Residual Soil Fertility Research Articles

Impact Assessment of Arbuscular Mycorrhiza Azospirillum and Chemical Fertilizer Application on Soil Health and Ecology

The study was conducted at the Agricultural Experimental Farm of the Indian Statistical Institute, Giridih, Jharkhand, India, during the winter season of 2007–2008 and 2008–2009. Baby corn cob and green fodder yields were greatest in T15 [100% recommended dose of fertilizers (RDF) + arbuscular mycorrhiza (AM) + Azospirillum]. Soil organic carbon (SOC) and residual soil fertility (NPK) were greatest in T16 (150% RDF + AM + Azospirillum). In contrast, soil microbial load [colony-forming units (CFUs) of bacteria, diazotrophs, fungi, and Azospirillum], AM biomass, soil respiration, microbial biomass carbon, metabolic quotient, microbial quotient, and enzymes (urease and acid phosphatase) were greatest in T13 (absolute control + AM + Azospirillum) followed by T14 (50% RDF + AM + Azospirillum)]. The values of all these parameters declined drastically with the increasing percentages of RDF. Coinoculated plots built up greater soil fertility and SOC.

Dry Matter, Nitrogen, Phosphorous, and Potassium Partitioning, Accumulation, and Use Efficiency in Transgenic Cotton-Based Cropping Systems

A better understanding of the fate of nutrients in transgenic cotton (Gossypium hirsutum L.) fields will improve nutrient efficiencies, will optimize crop growth and development, and may help to enhance soil quality. A study was made to evaluate and quantify the effect of cropping system [sole cotton and groundnut (Arachis hypogaea) intercropping with transgenic cotton] and nitrogen (N) management [control (0N), 100% recommended dose of nitrogen (RDN) through urea, substitution of 25% RDN through farmyard manure (FYM), and substitution of 50% RDN through FYM] on dry matter (DM) and nutrient partitioning and accumulation by transgenic cotton and groundnut at New Delhi during 2006–2007. Soil and plant samples were collected and analyzed at 60, 90, and 120 days after sowing and at harvest. Results revealed that intercropping of groundnut with cotton did not significantly affect DM and nutrient partitioning in cotton, but residual soil fertility in terms of potassium permanganate (KMnO4) N showed an improvement in contrast to Olsen's P and ammonium acetate (NH4OAc)–exchangeable K over sole cotton. At harvest, of total DM assimilated, leaves constituted 10–20%, stem 50%, and reproductive parts of cotton accounted for the rest. For each kilogram of seed cotton produced, the crop assimilated 61 g of N, of which 23 g was partitioned to harvested seed cotton. Substitution of 25% RDN through FYM, being on par with 100% RDN through urea, recorded greater DM, nutrient uptake in different parts of cotton, agronomic N-use efficiency (9.5 kg seed cotton kg N−1), and apparent N recovery (83.3%) over 50% RDN substitution through FYM and control. The control, being on par with 50% RDN substitution through FYM, recorded significantly greater DM and nutrient uptake by intercropped groundnut over other treatments. Apparent N and potassium (K) balance at the end of study was negative in all treatments; however, the actual change in KMnO4 N was positive in all the treatments except control. Our study suggests that intercropping of groundnut with transgenic cotton and substitution of 25% dose of N through FYM is sustainable in tropical countries.

Short-term crop and soil response to C-friendly strategies in two contrasting environments

In southern Europe (Italy), a two-site field experiment with contrasting soil conditions (high clay—SOC-protecting soil near Napoli versus low clay—non-SOC-protecting soil near Torino) was conducted to evaluate the short-term potential of a carbon (C) friendly management to sustain and possibly increase both crop yields and soil organic C (SOC). Compost distribution (COM1, COM2) and minimum tillage (MT) were compared to conventional management (CONV) in a maize-based cropping system. COM1, MT, and CONV each received 130kgNha−1 in compost or urea form. A double dose was applied to COM2 while the plowed control plots (0N) were not fertilized. Fertilizers were applied for three years (from 2006 to 2008); residual soil fertility was assessed during the fourth year (2009).Results suggested that only the SOC protection strategy via MT could be agronomically sustainable in the high clay content soil near Napoli. There, a short-term SOC increase was recorded with either compost or MT application. In fact, in the same soil, compost use depressed both yield and N availability for maize, which we attribute to the reduction of SOM mineralization due to hydrophobic protection by added humified organic matter coupled with soil physical protection. Compost addition increased SOC (55.1% of added C) in the soil near Torino, where high native N availability buffered its low mineralization and allowed high yields. Alternatively, MT showed no effect on short-term C dynamics, probably because the low organic matter protection favored oxidation and mineralization of root-derived C.

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).

Enhancement of late successional plants on ex-arable land by soil inoculations.

Restoration of species-rich grasslands on ex-arable land can help the conservation of biodiversity but faces three big challenges: absence of target plant propagules, high residual soil fertility and restoration of soil communities. Seed additions and top soil removal can solve some of these constraints, but restoring beneficial biotic soil conditions remains a challenge. Here we test the hypotheses that inoculation of soil from late secondary succession grasslands in arable receptor soil enhances performance of late successional plants, especially after top soil removal but pending on the added dose. To test this we grew mixtures of late successional plants in arable top (organic) soil or in underlying mineral soil mixed with donor soil in small or large proportions. Donor soils were collected from different grasslands that had been under restoration for 5 to 41 years, or from semi-natural grassland that has not been used intensively. Donor soil addition, especially when collected from older restoration sites, increased plant community biomass without altering its evenness. In contrast, addition of soil from semi-natural grassland promoted plant community evenness, and hence its diversity, but reduced community biomass. Effects of donor soil additions were stronger in mineral than in organic soil and larger with bigger proportions added. The variation in plant community composition was explained best by the abundances of nematodes, ergosterol concentration and soil pH. We show that in controlled conditions inoculation of soil from secondary succession grassland into ex-arable land can strongly promote target plant species, and that the role of soil biota in promoting target plant species is greatest when added after top soil removal. Together our results point out that transplantation of later secondary succession soil can promote grassland restoration on ex-arable land.

Sustainability of maize-based cropping systems in rural areas of Zimbabwe: an assessment of the residual soil fertility effects of grain legumes on maize (<I>Zea mays</I> [L.]) under field conditions

The residual soil fertility benefits of the preceding legumes to the following maize crop were demonstrated in the study. Incorporating stover of Bambara nut, cowpea, groundnut dry bean and soyabean gave higher maize yields compared to plots where the stover was removed. Total maize dry matter yield increases of 1.30 tha-¹ to 5.19 ha-¹ were recordedfollowing legume stover incorporation compared to stover removal. Even removal of stover of these same legumes gave significant maize yield increases compared to those from the maize after maize or after fallow plots. The total maize dry matter yield was greater after legumes with stover removed (ranging from 4.41 to 9.91 tha-¹) than after maize (2.16 to 2.26 tha-¹) or one season fallow (1.57 to 1.84 tha-¹). So farmers who keep livestock can still remove legume residues as fodder to supplement grazing in the dry winter period and still benefit from improved maize yields. International Journal of Engineering, Science and Technology, Vol. 2, No. 7, 2010, pp. 141-148

Effect of Nutrient Management and Planting Geometry on Productivity of Hybrid Rice (<i>Oryza sativa</i> L.) Cultivars

Field experiments were conducted during the wet seasons of 2006 and 2007 at the Agricultural Experimental Farm of the Indian Statistical Institute, Giridih, a part of eastern plateau region of India. The study was designed to investigate the effect of planting geometry and nutrient management practices on productivity of two hybrid rice cultivars. Split-plot design with three replications was adopted to carry out the experiment by allocating combinations of treatments of planting geometry and rice cultivar in main-plots and nutrient management treatments in sub-plots. “CNRH-3” rice proved its efficiency in terms of grain yield that was also reflected in yield attributing characters such as number of productive tillers, number of grains per panicle, length of panicle, panicle weight, test weight and harvest index. Higher rice grain yield was registered when the cultivars grown in 20 cm × 20 cm planting geometry. Rice cultivars grown with the application of inorganic fertilizers alone produced maximum grain yield and also recorded higher values of ancillary characters. The maximum amount of N, P and K was taken up by the “CNRH-3” rice, whereas maximum residual soil fertility was recorded in “Pro Agro 6201” rice. Maximum N, P and K uptake values were recorded in 20 cm × 20 cm crop geometry and inorganic fertilizers treatment.

Effect of organic and inorganic sources of nutrients on the winter crops-rice cropping system in sub-humid tropics of India

A field experiment was conducted during 2005–2006 and 2006–2007 on a winter crops-rice (Oryza sativa L.) cropping system at the Agricultural Experimental Farm of the Indian Statistical Institute, Giridih, Jharkhand, to evaluate nutrient management packages on yield and soil fertility status. Eight nutrient management practices were evaluated on three cropping sequences: linseed-rice, niger-rice and barley-rice. Significantly, a higher seed yield of winter crops was recorded where 100% nutrient through inorganic fertilizers was applied. Total biomass yield, barley equivalent yield, nitrogen and potassium uptake were also highest in this treatment. Maximum grain yield and harvest index of rice grown after the harvest of winter crops on residual soil fertility was registered where 100% nutrient was applied through organic manure to the previous winter crops. Lentil-rice grown on 25% N nutrient supplied through VC and 75% through inorganic fertilizers recorded the highest rice equivalent yield. The maximum economic return value was registered under the barley-rice sequence. Among the different sequences lentil-rice recorded maximum nutrients uptake values. Linseed-rice sequence built up the residual soil nitrogen maximum and barley-rice sequence increased the residual soil phosphorus content.

Nitrogen contribution through Sesbania green manure and dual-purpose legumes in maize–wheat cropping system: agronomic and economic considerations

Green manuring with Sesbania aculeata is a widely investigated practice in cereal-based cropping systems but adoption of this technology is low on farmers’ fields because of some practical and economic considerations. Dual-purpose legumes such as cowpea (Vigna unguiculata) and greengram (Vigna radiata) providing economic produce as well as stover for incorporation are a viable alternative for effecting N economy and enhancing crop productivity. Direct and residual effects of different legumes along with varying rates of N fertilizer were evaluated on productivity, profitability, N-use efficiency and residual soil fertility in maize–wheat cropping system at New Delhi during 2003–2005. The legumes, viz. cowpea, greengram and Sesbania were grown during summer (April/May to June), followed by maize in rainy season (July to October) at varying rates of N fertilizer, viz. 0, 40, 80 and 120 kg ha−1; and wheat in winter season (November to April) at 0, 60 and 120 kg Nha−1. Cowpea and greengram produced equal amount of economic produce (1.22–1.27 t ha−1 seed yield equivalent), which added 3.26 t and 2.79 t ha−1 of stover, and 49 kg N and 47 kg N ha−1 respectively into the soil. However, Sesbania accumulated maximum amount of biomass (4.75 t ha−1 dry weight) and N (131 kg N ha−1). Growth and yield of maize following summer legumes improved compared with that after fallow, and was maximum after Sesbania, followed by greengram and cowpea. Response of maize to N fertilizer rates was quadratic and there was saving of N to the extent of 57–67 kg ha−1 with Sesbania, and 37–49 kg ha−1 with cowpea and greengram. Wheat also performed better under the residual effect of summer legumes, and showed N economy of 18–23 kg ha−1 after cowpea and greengram, and 27 kg ha−1 after Sesbania. Nitrogen fertilizer applied to maize had only a marginal residual effect and direct N application was necessary to achieve the potential yield of wheat. Apparent recovery of N showed a decreasing trend with summer legumes and increasing rates of N fertilizer. There was significant improvement in soil organic C and KMnO4 oxidizable N after two cropping cycles with summer legumes. Despite higher yields and large N savings, Sesbania green manuring resulted in lower net returns on par with fallow, while greengram or cowpea followed by maize and wheat were found to be the most profitable cropping systems. It was recommended that cultivation of dual-purpose legumes during summer was a better option than Sesbania green manuring or fallow for improving productivity, profitability, N economy and soil fertility, leading to sustainability of maize–wheat cropping system.

Green leaf manuring with prunings of Leucaena leucocephala for nitrogen economy and improved productivity of maize (Zea mays)–wheat (Triticum aestivum) cropping system

Green leaf manuring with prunings of Leucaena leucocephala is regarded as a useful source of N to plants but the actual substitution of N fertilizer, release and recovery of N as well as effects on soil fertility are not adequately studied. The present studies investigated the effect of sole and combined use of Leucaena prunings and urea N fertilizer in different proportions on productivity, profitability, N uptake and balance in maize (Zea mays)–wheat (Triticum aestivum) cropping system at New Delhi during 2002–2003 and 2003–2004. Varying quantities of Leucaena green leaf biomass containing 3.83–4.25% N (18.2–20.5 C:N ratio) were applied to provide 0, 25, 50, 75 and 100% of recommended N (120 kg ha−1) to both maize and wheat before sowing. In general, direct application of urea N increased the productivity of both crops more than Leucaena green leaf manure, but the reverse was true for the residual effect of these sources. The productivity of maize increased progressively with increasing proportions of N through urea fertilizer and was 2.41–2.52 t ha−1 with 60 kg N ha−1 each applied through Leucaena and urea, which was at par with that obtained with 120 kg N ha−1 through urea alone (2.56–2.74 t ha−1). Similarly, wheat yield was also near maximum (4.46–5.11 t ha−1) when equal amounts of N were substituted through Leucaena and urea. Residual effects were obtained on the following crops and were significant when greater quantity of N (>50%) was substituted through Leucaena. Nitrogen uptake and recovery were also maximum with urea N alone, and N recovery was higher in maize (33.4–42.1%) than in wheat (27.3–29.8%). However, recovery of residual N in the following crop was more from Leucaena N alone (8.5–10.3%) than from urea fertilizer (1.7–3.8%). Residual soil fertility in terms of organic C and KMnO4 oxidizable N showed improvement with addition of Leucaena prunings, which led to a positive N balance at the end of second cropping cycle. Net returns were considerably higher with wheat than with maize, and were comparatively lower with greater proportion of Leucaena because of its higher cost. Nonetheless, it was beneficial to apply Leucaena and urea on equal N basis for higher productivity and sustainability of this cereal-based cropping system.

Recycling of legume residues for nitrogen economy and higher productivity in maize (Zea mays)–wheat (Triticum aestivum) cropping system

Contribution of legumes towards N economy in cereal-based cropping systems is well-known but there has been a gradual decline in the cultivation of grain legumes, threatening sustainability of maize (Zea mays)–wheat (Triticum aestivum) cropping system in north-western India. A study was made to evaluate and quantify the effect of different grain legumes on productivity, profitability, N economy and soil fertility in maize–wheat cropping system at New Delhi during 2002–2004. Five legumes, viz. blackgram (Vigna mungo), greengram (Vigna radiata), cowpea (Vigna unguiculata), groundnut (Arachis hypogaea) and soybean (Glycine max) were either intercropped with maize or grown in sole cropping, and their residues were incorporated before the following crop of wheat, which was grown with varying rates of N, viz. 0, 40, 80 and 120 kg N ha−1. Maize-equivalent productivity was significantly more with intercropped greengram (16.1–29.9%), cowpea (24.8%) and groundnut (11.1–16.6%) than in sole maize. Land equivalent ratio and other competitive functions were favourably influenced with intercropped maize + greengram and maize + cowpea. Addition of N through legume residues varied from 11.5–38.5 kg ha−1 in intercropped system and 17.5–83.5 kg ha−1 in sole cropping, which improved productivity of following wheat to a variable extent. Nitrogen economy in wheat was 21 kg ha−1 due to residue incorporation of intercropped greengram, cowpea and groundnut; and 49–56 kg N ha−1 of sole cropped greengram and groundnut. Residual soil fertility in terms of organic C and KMnO4-N showed an improvement under maize-based intercropping systems followed by wheat, and the beneficial effect was more pronounced with sole cropping of legumes due to greater addition of residues. Apparent N balance as well as actual change in KMnO4-N at the end of study was positive in most intercropped legumes as well as sole cropping systems, with greater improvement noticed under groundnut, soybean and greengram. Net returns were marginal with maize-based intercropping or sole cropping of legumes, but improved considerably with wheat, particularly when greengram, cowpea and groundnut were grown in the previous season. The studies suggested that inclusion of grain legumes, particularly greengram, cowpea and groundnut was beneficial for improving productivity, profitability, N economy and soil fertility in maize–wheat cropping system.

Integrated Nutrient Management for Production, Economics, and Soil Improvement in Winter Vegetables

ABSTRACT There is concern that use of inorganic fertilizers alone cannot sustain high levels of productivity and cause deterioration of the soil and environment. The use of vermicompost (VC) and microbial inoculants (Azotobactor® and phosphorus-solubilizing bacteria) to improve plant nutrition may address these issues. Effects of VC and microbial inoculants in combination with inorganic fertilizers on growth and yield of crops and soil health need to be better understood. The eastern Ghats region of Orissa, India, has a favorable climate for year-round cultivation of vegetables. An on-farm experiment with seven treatments including chemical fertilizers, VC, cow manure (CM), and microbial inoculants was carried out for 3 consecutive years during winters of 2001 to 2003, at Koraput, India, on a red soil to determine the most effective integrated nutrient management option for enhancing productivity of cabbage (Brassica oleracea L. Capitata group) and bell pepper (Capsicum annuum L.). Vermicompost appeared to be the best soil additive in both crops in terms of yield, net economic return, and water use efficiency (WUE). In bell pepper, use of VC+50% recommended rate of synthetic fertilizers (RRF) produced significantly higher yield over 100% RRF, with a net return increase of 29.8%. There was a similar effect for yield of cabbage. In the 50% RRF+VC treatment, WUE was 32.6% higher in bell pepper and 6.2% higher in cabbage over treatment with 100% RRF. Bulk density of the surface soil after 3 years was reduced; its organic carbon and available N and P status improved due to treatment with CM and VC. The data indicate that 5 Mt·ha−1 of VC can meet 50% of the fertilizer requirement of bell pepper and cabbage while providing higher productivity, income, and residual soil fertility.

Nitrogen and sulphur fertilizer management for growing canola on sulphur sufficient soils

Canola is a crop that demands high nitrogen (N) and sulphur (S) inputs to achieve maximum seed yield. The practice of balancing these two nutrients by applying them in a fixed ratio has shown yield benefits on soils deficient in both these nutrients. A 9 site-year study was conducted between 2002 and 2004 to determine whether this practice is necessary for soils containing sufficient S levels. The practice was tested for both hybrid (HC) and open pollinated (OPC) canola cultivars by applying six rates of N (0, 40, 80, 120, 160 and 200 kg N ha-1) and supplementing N rates with S, so that three N:S ratios (1.5, 6 and 12 to 1) were achieved. Seed yield, protein and oil content responses of both HC and OPC cultivars were obtained primarily with N, with no evidence for a need of balancing this nutrient with S additions to achieve a ratio within those applied at this study. Hybrid canola cultivars overall yielded 23.7% more than OPC cultivars when they received the N application rate at which maximum yield of the OPC cultivars was obtained (120 kg N ha-1). Application of an additional 30 kg ha-1 to obtain maximum HC seed yield only resulted in an additional 1.5% yield advantage for the OPC. As N application rate was increased, small increases in seed protein levels (≈2.5%) were accompanied by a small reduction (≈2%) in seed oil content. Increased yield by HC compared with OPC canola reduces N residual fertility, hence, assessment of soil fertility status by soil testing after growing HC canola is a highly beneficial management practice. Our results indicate that the practice of balancing N and S to a fixed ratio is unnecessary and wasteful on canola grown on soils containing sufficient S. Key words: Hybrid canola, N:S ratio, open pollinated, residual soil fertility

Rhinanthus: a tool for restoring diverse grassland?

The restoration of species-rich grasslands is often hindered by high residual soil fertility as a result of, e.g., intensive farming. The establishment of a diverse range of target species on such sites requires the reduction of soil fertility or of the vigour of competitive plants. Current methods to achieve these aims are often unsuccessful or complicated and expensive. It has been suggested thatRhinanthus species could be used to decrease the growth of competitive plants and enhance species diversity. We review evidence for this potential and suggest five key attributes that makeRhinanthus species a practical restoration tool.Rhinanthus species are natural components of species-rich grasslands (attribute 1), and seed of some species is relatively low cost and easily obtainable (2). Recent work has shown that certainRhinanthus species reduce the vigour of competitive species, especially agricultural grasses, and allow establishment and persistence of target species (3). We analyze demographic data and show that certainRhinanthus species have the ability for rapid population growth and spread, even in fertile grasslands (4). We also show that it is relatively easy for land managers to limit the population size ofRhinanthus species and prevent damage (e.g. excessive loss in production or invasion by weeds) to grasslands by excessive densities (5). We give suggestions for further research, including: the range of species-poor grasslands into whichRhinanthus can be introduced successfully and whichRhinanthus species should be used; the mechanisms by whichRhinanthus enhances diversity in restored grasslands; whether the ecotype or subspecies ofRhinanthus used affects restoration success; how management methods affect population growth and spread ofRhinanthus; and whether other parasitic plants could be used in habitat restoration.

Fallow management for soil fertility recovery in tropical Andean agroecosystems in Colombia

Andean hillsides dominate the landscape of a considerable proportion of Cauca Department in Colombia. The typical cropping cycle in the region includes monocrops or intercrops of maize (Zea mays L.), beans (Phaseolus vulgaris L.) and/or cassava (Manihot esculenta Crantz). Cassava is usually the last crop before local farmers leave plots to natural fallow until soil fertility is recovered and a new cropping phase can be initiated. Previous studies on land use in the Río Cabuyal watershed (6500 ha) show that a considerable proportion of land (about 25–30%) remains under natural fallow every year. The focus of our studies is on systems of accelerated regeneration of soil fertility, or improved fallow systems, as an alternative to the natural regeneration by the native flora. Fallow improvement studies were conducted on plots following cassava cultivation. The potential for soil fertility recovery after 12 and 28 months was evaluated with two fast growing trees, Calliandra calothyrsus Meissn (CAL) and Indigofera constricta L.(IND), and one shrub, Tithonia diversifolia (Hemsl.) Gray (TTH), as slash/mulch fallow systems compared to the natural fallow (NAT). All planted slash/mulch fallow systems produced greater biomass than the natural fallow. Greatest dry biomass (16.4 Mg ha−1 year−1) was produced by TTH. Other planted fallows (CAL and IND) produced about 40% less biomass than TTH and the control (NAT) about 75% less. Nutrient levels in the biomass were especially high for TTH, followed by IND, CAL, and NAT. The impact of fallow management on soil chemical, physical and biological parameters related to residual soil fertility during the cropping phase was evaluated. Soil parameters most affected by slash/mulch fallow systems included soil total N, available N (ammonium and nitrate), exchangeable cations (K, Ca, Mg and Al), amount of P in light fraction, soil bulk density and air permeability, and soil macrofauna diversity. Results from field studies suggest that the Tithonia slash/mulch fallow system could be the best option to regenerate soil fertility of degraded volcanic-ash soils of the Andean hillsides.

Comparative effectiveness of different levels of poultry manure with NPK fertilizer on residual soil fertility, nutrient uptake and yield of maize

The comparative effectiveness of residual effects of 300 kg/ha NPK 15-15-15 fertilizer, 7t/ha poultry manure (Pm), five combinations of reduced levels of NPK 15-15-15 fertilizer and poultry manure, and control (no fertilizer) on soil and plant nutrient uptake and maize yield were investigated in a field trial during the 1996 and 1997 second cropping seasons at the Teaching and Research Farm of the Federal University of Technology, Akure (7o 16” N, 5 o 12”E), Nigeria. The soil type of the trial site was lowly fertile loamy sand. Application of poultry manure, and combinations of poultry manure with NPK fertilizer gave high residual effects on soil chemical composition and increased plant height, leaf area, dry matter yield, plant nutrient uptake and grain yield of maize significantly. Residual effects of poultry manure, and combined application of reduced quantities of poultry manure and NPK fertilizer gave higher soil organic matter, N, P, K, Ca, Mg and micro-elements contents compared to application of 300 kg/ha NPK 15-15-15 fertilizer and control. The residual effects of 3t/ha poultry manure plus 200kg/ha NPK fertilizer and 7t/ha poultry manure produced non-significantly different values. However, the 7t/ha poultry manure had the best residual effects on maize yield and soil fertility. The 3t/ha poultry manure plus 200kg/ha NPK fertilizer is recommended as substitute for 7t/ha poultry manure or 300kg/ha NPK fertilizer. Key words:Poultry manure; NPK fertilizer; residual soil fertility; nutrient uptake; maize yield Moor Journal of Agricultural Research Vol.4(2) 2003: 191-197

Relative importance of burning, mowing and species translocation in the restoration of a former boreal hayfield: responses of plant diversity and the microbial community

Summary The extensive loss of species‐rich grasslands in Europe as a result of agricultural intensification has triggered a desire to recreate more diverse and natural grassland systems in set‐aside fields. Appropriate management and species introductions are necessary to overcome residual soil fertility, lack of suitable plant propagules and dominance of undesirable invasive species. A field experiment was performed in a boreal former hayfield to test the effect of turf inoculation, mowing (twice annually) and spring burning. We surveyed changes in plant diversity, composition and productivity over a 3‐year period. Signature fatty acids and soil respiration measurements were employed to survey changes in the soil community. Few changes in the vegetation and soil communities could be related to inoculation of turf monoliths. Most of the measured variables in mown plots differed from the set‐aside (control) plots, while burned plots displayed mainly similar responses. Mowing increased plant species richness and diversity, mainly by enhancing the number and frequency of forb species. Small‐statured forb species were promoted by mowing, whereas tall leafy grasses declined. Effects of mowing on soil communities comprised an increased soil respiration and stimulation of arbuscular mycorrhizal fungi. Synthesis and applications. The results demonstrate the importance of reducing sward height in order to promote plant species coexistence in former boreal hayfields. In such systems, eliminating accumulated litter by spring burning has little influence on species composition when the sward is allowed to grow tall. Mowing is therefore the most efficient way of enhancing biodiversity. The results also show that mowing‐mediated changes in above‐ground plant communities may stimulate below‐ground symbiotic micro‐organisms, potentially resulting in a positive feedback on ecosystem development.

Productivity, profitability and quality of soybean (Glycine max) and residual soil fertility as influenced by integrated nutrient management

A field experiment was conducted at Pantnagar to assess the effect of various fertilizer and manurial treat- ments on soybean [ Glycine max (L.) Merrill] productivity, quality and residual soil fertility during kharif seasons of 2003 and 2004. Fourteen treatments that include use of FYM, B and Fe over 50 and 100% recommended dose of fertilizers (RDF) viz., 20.0-26.4-33.3 kg N-P-K/ha. Integrated use of RDF with FYM or soil application of Fe/B being at par increased the seed yield of soybean significantly over RDF alone (3.13 tonne/ha). Highest net re- turns were recorded with the application of RDF + 10 tonne FYM/ha. Application of FYM/Fe/B with both 50% RDF and RDF markedly improved the unsaturated fatty acids content (linolenic, linoleic and oleic) and reduced satu- rated fatty acids (palmatic and stearic) content. Use of FYM and micronutrients helped in maintaining soil fertility and rhizospheric microbial population.

Influence of non-monetary inputs on growth and yield of rice (Oryza sativa) under system of rice intensification (SRI)

Field experiments were carried out from 2003 to 2005 at Agricultural College and Research Institute, Killikulam, Tamil Nadu to optimize the establishment techniques of System of Rice Intensification (SRI). The treat- ments consisted of types of nursery and age of seedling in main plot, three different plant geometry in sub-plot and two number of seedlings/ hill in sub sub-plot and replicated thrice. SRI and conventional nursery with 14- days-old seedlings had registered statistically similar yields as that of conventional nursery with 21 days old seedlings. However, conventional nursery recorded higher nutrient uptake leading to more depletion of soil fertil- ity. Closer spacing (20 cm x 20 cm) had higher number of productive tillers/m2 (491) but number of filled grains/ panicle (116.7) are lower resulting in significantly higher grain (8.0 t/ha) and straw yield (9.1t/ha). Number of seedlings/hill failed to exert any significant influence on either yield, nutrient uptake or residual soil fertility.

Effect of integrated nutrient management on productivity and residual soil fertility status under different rice (Oryza sativa) pulse cropping systems in rainfed lateritic belt of West Bengal r S. BANDYOPADHYAY , A.M. P JSTE

A fleld trial was conducted on red and laterite soil of Sekhampur, West Bengal, during June 1996 April 1998, to evaluate the prospect of growing rice (Oryza sativa L.) pulse sequence under rainfed condition and study the effect of cesidual soil fertility status on pulses inoculated with or without Rhizobium sp. Higher yield and yield attributes of rainy season rice, lentil (Lens culinaris Medikus), gram (Cicer arietinum L.) and grass pea (Lathyrus sativus L.) crops were achieved where 25% of chemical fertilizer in rainy season rice was replaced either by FYM or rice straw 3.0 or 3.65 tonneslha. Addition of FYM or decomposed straw of rice improved the N, P, K status of the soil. Seed Inoculation of pulses with Rhizobium sp. also played a positive role towards the total crop productivity and residual soil fertility status.