Effects of Two Organic Wastes in Combination with Phosphorus on Growth and Chemical Composition of Spinach and Soil Properties

Abstract

Most agricultural soils in Iran are usually low in organic matter (OM). Therefore, increasing OM in these soils is of great concern. Environmental pollution caused by chemical fertilizers has created an interest in the integrated use of organic wastes with inorganic fertilizers. The main purpose of this greenhouse study was to evaluate the impact of two organic wastes and phosphorus (P) on the growth, and elemental composition of spinach (Spinacia oleracea L.) and soil chemical properties. Treatments consisted of four levels of municipal waste compost, MWC (0, 1, 2, and 4%), five rates of poultry manure, PM (0, 1, 2, 3, and 4%), and three P levels (0, 25, and 50 mg kg^?1 as KH₂PO₄). Application of P and MWC alone or in combination significantly increased the top dry weight of spinach. However, spinach growth was markedly increased up to 3% PM and suppressed with the higher rate, probably due to an excess of soluble salts in the soil. Moreover, the enhancing influence of P on spinach seedling growth was more pronounced at lower levels of MWC and PM. Plant P concentration tended to increase with increasing P, MWC, and PM application rates, whereas nitrogen (N) concentration was only affected by the two organic wastes treatment. Manganese (Mn) concentrations decreased, and copper (Cu), lead (Pb), and cadmium (Cd) increased by soil P application. However, P addition significantly decreased zinc (Zn) concentration only in MWC-treated spinach. Spinach plants enriched with either of the two biosolids accumulated more Mn, Zn, Pb, Cd, chloride (Cl), and sodium (Na) than control plants. Furthermore, spinach grown on MWC-amended soil contained higher Mn, Zn, Cu, and Pb and lower N, Cl, and Na than those raised on PM-treated soil. Postharvest soil sampling indicated that application of the two biosolids significantly increased concentration of soluble salts, (EC_e), OM, TN, NaHCO₃-extractable P, and DTPA-extractable iron (Fe), Mn, Zn, Cu, Pb, and Cd.     

镉污染下不同类型水稻土氮素供应特征及其影响因素

污染条件下的土壤氮素供应影响了作物生产和植物生态修复。采用温室盆栽试验,研究了两种剂量镉污染下我国21种水稻土无机氮的供应特征和影响因素。结果表明：淹水10天后,不同水稻土土壤溶液无机态氮含量变幅为1.42 ~ 70.40 mg/L （(平均值为16.76 mg/L）),其中NH4+-N和NO3--N分别占62.5% 和33.7%;与施肥对照相比,镉污染降低了大多数水稻土土壤溶液无机态氮的含量,平均降幅为58.4%,主要是由土壤溶液NH4+-N含量下降所致;土壤溶液NO3--N含量受镉污染的影响程度则因土壤类型而异。基于典范对应分析的偏因子分析（(VPA）)表明镉污染对水稻土土壤溶液无机氮含量的影响最大,其次是土壤类型,施肥影响最小,三类因子单独作用的影响比例分别为40.38%、6.51% 和0.05%。镉污染下,pH、CEC和土壤质地显著影响水稻土无机氮供应,其中土壤pH是镉污染条件下影响NH4+-N含量变化的首要因子。     

河西农田磷钾养分平衡及肥料利用率长期定位研究

采用连续24年田间定位试验和养分差减法研究了河西农田磷钾养分投入产出平衡及肥料利用率,结果表明,磷素养分投入始终大于产出为正平衡,化学磷肥连施(NP、NPK)平均盈余率43.3% ~ 97.0%;小麦、玉米化肥磷总利用率平均为37.3% ~ 40.5% 和22.3% ~ 30.5%,比短期试验利用率分别增加12.8% ~ 22.9% 和5.9% ~ 9.5%。有机肥与化学磷肥配施(MNP、MNPK)平均盈余率211.3% ~ 277.9%;小麦、玉米磷素总利用率分别为18.0% ~ 18.3%?和16.3% ~ 19.4%,比试验初利用率增加5.4% ~ 8.5% 和5.8% ~ 6.6%。连施有机肥适量减少化学磷肥用量是平衡施磷的科学之举。钾素投入始终不抵作物携带量,农田钾素为负平衡,长期施用有机肥(MN、MNP)不能平衡土壤钾素,平均亏缺?-38.6% ~ -47.2%,小麦、玉米作物有机肥钾总利用率57.8% ~ 59.8% 和34.1% ~ 54.1%,比试验初增加8.4% ~ 22.3%;连施化学钾肥平均亏缺?-36.2% ~ -67.8%,小麦、玉米钾肥利用率53.1% 和29.5%,比试验初增加7.4% ~ 36.4%。在有机肥基础上增施化学钾肥是现代作物生产的必需措施。     

Efficacy of seed,foliar and soil amendments for enhanced phenological growth of maize

The effect of industrially manufactured biological amendments (IMBAs) on maize crop growth was studied over three seasons (2006/07 to 2008/09) on sandy and clayey soil. The IMBAs were distinguished on the basis of their active ingredients consisting of effective microorganisms (EMs) (Biozone and Gliogrow), poultry manure (Gromor and Promis), humic acid (K-humate, Crop care and Montys) and their combinations, namely composted human manure + conventional NPK (Growmax) and EMs + humic acid (Lanbac). Treatments were arranged in a randomised complete block design with four replications. The IMBAs were applied based on recommended rates by manufacturers of these amendments. An optimum inorganic NPK rate at each site and untreated control were included as checks. The IMBAs showed inconsequential effects on investigated phenological maize growth traits compared to the NPK check in both soil types. The use of EMs-based IMBAs and the combination of EMs + humic acid resulted in significant increase in biomass yield and leaf area index at silking stage in both soil types. Plant stature from either EMs or humic acid-based IMBAs as well as Growmax was statistically comparable with the NPK check. Achieving improved phenological maize growth will require a combination of the IMBAs with conventional NPK fertiliser.     

Fifteen-year fallow altered the dynamics of soil phosphorus and cationic balance of a savannah Alfisol

This study was designed to evaluate changes in the dynamics of soil phosphorus and cationic balances of a savannah soil subjected to 45 years of continuous cultivation under different fertilizer management and later left fallow for 15 years. It was conducted on the experimental plots at the Institute for Agricultural Research, Ahmadu Bello University, Nigeria. Treatments consisted of nitrogen (N), phosphorus (P), potassium (K), cow dung manure (D) and their combination (DNPK). Results of P fractionation and cationic distribution were compared with previous studies on the same plot 15 years ago. Organic carbon increased from a range of 3–5 g kg^?1 in 1997 to 10.9 g kg^?1 in 2012. Similarly, the cation exchange capacity (CEC) of the soil increased from 6.40 cmol_c kg^?1 in 1997 to 16.4 cmol_c kg¹ in the present study. The degree of saturation of the CEC by Ca²⁺ was 68–79% and 10–20% for Mg²⁺, while that of K⁺ was 1.5–2%. Although there was an uneven trend in depletion and enrichment of the various P pools, however, the fallow period substantially improved the CEC and the plant available P pools of the soil by more than 200% and 6–259%, respectively.     

Soil phosphorous buffer coefficient as influenced by time and rate of P addition

Abstract

This study was conducted to investigate the effect of time and rate of phosphorus (P) addition on phosphorus availability and phosphorus buffer coefficient in some calcareous soils. Phosphorus was added to the samples at rates of 0, 50, 100, 200, 400, 600 and 800 mg P kg^?1 soil. The samples were incubated for 0.041, 1, 7, 14, 21, 30, 60 and 90 days at constant temperature and moisture. Extractable phosphorus was determined after the incubation. The results showed a sharp decrease in available P within 1 h after P addition. There was a linear relation between added P and extractable P in all soils. The buffer coefficients of soils were estimated by Olsen P for above incubation periods. Generally the buffer coefficient decreased with increasing time of incubation. The results indicated that inputs of between 23 – 59 mg kg^?1 are required to raise Olsen P by 10 mg kg^?1 in these calcareous soils, which assuming 2500 t soil ha^?1, gives a required input of 58 – 148 kg P ha^?1.     

红壤丘陵区生猪规模化养殖及其对土壤与水环境的影响——以江西省余江县为例

以南方红壤丘陵典型地区——江西省余江县为案例,研究了规模化养猪业发展现状及其对周边土壤和水环境的影响.结果表明,余江县2011年389家规模化养猪场出栏73.2万头,其中年出栏1 000～5 000头的猪场占规模化猪场总数50.6％.规模化猪场主要分布在中南部的低丘缓岗地带,尤其集中分布于320国道沿线.全县规模化养猪的粪、尿、污水年产生量分别约为2.96×105 t、4.64×105 t、1.09×106 t,COD、N、P、Cu、Zn污染物年排放量分别为1.96×104t、3.27 × 103t、1.25×103t、50 t和116 t.据估算全县110万头生猪养殖的粪、尿、污水年产生量分别约为4.47×105t、7.00×105 t和1.09×106t,COD、N、P、Cu、Zn污染物年排放量分别为2.96×104 t、4.94×103 t、1.89×103t、76 t和176 t.以总氮为指标,规模化猪场周边采样水体有90.9％山塘、66.6％水库、50％河流的水体水质属于劣Ⅴ类;土壤养分严重失衡,速效磷过量积累,重金属Cu、Zn在土壤中也有明显积累.因此,应加强区域生猪养殖业发展规划及规模养猪粪污无害化、资源化循环利用技术研究,以促进红壤丘陵区规模养殖业健康发展与生态环境保护.     

Development of potato late blight (Phytophthora infestans) in differently developed potato crops and the potential to graduate the fungicide dose according to crop biomass

Phytophthora infestans is a serious disease in potato production and control of the disease often requires 10 or more fungicide applications during the growing season. Control is typically carried out using a constant fungicide dose in the entire field although there may be large differences in crop development and biomass across the field. The objective of the study reported in this paper was to test whether the fungicide dose response curve controlling P. infestans was dependent on the crop development and biomass level. If such a biomass-dependent dose response was found it was further the purpose to evaluate the potential to optimize fungicide inputs in potato crops applying a site-specific crop density-dependent fungicide dose. The study was carried out investigating the fungicide dose response controlling P. infestans in potatoes at three biomass densities obtained growing the potato crop at three nitrogen levels. Furthermore, the field experiments included four levels of fungicide dose rate at each nitrogen rate, an untreated control, the recommended fungicide dose rate and two reduced dose rates and the experiments were replicated for three years. Nitrogen level and thus crop density had a limited although significant influence on attack of P. infestans whereas fungicide dose rate by far was the most influential variable. In contrast the interaction of nitrogen rate and fungicide dose rate that would indicate a biomass-dependent dose response was insignificant. If the variation in crop density and biomass level obtained in the study is representative for the variation found cultivating potatoes in heterogeneous fields there seem to be limited potential for fungicide optimization applying fungicides against P. infestans site-specific according to crop density or biomass.     

不同土地利用方式下土壤温度与土壤水分对黑土N2O排放的影响

采用静态箱一气象色谱法,对黑土区3种不同土地利用方式（草地、裸地和农田）下土壤氧化亚氮（N：O）的排放特征及其与土壤温度和土壤水分的关系进行研究。结果显示：试验监测期间（2011年5月27日-9月30日）,不同土地利用方式下,土壤N：0累积排放量分别为草地52．08mgN·m^-2裸地64．43mgN·m^-2农田70．16mgN·m^-2,农田土壤N：O累积排放量比草地和裸地分别高出35％和9％,草地、裸地和农田的N2O平均排放通量分别为16．56、20．36、21．44μgN·m^-2·h^-1。草地和裸地中,土壤N2O排放通量与土壤温度和土壤水分（充水孔隙度,WFPS）相关性均不显著,但在农田中,土壤N20排放通量与土壤温度（5cm和10cm）和土壤水分（5cm）均呈显著正相关（P〈0．05）。另外,土壤N2O累积排放量与土壤硝态氮和矿质氮含量均呈正相关关系。研究表明,黑土草地开垦可促进土壤N2O的排放,且不同土地利用方式下土壤N2O排放的主要影响因子不同。     

Growth responses of cereal crops to organic nitrogen in the field

Eleven rice varieties differing in grain size were grown under controlled environmental conditions during the grain-filling period. The grain weight of upper grains in a panicle was examined at successive stages of growth during the grain-filling period. The effect of temperature on the rate and the duration of the period of grain-filling was determined using Khao Lo, a large-grain variety, and Bom Dia, a small-grain variety. Both the grain-filling rate and duration of the period of grain-filling differed among rice varieties and were positively and significantly correlated with the grain size. The duration of the grain-filling period from flowering to the time when almost maximum grain weight was attained ranged from 12 days at 32/24°C in Bom Dia to 36 days at 20/12°C in Khao Lo. The grain-filling rate was low in small-grain varieties, and generally increased with increasing grain size.

By lowering the temperature, the grain-filling rate decreased, the duration of the grain-filling period increased but the grain weight was almost constant.

Weight per grain was closely correlated with hull size. No relationship was found between weight per grain and nitrogen percentage of brown rice.