Auswirkungen eines 10-jährigen Miscanthusanbaus auf ausgewählte Eigenschaften eines Mineralbodens in Nordostdeutschland

Effects of 10 years of Miscanthus cultivation on different properties of mineral soil in North-east Germany
The effects of 4–10 years of Miscanthus cultivation on different soil properties was investigated at Klein Markow (Mecklenburg-Pommerania, Germany) in variants with and without Miscanthus between 1994 and 2000. Soil containing Miscanthus showed higher concentrations of organic carbon (C_org) (+0,29 %) and total nitrogen (N_t) (+0,03 %) and consequently an increased storage of soil organic matter (SOM) (+15,5 t ha^–1) as a result of high amounts of leaves, roots and rhizomes. With regard to concentrations of C_org, cation exchange capacity, porosity and water retention significantly increased, while the wet and bulk density decreased in Miscanthus variants. The concentration of C_org and storage of SOM were increased significantly during the experimental period of Miscanthus treatments. The mineralization of the organic soil compounds which developed was comparable with those of the SOM. The reintegration of the Miscanthus area into a crop rotation system was possible only after the last harvest in February and seed of winter rape in August of the same year. The application of Glyphosat and the later shading by rape stands led to failure of the Miscanthus cultivations.     

Effects of Irrigation at Different Growth Stages and Source-Sink Manipulations on Yield and Yield Components of Mung Bean, Vigna radiata (L.) Wilczek, in Dry and Intermediate Zones of Sri Lanka

Irrigation is a management option available to farmers in the subhumid zones of Sri Lanka to increase mung bean yields during the dry Yala season. The objective of this study was to quantify the yield gain in response to irrigation at different stages of the crop and thereby determine the most suitable stage/s of irrigation. Four field experiments were conducted during Yala in 1995 and 1996 at two sites, Maha-Illuppallama (MI) and Kundasale (KS). Eight irrigation regimes consisting of all possible combinations of irrigation at three growth stages of the crop were defined. The respective growth stages were vegetative (from germination to appearance of first flower), flowering (from appearance of first flower to 75 % pod initiation) and pod-filling (from 75 % pod initiation to maturity). The treatments which received irrigation during two or more stages had significantly higher yields (793–1396 kg ha⁻¹) than those which received irrigation during only one stage (401–756 kg ha⁻¹) with the lowest yield being shown by the rain-fed treatment (227–396 kg ha⁻¹). When at least two stages can be irrigated, irrigation during the flowering and pod-filling stages was most effective. Irrigation during flowering produced the highest yield gain when only one stage could be irrigated. Seed yield showed a strong positive correlation with number of pods m^−2. Fifity per cent de-podding caused yield reductions at both sites, indicating sink limitation. In contrast, 50 % defoliation reduced the yields only at MI where the number of pods m⁻² was greater than at KS. Hence, source limitation was present only when the number of pods was higher.     

Maximizing Sugarcane Yield by Increasing Plant Population Density, Minimizing NO3-N Leaching and Improving Soil Organic Matter in Different Crop Rotations

In a field experiment conducted during 1992–95 at Lucknow, India, sugarcane was planted in rows 60 and 90 cm apart in three crop rotations (rice-sugarcane-ratoon, Sesbania aculeata for green manure-sugarcane-ratoon, and cowpea-sugarcane-ratoon) with 0, 150 and 300 kg N ha⁻¹ as urea either with or without farmyard manure (FYM) at 10 t ha⁻¹. Sugarcane yields were significantly greater in the Sesbania rotation than in the other because of a larger N uptake. N uptake of the crop was significantly affected by soil organic carbon, and available N and K contents. Ratoon yields, however, were largest in the cowpea sequence followed by the rice rotation, probably due to a prolonged residual effect of cowpea and rice root residues. The residual effect of a Sesbania green manure was negligible as demonstrated by the low NO₃-N content of the soil profile after sugarcane harvest compared to the other two crop sequences. The total cane productivity (main sugarcane plus ratoon) was greater (156 t ha⁻¹) in the cowpea rotation than the Sesbania (152 t ha⁻¹) and rice (140 t ha⁻¹) rotations.     

Effect of Integrated Use of Farmyard Manure and Sulphur in a Soybean and Wheat Cropping System on Nodulation, Dry Matter Production and Chlorophyll Content of Soybean on Swell-Shrink Soils in Central India

In a 3-year experiment on a Typic Haplustert low in soil test sulphur (S), the response to applied farmyard manure (FYM) and S was studied in terms of the nodule production, nodule dry weight, chlorophyll content, dry matter production and seed yield of soybean. FYM was applied to soybean at four levels (0–16 t ha⁻¹). S as gypsum was also applied at four levels (0–60 kg ha⁻¹) to both soybean and wheat every year. Both total and active nodule production, nodule dry weight, dry matter production and seed yield of soybean were increased significantly by the application of both FYM and S. However, the proportion of total nodules to active nodules fell sharply for applications higher than 8 t FYM and 40 kg S ha⁻¹.     

Nitrogen Nutrition of Potato Cultivars Differing in Maturity

In potato, dry matter (DM) production and partitioning between plant organs and N accumulation are affected by N application; however, since cultivars differ in these processes, N fertilization must be adjusted to each cultivar. This paper studies the response of potato cultivars differing in maturity to N fertilization in the south-east of the Buenos Aires Province (37°45'S, 58°18'W) in two growing seasons. Treatments combined four N doses (0–180 kg ha⁻¹) and four cultivars: Jaerla (early), Spunta (mid-early), Mailén INTA (medium late) and Huinkul MAG (late). DM and N content were measured in leaves, stems and tubers throughout the growing season and intercepted photosynthetically active radiation was regularly assessed. There was an increase in tuber yield up to intermediate N doses (60 kg ha⁻¹ in 1990 and 120 kg ha⁻¹ in 1991). Tuber yield was similar for Spunta and Huinkul MAG. There was no interaction between cultivar and N fertilization for tuber dry matter yield. DM partitioning to leaves and tubers during the growing season differed among cultivars, but N availability affected partitioning similarly for all cultivars. Jaerla had a high and Huinkul MAG had a low radiation use efficiency between plant emergence and the beginning of tuber formation. Jaerla, Spunta and Mailén INTA reached maximum N content in foliage at ≈60 days after emergence and Huinkul MAG 20 days later. Total N content at maturity varied between 120 and 250 kg ha⁻¹ and was affected by cultivar and N dose. The results will help to improve N fertilization recommendations and management practices as related to each cultivar under the environmental conditions of this region.     

Organic Recycling for Soil Quality Conservation in a Sub-tropical Plateau Region

The long-term effect of organic recycling on some aspects of quality in a lowland rice soil of an Indian plateau region was studied. The experiment was set up at the agricultural experimental farm of the Indian Statistical Institute, Giridih, Bihar, India. Two rice cultivars, and treatments with four organic supplements (cowdung manure, Leuceana leaves, decomposed farm residue and Sesbania ), chemical fertilizers (urea, superphosphate and muriate of potash) and no input were arranged in a factorial randomized block design. Organic supplements improved soil quality parameters such as water holding capacity, total organic C, microbial biomass C, urease and acid phosphatase activities of soils in comparison to chemical fertilizers and no input. Among the organic supplements, cowdung manure gave significantly higher organic C (1.39%), microbial biomass C (276.46 μg g⁻¹ dry soil), urease activity (32.79 and 21.22 μg urea hydrolized g⁻¹ dry soil h⁻¹ at 37 °C by the buffer and non-buffer method, respectively) and acid phosphatase activity (1.99 μmol p-nitrophenol released g⁻¹ dry soil h⁻¹ at 37 °C) than the others. The conversion of organic C into biomass C (2.46%) was highest in Leuceana -treated soil.     

Analysis of Growth and Productivity of Indian Mustard (Brassica juncea) in Relation to FYM, Nitrogen and Source of Fertilizer

A field experiment was conducted during the winter seasons of 1992–93 and 1993–94 at Anand to study the effect of FYM, nitrogen and source of fertilizer on growth and yield of mustard [ Brassica juncea (L.) Czernj & Cosson]. The results showed significant variation in leaf area index (LAI), crop growth rate (CGR), dry matter production and seed yield. The direct effect of farmyard manure (FYM) was conspicuous in improving the growth of mustard. FYM application at 10 tonnes ha⁻¹ significantly increased the LAI, CGR and dry matter accumulation per plant at almost all the stages during first year study (1992–93) and in pooled analysis. Similarly, nitrogen application registered maximum LAI, CGR at 75 kg level and RGR and NAR at 50 kg level at almost all the during both years. Sulphur carrying source (Ammonium sulphate plus single super phosphate) increased all stages growth characters. Maximum dry matter accumulation per plant and seed yield were recorded with highest levels of FYM (20 tonnes ha⁻¹), N (75 kg ha⁻¹) and source having S. Seed yield was strongly associated with LAI and dry matter accumulation per plant at all the stages.     

Response of Mustard (Brassica juncea L.) to Applied Nitrogen with or without Ethrel Spray under Non-irrigated Conditions

Field studies were conducted during the winter seasons of 1995–96 and 1996–97 at the Agricultural Farm of Aligarh Muslim University, Aligarh, India on mustard ( Brassica juncea L. Czern & Coss., var. Alankar) under non-irrigated conditions, to evaluate the effect of foliar spray of 200 p.p.m. ethrel (2-chloroethyl phosphonic acid) at flowering growth stage along with basal 0, 40, 80 or 120 kg N ha⁻¹ on net photosynthetic rate (P_N), stomatal conductance (C_S), stomatal resistance (R_S), leaf K content, relative water content (RWC), leaf area index (LAI) and total dry matter (TDM) production monitored at 20 days after spray application, and plant N content, seed N content, nitrogen harvest index (NHI), nitrogen yield merit (NYM), pods plant⁻¹, 1000 seed weight, seed yield, biological yield, harvest index (HI), seed yield merit (SYM) and merit of genotype (MOG) at harvest. Results indicated that, at 0 or 40 kg N ha⁻¹, ethrel did not produce any significance effect, but at basal 80 kg N ha⁻¹, ethrel affected the parameters favourably with the exception of 1000 seed weight, HI, seed N and NHI. Ethrel-sprayed plants utilized N from the soil more effectively and showed increased NYM. Yield attributes, seed yield and merit of genotype (in terms of NYM and SYM) were also enhanced. Ethrel spray enhanced seed yield under water stress conditions mainly by increasing K uptake and retaining higher RWC, thereby decreasing R_S and increasing LAI, P_N and TDM production.     

Studies on Sowing Depth for Chickpea (Cicer arietinum L.), Faba Bean(Vicia faba L.) and Lentil (Lens culinaris Medik) in a Mediterranean-type Environment of South-western Australia

Pulses such as chickpea, faba bean and lentil have hypogeal emergence and their cotyledons remain where the seed is sown, while only the shoot emerges from the soil surface. The effect of three sowing depths (2.5, 5 and 10 cm) on the growth and yield of these pulses was studied at three locations across three seasons in the cropping regions of south-western Australia, with a Mediterranean-type environment. There was no effect of sowing depth on crop phenology, nodulation or dry matter production for any species. Mean seed yields across sites ranged from 810 to 2073 kg ha⁻¹ for chickpea, 817–3381 kg ha⁻¹ for faba bean, and 1173–2024 kg ha⁻¹ for lentil. In general, deep sowing did not reduce seed yields, and in some instances, seed yield was greater at the deeper sowings for chickpea and faba bean. We conclude that the optimum sowing depth for chickpea and faba bean is 5–8 cm, and for lentil 4–6 cm. Sowing at depth may also improve crop establishment where moisture from summer and autumn rainfall is stored in the subsoil below 5 cm, by reducing damage from herbicides applied immediately before or after sowing, and by improving the survival of Rhizobium inoculated on the seed due to more favourable soil conditions at depth.     

Effect of Plant Spacing and Nitrogen Levels on Growth, Herb and Oil Yields of Lemongrass (Cymbopogon flexuosus (Steud.) Wats. var. I cauvery)

A field experiment was conducted for 2 years during 1991–93 at the Central Institute of Medicinal and Aromatic plants, Bangalore, India to study the effect of plant spacings (60 × 60, 60 × 45, 60 × 30 and 45 × 45 cm) and nitrogen levels (0, 50, 100 and 150 kg N ha⁻¹ year⁻¹) on growth, herb and oil yield of lemongrass. A closer plant spacing of 45 × 45 cm resulted in higher herb and oil yields compared to wider spacing of 60 × 60 cm. Application of 150 kg N ha⁻¹ year⁻¹ resulted in higher herb and oil yields. Higher nitrogen applications also increased the plant height and number of tillers per clump. The oil content and quality-was not influenced by spacing and nitrogen levels.     

Re-Introduction of Quínoa into Arid Chile: Cultivation of Two Lowland Races under Extremely Low Irrigation

Annual rainfall in Chile at 30°S decreased from 170 to 70 mm in the last century, forcing a search for new low-rain adapted crops. Chenopodium quinoa Willd. was cultivated by pre-Hispanic cultures, but it disappeared in this region since the Spanish conquest. Two quínoa landraces (Don Javi and Palmilla) were re-introduced from lowlands of central Chile (34°S) evaluating seed saponin content and grain yields under low irrigation. Replicated assays were conducted in two sites with distinct microclimates after august (end of the rains in 2004 and 2005). Treatments included low (40–75 mm) and high (150–250 mm) irrigation and were distributed along the five cultivation months. Fertilization, with the humus of the worms, was carried out in the second season, as soils are poor in organic matter. Results showed significantly higher saponin content in the seeds of Don Javi landrace (1.2 %) with respect to Palmilla seeds (0.3 %). However, grain yields were not different between landraces under the same treatments. Yields were instead affected by microclimate, irrigation and fertilization. Although higher yields corresponded with higher irrigation, 2.6 tons ha⁻¹ was obtained under high irrigation, but surprisingly, also under low irrigation in the more humid site. Yields of 2006 harvesting season (ca. 7 tons ha⁻¹) were higher than that of the previous season (ca. 5.5 tons ha⁻¹), mainly because of the addition of organic matter. We suggest that re-introduction of Quinoa in arid Chile is feasible even under the prevailing conditions of low rainfall and deficient soils, but better yields will need some irrigation and addition of organic matter.     

Effects of Tillage and Cropping Systems on Soil Moisture Balance and Pearl Millet Yield

A 2-year study was conducted to determine the effects of tillage and cropping systems on soil moisture balance, growth and yield of pearl millet (Pennisetum glaucum (L.) R.Br.). Three tillage treatments, viz. minimum tillage (one harrowing), conventional tillage (two harrowing, cross) and deep tillage (ploughing followed by two har-rowings), and four cropping systems, viz. monoculture of pearl millet, pearl miliet-clusterbean (Cyamopsis tetra-gonoloba (L.) Taub.) rotation, monoculture of pearl millet with 5 t ha⁻¹ farm yard manure (FYM), and intercropping of pearl millet and clusterbean, were compared. Deep tillage improved the soil moisture storage, water use efficiency and grain yield of pearl millet while consumptive use of water was higher with minimum tillage. Total dry matter yield with deep tillage and conventional tillage was 23.2 and 10.2% higher than minimum tillage in the season 1, and the corresponding values for season 2 were 30.7 and 13.3%. The Pearl millct-clusterbean rotation and monoculture of pearl millet with the application of 5 t ha⁻¹ FYM gave 17.2 and 6.1% higher yield than monoculture of pearl millet, respectively. Maximum water use efficiency was observed in rotation followed by FYM application.     

Performance of Agricultural Systems under Contrasting Growing Season Conditions in South-western Quebec

Climate change will alter temperature and rainfall patterns over North American agricultural regions and there will be a need to adapt crop production systems to the altered conditions. A set of field experiments were conducted in south-western Quebec, Canada, with soybean ( Glycine max L.), corn ( Zea mays L.), sorghum ( Sorghum bicolor L.) × sudangrass ( Sorghum sudanense Piper) hybrid and switchgrass ( Panicum virgatum L.) under two tillage and three nitrogen fertility regimes, to study their performance in three successive growing seasons (2001–2003), two of them with unusually warm and dry conditions. The annual crops were established in two tillage systems: conventional and no-till (NT). All crops except soybean were fertilized with three levels of nitrogen: corn – 0, 90 and 180 kg N ha⁻¹, sorghum-sudangrass – 0, 75 and 150 kg N ha⁻¹, switchgrass – 0, 30 and 60 kg N ha⁻¹. The 2001 and 2002 seasons were hotter and drier than the 2003 season, which was the most favourable for crop growth. The capacity of the crops to yield in dry seasons was as follow: switchgrass > sorghum-sudangrass > corn > soybean. The corn and sorghum-sudangrass responses to nitrogen fertilizer were low in 2001 due to the combined effect of dry growing season and coarse soil texture. Soybean did not perform well under NT. Corn yielded better at the highest nitrogen fertilizer rate under NT when the early season was warmer than the normal. Our results show that switchgrass and sorghum-sudangrass could be an option in south-western Quebec if the frequency of hot and dry seasons increase in the future, because of climate change.     

Yield and Resource Use Optimization in Late Transplanted Mint (Mentha arvensis) under Subtropical Conditions

A field experiment was conducted during 1994 and 1995 at Lucknow (26.5°N, 80.5°E, 120 m above mean sea level) to optimize planting density and fertilizer-N application for high essential oil yield of late transplanted mint ( Mentha arvensis ). The treatments studied were 2.5, 2.0 and 1.66 × 10⁵ mint seedlings ha⁻¹ and 0, 80, 160 and 240 kg N ha⁻¹. Under 3 months delayed planting conditions using 2-month-old seedlings, the high planting density of 2.5 × 10⁵ plants ha⁻¹combined with 160 kg N ha⁻¹ gave significantly higher herb and essential oil yields compared with those of lower planting densities (2 and 1.66 × 10⁵ plants ha⁻¹) and all other rates of N application. It is demonstrated that a transplanted mini crop, yielding essential oil at a level of 164 kg ha⁻¹, is feasible after the harvest of rabi cereal, oil seed or legume crops in the north Indian plains.     

Effect of Nitrogen and Phosphorus Levels on Barley Cultivars Grown in Semi-arid Conditions

Most farmers in the rainfed parts of Jordan who use fertilizers use less than optimum rates of N and P because of the uncertainties associated with rainfall. Research results obtained by the national program indicated that the use of improved barley cultivars and fertilizers would result in substantial yield increases. The objective of the present investigation was to determine the optimum combination level of N and P for newly promising cultivars. The effect of 0–0, 5–10, 10–20 and 15–30 kg.ha⁻¹ of nitrogen (N) and phosphorus (P) levels on barley cultivas Rum, Giza, Fun, Harmel and Arta under rainfed conditions in the Mediterranean climate was studied during two cropping seasons, 1994-95 and 1995–96. Increased grain and straw yields, total N and P uptake and RUE were recorded with increasing N and P levels for almost all cultivars. Rum was significantly (P = 0.05) the highest grain and straw producer and highest RUE at the 10 N- and 20 P kg.ha⁻¹ level. The cultivar × fertility level (N–P) interactions were not significant for both grain and straw yields and for total N and P uptake.     

Influence of Oil Seed Rape and Faba Bean as Green Manure on Nitrogen Utilization in a Spring Cereal Rotation

A lysimeter study was conducted to investigate how nitrogen uptake of spring wheat and oats and N leaching losses are differing when either oilseed rape or faba bean are grown as green manure. The experiment was conducted during 1982–1988, and fertilizer applied to the cereals was either farmyard manure, FYM, (6 and 12 g N/m²/year) or mineral fertilizer, MiF, at a rate of 6 g N/m². On average of the 7 year period faba bean increased N uptake of the cereals fertilized with FYM at harvest by 3–4 g/m². Differences between the two application rates were negligible. N-leaching losses increased twofold when faba bean was grown instead of oilseed rape. Growing faba bean after cereals supplied with MiF, too, increased N uptake of the cereals and significantly increased leaching losses.     

Long-Term Effects of Fertilizers on the Soil Fertility and Productivity of a Rice–Wheat System

Rice–wheat cropping system to which graded levels of NPK fertilizers had been applied for 20 years were compared for yield trends, and changes in response function, soil organic-C and available N, P, K and S status. This study of system in which only chemical fertilizers had been used over a long period enabled long-term yield declines of rice and wheat at different levels and combinations of NPK fertilizers to be evaluated. The highest rate of yield decline in both rice and wheat was found when 120 kg ha⁻¹ N was applied alone. The lowest rate of decline was observed when all three nutrients (N, P and K) were applied, at 40, 35 and 33 kg ha⁻¹ for N, P and K, respectively, followed by 120, 35 and 33 kg ha⁻¹ (currently recommended levels). The yield response of rice and wheat to N fertilizer declined over the 20 years, with a higher rate of decline in wheat. In contrast, the response to applied P and K increased with time in both crops, with a higher response rate in wheat. With continuous application of N and P fertilizers, there was a marginal change in available N and K in the soil over time, but an approximately 3-fold increase in available P and an approximately 2-fold increase in available S were obtained by regular dressing of P fertilizer (SSP: 7 % P, 12 % S) over 20 years. The results revealed that balanced, high doses of NPK fertilizers are required to maintain soil fertility and raise grain yields.     

Effect of Lentil Residues on the Yield and Response of Succeeding Rice to Nitrogen

A field experiment was conducted at the Division of Agronomy, Indian Agricultural Research Institute, New Delhi during 1983-84 and 1984-85 to study the effect of lentil residues on the yield and response of succeeding rice to nitrogen. Lentil residues benefitted the succeeding rice and gave longer and heavier panicles, more grains per panicle, higher 1000-grain weight and higher grain and straw yield of rice as compared to fallow. Rice responded well to applied nitrogen both in the absence and presence of lentil residues. The effect of lentil root residues and root residues plus incorporation of lentil straw was equivalent to 11 and 33 kg N ha⁻¹ when 60 kg N ha⁻¹ was applied to rice; the corresponding values being 54 and 60 kg N ha⁻¹ when 120 kg N ha⁻¹ was applied to rice.     

Effect of Irrigation and N-Fertilization (Fertigation) Scheduling on Tomato in the Jordan Valley

Tomato ( Lycopersicon esculentum mill. cv. Petopride ) is the most important vegetable crop in Jordan; its production is characterized by inadequate irrigation and fertilization practices, especially under open field conditions. A field study was carried out to determine the effect of different irrigation intervals and different N-fertilizer doses on water use, tomato yields and residual soil nitrogen.
Results indicated significant differences in water use and tomato yields between irrigation treatments. Highest yield (51.4 ton ha⁻¹) was obtained under three irrigations per week with 504 mm total water supply, whereas under irrigation once a week 35.3 ton ha⁻¹were produced with 353 mm total water supply. There were no significant differences in yield between fertigation with ten equal time intervals and fertigations with intervals as per crop requirements, the yields were 47.1 ton ha⁻¹ and 44.5 ton ha⁻¹, respectively. However, yield was significantly lower with three fertigations at equal intervals and equal doses (35.8 ton ha⁻¹) throughout the season. There were no significant differences between mineral nitrogen forms in terms of yield effects. Significant irrigation effects were observed on total soil nitrogen. Residual soil N was 0.052% in the surface layer (0–30 cm), and 0.030% in the subsurface layer (30–60 cm).     

Optimum Seed Rate and Nitrogen Fertilizer Requirement of Rice Under Semi-deepwater Ecosystem

The effect of varying seed rates (100–1000 seeds m⁻²) and nitrogen fertilizer (0–60 kg N ha_-1) applied either in a single basal dose or in splits was investigated on a tall elongating, photosensitive rice variety, Nalini, under semi-deepwater conditions (0–100cm) during 1993 and 1994 at Cuttack, India. Seedling emergence was higher in 1993 (53.9 %) than in 1994 (44.1 %) and it increased proportionately with increasing seed rate, Increase in the number of tillers and panicles m⁻² at higher seed rates was associated with a corresponding decrease in panicle weight. Regression analysis indicated a decrease of 0.91–1.28g in panicle weight for an increase of 100 panicles m⁻². The grain yield of rice was significantly higher at 400 seeds m⁻² in 1993 and at 600 seeds m⁻² in 1994 than at low seed rates but further increase in seed rate did not increase the yield. Application of N fertilizer increased the panicle number and thereby grain yield significantly. The effect of basal and split applied N at active or maximum tillering stages as well as between 30 and 60 kg N ha⁻¹ was not significant on the grain yield. The results suggest that a basal dose of 30kg N ha⁻¹ and seeding density of 400–600 seeds m⁻², resulting in 40–50 % seedling emergence and 150–200 panicles m⁻², each with 2.0–2.5 g weight, may be adequate for optimum productivity of rice under semideepwater conditions.