solubilizing bacteria exerted more positive result over uninoculated treatments and benefits of biofertilizer application were more in presence of vermicompost as compared to farmyard manure. The maximum head yield (27.86 tonnes/ha), shelf-life (12 days), head firmness (93.32 kg/ cm2) as well as TSS (4.18º Brix), vitamin A (126.76 µg/100g), vitamin C (44.62 mg/100g) and lowest nitrate content of head (217.17 mg/kg) were realized for the plants grown with the application of 75% of recommended inorganic fertilizers along with vermicompost (5 tonnes/ha) in presence of biofertilizers. Substitution of 25% recommended inorganic nitrogen with higher levels of organic manure and biofertilizer prolonged shelf-life as well as improved nutritional qualities of cabbage heads.

Effects of Organic and Inorganic Nutrient Sources on the Growth, Total Chlorophyll and Yield of Three Bambara Groundnut Landraces in the Coastal Region of Cameroon

Growth and yield parameters of bambara groundnut [Vigna subterranea L. Verdc. landraces: White Seed Coat (WSC), Black Seed Coat (BSC) and Light Red Seed Coat (RSC)] were evaluated under organic and inorganic fertilization in order to determine the field performance, for the improvement of smallholder agriculture in Cameroon. Four fertilizer application rates (0, 3, 6 and 12 t ha-1) of Water Lettuce (WL) and Poultry Manure (PM) and four fertilization rates (0, 100, 150 and 200 kg ha-1) of N, P and K were used in a randomized complete block design experiment with four replications. Application of WL or PM at 12 t ha-1 significantly (p<0.001) increased leaf water content, plant dry weight and total chlorophyll content in RSC landrace. Application of PM at 12 t ha-1 increased significantly (p<0.001) the number of pods per plant, the number of seeds per pods, the 1000 grain weight, the grain yield and the pod yield in RSC landrace. Significant (p<0.001) increase in plant dry weight was observed in all landraces at 100 kg ha-1 N, P or K fertilization. The fertilization rates above 100 kg ha-1 N, P or K led to a decline in yield in all the bambara groundnut landraces compared to the optimum 100 kg ha-1 N, P or K fertilization. RSC landrace showed better growth and yield than WSC and BSC landraces revealing a greater response of this cultivar to fertilization.

Effect of integrated nutrient management on baby corn–rice cropping system: economic yield, system productivity, nutrient-use efficiency andsoil nutrient balance

The study was conducted to estimate the nutrient-use efficiency and soil nutrient balance of integrated nutrient management, five combinations of organic and inorganic sources of nutrients. Both partial factor productivity and agronomic- use efficiency of nitrogen, phosphorus and potassium was recorded maximum in F3 (70% RD of NPK through inorganic fertilizers + 30% N through FYM), F2 (70% RD of NPK through inorganic fertilizers + 30% N through vermicompost) and F1 (recommended dose (RD) of NPK (150:26:33) through fertilizers), respectively. Apparently recovery efficiency for N and K was highest in F1, whereas P in F3. Physiological-use efficiency (PFP) was highest in F3, followed by F1 and F2 treatment. INM showed actual N gain but apparent N losses. Maximum actual N gain was recorded where nutrients were applied through equal proportion (50:50) of organic and inorganic sources. Similar trend was recorded for actual and apparent P loss/gain as recorded for N. Results showed losses in actual K but gain in apparent K for all the treatments.

Influence of long-term crop management practices on grain yield and incidence of brown planthopper in rice

A correct ratio between organic and inorganic sources of nutrients is essential to ensure optimum yield in any crop, including rice. A long-term experiment to study the influence of organic and inorganic nutrient sources on rice yield started in the 1991 kharif season at ARS, Siruguppa, in the Tungabhadra project area of Karnataka, India. The experiment was laid out in a randomized block design with four replications at a fixed site. Different levels of inorganic fertilizers (NPK), organic sources (farmyard manure, Gliricidia, Sesbania), and plant population were included as treatments (see table). A common dose of zinc (at 20 kg ha -1 ) in the form of zinc sulfate was applied to all treatments. Rice variety BPT-5204 was planted every kharif season at 20 × 10-cm spacing, except in treatments where 25% more seedlings were transplanted, which used a spacing of 15 × 10 cm. Brown planthopper (BPH) was recorded in the 1999 kharif season 90 d after transplanting (DAT) on 10 hills in each treatment and computed per hill. Both grain yield and BPH population data were subjected to statistical analysis.