Nutritional standards and nutritional diagnosis of the Conilon coffee plants in phenological growth stages

The objective of this study was to establish a nutrient sufficiency range and DRIS standards of Conilon coffee grown in southern Bahia, Brazil for the pre-flowering and grain-filling stages and to perform a nutritional diagnosis of these plants using different methods. The collections were performed in 24 Conilon coffee farm fields to establish the leaf nutritional standards, and 278 samples were collected to the nutritional diagnosis. The nutritional diagnosis was performed by using the sufficiency range criterion and the DRIS method. The nutrient sufficiency range and the DRIS standards must be specific to each phenological stage of the Conilon coffee plants. The leaf concentrations of calcium (Ca), sulfur (S), and boron (B) were higher in the pre-flowering stage; and the leaf concentrations of nitrogen (N), potassium (K), copper (Cu), and zinc (Zn) were higher in the grain-filling stage.     

Gas exchanges and chlorophyll fluorescence of young coffee plants submitted to water and nitrogen stresses

Abstract

This research aims to evaluate the impact of nitrogen deprivation and water stress on gas exchange and chlorophyll fluorescence in young plants of five cultivars of Arabic coffee. A factorial experiment 5 (cultivars) × 3 (treatments: control without stress, water stress of ?1.5?MPa and stress of N – 0.0?mmol L^?1 N) was carried out in a complete randomized block design with three replicates. Before being submitted to the treatments, the plants were grown in a greenhouse for 240?days, and then transferred to a growth chamber under controlled conditions. Subsequently, after the experimental period of 96?h we measured photosynthetic rate (A), stomatal conductance to water vapor (g_s), transpiratory rate (E), internal and external carbon ratio (Ci/Ca), water use efficiency (A/E), electron transport rate (ETR), actual quantum yield of PS II electron transport (φFSII), and maximum photochemical efficiency of PS II (Fv/Fm). Water stress reduced A, g_s, E, A/E, ETR, φFSII, and Fv/Fm. The nitrogen deficiency reduced ETR, φFSII, and Fv/Fm. Under short-term water stress Catuaí Vermelho maintain the A values due to better stomatal control, reduced water lost by transpiration (E) and better water use efficiency A/E, while Mundo Novo and Acauã show lower damage to Fv/Fm. Short-term nitrogen stress has low impact on A of young plants of Coffea arabica cultivars with adequate N-nutrition.     

Dynamics of Macro- and Micronutrients in Cuphea

Temporal dynamics of nutrient densities, their interrelationships, and remobilization from leaves to seeds of cuphea were quantified in growth chamber and field studies. Temporal nutrient densities in leaf samples exhibited large levels of variation, whether remobilized and largely accumulated in the seed [copper, (Cu), potassium (K), phosphorus (P), sulfur (S) and zinc (Zn)], remobilized and accumulated in the seed coat [boron (B), calcium (Ca), iron (Fe), magnesium (Mg), manganese (Mn), and sodium (Na)] or almost excluded from the seed [barium (Ba), selenium (Se) and strontium (Sr)]. The temporal seed-to-leaf nutrient density “[S]/[L]” ratios and the proportion of variance unique to each nutrient separated the nutrients into a group (Cu, Fe, S, and Zn) with large [S]/[L] ratios and large unique variances, and another group (B, Ca, Mg, Mn and Sr) with small [S]/[L] ratios and small unique variances; the first group was selectively stored in the developing embryo. Nutrients with large densities in leaves at harvest may constitute a resource potentially available for subsequent crops.     

冬油菜叶片的物质及养分积累与转移特性研究

为优化当季和下季作物的养分管理,采用田间试验研究了冬油菜品种:华双5号与中油杂12号叶片的干物质及氮、磷、钾的积累及转移规律,并比较了品种间的异同。结果表明,两个油菜品种的绿叶干物质量在苗后期基本达最大值,花后期迅速降低;苗期的落叶干物质量较小,蕾薹期后直线增加;叶片总干物质先增后减,花期达最大值。中油杂12号的落叶及叶片总干物质均高于华双5号,差异随生育期的推进逐渐明显。绿叶氮含量出苗后逐渐降低,后因越冬肥的施用又略有升高,蕾薹期后便迅速下降;落叶氮含量持续降低,苗后期降至最低点,其后一直保持稳定。绿叶磷含量在苗期缓慢增加,蕾薹期达到最大值,而后迅速下降;苗期落叶的磷含量逐渐降低,蕾薹期降至最低值,角果期后又略有升高。出苗50d后绿叶钾含量快速下降,70d达到最低值,其后保持稳定;落叶钾含量在蕾薹期达到最低值,其后波动较大。两品种叶片养分含量的变化趋势相似,但无论绿叶还是落叶,华双5号的养分含量总体略低于中油杂12号。绿叶的养分与叶片总养分积累的变化规律一致,即氮、磷、钾积累量均先增加后降低,分别在蕾薹期、苗后期和花期达到最高值。落叶的养分积累量在抽薹后迅速增加,收获期达最大值。华双5号叶片的干物质、N、P2O5、K2O转移率分别为25.5%、82.9%、75.4%、45.8%;中油杂12号则分别为8.4%、76.0%、60.2%、38.8%,品种间差异显著。     

Nutrient leaching from the plow layer by water percolation and accumulation in the subsoil in an irrigated paddy field

To estimate the impact of water percolation on the nutrient status in paddy fields, the seasonal variations of the concentrations of cations, anions, inorganic carbon (IC), and of dissolved organic carbon (DOC) in percolating water that was collected from just below the plow layer (PW-13) and from drainage pipes at the 40 em depth (PW-40), as well as in irrigation water were measured in an irrigated paddy field. Total amounts of Ca, Mg, K, Fe, and Mn leached from PW-13 during the period of rice cultivation were estimated to range from about 390 to 770, 65 to 130, 33 to 66, 340 to 680, and 44 to 87 kg ha^-1, respectively. Amounts of losses that were estimated from the differences between the input by irrigation water and the output by percolation water from the plow layer corresponded to 11 to 26, 22 to 47,5.9 to 12, and 13 to 26% of exchangeable Ca and Mg, amorphous Fe, and easily reducible Mn in the plow layer, respectively. The concentrations of Ca, Mg, K, Fe, and Mn in PW13 were higher than those in PW-40. The amounts of these nutrients that were retained in the subsoil between the 13 em and 40 em soil depth corresponded to 83, 86, 61, 99, and 89% of the amounts that percolated from the plow layer, respectively. Total amounts of IC and DOC that percolated from the plow layer ranged from 750 to 1,500 and 85 to 170 kg-C ha^-1, which corresponded to 5.0 to 10.0% and 0.6 to 1.1% of the total carbon content in the plow layer, respectively. Eighty eight % of IC in the percolating water from the plow layer was also retained in the subsoil.     

Comparison of nutrient concentrations in leaves of five plants

The paper describes investigation on bioaccumulation of mineral elements and identification of plants based on the concentrations of the elements in the plant leaves. Five native plant species (Elytrigia repens, Plantago major, Urtica dioica, Chelidonium majus, and Taraxacum officinale) were studied. To exclude the effects from different growth conditions and developmental stages, the plants were collected simultaneously from the same site (park in St. Petersburg, Russia). It was found that for all plants high concentrations of potassium, sodium, phosphorus and magnesium (K, Na, P, and Mg) were typical, while concentrations of zinc (Zn) and copper (Cu) were the lowest. The most significant difference was found between concentrations of elements in monocots and eudicots. Among other species, T. officinale had the highest concentrations of almost all elements. Excellent separation of the plants into different groups which was due to different element concentrations in the plant leaves was demonstrated.     

Growth and nutritional disorders of coffee cultivated in nutrient solutions with suppressed macronutrients

The objective was to evaluate the effect of omitting macronutrients in the nutrients solution on growth characteristics and nutritional status of coffee. The treatments were complete nutrients solutions and solutions with nutrient omission: N (nitrogen), P (phosphorus), K (potassium), Ca (calcium), Mg (magnesium) and S (sulfur). The experiment was carried out under greenhouse conditions with 3 replicates in a completely random design. Plant height, number of leaves per plant, stem diameter, relative chlorophyll index, photosynthesis rate, stomatal conductance, transpiration, carbon dioxide (CO₂) concentration, dry matter, content levels of macronutrients in plant aerial part and root system, and nutritional disorders were evaluated. Macronutrients suppression affected nutrients concentration in many plant parts, inducing the appearance of symptoms characteristic of each nutrient. The most limiting nutrients for coffee plants development were nitrogen and calcium, reflected in the lower dry matter accumulation and nitrogen the most required.     

Using Moringa oleifera extract as biostimulant enhancing the growth,yield and nutrients accumulation of pea plants

Trials on the potentials of moringa for organic farming have shown that leaves contain substances, which when sprayed on crops enhance growth and yield of crops. Moringa is nutrient-rich plant with combination of antioxidants, amino acids, nutrients, potassium (K), calcium (Ca), iron (Fe) and vitamins. A field experiment was conducted on a sandy soil conditions at Salhia El-gdida county, El-Sharkia Government, Egypt during the growth seasons of 2014/2015 to study the effect of moringa leaves extract (MLE) at different rates on yield and nutrient accumulation of pea plants (pisum sativum L.). Foliar spraying of MLE was done in three equal doses at 25, 35 and 45 after planting at a rate of 0%, 1%, 2%, 3% and 4%. All treatments of MLE significantly increased fresh pods yield, shoot and seeds dry weight, biological yield, 100 seed weight, yield efficiency, protein content and nutrient accumulation as compared to control. The highest values of photosynthetic pigments, growth parameters and nutrient accumulation of plants were obtained with 4% of MLE. Also, the highest percentage increase in fresh pods yield and protein content of 82.5% and 45%, respectively, was recorded from the treatment of 4% MLE.     

新建日光温室土壤养分平衡与累积特性

连续3年定点监测位于黄土高原南部陕西杨凌的10余个新建日光温室栽培蔬菜种类、产量及施肥情况,并在每季作物种植前及收获后测定0~100 cm土壤电导率、有机质、全氮、有效磷、速效钾及0~200 cm土壤硝态氮等理化性质。结果表明,过量施用有机肥及化肥导致新建温室土壤养分大量盈余,前3年土壤氮、磷、钾养分(以N、P2O5、K2O计)表观盈余量之和分别高达3 784、4 097及2 727 kg/hm2。种植前3年有机质、全氮呈线性增加,年均增加量分别为4.25、0.25 g/kg;土壤有效磷、速效钾累积更加突出,种植2年后,耕层有效磷及速效钾已达高或极高水平;随着种植年限的增加,土壤剖面硝态氮累积量显著增加,耕层以下土壤有效磷、速效钾含量也有所增加。说明新建日光温室在种植初期就存在施肥过量问题,由此引发的问题值得关注。     

Effect of copper sprays oh the mineral nutrient content and growth of arabica coffee seedlings in Kenya

Abstract

Coffea arabica L. seedlings (cv. S.L.34) were sprayed with varying concentrations of cuprous oxide at 0.0, 0.25, 0.50 and 0.75% for 30 days. Significant increases in the total mean fresh and dry weight; rate of transpiration; stomatal apertures; the total leaf area and plant vigor were observed on the seedlings with increasing concentrations of Cu treatments. The content of N, K, Ca and Cu were significantly increased in the seedlings at Cu spray treatments of 0.50 and 0.75% It is possible that the growth promoting effects produced in coffee by spraying high concentrations of copper is partly nutritional. This is brought about by the catalysing effects of the absorbed Cu ions, by accelerating enzymatic activities within the plant and hence increasing nutrient uptake.     

Impact of water percolation on nutrient leaching from an irrigated paddy field in Japan

Abstract. We examined the effect on soil nutrient status and sustainability of water percolation through an irrigated paddy field in Japan, to the depth of drainage (40 cm). The difference between amounts of nutrients leached by percolation and those supplied by irrigation indicated that 25–130 kg ha⁻¹ Ca, 8–24 kg ha⁻¹ Mg, from −1 to 9 kg ha⁻¹ K, and 8–17 kg ha⁻¹ Fe, respectively, were lost each year from the 0–40 cm soil layer during rice cultivation, when the supply from fertilization and rainfall and the loss in grain harvest were not accounted for. When the supply of K from rainfall and the loss in grain harvest were taken into account, a total K loss of about 10 kg ha⁻¹ was estimated. The electrical neutrality of inorganic ions in the percolating water was always maintained. From these results we estimate that the amounts of exchangeable Ca and Mg in the soil to a depth of 40 cm would decrease by 50% within 50–260 and 30–100 years, respectively, if similar management were continued without fertilization. The total amount of carbon dioxide (ΣCO₂) leached in percolating water during the period of rice cultivation was 120–325 kg C ha⁻¹, which corresponded to 0.47–0.94% of the soil organic carbon to 40 cm depth.     

Origin and properties of humus in the subsoil of irrigated rice paddies

A pot experiment was conducted to estimate the amount of dissolved organic carbon (DOC) leached from the submerged plow layer of rice paddies during the cultivation period and its accumulation in the subsoil. Organic matter in the leachate was fractionated using insoluble polyvinylpyrrolidone (PVP) which can adsorb aromatic components having hydroxyl and/or carboxyl groups. Total amount of DOC leached throughout the growth period of rice plant corresponded to ca. 0.5% of total-C in the plow layer soil sample (total C, 17.8 g kg^-1) irrespective of the presence of rice plant, and the PVP-adsorbed fraction accounted for 34–43% of it. The amount of DOC in the leachate decreased by more than 50%, and that of the PVP-adsorbed and non-adsorbed fractions decreased by 79–82 and 45–47% by passing through the subsoil packed in the glass columns, respectively. The decreases were considered to be due to the adsorption to the subsoil, since a corresponding increase was observed in the total carbon content in the subsoil. Successive extraction of organic matter from the subsoil before and after the rice growth period with water, 0.25 M NaNSON and 0.1 m Na₄P₂O₇ (pH 7.0) solutions showed that the amount of organic carbon adsorbed on PVP mainly increased in the Na₄P₂O₇ (pH 7.0)-extractable fractions during the rice growth period, while the amount of organic carbon non-adsorbed on PVP increased in all the fractions extracted. These results suggested that the PVP-adsorbed fractions in the leachate were adsorbed to the subsoil mainly by coordinate bonding while the PVP-non-adsorbed fractions were adsorbed by physical adsorption, weak hydrogen bonding, ion bonding, and coordinate bonding.     

在施钾条件下灌溉水稻的养分吸收和利用效率研究

Potassium is one of the most important nutrients for rice production in many areas of Asia, especially in southeast China where potassium deficiency in soil is a widespread problem. Field experiments were conducted for four consecutive years in Jinhua City, Zhejiang Province, to determine utilization of nutrients (N, P and K) by inbred and hybrid rice and rice grain yields as affected by application of potassium fertilizer under irrigated conditions. Grain yield and nutrient harvest index showed a significant response to the NPK treatment as compared to the NP treatment. This suggested that potassium improved transfer of nitrogen and phosphorus from stems and leaves to panicles in rice plants. N and P use efficiencies of rice were not strongly responsive to potassium, but K use efficiency decreased significantly despite the fact that the amount of total K uptake increased. A significant difference between varieties was also observed with respect to nutrient uptake and use efficiency. Hybrid rice exhibited physiological advantage in N and P uptake and use efficiency over inbred rice. Analysis of annual dynamic change of exchangeable K and non-exchangeable K in the test soil indicated that non-exchangeable K was an important K source for rice. Potassium application caused an annual decrease in the concentration of available K in the soil tested, whereas an increase was observed in non-exchangeable K. It could be concluded that K fertilizer application at the rate of 100 kg ha^-1 per season was not high enough to match K output, and efficient K management for rice must be based on the K input/output balance.     

拔节期水分亏缺对沙地农田玉米光合特性及物质积累的影响

[目的]分析拔节期水分亏缺对玉米光合特性及物质分配规律的影响,为作物调亏灌溉技术在沙地农田的应用提供理论依据。[方法]在黑河流域中游边缘绿洲新垦沙地农田进行田间试验。[结果](1)玉米拔节期水分亏缺使新垦沙地农田0—40cm土层土壤含水量显著降低,农田CO2浓度升高0.5%,相对湿度降低6%,玉米叶片温度升高了8%;(2)水分亏缺处理玉米叶片净光合速率日均值比正常供水处理降低了74%;水蒸腾速率日均值比正常供水处理降低了79%;(3)水分亏缺处理玉米茎、叶及根系生物量分别比正常供水处理低63%,47%和51%,总干物质积累量比正常供水处理减少了53%。[结论]在沙地农田,作物对土壤水分的反映较为敏感,小幅的土壤含水量降低即造成玉米光合能力的大幅下降,并最终对光合产物的积累和分配产生不利影响。     

6种水土保持植物枝条的数量特征

植物枝条生物力学特性是研究植物地上部分防风抗蚀作用的基础。以内蒙古准格尔露天煤矿排土场平台和边坡上栽植的柠条、沙棘、紫花苜蓿、沙打旺、杨柴、草木犀6种常见水土保持植物的地上部分枝条为研究对象,研究枝条数量特征,确定其代表枝,从而为几种植物枝条生物力学性质的研究提供基础数据和相关参数。代表枝的确定将枝条以0.5 mm为一个径级进行分级,分别计算每个径级组的累计枝数量比例、累计枝长比例、累计枝表面积比例和累计枝干质量比例,取这4个值相对较大的径级组作为各自的代表枝。结果表明：柠条代表枝径级为0.5～1和1～1.5 mm,沙棘为1～1.5和1.5～2 mm,杨柴为0～0.5和0.5～1 mm,紫花苜蓿为0.5～1 mm,沙打旺为0.5～1和1～1.5 mm,草木犀为1～1.5 mm。因此,在内蒙古准格尔采煤矿区及相似地区,在植物防风抗蚀生物力学性质的研究中,建议以上述6种水土保持植物作代表枝径级为主要研究范围。     

Accumulation of calcium,magnesium, potassium and sodium with growth of individual leaves,petioles and stems of cucumber plants

Abstract

Accumulation of Ca, Mg, K and Na in each individual leaf, petiole and stem of the cucumber plant (Cucumis sativus L. cv. Kasairaku) was investigated in relation to the growth of these organs under water culture condition. Growth of each individual organ followed a sigmoidal curve showing two distinctive phases, the exponential and stationary phases. Accumulation patterns of these major cations showed a elose relationship with the growth characteristics of the organs.

1) Leaf Although the rate of accumulation of the cations declined during the stationary phase of growth, both Ca and Na accumulated in all the leaves throughout the whole period of growth. A higher Ca content was observed in the older leaves while the younger leaves showed a higher Na content. Mg and K accumulated during the exponential phase, whereas no appreciable accumulation was observed during the stationary phase.

2) Petiole and stem. Accumulation of Ca, Mg and Na continued throughout the whole period of growth. No deeline in the rate of accumulation of these cations was observed during the stationary phase unlike in the leaf, whereas K accumulation was observed only during the exponential phase of growth, as in the leaf.

All three organs showed that the content of these cations in each individual organ decreased during the exponential phase of growth. The rate of decrease was greater in younger organs than in older ones.     

Trace elements accumulation in soil and rice plants irrigated with the contaminated water

We carried out a study to see the effect of contaminated water of Nullah Dek on fine rice paddy and straw yields and trace elements accumulation in different parts of rice plants and soil. A site was selected near the bank of Nullah Dek at Kot Pindi Das in the District of Sheikhupura, Pakistan. The water of this nullah is contaminated by industrial effluents carrying different micronutrients. This water was employed to grow rice crop. Water samples were collected before transplanting and during the season with 15 days interval for analysis from 20 July to 1 November 2002 from a spot near village Shamke. Three fine rice varieties, viz. Super Basmati, Shaheen Basmati and Basmati 2000 were transplanted. These rice varieties were grown up to maturity. Paddy and straw yields data were recorded. Six composite soil samples from three random spots were collected from the experimental site before the start of the study to see the status of trace elements in soil. After the harvest of rice crop, soil, paddy and straw samples were analysed for Zn, Cu, Fe and Mn. The chemical analysis of Nullah Dek water showed that total salts concentration was greater than the safe limit, i.e. electric conductance (EC) > 1.0 dS m⁻¹. Even sodium adsorption ratio (SAR) was very high, but there was no problem of high residual sodium carbonate (RSC). Zn, Cu, Fe and Mn were present but within safe limits. The water of Nullah Dek remained within permissible limits of irrigation from onset of rainy season till 15 October. There was an increase in EC, SAR and trace elements concentrations after 15 October but within safe limits. Soil analysis revealed its saline nature, devoid of sodicity. Among trace elements, the zinc ranged between deficiency (<0.5 mg kg⁻¹) and adequate limits (>1.0 mg kg⁻¹). Copper, Mn and Fe were present in adequate amounts. After the harvest of rice crop there was a slight decrease in pH, EC_e and SAR at both the depths, while the concentrations of all trace elements were slightly increased with more in upper layer than the lower layer. Shaheen Basmati produced the maximum paddy yield followed by Basmati 2000 and then Super Basmati. The chemical analysis of paddy samples indicated a sufficient accumulation of zinc (1.68–1.78 mg kg⁻¹), copper (1.38–1.45 mg kg⁻¹), iron (6.12–6.37 mg kg⁻¹) and manganese (2.22–2.42 mg kg⁻¹). Analysis of rice straw also showed sufficient accumulation of zinc (27.50–28.50 mg kg⁻¹), copper (20.0–20.50 mg kg⁻¹), iron (270–280 mg kg⁻¹) and manganese (2.38–2.41 mg kg⁻¹).     

亏缺灌溉对马铃薯生长产量及水分利用的影响

为了解析马铃薯不同品种对水分亏缺的响应,探讨不同品种对水分需求量的差异,该研究在大田遮雨棚滴灌下,以马铃薯品种‘青薯9号’和‘大西洋’为材料,参考西北区和本试验区的年平均降雨量,设置5个水分处理,将参考试验区年平均降雨量的值划分为正常灌水(A),逐级调亏灌水量的值划分为轻度(B)、中度(C)、重度(D)和特重度(E)亏缺灌水处理,研究灌水量对不同品种马铃薯植株生长(株高、茎粗、叶面积)、生物量与分配、叶片相对含水量、产量与构成因素、水分利用的影响。结果表明:正常灌水下,‘青薯9号’株高增长速度大于‘大西洋’,且测定期内持续增高,但‘大西洋’叶面积快速扩增期的扩增速度大于‘青薯9号’;2个品种各器官干质量变化趋势不一致,‘大西洋’各器官干质量呈增长趋势,‘青薯9号’茎叶和根干质量呈前期增长后期下降、块茎干质量呈显著增加趋势(P0.05),且‘青薯9号’块茎生物量分配比例最高值为57.96%,仅是‘大西洋’最高值的67.43%;2个品种叶片相对含水量均呈先升高后降低的变化趋势;‘大西洋’单株结薯数、单株产量、公顷产量、商品薯率高于或显著高于亏缺灌溉(P0.05),‘青薯9号’仅商品薯率和大薯率高于或显著高于亏缺灌溉(P0.05),其他指标则显著低于轻度亏缺灌溉(P0.05),水分利用效率和灌水效率分别为152.62kg/(hm~2·mm)和130.70%。亏缺灌溉下,随水分亏缺度加重,‘大西洋’株高、茎粗和叶面积扩增的抑制大于‘青薯9号’,2个品种叶片相对含水量降低、生物量积累的增速和绝对值降低、产量和大薯率显著下降(P0.05),且‘青薯9号’上述指标的降幅小于‘大西洋’,其中轻度亏缺灌溉下,‘青薯9号’单株结薯数和公顷产量具有补偿效应,较正常灌水分别增加22.79%和11.71%,水分利用效率提高41.48%、灌水效率提高60.05%,抗旱系数为1.12。因此,‘青薯9号’轻度亏缺灌溉,可控制其地上部旺盛生长,利于块茎形成和膨大,‘大西洋’应保证充足水分供给,不宜亏缺灌溉。     

Spatial Distribution and Management Zones for Sulphur and Micronutrients in Shiwalik Himalayan Region of India

Agricultural land degradation due to nutrient deficiencies is a threat to agricultural sustainability. As nutrients availability is influenced by soil heterogeneity, climatic conditions and anthropogenic activities; hence, delineation of nutrient management zones (MZs) based on spatial variability could be an effective management option at regional scale. Thus, the present study was carried out to delineate MZs in the Shiwalik Himalayan region of India by capturing spatial variability of soil properties and secondary and micronutrients status because of the emerging nutrient deficiencies. For the study, a total of 2575 geo‐referenced representative surface (0–15 cm depth) soil samples were collected from the study region covering an area of 53,483 km². The soils were analysed for pH, electrical conductivity, soil organic carbon, available sulphur (S) and micronutrients (Zn, Fe, Cu, Mn, B and Mo) concentrations. There was a wide variation in soil properties with coefficient of variation values of 14 (for pH) to 86% for available Mo. Geostatistical analysis revealed spherical, Gaussian, exponential, stable, circular and K‐Bessel best‐fit models for soil properties. Most of the soil properties were having moderate spatial dependence except soil pH and S (strong spatial dependence) and Zn (weak spatial dependence). About 49%, 10%, 2%, 13%, 11%, 12% and 8% area of the study region were found to be deficient (including acute and marginal deficiency) in S, Zn, Fe, Cu, Mn, B and Mo, respectively. The principal component analysis and fuzzy c‐mean clustering were performed to develop the MZs. Four principal components with eigenvalues greater than 1 and accounting 65·4% of total variance were retained for further analysis. On the basis of fuzzy performance index and normalized classification entropy, four potential MZs were identified. Analysis of variance confirmed the heterogeneity in most of the studied soil properties among the MZs. The study indicated that the methodology of delineating MZs can be effectively used in site‐specific S and micronutrients management in the Shiwalik Himalayan region of India. Copyright © 2016 John Wiley & Sons, Ltd.     

Biomass Accumulation and its Relationship with the Demand and Concentration of Nitrogen,Phosphorus, and Potassium in Lettuce

Lettuce (Lactuca sativa L.) has a short cultivation cycle and a rare growth pattern. The nutritional management program of this species must be designed before its establishment in field or greenhouse. There are two scientifically based methods to design its fertilization management: the simplified rational model and the dynamics of nutritional accumulation. There is not much information to input into these methods. The present study reports about the biomass accumulation pattern of lettuce, cv. Coolward, and its relationship with the demand and concentration of nitrogen (N), phosphorus (P), and potassium (K). The study was conducted in a greenhouse with a slightly acidic sandy-loam substrate (pH 6.5) and a medium/high content of organic matter and nutrients. Twenty-one replicates were set in pots with increasing amounts of soil, depending on the time of harvest. Nine samplings were conducted from emergence up to commercial maturity (MC) (0–65 days after emergence, DDE). The plants collected were divided into two parts, aboveground (PA) and root (PR), and their dry weights and concentrations of N, P, and K were measured. With these data, biomass relative accumulation and nutrients were calculated. Total biomass association (BT) with the demand and concentrations of N, P, and K was estimated. The growth of lettuce during the first 35 DDE was slow and only represented 10% of the total accumulation of biomass, N, P, and K, mainly in PA. From the beginning of the rosette formation (IFRO) up to MC, the linear accumulation stage of MS, N, P, and K emerged. Over the last 22 days of its cycle, the crop acquired more than 60% of MS and nutrients measured at harvest. The PA accumulated nearly 90% of MS, N, P, and K, and the remaining 10% was found in PR. A close linear association was established between BT and the demand of N, P, and K in lettuce (R² = 0.99), which leads us to assume that the simplified rational model might be employed to estimate the dose of fertilization in this crop. The concentrations of N, P, and K in BT at MC were 4.0, 0.46, and 4.3%, respectively. These values are similar to those reported as internal requirements for this crop in other countries; on this account, they could be used tentatively to feed the models proposed.