Gaseous emissions of nitrogen and carbon from urban vegetable gardens in Bobo‐Dioulasso,Burkina Faso

Urban and peri‐urban agriculture (UPA) is an important livelihood strategy for the urban poor in sub‐Saharan Africa and contributes to meeting increasing food demands in the rapidly growing cities. Although in recent years many research activities have been geared towards enhancing the productivity of this land‐use system, little is known about turnover processes and nutrient efficiency of UPA. The aim of our study therefore was to determine horizontal fluxes of N, P, K, and C as well as gaseous N and C emissions in urban vegetable gardens of Bobo‐Dioulasso, Burkina Faso. Two gardens referred to as “Kodéni” and “Kuinima” were selected as representative for urban and peri‐urban systems classified as: (1) “commercial gardening + field crops and livestock system” and (2) “commercial gardening and semicommercial field crop system”, respectively. A nutrient‐balance approach was used to monitor matter fluxes from March 2008 to March 2009 in both gardens. Ammonia (NH₃), nitrous oxide (N₂O) and carbon dioxide (CO₂) emissions from the respective soils were measured during the coolest and the hottest period of the day using a closed‐chamber system. Annual partial balances amounted to 2056 kg N ha^–1, 615 kg P ha^–1, 1864 kg K ha^–1, and 33 893 kg C ha^–1 at Kodéni and to 1752 kg N ha^–1, 446 kg P ha^–1, 1643 kg K ha^–1, and 21 021 kg C ha^–1 at Kuinima. Emission rates were highest during the hot midday hours with peaks after fertilizer applications when fluxes of up to 1140 g NH₃‐N ha^–1 h^–1, 154 g N₂O‐N ha^–1 h^–1, 12 993 g CO₂‐C ha^–1 h^–1 were recorded for Kodéni and Kuinima. Estimated annual gaseous N (NH₃‐N + N₂O‐N) and C (CO₂‐C + CH₄‐C) losses reached 419 kg N ha^–1 and 35 862 kg C ha^–1 at Kodéni and 347 kg N ha^–1 and 22 364 kg C ha^–1 at Kuinima. For both gardens, this represented 20% and 106% of the N and C surpluses, respectively. Emissions of NH₃, largely emitted after surface application of manure and mineral fertilizers, accounted for 73% and 77% of total estimated N losses for Kodéni and Kuinima. To mitigate N losses nutrient‐management practices in UPA vegetable production of Bobo‐Dioulasso would greatly benefit from better synchronizing nutrient‐input rates with crop demands.     

Nutrient flows and balances in intensively managed vegetable production of two West African cities

This study reports and analyzes nutrient balances in experimental vegetable production systems of the two West African cities of Tamale (Ghana) and Ouagadougou (Burkina Faso) over a two‐year period comprising thirteen and eleven crops, respectively. Nutrient‐use efficiency was also calculated. In Tamale and Ouagadougou, up to 2% (8 and 80 kg N ha^?1) of annually applied fertilizer nitrogen were leached. While biochar application or wastewater irrigation on fertilized plots did not influence N leaching in both cities, P and K leaching, as determined with ion‐absorbing resin cartridges, were reduced on biochar‐amended plots in Tamale. Annual nutrient balances amounted to +362 kg N ha^?1, +217 kg P ha^?1, and –125 kg K ha^?1 in Tamale, while Ouagadougou had balances of up to +692 kg N ha^?1, +166 kg P ha^?1, and –175 kg K ha^?1 y^?1. Under farmers' practice of fertilization, agronomic nutrient‐use efficiencies were generally higher in Tamale than in Ouagadougou, but declined in both cities during the last season. This was the result of the higher nutrient inputs in Ouagadougou compared to Tamale and relatively lower outputs. The high N and P surpluses and K deficits call for adjustments in local fertilization practices to enhance nutrient‐use efficiency and prevent risks of eutrophication.     

Mineral‐nitrogen and phosphorus leaching from vegetable gardens in Niamey,Niger

Urban and periurban agriculture (UPA) contributes significantly to meeting increasing food demand of rapidly growing urban populations in West African cities. The often intensive high‐input vegetable production within UPA results in large positive nutrient balances, being presumably linked to strong nutrient leaching which needs quantification. This study aimed at estimating leaching losses of mineral N and P in three representative urban gardens of Niamey, Niger, using ion‐exchange‐resin cartridges installed below the crop rooting zone at 0.6 m soil depth. In 2007, a year with below‐average annual rainfall (425 mm as compared to 542 mm), mean leaching of mineral N amounted to 5.9 and 7.3 kg N ha^–1 for two gardens with > 80% sand fraction and only 2.2 kg N ha^–1 for a garden with 40% silt and clay. Apparent annual P leaching was 0.7 kg P ha^–1 in all three gardens. Additional multiannual studies are necessary to assess the effect of inter‐ and intraannual variation in precipitation on nutrient leaching in intensive UPA vegetable production of semiarid West Africa.     

Nutrient and carbon balances in organic vegetable production on an irrigated,sandy soil in northern Oman

Our understanding of nutrient and carbon (C) fluxes in irrigated organic cropping systems of subtropical regions is limited. Therefore, leaching of mineral nitrogen (N) and phosphorus (P), gaseous emissions of NH₃, N₂O, CO₂, and CH₄, and total matter balances were measured over 24 months comprising a total cropping period of 260 d in an organic‐cropping‐systems experiment near Sohar (Oman). The experiment on an irrigated sandy soil with four replications comprised two manure types (ORG1 and ORG2) characterized by respective C : N ratios of 19 and 25 and neutral detergent fiber (NDF)‐to‐soluble carbohydrates (SC) ratios of 17 and 108. A mineral‐fertilizer (MIN) treatment with equivalent levels of mineral N, P, and potassium (K) served as a control. The three treatments were factorially combined with a cropping sequence comprising radish (Raphanus sativus L.) followed by cauliflower (Brassica oleracea L. var. botrytis) or carrot (Daucus carota subsp. sativus). Over the 24‐months experimental period gaseous N emissions averaged 45 kg ha^–1 (59% NH₃‐N, 41%N₂O‐N) for MIN, 55 kg N ha^–1 (69% NH₃‐N, 31%N₂O‐N) for ORG1, and 49 kg N ha^–1 (59% NH₃‐N, 41% N₂O‐N) for ORG2. Carbon losses were 6.2 t ha^–1 (98% CO₂‐C, 2% CH₄‐C) for MIN, 9.7 t C ha^–1 (99% CO₂‐C, 1% CH₄‐C) for ORG1, and 10.6 t ha^–1 (98% CO₂‐C, 2% CH₄‐C) for ORG2. Exchange resin–based cumulative leaching of mineral N amounted to 30 kg ha^–1 for MIN, 10 kg ha^–1 for ORG1, and 56 kg ha^–1 for ORG2. Apparent surpluses of 361 kg N ha^–1 and 196 kg P ha^–1 for radish‐carrot and 299 kg N ha^–1 and 184 kg P ha^–1 for radish‐cauliflower were accompanied by K deficits of –59 kg ha^–1 and –73 kg ha^–1, respectively, for both cropping systems. Net C balances for MIN, ORG1, and ORG2 plots were –7.3, –3.1, and 1.5 t C ha^–1 for radish‐carrot and –5.0, 1.3, and 4.6 t C ha^–1 for radish‐cauliflower. The results underline the difficulty to maintain soil C levels in intensively cultivated, irrigated subtropical soils.     

Input and output of major nutrients under monocropping sisal in Tanzania

A semiquantitative nutrient balance is presented for a field monocropped with sisal on Ferralsols in Tanzania. Input of nutrients included wet deposition, non-symbiotic nitrogen fixation and nutrients added with planting material. Nutrient output consisted of the harvested product. The average annual shortfall between 1966 to 1990 was 12 kg N ha⁻¹, 2·8 kg P ha⁻¹, 38 kg K ha⁻¹, 44 kg Ca ha⁻¹ and 19 kg Mg ha⁻¹. The nutrient balance was compared to changes in topsoil (0–20 cm) nutrient contents of the sisal field during the same period. Average annual decrease in soil nutrient contents was: 104 kg N ha⁻¹, 1·8 kg P ha⁻¹, 11 kg K ha⁻¹, 29 kg Ca ha⁻¹ and 10 kg Mg ha⁻¹. Much more nitrogen was lost from the topsoil than can be explained by the nutrient balance, indicating significant losses. Changes in soil phosphorus content are almost explained by the nutrient balance. More exchangeable cations were removed with the yield than were lost from the topsoil, which may imply that cations are extracted from the subsoil. Both the nutrient balance and the changes in soil nutrient contents showed that monocropping sisal is mining nutrients. © 1997 John Wiley & Sons, Ltd.     

Eucalyptus biochar application enhances Ca uptake of upland rice,soil available P,exchangeable K,yield, and N use efficiency of sugarcane in a crop rotation system

It was hypothesized that the application of eucalyptus biochar enhances nutrient use efficiencies of simultaneously supplied fertilizer, as well as provides additional nutrients (i.e., Ca, P, and K), to support crop performance and residual effects on subsequent crops in a degraded sandy soil. To test this hypothesis, we conducted an on‐farm field experiment in the Khon Kaen province of Northeastern Thailand to assess the effects of different application rates of eucalyptus biochar in combination with mineral fertilizers to upland rice and a succeeding crop of sugarcane on a sandy soil. The field experiment consisted of three treatments: (1) no biochar; (2) 3.1 Mg ha^?1 biochar (10.4 kg N ha^?1, 3.1 kg P ha^?1, 11.0 kg K ha^?1, and 17.7 kg Ca ha^?1); (3) 6.2 Mg ha^?1 biochar (20.8 kg N ha^?1, 6.2 kg P ha^?1, 22.0 kg K ha^?1, and 35.4 kg Ca ha^?1). All treatments received the same recommended fertilizer rate (32 kg N ha^?1, 14 kg P ha^?1, and 16 kg K ha^?1 for upland rice; 119 kg N ha^?1, 21 kg P ha^?1, and 39 kg K ha^?1 for sugarcane). At crop harvests, yield and nutrient contents and nitrogen (N) use efficiency were determined, and soil chemical properties and pH₀ monitored. The eucalyptus biochar material increased soil Ca availability (117 ± 28 and 116 ± 7 mg kg^?1 with 3.1 and 6.2 Mg ha^?1 biochar application, respectively) compared to 71 ± 13 mg kg^?1 without biochar application, thus promoting Ca uptake and total plant biomass in upland rice. Moreover, the higher rate of eucalyptus biochar improved CEC, organic matter, available P, and exchangeable K at succeeding sugarcane harvest. Additionally, 6.2 Mg ha^?1 biochar significantly increased sugarcane yield (41%) and N uptake (70%), thus enhancing N use efficiency (118%) by higher P (96%) and K (128%) uptake, although the sugar content was not increased. Hence, the application rate of 6.2 Mg ha^?1 eucalyptus biochar could become a potential practice to enhance not only the nutrient status of crops and soils, but also crop productivity within an upland rice–sugarcane rotation system established on tropical low fertility sandy soils.     

Management practices of macronutrients for potato for smallholder farming system at alluvial soil (Entisols) of India

In the present study, seven fertilizer treatments [T₁, 50% NPK; T₂, 100% NPK (Recommended dose of fertilizer, 200–65.4–124.5 kg N-P-K ha^?1); T₃, 150% NPK; T₄, 100% PK; T₅, 100% NK; T₆, 100% NP and T₇, control (zero NPK)] with four replications were assessed in the new alluvial soil zone (Entisols) of West Bengal, India. The objectives of the study were to generate information on potato productivity, profitability, indigenous nutrient supply and net gain/loss of NPK in post-harvest soil. Plants grown under higher NPK supply resulted in higher tuber yield and there were significant (p ≤ 0.05) reductions in total yield with nutrient omissions. Nutrient?limited yields were 19.78, 2.83 and 1.77 t ha^?1 for N, P and K, considering total tuber yield (28.24 t ha^?1) obtained under 100% NPK as targeted yield. Indigenous nutrient supply of N, P and K were estimated at 24.1, 22.34 and 110.22 kg ha^?1, respectively that indicates higher K?supplying capacity of experimental soil as compared to N and P. Net income (US$1349 ha^?1 year^?1) and B:C ratio (1.91) was highest with 100% NPK, and further addition of NPK (150%) resulted in decrease on net return (US$1193 ha^?1 year^?1) and B:C ratio (1.73).     

Role of crop diversification and integrated nutrient management in resilience of soil fertility under rice-wheat cropping system

A field study conducted for two crop cycles of five cropping systems supplied with six nutrient combinations at the Indian Agricultural Research Institute, New Delhi indicated that the cropping systems having a legume increased organic C content over initial level by 0.02?–?0.05%, available N by 3.5?–?14.1?kg ha^???1, whereas the rice-wheat cropping system resulted in a reduction in organic C and available N over initial level by 0.05% and 1.5?kg ha^???1, respectively after 2 years of study. Rice-potato-mungbean cropping system resulted in a negative balance of available P and rice-clover cropping system had a negative balance of both available P and available K content in soil and thus call for adequate P and K fertilization. Application of P and K helped in building up their content in soil; NPK?+?FYM showed the highest increase in organic C, available N, available P and available K content in soil. These results suggest the inclusion of a legume in a cropping system for maintaining organic C and available N in soil and adequate P and K fertilization for arresting the depletion of available P and K content in soil. Integrated nutrient management is one of the best methods for resilience of soil fertility under rice-wheat cropping system.     

System productivity,nutrient use efficiency and apparent nutrient balance in rice-based cropping systems

A 2-year field experiment was conducted to assess system productivity, nutrient use efficiency and apparent balances of phosphorus (P) and potassium (K) in diversified rice-based cropping systems at Gazipur, Bangladesh. Four cropping systems: wheat–fallow–rice, maize–fallow–rice, potato–fallow–rice and mustard–fallow–rice in main plots and four nutrient combinations: NPK, NK, NP and PK in sub-plots were arranged in a split-plot design with three replications. Receiving the NPK treatment, all the component crops gave the highest yield, and omission of N from fertilizer package gave the lowest yield. The maize–rice system removed the highest amount of N (217 kg ha^?1), P (41 kg ha^?1) and K (227 kg ha^?1) followed by wheat–rice, potato–rice and the least in mustard–rice system. The wheat–rice and maize–rice system showed negative K balance of –35.5 and –60.4 kg ha^?1 in NPK treatment, while potato–rice system showed a positive K balance of 31.0 kg ha^–1 with NPK treatment. The N, P and K uptake and apparent recovery by the test crops may be used for site-specific nutrient management. The K rates for fertilizer recommendation in wheat and maize in Indo-Gangetic plain need to be revised to take account for the negative K balance in soil.     

轮作体系下冬油菜养分利用效率的区域研究

Fertilization is essential for oilseed rape because it is sensitivity to nutrient deficiency, especially for winter oilseed rape(Brassica napus L.). To investigate regional nutrient efficiency and nutrient uptake-yield relationship of winter oilseed rape in an intensive cropping system, this study used data from 619 site-year on-farm experiments carried out in the winter oilseed rape planting area of the Yangtze River Basin, China from 2005 to 2010, with large yield in the range of 179–4 470 kg ha~(-1). Currently recommended application rates of N, P and K fertilizers increased rapeseed yield at different levels of soil indigenous nutrient supply(INS) in this region. Boundary values of plant nutrient uptake were established to analyze the nutrient uptake-yield relationship of winter oilseed rape(internal nutrient efficiency), i.e., 128 kg N ha~(-1), 24 kg P ha~(-1), and 122 kg K ha~(-1). The internal nutrient efficiency declined by 48.2%–64.1% when nutrient uptake exceeded the boundary value, resulting in excessive nutrient uptake(i.e., low yield response with high nutrient uptake), especially for K. In the intensive cropping system, agronomic efficiencies of N, P, and K were 5.9, 3.4, and3.6 kg kg~(-1), and recovery efficiencies of N, P, and K were 35.6%, 24.1%, and 36.8%, respectively. These findings showed that the fertilization rate should be optimized by considering INS, nutrient status, and nutrient efficiency of winter oilseed rape. In this study,considering the lower yield improvement to high K uptake levels and low K fertilizer efficiency, application rate of K fertilizer should be reduced since soil K deficiency has already been mitigated.     

Carbon and nutrient budgets of the Chagga home garden system in the Kilimanjaro highlands,Tanzania

Sustainable land management of smallholder farms is crucial for ensuring food security in sub-Saharan Africa. However, little is known about the nutrient dynamics of smallholder farming systems at the farm level based on primary data. In this study, carbon (C) and nutrient budgets of the home garden system in the Kilimanjaro highlands, where Andosols predominate, were quantified at the farmer's field. We evaluated (1) the soil C and nutrient flow in the main three land-use blocks (banana (Musa spp.) garden, maize (Zea mays L.) field and grassland) in one representative home garden and (2) the internal flow between farmland and livestock and the external nutrient flow across the inside and outside of the six home gardens. Intensive applications of livestock dung to the banana trees resulted in a positive C budget (7.2 Mg C ha⁻¹ year⁻¹) in the banana garden. Nitrogen loss through the harvesting of feed and crops was almost balanced with the livestock dung application, while nitrogen loss through leaching only accounted for 3% of that applied. Banana productivity has been maintained despite a negative potassium budget (−241 kg K ha⁻¹ year⁻¹), probably owing to the replenished exchangeable potassium from Andosols. In the maize field, the C budget was negative (−1.7 Mg C ha⁻¹ year⁻¹) owing to high organic matter decomposition. Carbon and nutrient budgets in the grassland were all negative. Our results revealed that the village average livestock density (4.4 TLU ha⁻¹: TLU means tropical livestock unit) was sufficient for P, Ca and Mg balance in the home garden, whereas it was not sufficient for N and K balance. Increasing livestock density improved the nutrient balance of the system. However, it is noteworthy that 33%–47% of the feed supplied as C and nutrients was collected from outside the home gardens, suggesting a high reliance on external inflow to fulfil feed demands. In conclusion, intensive livestock dung application to banana cultivation was fundamental for maintaining agricultural productivity to replenish the nutrients lost from the system. At the same time, this system was sustained not only by C and nutrient cycling within the system, but also by transporting resources from the external environment into the system.     

Influence of Soil and Fertilizer Nutrients on Sustainability of Rainfed Finger Millet Yield and Soil Fertility in Semi-arid Alfisols

Productivity of rainfed finger millet in semiarid tropical Alfisols is predominantly constrained by erratic rainfall, limited soil moisture, low soil fertility, and less fertilizer use by the poor farmers. In order to identify the efficient nutrient use treatment for ensuring higher yield, higher sustainability, and improved soil fertility, long term field experiments were conducted during 1984 to 2008 in a permanent site under rainfed semi-arid tropical Alfisol at Bangalore in Southern India. The experiment had two blocks—Farm Yard Manure (FYM) and Maize Residue (MR) with 5 fertilizer treatments, namely: control, FYM at 10 t ha^?1, FYM at 10 t ha^?1 + 50% NPK [nitrogen (N), phosphorus (P), potassium (K)], FYM at 10 t ha^?1 + 100% NPK (50 kg N + 50 kg P + 25 kg K ha^?1) and 100% NPK in FYM block; and control, MR at 5 t ha^?1, MR at 5 t ha^?1 + 50% NPK, MR at 5 t ha^?1 + 100% NPK and 100% NPK in MR block. The treatments differed significantly from each other at p < 0.01 level of probability in influencing finger millet grain yield, soil N, P, and K in different years. Application of FYM at 10 t ha^?1 + 100% NPK gave a significantly higher yield ranging from 1821 to 4552 kg ha^?1 with a mean of 3167 kg ha^?1 and variation of 22.7%, while application of maize residue at 5 t ha^?1 + 100% NPK gave a yield of 593 to 4591 kg ha^?1 with a mean of 2518 kg ha^?1 and variation of 39.3% over years. In FYM block, FYM at 10 t ha^?1 + 100% NPK gave a significantly higher organic carbon (0.45%), available N (204 kg ha^?1), available P (68.6 kg ha^?1), and available K (107 kg ha^?1) over years. In maize residue block, application of MR at 5 t ha^?1 + 100% NPK gave a significantly higher organic carbon (0.39%), available soil N (190 kg ha^?1), available soil P (47.5 kg ha^?1), and available soil K (86 kg ha^?1). The regression model (1) of yield as a function of seasonal rainfall, organic carbon, and soil P and K nutrients gave a predictability in the range of 0.19 under FYM at 10 t ha^?1 to 0.51 under 100% NPK in FYM block compared to 0.30 under 100% NPK to 0.67 under MR at 5 t ha^?1 application in MR block. The regression model (2) of yield as a function of seasonal rainfall, soil N, P, and K nutrients gave a predictability in the range of 0.11 under FYM at 10 t ha^?1 to 0.52 under 100% NPK in FYM block compared to 0.18 under MR at 5 t ha^?1 + 50% NPK to 0.60 under MR at 5 t ha^?1 application in MR block. An assessment of yield sustainability under different crop seasonal rainfall situations indicated that FYM at 10 t ha^?1 + 100% NPK was efficient in FYM block with a maximum Sustainability Yield Index (SYI) of 41.4% in <500 mm, 64.7% in 500–750 mm, 60.2% in 750–1000 mm and 60.4% in 1000–1250 mm rainfall, while MR at 5 t ha^?1 + 100% NPK was efficient with SYI of 29.6% in <500 mm, 50.2% in 500–750 mm, 40.6% in 750–1000 mm, and 39.7% in 1000–1250 mm rainfall in semi-arid Alfisols. Thus, the results obtained from these long term studies incurring huge expenditure provide very good conjunctive nutrient use options with good conformity for different rainfall situations of rainfed semiarid tropical Alfisol soils for ensuring higher finger millet yield, maintaining higher SYI, and maintaining improved soil fertility.     

Long-term fertilizer trials on loam soil at M⊘ystad,south-eastern Norway: Crop yields,nutrient balances and soil chemical analyses from 1983 to 2003

Abstract

Factorial combinations of N, P and K fertilizer have been compared with the use of farmyard manure at M?ystad since 1922 in a seven-year crop rotation (3 ley, oat, potato, wheat, barley). Until 1982, low inputs of N fertilizer (22 kg ha^?1) were used. In 1983, they were brought into line with current farming practice. This paper presents the results of three subsequent rotations. Yields without any fertilizer were on average 48% of those with 100 kg N ha^?1 in compound fertilizer, whilst those with 20, 40 and 60 Mg ha^?1 farmyard manure were 81, 87 and 90%, respectively. Yields with other combinations of N, P and K declined in the order NP, NK, N, PK and K. When NPK fertilizer was used, apparent recoveries of applied fertilizer were close to 50% for N and K, and around 40% for P. Much lower values were found for nutrients applied singly. Balance between N supply and removal was indicated at rates of about 60 kg N fertilizer ha^?1 in potatoes, 75 kg ha^?1 in cereals and 90 kg ha^?1 in leys. A surplus of P was found in all crops at all N levels, and of K in cereals and potatoes. In leys, K balance was achieved with an N supply of 90 kg N ha^?1. Nutrient balance was indicated at a little below 20 Mg ha^?1 yr^?1 farmyard manure. Larger manure applications gave large nutrient surpluses, particularly of N. Soil reaction remained close to neutral with the use of calcium nitrate and manure, but declined with the use of ammonium nitrate. Manure use gave the highest amounts of available P, K and Mg in soil. Similar increases in total inorganic P were found with manure use as with fertilizer use, but amounts of organic P and total K were little affected.     

Potassium leaching from cut grassland and from urine patches

In grassland farming, especially on coarse‐textured soils, K can be a critical element. On these soils, the actual K management as well as fertilizer history to a large extent determine the leaching of K. The effects of four fertilizer regimes on the nutrient balances and leaching of K from grassland grown on a sandy soil were investigated. The swards differed in the source and level of N input and K fertilizer: no fertilizer N + 166 kg K ha^?1 year^?1 (Control), 320 kg inorganic N ha^?1 + 300 kg K ha^?1 year^?1 (MIN 320), 320 kg N + 425 kg K ha^?1 year^?1 in form of cattle slurry (SLR 320) and a grass–clover sward + 166 kg K ha^?1 year^?1 (WCL 0) without any inorganic N input. In a second experimental phase, cores from these swards were used in a mini‐lysimeter study on the fate of K from urine patches. On cut grassland after 6 years K input minus removal in herbage resulted in average K surpluses per year of 47, 39, 56 and 159 kg K ha^?1 for the Control, MIN 320, WCL 0 and SLR 320, respectively. Related leaching losses per year averaged 7.5, 5, 15 and 25 kg K ha^?1. Losses of urinary‐K through leaching were 2.2–4.5 and 5.7–8.4% of the K supplied in summer and autumn applications, respectively. Plant and soil were the major sinks for K from fertilizer or urine. High levels of exchangeable K in the soil and/or large and late fertilizer or urine applications stimulated leaching of K.     

Effects of Organic and Inorganic Fertilizers on Soil and Plant Nutrients and Yields of Pearl Millet and Wheat under Semi-arid Inceptisols in India

A study was conducted to assess fertilizer effect on pearl millet–wheat yield and plant-soil nutrients with the following treatments: T₁, control; T₂, 100% nitrogen (N); T₃, 100% nitrogen and phosphorus (NP); T₄, 100% nitrogen, phosphorus and potassium (NPK); T₅, 100% NPK + zinc sulfate (ZnSO₄) at 25 kg ha^?1; T₆, 100% NPK + farmyard manure (FYM) at 10 t ha^?1; T₇, 100% NPK+ verimcompost (VC) at 2.5 tha^?1; T₈, 100% NPK + sulfur (S) at 25 kg ha^?1; T₉, FYM at 10 t ha^?1; T₁₀, VC at 2.5 t ha^?1; T₁₁, 100% NPK + FYM at 10 t ha^?1 + 25 kg S ha^?1 + ZnSO₄ at 25 kg ha^?1; and T₁₂, 150% NPK treatments. Treatments differed significantly in influencing soil-plant nutrients and grain and straw yields of both crops. Grain yield had significant correlation with soil-plant N, P, K, S, and zinc (Zn) nutrients. The study indicated superiority of T₁₁ for attaining maximum pearl millet grain yield (2885 kg ha^?1) and straw yield (7185 kg ha^?1); amounts of N (48.9 kg ha^?1), P (8.8 kg ha^?1), K (26.3 kg ha^?1), S (20.6 kg ha^?1), and Zn (0.09 kg ha^?1) taken up; and amounts of soil N (187.7 kg ha^?1), P (13.7 kg ha^?1), K (242.5 kg ha^?1), S (10.1 kg ha^?1), and Zn (0.70 kg ha^?1). It was superior for wheat with grain yield (5215 kg ha^?1) and straw yield (7220 kg ha^?1); amounts of N (120.7 kg ha^?1), P (13.8 kg ha^?1), K (30 kg ha^?1), S (14.6 kg ha^?1), and Zn (0.18 kg ha^?1) taken up; and maintaining soil N (185.7 kg ha^?1), P (14.5 kg ha^?1), K (250.5 kg ha^?1), S (10.6 kg ha^?1), and Zn (0.73 kg ha^?1). Based on the study, 100% NPK + FYM at 10 tha^?1 + Zn at 25 kg ha^?1 + S at 25 kg ha^?1 could be recommended for attaining maximum returns of pearl millet–wheat under semi-arid Inceptisols.     

Long‐term effects of fertilization on some soil properties under rainfed soybean‐wheat cropping in the Indian Himalayas

This study aims to examine the effects of long‐term fertilization and cropping on some chemical and microbiological properties of the soil in a 32 y old long‐term fertility experiment at Almora (Himalayan region, India) under rainfed soybean‐wheat rotation. Continuous annual application of recommended doses of chemical fertilizer and 10 Mg ha^–1 FYM on fresh‐weight basis (NPK + FYM) to soybean (Glycine max L.) sustained not only higher productivity of soybean and residual wheat (Triticum aestivum L.) crop, but also resulted in build‐up of total soil organic C (SOC), total soil N, P, and K. Concentration of SOC increased by 40% and 70% in the NPK + FYM–treated plots as compared to NPK (43.1 Mg C ha^–1) and unfertilized control plots (35.5 Mg C ha^–1), respectively. Average annual contribution of C input from soybean was 29% and that from wheat was 24% of the harvestable aboveground biomass yield. Annual gross C input and annual rate of total SOC enrichment from initial soil in the 0–15 cm layer were 4362 and 333 kg C ha^–1, respectively, for the plots under NPK + FYM. It was observed that the soils under the unfertilized control, NK and N + FYM treatments, suffered a net annual loss of 5.1, 5.2, and 15.8 kg P ha^–1, respectively, whereas the soils under NP, NPK, and NPK + FYM had net annual gains of 25.3, 18.8, and 16.4 kg P ha^–1, respectively. There was net negative K balance in all the treatments ranging from 6.9 kg ha^–1 y^–1 in NK to 82.4 kg ha^–1 y^–1 in N + FYM–treated plots. The application of NPK + FYM also recorded the highest levels of soil microbial‐biomass C, soil microbial‐biomass N, populations of viable and culturable soil microbes.     

Nutrient storage in termite (Macrotermes bellicosus) mounds and the implications for nutrient dynamics in a tropical savanna Ultisol

The role of mounds of the fungus-growing termite Macrotermes bellicosus (Smeathman) in nutrient recycling in a highly weathered and nutrient-depleted tropical red earth (Ultisol) of the Nigerian savanna was examined by measuring stored amounts of selected nutrients and estimating their rates of turnover via the mounds. A study plot (4?ha) with a representative termite population density (1.5?mounds?ha^?1) and size (3.7?±?0.4?m in height, 2.4?±?0.2?m in basal diameter) of M. bellicosus mounds was selected. The mounds were found to contain soil mass of 9249?±?2371?kg?ha^?1, composed of 7502?±?1934?kg?ha^?1 of mound wall and 1747?±?440?kg?ha^?1 of nest body. Significant nutrient enrichment, compared to the neighboring topmost soil (Ap1 horizon: 0–16?cm), was observed in the nest body for total nitrogen (N) and exchangeable calcium (Ca), magnesium (Mg) and potassium (K), and in the mound wall for exchangeable K only. In contrast, available (Bray-1) phosphorus (P) content was found to be lower in both the mound wall and the nest body than in the adjacent topmost soil horizon. Consequently, the mounds formed by M. bellicosus contained 1.71?±?0.62?kg?ha^?1 of total N, 0.004?±?0.003?kg?ha^?1 of available P, 3.23?±?0.81?kg?ha^?1 of exchangeable Ca, 1.11?±?0.22?kg?ha^?1 of exchangeable Mg and 0.79?±?0.21?kg?ha^?1 of exchangeable K. However, with the exception of exchangeable K (1.2%), these nutrients amounted to less than 0.5% of those found in the topmost soil horizon. The soil nutrient turnover rate via M. bellicosus mounds was indeed limited, being estimated at 1.72?kg?ha^?1 for organic carbon (C), 0.15?kg?ha^?1 for total N, 0.0004?kg?ha^?1 for available P, 0.15?kg?ha^?1 for exchangeable Ca, 0.05?kg?ha^?1 for exchangeable Mg, and 0.06?kg?ha^?1 for exchangeable K per annum. These findings suggest that the mounds of M. bellicosus, while being enriched with some nutrients to create hot spots of soil nutrients in the vicinity of the mounds, are not a significant reservoir of soil nutrients and are therefore of minor importance for nutrient cycling at the ecosystem scale in the tropical savanna.     

Leaching and crop uptake of N, P and K from organic and conventional cropping systems on a clay soil

In this study, three types of cropping systems with different nutrient management strategies were studied on a clay soil with the aim of comparing leaching of N, P and K and obtaining knowledge on nutrient budgets. A conventional cropping system with cereals and application of mineral fertilizers (CON) was compared with two organic cropping systems, one without animal manure in which green manure crops were used for N supply (OGM) and one where animal manure (cattle slurry) was applied (OAM). Leaching and crop uptake of N, P and K, and soil mineral N were measured in pipe‐drained plots over a 6‐year period. The mean annual leaching loads of N were moderate and did not differ significantly (P > 0.05) between treatments; 13 kg N ha^?1 in CON, 11 kg N ha^?1 in OGM and 7.4 kg N ha^?1 in OAM. Average annual P leaching showed greater variation than N leaching and was significantly greater in OGM (0.81 kg ha^?1 year^?1) than in CON (0.36 kg ha^?1) and OAM (0.41 kg ha^?1). For all cropping systems, removal in harvested crops was the most important export of nutrients from the field and constituted between 80 and 94% of total N outputs (harvested and leached N). Yields of cereals in the organic systems were considerably less (15–50%) than in the CON system, leading to a less efficient use of N than in the conventional system.     

On-Farm Participatory Technology Development Effects on Resource Conservation Technologies in Rainfed Upland Paddy in Himachal Pradesh,India

Rice is a major cereal crop in Himachal Pradesh, a Himalayan state of India, where paddy acreage is about 78,000 ha with a low average yield of 19.62 q ha^?1 due to rainfed upland farming. High seeding rates and poor resource-use efficiency of conventional fertilizer nitrogen (N) management practices in rainfed upland paddy have also been major production constraints in rainfed upland ecosystems. To validate and refine the production technology on seed rate and fertilizer N management, the Farm Science Centre, Sundernagar, India, conducted numerous on-farm trials (OFTs) during 2006–2010 under an on-farm participatory technology development approach to enhance resource use efficiency through these resource conservation technologies and boost the paddy productivity in the region. Results of two OFTs conducted during Kharif 2006 in the Mandi District of Himachal Pradesh on different seed rates under different sowing methods on VL Dhan-221 and Sukaradhan-1 (HPR-1156) cultivars suitable for rainfed upland conditions revealed that the seed rate at 80 kg ha^?1 sown in rows 20 cm apart resulted in the greatest average paddy productivity to the tune of 25.6 q ha^?1 besides greater profitability, followed by a seed rate at 60 kg ha^?1 sown in rows 20 cm apart (25.2 q ha^?1), over the earlier State Agricultural University (SAU)–recommended practice, that is, seed rate at 100 kg ha^?1 in rows 20 cm apart. This refinement in the seed rate was accepted by the participating farmers of the region. The greatest average benefit/cost (B/C) ratio was observed in plots with seed rate at 60 kg ha^?1 sown in rows 20 cm apart. Based on these results and data compilation from other locations of the state, now the SAU has refined the seed rate from earlier recommendation of 100 kg ha^?1 to 60 kg ha^?1 in rows 20 cm apart as well as 80 kg ha^?1 through broadcast method under rainfed upland paddy in Himachal Pradesh. Results of two OFTs conducted during Kharif 2009 on integrated nutrient management in rainfed upland paddy revealed that farmyard manure (FYM) at 10 t ha^?1 + nitrogen, phosphorus, and potassium (N, P, K) at 15:30:30 kg ha^?1 at sowing followed by 15 kg N ha^?1 15 days after sowing (DAS) and remaining the N [i.e., 30 kg N ha^?1] at tillering (45–50 DAS) resulted in the greatest grain yield of 29.85 and 31.67 q ha^?1 in VL Dhan-221 and HPR-1156, respectively, with respective greater yields of 35.99 and 36.51% over farmers’ practice, besides better profitability. To further standardize fertilizer N split doses and assess their effect on paddy productivity, another OFT was conducted during Kharif 2010 under rainfed upland paddy conditions in HPR-1156. The results revealed that NPK at 60:30:30 kg ha^?1 (whole of P and K as basal, 50% N at 15 DAS, 25% N each at 45–50 DAS and 70–75 DAS splits) resulted in better grain yield (34.3 q ha^?1) and net profitability (?29,786 ha^?1) over other treatments. Overall, it is concluded that these resource conservation technologies developed under the OFT participatory approach can enhance the rainfed upland paddy productivity and strongly show that there is dire need to split the N requirement of rainfed upland paddy in 2–3 splits to reduce the fertilizer N losses, enhance resource-use efficiency, and increase productivity and profitability in Himachal Pradesh, India.     

Nitrogen use Rationalization and Boosting Wheat Productivity by Applying Packages ‎of Humic,Amino Acids,and Microorganisms

ABSTRACT

Integrated management of soil organic matter and nutritional status of crop plants is essential to sustain the production of organic farming systems. Thus, a 2–year field experiment was conducted to examine the effects of soil additions (192 kg N ha^–1, humic+192 kg N ha^–1, humic+144 kg N ha^–1 and humic+96 kg N ha^–1) and foliar applications (amino acids, Azotobacter+yeast, and amino acids plus Azotobacter+yeast) as various fertilizer resources on growth and yield of wheat. Results showed that humic+192 kg N ha^–1 × amino acids plus Azotobacter+yeast were the effective combination for producing the highest values of flag leaf area, total dry weight, tiller number m^–2, spike weight m^–2, and grain yield ha^–1. Under foliar application of amino acids plus Azotobacter+yeast, reducing N supply from recommended rate (192 kg N ha^–1) to 144 kg N ha^–1+ humic achieved higher values of all yield traits, with a saving of 25% of applied mineral nitrogen as well as enhancing nitrogen use efficiency.