Effect of nitrogen,phosphorus and molybdenum application on growth and symbiotic N2-fixation of groundnut in an acid sandy soil in Niger

Two field experiments were conducted in 1988 and 1989 on an acid sandy soil in Niger, West Africa, to assess the effect of phosphorus (P), nitrogen (N) and micronutrient (MN) application on growth and symbiotic N₂-fixation of groundnut (Arachis hypogaea L.). Phosphorus fertilizer (16 kg P ha^–1) did not affect pod yields. Addition of MN fertilizer (100 kg Fetrilon Combi 1 ha^–1; P + MN) containing 0.1% molybdenum (Mo) increased pod yield by 37–86%. Nitrogen concentration in shoots at mid pod filling (72 days after planting) were higher in P + MN than in P – MN fertilizer treatment. Total N uptake increased from 53 (only P) to 108 kg N ha^–1 by additional MN application. Seed pelleting (P + MoSP) with 100 g Mo ha^–1 (MoO₃) increased nitrogenase activity (NA) by a factor of 2–4 compared to P treatment only. The increase in NA was mainly due to increase in nodule dry weight and to a lesser extent to increase in specific nitrogenase activity (SNA) per unit nodule dry weight. The higher NA of the P + MoSP treatment was associated with a higher total N uptake (55%) and pod yield (24%). Compared to P + MoSP or P + MN treatments application of N by mineral fertilizer (60 kg N ha^–1) or farmyard manure (130 kg N ha^–1) increased only yield of shoot dry matter but not pod dry matter. Plants supplied with N decreased soil water content more and were less drought tolerant than plants supplied with Mo. The data suggest that on the acid sandy soils in Niger N deficiency was a major constraint for groundnut production, and Mo availability in soils was insufficient to meet the Mo requirement for symbiotic N₂-fixation of groundnut.     

Effect of the integrated use of legume residue,poultry manure and inorganic fertilizers on maize yield,nutrient uptake and soil properties

Identification of a sustainable integrated soil fertility management option in the tropics will not only salvage the degraded soils but also enhances the attainment of the goal of food security. This study was conducted in 2004 and 2005 on a degraded tropical Alfisol in south western Nigeria to evaluate the effect of legume residue, poultry manure and inorganic fertilizers on maize yield, nutrient uptake and soil properties. The treatments consisted of two rates of poultry manure (0 and 5 t ha⁻¹), three rates of N fertilizer (0, 50 and 100 kg N ha⁻¹ applied as urea), three rates of P fertilizer (0, 30 and 60 kg P ha⁻¹ applied as single super phosphate) and two soybean treatments (with or without incorporation of legume residue) in various combinations as a factorial experiment in Randomized Complete Block design with three replicates. Results showed that poultry manure alone led to significant increase in maize yield (60%) and soil organic matter (45%). In contrast, legume residue incorporation gave significantly lower increase in yield (7%) and soil organic matter (11%). However, the combined application of poultry manure and legume incorporation led to 72% increase in maize yield as opposed to 63 and 10% increase recorded when manure alone or legume alone were incorporated, respectively. Optimal maize yield was achieved when manure application was integrated with P fertilizer application. The interaction of P fertilizer and legume incorporation indicated that soil phosphorus and maize P concentration were significantly increased with the application of the P fertilizer and legume incorporation. Hence, the application of P fertilizer alone is most likely to be economical compared with its integration with legume incorporation.     

Application of liquid cattle manure and inorganic fertilizers affect dry matter,nitrogen accumulation,and partitioning in maize

Efficient use of N applied in the form of organic and inorganic fertilizers is important in maize (Zea mays L.) production to maximize producer’s economic returns and maintain soil and water quality. A field study was conducted for three consecutive years (2003–2005) in Thessaloniki, Greece to investigate whether liquid cattle manure can be used to replace inorganic fertilizers and also whether inorganic fertilizer can be applied preplant or as a combination of preplant and sidedress and can affect maize growth, development and N use efficiency. The treatments were control (unfertilized), liquid dairy cattle manure (Manure), application of 260 kg N ha⁻¹ year⁻¹ as basal dressing (N-single), application of 130 kg ha⁻¹ year⁻¹ N as basal dressing before sowing and 130 kg N ha⁻¹ when plants were at the eight-leaf stage (V8) (N-split). In 2 out of the 3 years of the study there was a significant positive effect of fertilizer application on maize growth, development, N uptake, and partitioning compared with the control. Dry matter production was increased by an average of 39% during the 2 years in plots fertilized either with manure or inorganic fertilizers than the control plots. Also from the yield components kernel weight per ear and number of kernels per ear were increased by an average of 35% and 32%, respectively in the fertilized plots compared with the control plots. Chlorophyll level was affected as it was increased by an average of 18%, 14%, and 18% at the ten-leaf stage (V10), silking and milk stage, respectively in the fertilization treatments compared with the control. Similar trend was observed in the other parameters that were studied. No differences were found between the manure and the different times of N application which indicates that manure can be used to replace inorganic fertilizer. Applying N either preplant in a single application or in split application (half of N preplant and half as sidedress) did not have any effect on any characteristics that were studied indicating that preplant application can be used as it is more cost effective. The present study indicates that liquid cattle manure can be used to replace inorganic fertilizers and also that there was no difference between preplant and sidedress application of N.     

Effects of different manuring systems with and without biogas digestion on nitrogen cycle and crop yield in mixed organic dairy farming systems

Field trials were carried out between 2002 and 2005 to investigate the effects of biogas digestion in a mixed organic dairy farming system with arable land and grassland on nutrient cycling, nitrogen (N) uptake and crop yields within a cropping system comprising a whole crop rotation. Five treatments were carried out: (i) solid farmyard manure, (ii) undigested liquid slurry, (iii) digested liquid slurry, (iv) digestion of liquid slurry and field residues such as crop residues and cover crops, and (v) similar to iv, but with additional N inputs at the equivalent of 40 kg N ha⁻¹ farmland through digestion of purchased substrates. The term “manure” is used in the present study to mean all kind of aboveground organic residues left on the field (“immobile manures”, such as crop residues and green manures incorporated directly into the soil) or added as stable wastes or effluents of biogas digestion (“mobile manures”). The total aboveground biomass growth and the overall aboveground N uptake of non-legume maincrops were higher in the liquid slurry manure treatment than in the solid farmyard manure system (+5% and +9%, respectively). The digestion of the liquid slurry increased N uptake and crop yields only after soil incorporation of the slurry shortly after field spreading. The additional collection and digestion of field residues such as cover crops and crop residues, combined with a reallocation of the effluents, strongly increased the amounts of “mobile” manure, allowing a more focussed allocation of the available N. This led to an increase in the aboveground N uptake (+12%) and biomass yield (+4%) of the five non-legume crops, due to a better adapted allocation of nutrients in space and time. Results obtained with spring wheat showed that removal of cover crops in autumn, and their digestion, combined with subsequent use as manure in spring resulted in a better synchronisation of the crop N demand and the soil N availability, in comparison with a strategy where the biomass was left on the field as green (immobile) manure. The inclusion of external substrates led to a further increase of 8% in N uptake, but not to a significant increase in aboveground dry matter yields.     

2016年全球钾资源现状及开发利用

介绍世界钾资源的分布及储量.2016年世界资源性钾盐产品(氯化钾、硫酸钾、硫酸钾镁)生产总量折K2O 3970万t,比2015年降低1.2%;全球钾盐销量达到(KCl)6350万t,比2015年略增;2017年我国钾肥进口合同价格230美元/t,较上年涨11美元/t.建议完善钾肥产业链,建设肥料生产、销售企业联盟,降低肥料供应风险.     

The effect of nitrogen source and crop rotation on the growth and yield of processing tomatoes

Four crop rotation and management systems were studied in 1994 and 1995 in relation to growth and yield of irrigated processing tomatoes (Lycopersicon esculentum Mill.). The four treatments were three four-year rotation systems [conventional (conv-4), low input and organic] and a two-year rotation system [conventional (conv-2)]. The four-year rotation was tomato-safflower-corn-wheat(or oats+vetch)/beans, and the two-year rotation was tomato-wheat. Purple vetch (Vicia sativa L.) was grown as a green manure cover crop preceeding tomatoes in the low input and organic systems. Nitrogen was supplied as fertilizer in the conventional systems, as vetch green manure plus fertilizer in the low input system and as vetch green manure plus turkey manure in the organic system. Tomato cv. Brigade was direct-seeded in the conventional systems and transplanted to the field in the low input and organic systems. In both years the winter cover crop was composed of a mixture of vetch and volunteer oats with N contents of 2.2% in 1994 and 2.7% (low input) or 1.8% (organic) in 1995. In 1994 yields were higher in conventionally grown tomatoes because a virus in the nursery infected the transplants used in the low input and organic systems. In 1995 tomatoes grown with the low input and conv-4 systems had similar yields, which were higher than those of tomatoes grown with the conv-2 and organic systems. N uptake by the crop was greater than 200 kg N ha^–1 for high yield (> 75 t ha^–1) and uptake rates of 3 to 6 kg N ha^–1 day^–1 during the period of maximum uptake were observed. The lower yield with the organic system in 1995 was caused by a N deficiency. The main effect of the N deficiency was a reduced leaf area index and not a reduction of net assimilation rate (NAR) or radiation use efficiency (RUE). Nitrogen deficiency was related to low concentration of inorganic N in the soil and slow release of N from the cover crop + manure. A high proportion of N from the green manure but only a low proportion of N from the manure was mineralized during the crop season. In the conventional systems, the estimated mineralized N from the soil organic matter during the crop season was around 85 kg ha^–1. A hyperbolic relationship between N content and total dry weight of aboveground biomass was observed in procesing tomatoes with adequate N nutrition. Lower yields with the conv-2 than with the conv-4 system were due to higher incidence of diseases in the two year rotation which reduced the NAR and the RUE. Residual N in the soil in Oct. (two months after the incorporation of crop residues) ranged between 90 and 170 kg N ha^–1 in the 0–90 cm profile.Department of Vegetable Crops.     

Fertilizer requirements for wheat and maize in China: the QUEFTS approach

Wheat and maize are two major food crops in China. Conventional fertilizer recommendations result in higher than necessary costs to farmers and increased environmental pollution. It is essential to quantitatively estimate optimal fertilizer requirements to alleviate the problems of the two crops in China. The QUEFTS (QUantitative Evaluation of the Fertility of Tropical Soils) model was used to estimate region-specific nitrogen (N), phosphorus (P) and potassium (K) requirements as well as fertilizer applications needed to realize target yields of wheat and maize. Data of field experiments with different fertilization treatments of various regions in China during the years of 1985–1995 were used to calibrate the QUEFTS model for both wheat and maize. Minimum and maximum internal nutrient efficiencies (kg grain kg⁻¹) for the model were estimated at N (25 and 56), P (171 and 367), K (24 and 67) for wheat, and N (21 and 64), P (126 and 384), K (20 and 90) for maize. The model suggested a linear increase of grain yields for scenarios with nutrient contents of 24.6, 3.7 and 23.0 kg N, P and K per 1000 kg of wheat grain and 25.8, 4.3 and 23.1 kg N, P and K per 1000 kg of maize grain. These results suggest that the average N: P: K ratio in the plant dry matter is about 6.7: 1: 6.2 for wheat and 6.0: 1: 5.4 for maize. Relationships between internal N, P and K levels and soil properties were established and relationships between the recovery efficiencies of applied fertilizer – N, P and K were found. Running the calibrated QUEFTS model with observed field data produced a good fit between predicted and observed data. It was concluded that the calibrated QUEFTS model could be a useful tool for improving fertilizer recommendations for wheat and maize in China.     

Improving nutrient use efficiency from decomposing manure and millet yield under Plinthosols in Niger

To improve synchronicity between nutrients released from the decomposing manure with millet nutrient requirement under zaï technique, a 2-year field experiment was conducted at the International Crops Research Institute for the Semi-Arid Tropics Research Station, Sadoré, Niger. The treatments consisted of factorial combination of two rates of cattle manure (200 and 300 g per zaï hole), three periods of manure application (before planting, at planting and 15 days later) and two rates of mineral fertilizer [nitrogen (N), phosphorus (P) and potassium (K) 15–15–15] applied at 6 g per zaï hole and a control, without mineral fertilizer). Manure dry mass losses did not significantly differ among manure application periods in 2013. However, in 2014 the highest manure dry mass loss occurred when manure was applied before planting with 70% of manure applied being decomposed at millet maturity stage (115 days after litterbag installation) followed by manure applied at planting with almost 50% of dry mass losses. The quantities of N and P absorbed by millet at tillering stage represented, 61, 52 and 33% of N released and 15, 12 and 15% of P released at the same time when manure was applied before planting, at planting and 15 days after planting, respectively. Application of manure before planting increased on an average millet grain yield by 16 and 20% and N utilization efficiency by 25 and 31% compared to application of manure at planting and 15 days after planting respectively. Addition of mineral fertilizer induced a synergetic effect on millet grain yield (p = 0.002). Millet grain yields increased on average by 5, 17 and 57% when 6 g per zaï pit of NPK fertilizer were added to plots receiving manure application before planting, at planting and 15 days after planting, respectively. We conclude that application of manure prior to planting satisfies better millet nutrients demand, thereby increasing nutrient use efficiency and grain yield under zai pits.     

Crop residue,manure and fertilizer in dryland maize under reduced tillage in northern China: I grain yields and nutrient use efficiencies

The rapidly increasing population and associated quest for food and feed in China has led to increased soil cultivation and nitrogen (N) fertilizer use, and as a consequence to increased wind erosion and unbalanced crop nutrition. In the study presented here, we explored the long-term effects of various combinations of maize stover, cattle manure and nitrogen (N) and phosphorus (P) fertilizer applications on maize (Zea mays L.) yield and nutrient and water use efficiencies under reduced tillage practices. In a companion paper, we present the effects on nutrient balances and soil fertility characteristics. The ongoing factorial field trial was conducted at Shouyang Dryland Farming Experimental Station in northern China from 1993 onwards. The incomplete, determinant-optimal design comprised 12 treatments, including a control treatment, in duplicate. Grain yields and N, P, and potassium (K) uptakes and N, P and K use efficiencies were greatly influenced by the amount of rain during the growing season (GSR), and by soil water at sowing (SWS). There were highly significant interactions between GSR and added stover and manure, expressed in complex annual variations in grain yield and N, P and K use efficiencies. Annual mean grain yields ranged from 3,000 kg ha⁻¹ to 10,000 kg ha⁻¹ and treatment mean yields from 4,500 kg ha⁻¹ to 7,000 kg ha⁻¹. Balanced combination of stover (3,000–6,000 kg), manure (1,500–6,000 kg) and N fertilizer (105 kg) gave the highest yield. Stover and manure were important for supplying K, but the effects differed greatly between years. Overall mean N recovery efficiency (NRE) ranged from 28% to 54%, depending on N source. NRE in wet years ranged from 50% to 90%. In conclusion, balanced combinations of stover, manure and NP fertilizer gave the highest yield and NRE. Reduced tillage with adding stover and manure in autumn prior to ploughing is effective in minimizing labor requirement and wind erosion. The potentials of split applications of N fertilizer, targeted to the need of the growing crop (response farming), should be explored to further increase the N use efficiency.     

Long-term effect of fertilizer and manure application on soil-carbon sequestration and soil fertility under the wheat–wheat–maize cropping system in northwest China

Maintenance of soil organic carbon (SOC) is important for the long-term productivity of agroecosystems. An investigation was conducted to study the effects of long-term application of inorganic fertilizers and farmyard manure (FYM) on soil organic carbon (SOC), nitrogen, phosphorus, and potassium nutrient content, water-stable aggregate distribution, and aggregate-associated carbon in a field experiment started in 1982 in an arid region of northwest China. Application of inorganic fertilizer alone (N, NP, or NPK treatments) did not increase SOC concentrations compared with no application of fertilizers (CK) and SOC concentration was significantly reduced, by 18% on average, compared with the initial value at the beginning of the experiment. Application of imbalanced inorganic fertilizer (N and NP), especially, resulted in a significant decrease in available phosphorus and potassium nutrients at a depth of 20 cm. This indicates that long-term application of inorganic fertilizers were inadequate to maintain levels of SOC and nutrients under conventional management with no aboveground crop residues returning to the soil. Long-term application of FYM alone or combined with inorganic fertilizers (M (FYM), MN, MNPK, or MNPK treatments), however, improved SOC and total nitrogen concentrations from initial values of 12.1 and 0.76 g kg⁻¹, respectively, to 15.46 and 1.28 g kg⁻¹, on average, and also enhanced available nitrogen, phosphorus, and potassium concentrations by 47, 50, and 68%, respectively, during the 23-year period. Treatment with FYM resulted in a 0.48 mm greater average mean weight diameter (MWD) of aggregates and a higher percentage of macro-aggregates (>2 mm) and small macro-aggregates (2–0.25 mm) than treatment without FYM. The MWD increased with increasing SOC concentration (R ²=0.75). The SOC concentration was highest in small macro-aggregates, intermediate in macro-aggregates, and lowest in micro-aggregates (0.25–0.05 mm). Approximately 54–60% of total SOC was stored in micro-aggregates (0.25–0.05 mm) and sand+silt fractions (<0.05 mm) after treatment without FYM but 57–64% of total SOC was stored in macro-aggregates (>0.25 mm) after treatment with FYM. MNPK treatment had the greatest effect on improving the levels of SOC and NPK nutrients and in enhancing the formation and stability of macro-aggregates.     

Transfers of phosphorus within three dairy farming systems receiving varying inputs in feeds and fertilizers

Inputs of phosphorus (P) above requirements for production on dairy farms lead to surplus P with increased risk of P transfer in land run-off to surface waters causing eutrophication. The impact of reducing surplus P inputs in purchased feeds and fertilizers on milk and forage production was investigated in a comparison of three dairy farm systems on chalkland soils in southern England over a 3-year period. In accordance with current commercial practice, no attempt was made to regulate P inputs in system 1, which accumulated an average annual surplus of 23 kg P ha^-1. Progressive reductions in purchased feed and/or fertilizer inputs into systems 2 and 3 decreased surplus P to 17 and 3 kg ha^-1, respectively, without apparently limiting either milk or herbage dry matter production. The estimated reduction in faecal P output from system 3 cows fed a low P diet compared to system 1 cows fed a high P diet was 26%. Milk P concentrations significantly (P <0.001) increased in systems 2 and 3 which included maize in the diet. Output of P in milk and meat products, as a proportion of the total dietary P inputs, increased from 28% in system 1 to 36% in system 3. Surplus P was greatest in continuous maize fields receiving both dairy manure and starter P fertilizer. Withholding P fertilizer in system 3 did not reduce P offtake in cut herbage on soils of moderate P fertility. Total annual losses of P in storm run-off and leaching were no greater than annual inputs of P from the atmosphere (0.5 kg ha^-1). The results indicate there is scope to reduce surplus P on commercial dairy farms without sacrificing production targets at least in the short term. Purchased feeds are the largest of the P inputs on intensive dairy farms, yet these are rarely quantified on commercial holdings.     

Nutrient evolution in soil and cereal yield under different fertilization type in dryland

Under semiarid conditions the response of crops to synthetic fertilizers is often reduced. Organic fertilizers can be used to provide a continuous source of nutrients for the crops. The soil nitrogen and crop yield in a rotation of durum wheat (Triticum durum)–fallow-barley (Hordeum vulgare)–vetch (Vicia sativa) were studied during 4 years when synthetic fertilizer (chemical), compost (organic) or no fertilizer (control) were applied in a field with high initial contents of soil NO₃–N (> 400 kg N ha⁻¹), phosphorus (22 mg kg⁻¹) and potassium (> 300 mg kg⁻¹). Changes in soil organic matter, phosphorus and potassium were also measured. During the crop period, chemical fertilization significantly increased the content of soil NO₃–N in the first 0.30 m of soil with respect to organic fertilization and the control. The yield of wheat and barley was not increased after applying chemical or organic fertilizer with respect to the unfertilized plots. The estimated losses of nitrogen were similar for the three types of fertilization, as well as the uptake of nitrogen for the total biomass produced. The initial levels of organic matter and phosphorus were maintained, even in the plots that were not fertilized, while the potassium decreased slightly. Thus, the rotation and burying of crop residues were enough to maintain the crop yield and the initial content of nutrients.     

Effects of Biochar and Nitrogen Application on Rice Biomass Saccharification,Bioethanol Yield and Cell Wall Polymers Features

Rice is a major food crop that produces abundant biomass wastes for biofuels. To improve rice biomass and yield, nitrogen (N) fertilizer is excessively used, which is not eco-friendly. Alternatively, biochar (B) application is favored to improve rice biomass and yield under low chemical fertilizers. To minimize the reliance on N fertilizer, we applied four B levels (0, 10, 20, and 30 t B ha⁻¹) combined with two N rates (low-135 and high-180 kg ha⁻¹) to improve biomass yield. Results showed that compared to control, the combined B at 20–30 t ha⁻¹ with low N application significantly improved plant dry matter and arabinose (Ara%), while decreasing cellulose crystallinity (Crl), degree of polymerization (DP), and the ratio of xylose/arabinose (Xyl/Ara), resulting in high hexoses (% cellulose) and bioethanol yield (% dry matter). We concluded that B coupled with N can alter cell wall polymer features in paddy rice resulting in high biomass saccharification and bioethanol production.     

Nitrogen balances in farmers fields under alternative uses of a cover crop legume: a case study from Nicaragua

Canavalia brasiliensis (canavalia), a drought tolerant legume, was introduced into the smallholder traditional crop-livestock production system of the Nicaraguan hillsides as green manure to improve soil fertility or as forage during the dry season for improving milk production. Since nitrogen (N) is considered the most limiting nutrient for agricultural production in the target area, the objective of this study was to quantify the soil surface N budgets at plot level in farmers fields over two cropping years for the traditional maize/bean rotation and the alternative maize/canavalia rotation. Mineral fertilizer N, seed N and symbiotically fixed N were summed up as N input to the system. Symbiotic N₂ fixation was assessed using the ¹⁵N natural abundance method. Nitrogen output was quantified as N export via harvested products. Canavalia derived in average 69% of its N from the atmosphere. The amount of N fixed per hectare varied highly according to the biomass production, which ranged from 0 to 5,700 kg ha^?1. When used as green manure, canavalia increased the N balance of the maize/canavalia rotation but had no effect on the N uptake of the following maize crop. When used as forage, it bears the risk of a soil N depletion up to 41 kg N ha^?1 unless N would be recycled to the plot by animal manure. Without N mineral fertilizer application, the N budget remains negative even if canavalia was used as green manure. Therefore, the replenishment of soil N stocks by using canavalia may need a few years, during which the application of mineral N fertilizer needs to be maintained to sustain agricultural production.     

Effect of planting technique and amendment type on pearl millet yield, nutrient uptake, and water use on degraded land in Niger

Due to increased population pressure and limited availability of fertile land, farmers on desert fringes increasingly rely on marginal land for agricultural production, which they have learned to rehabilitate with different technologies for soils and water conservation. One such method is the indigenous zai technique used in the Sahel. It combines water harvesting and targeted application of organic amendments by the use of small pits dug into the hardened soil. To study the resource use efficiency of this technique, experiments were conducted 1999–2000, on-station at ICRISAT in Niger, and on-farm at two locations on degraded lands. On-station, the effect of application rate of millet straw and cattle manure on millet dry matter production was studied. On-farm, the effects of organic amendment type (millet straw and cattle manure, at the rate of 300 g per plant) and water harvesting (with and without water harvesting) on millet grain yield, dry matter production, and water use were studied. First, the comparison of zai vs. flat planting, both unamended, resulted in a 3- to 4-fold (in one case, even 19-fold) increase in grain yield on-farm in both years, which points to the yield effects of improved water harvesting in the zai alone. Zai improved the water use efficiency by a factor of about 2. The yields increased further with the application of organic amendments. Manure resulted in 2–68 times better grain yields than no amendment and 2–7 times better grain yields than millet straw (higher on the more degraded soils). Millet dry matter produced per unit of manure N or K was higher than that of millet straw, a tendency that was similar for all rates of application. Zai improved nutrient uptake in the range of 43–64% for N, 50–87% for P and 58–66% for K. Zai increased grain yield produced per unit N (8 vs. 5 kg kg⁻¹) and K (10 vs. 6 kg kg⁻¹) compared to flat; so is the effect of cattle manure compared to millet straw (9 vs. 4 kg kg⁻¹, and 14 vs. 3 kg kg⁻¹), respectively, Therefore zai shows a good potential for increasing agronomic efficiency and nutrient use efficiency. Increasing the rate of cattle manure application from 1 to 3 t ha⁻¹ increased the yield by 115% TDM, but increasing the manure application rate further from 3 to 5 t ha⁻¹ only gave an additional 12% yield increase, which shows that optimum application rates are around 3t ha⁻¹.     

大蒜测土配方营养套餐施肥技术

介绍大蒜测土配方套餐施肥方案的设计原则及施肥的具体技术方案。根据大蒜喜钾、喜硫的需肥特点,除基肥施(667m2)2000kg农家肥、50kg生物有机肥及16-10-22的复混肥100kg外,并追施(随水冲施)高氮全营养肥(21-8-11)2.5kg、高钾全营养肥(12-12-17)12.5kg各2次,叶面肥喷施若干次,并使用大蒜凯普克促进根系生长。通过3年大面积示范试验,与常规施肥对照,大蒜年平均增产14.4%,667m2净增产量约235kg,净增产值约643元。     

Diagnosis of nitrogen deficiency in barley,growing in different rotation systems,by plant analysis

Nitrate concentrations were determined in stems of barley taken at the tillering stage from a 2-year rotational/N fertilizer experiment carried out at 2 locations in Cyprus. In the second year leaf laminae were also analysed for total nitrogen (N) concentration.At sampling maximum dry matter (DM) production was obtained with NO₃-N concentration above 1000 mg kg^–1, which increased with N fertilizer supply. Even though there were differences in DM and NO₃ concentration between rotation treatments the relationship between DM and NO₃ was similar.Nitrate in stems was more sensitive than total N in leaf laminae as an indicator of N nutrition status.     

Residual N and P fertilizer effect and fertilizer recovery on intercropped and sole-cropped corn and bean in semiarid northeast Brazil

The effects of a single ¹⁵N and P fertilizer application (16 and 12 kg ha^–1) on intercropped and sole-cropped corn and beans was followed over three consecutive years. Grain (0.1–0.9 ton ha^–1 yr^–1) and straw productions (0.2–2.5 ton ha^–1 yr^–1) were limited by rainfall and showed small responses to fertilizer. In the first year, plant N uptake was more than twice the fertilizer amounts, while P uptake was less than half the fertilizer amounts. Plant N derived from fertilizer was low (9–19%). Sole corn took up more (34%) than beans (16%) and the combined intercrop (26%) and also had higher recovery of fertilizer in the soil than single beans (50% against 28%). The distribution of fertilizer N and P in the soil showed a similar pattern in all treatments, with a high concentration around the application spot and decreasing concentrations at greater distances and above and below this point. Total P increases in a soil volume 10 cm around the application spot corresponded to 60% of the amount applied. Fertilizer contributions to the second crop were < 3% of total plant N and represented <6% of the applied amount. Therefore, the residual fertilizer effect on production was attributable to P. The patterns of fertilizer N and P distribution in the soil remained similar but N recoveries decreased 14–18%. Despite low rainfall, low productivities and reasonable proportions of fertilizer N remaining in the soil, the residual effects of the applied fertilizer N were too low to justify a fertilizer recommendation based on economic returns on the investment.     

Growth,grain yield and nitrogen use efficiency of Mediterranean wheat in soils amended with municipal sewage sludge

The application of sewage sludge (SS) to agricultural land can improve soil fertility and physical properties, and enhance crop production. This field study was conducted for two consecutive growing seasons to investigate the influence of SS application on winter wheat growth, grain yield, N accumulation, translocation and use, and on trace elements concentrations in soil and wheat plants under Mediterranean conditions. Treatments consisted of three rates of SS, i.e. 20, 40, and 60 Mg dry weight ha^?1 year^?1, one rate of inorganic fertilizer (IF, 120 kg N ha^?1 year^?1 plus 80 kg P₂O₅ ha^?1 year^?1), and an unamended control. The application of SS resulted in tall plants with high early dry matter and N accumulation similar to or significantly higher than those obtained with IF. The lowest SS application rate resulted in grain yield similar to that obtained with IF. Nitrogen use efficiency (NUE) in SS treatments was mainly determined by uptake efficiency, which decreased with increasing SS application rate. Values of NUE and biomass production efficiency with the lowest SS rate were similar to those obtained with IF. SS application resulted in increased concentrations of total and DTPA-extractable trace elements in the soil after the first year, but concentrations were much lower than the regulation limits. Concentrations of Cu, Mn and Zn in wheat plants did not exceed those obtained with IF. Overall, SS could be considered for use as a fertilizer in wheat production systems in the area, serving also as an alternative method of SS disposal.     

A comparison between legume technologies and fallow, and their effects on maize and soil traits, in two distinct environments of the West African savannah

Legume–maize rotation and maize nitrogen (N)-response trials were carried out simultaneously from 1998 to 2004 in two distinct agro-ecological environments of West Africa: the humid derived savannah (Ibadan) and the drier northern Guinea savannah (Zaria). In the N-response trial, maize was grown annually receiving urea N at 0, 30, 60, 90 and 120 kg N ha⁻¹. In Ibadan, maize production increased with N fertilization, but mean annual grain yield declined over the course of the trial. In Zaria, no response to N treatments was observed initially, and an increase in the phosphorus (P) and sulphur (S) fertilizer application rate was required to increase yield across treatments and obtain a response to N applications, stressing the importance of non-N fertilizers in the savannah. In the rotation trial, a 2-year natural fallow–maize rotation was compared with maize rotated with different legume types: green manure, forage, dual-purpose, and grain legumes. The cultivation of some legume types resulted in a greater annual maize production relative to the fallow–maize combination and corresponding treatments in the N-response trial, while there was no gain in maize yield with other legume types. Large differences in the residual effects from legumes and fallow were also observed between sites, indicting a need for site-specific land management recommendations. In Ibadan, cultivation of maize after the forage legume (Stylosanthes guianensis) achieved the highest yield. The natural fallow–maize rotation had improved soil characteristics (Bray-I P, exchangeable potassium, calcium and magnesium) at the end of the trial relative to legume–maize rotations, and natural fallow resulted in higher maize yields than the green manure legume (Pueraria phaseoloides). In Zaria, maize following dual-purpose soybean achieved the highest mean yield. At both sites, variation in aboveground N and P dynamics of the legume and fallow vegetation could only partly explain the different residual effects on maize.