Recommended Mineral Fertilizer Research Articles

Influence of continuous application of inorganic nutrients to a Maize–Wheat rotation on soil enzyme activity and grain quality in a rainfed Indian soil

To explore long-term impact of organic and inorganic fertilizers on soil health and grain quality, we monitored the enzyme activities and chemical properties of soil; and chemical composition of grain from eight treatments at an experimental field site established in 1996. There were eight treatments applied to both wheat and maize seasons: a control; four inorganic fertilizers, that is, nitrogen and phosphorus (NP), nitrogen and potassium (NK), phosphorous and potassium (PK) and nitrogen, phosphorus and potassium (NPK); farm yard manure alone (FYM) and addition of FYM at two different doses (100 and 50% of recommendation) to NPK that is, NPK + FYM and ½ NPK + FYM. After 11 years of the experiment the NPK + FYM and ½ NPK + FYM treatments had the highest yields, about 5 Mg maize ha −1 and 2 Mg wheat ha −1 with about 2 and 0.5 Mg ha −1, respectively more than the NPK treatments. The dehydrogeanse activity of soils increased significantly in FYM and ½ NPK + FYM. Except urease all other enzymatic activities were increased in those treatments, which received manure. Urease activity was higher in mineral-N applied plots. Grain protein content of both maize and wheat was highest in mineral fertilized plots. Test weight also increased significantly on application of mineral fertilizer. Plots treated with half dose of recommended mineral fertilizer along with FYM were higher in urease, phosphomono and diesterase activities than that of NPK + FYM treated plots. Long-term application of inorganic nutrients along with FYM improved grain mineral composition and yield. Inhibition of few enzymatic activities were also observed upon application of inorganic nutrients either alone or in combination.

Atributos químicos de um latossolo vermelho sob diferentes sistemas de preparo, adubações e plantas de cobertura

Os sistemas de preparo do solo e tipos de adubações levam à disposição diferenciada dos elementos minerais no perfil do solo, influenciando os seus atributos químicos. O objetivo deste trabalho foi verificar as alterações de alguns atributos químicos de um Latossolo Vermelho de cerrado, sob as adubações orgânica e mineral e plantas de cobertura, estabelecidas nos sistemas de semeadura direta e preparo convencional, sendo cultivado com feijão de inverno e algodão. O delineamento experimental utilizado foi em blocos casualizados com parcelas subdivididas. Nas parcelas foram instalados dois tratamentos (semeadura direta e preparo convencional) e, nas subparcelas, seis (esterco de galinha, esterco de galinha + metade da adubação mineral recomendada, adubação mineral, crotalária, milheto e testemunha). Foram avaliados P, MO, pH, K+, Ca2+, Mg2+, H + Al, Al3+, SB, CTCe e V nas camadas de solo de 0,00-0,10 e 0,10-0,20 m. O uso do adubo orgânico isolado ou associado com adubação mineral contribuiu para os melhores resultados dos atributos químicos do solo avaliados; as plantas de cobertura apresentaram-se semelhantes quanto aos efeitos nas propriedades químicas do solo; e a distribuição dos elementos minerais na camada superficial do solo (0,00-0,20 m) teve comportamento semelhante entre a semeadura direta e o preparo convencional.

Evaluation of nitrogen fertilizing value of composted household solid waste under greenhouse conditions

Accumulation of municipal solid wastes, such as household solid waste, can be rated as a harmful, if not critical, pollution problem. However, if these wastes can be composted and the end product used as soil organic amendment or fertilizer, this may represent one of the alternatives for achieving the goal of ensuring integrated and sustainable waste management. The objective of the present work is to evaluate the nitrogen fertilizing value of household solid waste compost in two soils of Morocco with contrasting properties: a sandy soil and a loamy-clay soil. The compost used in this study was prepared by aerobic biodegradation using the organic fraction after its separation from the non-compostable materials. A study of nitrogen availability of the compost was carried out in a Soil - Compost - Crop system under greenhouse conditions using lettuce as a test crop. Four increasing compost rates of 0, 10, 20 and 30 tons/ha were applied to the soils. The recommended mineral fertilizer rate by the Agricultural Extension Service for lettuce and its half values constituted additional treatments. The results show a high stock of mineral nitrogen in the loamy-clay soil before crop installation. Unlike the loamy-clay soil, the sandy soil generated a better yield increase and a better response to mineral fertilizers. The effect of compost rate on nitrogen mineralization was significant in the two studied soils. The quantities of mineralized nitrogen of the compost varied between 15 and 24% of the compost total nitrogen applied to the sandy and the loamy-clay soils during the lettuce growing season. Therefore the use of household solid waste compost as soil amendment constitutes a beneficial alternative in Mediterranean soils because it permits the generation of a high nitrogen fertilizing value.

Sewage sludge effects on gas fluxes at the soil–atmosphere interface, on soil δ13C and on total soil carbon and nitrogen

The objective of this work was to study the effect of long-term and continued application of sewage sludge on total carbon and nitrogen, soil δ 13C and on the gas fluxes at the soil–atmosphere interface under field conditions in the tropical region. To that effect, four applications of sewage sludge from an industrialized region were performed on a Dark Red Dystroferric Latosol. Sludge was incorporated to the soil at concentrations of 0, 1, 2, 4 and 8 times the recommended rate based on their nitrogen content in four consecutive corn cultivations. All sludge rates increased the concentration of soil C and N as compared to the control. The soil C contents at the highest sewage sludge rate increased by 55% and 48% at the layers from 0 to 10 cm and from 10 to 20 cm, respectively, as compared to the control. In the case of soil N, the increase was in the order of 59% and 66% at the highest sludge rate at the layers from 0 to 10 cm and from 10 to 20 cm, respectively, relative to the control. The increase in soil C content was derived from the sewage sludge, as demonstrated by δ 13C analyses and, since the soil's δ 13C contents were negative, it is suggested that the soil is sequestering carbon contained in the sewage sludge. The application of sewage sludge increased the flux of CO 2, N 2O and CH 4 to the atmosphere, by 220%, 320% and 165% respectively, for the highest sewage sludge rate, when compared to the control. Even though greater emission of gases was observed as compared to the control and to the treatment corresponding to the crop's recommended mineral fertilization, it is important to note that part of the C added via sewage sludge is becoming sequestered in the soil.

Cropping system impact on soil quality determinants

Worldwide interest in soil quality evaluation has increased rapidly throughout the past decade, prompting us to evaluate the long-term impact of four cropping systems on several biological, chemical and physical determinants of soil quality. We hypothesized that after 17 years several of the determinants would show significant differences between conventional cereal and low input/organic rotations. Four crop rotations were imposed on a silt soil from 1982 through 1999. Rotation A was a conventionally managed cereal rotation that received 100% of the recommended mineral fertilizer each year. Rotation B was also managed conventionally from 1982 until 1993, although it received only 50% of the recommended mineral fertilizer. From 1994 through 1999, rotation B was managed as an organic rotation. Rotations C and D were low-input rotations with plant residues returned either untreated (C)or composted (D)from 1982 until 1994.From 1994 through 1999,they were also anaged organically. Significant decreases in extractable phosphorus (P)and potassium were observed in rotations C and D compared with rotation A, presumably because their yearly nutrient inputs were somewhat lower. The amount of soil organic carbon (Corg), soil water holding capacity, the numbers and biomass of earthworms and the microbial biomass carbon and nitrogen were or tended to be higher in low input/organic than in conventionally managed plots. These effects may be in connection with the slightly increased levels of Corg in soil of the organic rotations. Activities of twelve enzymes were strongly affected by sampling time (early-versus late-summer), but much less by long-term management. Litter decomposition, numbers of soil nematodes, arbuscular mycorrhizal (AM)fungal diversity,AM spore density and AM functioning were little affected by rotation. However,AM spore density correlated positively with the high amounts of extractable calcium and P which were a result from excessive liming applied to some plots in 1982. The crucial question to be answered in future is whether plant growth and yield will correlate with the changes in soil properties. This question will be dealt with in a further paper using data from the same experiment.;

Application of soil enzyme activity test kit in a field experiment

We developed a test kit utilizing fluorogenic substrate analogues for the measurement of several enzyme activities in soil samples. Our hypothesis was that the pattern of different enzyme activities reflects changes in microbial structure and activity in a more sensitive way than total microbial biomass or activities of individual enzymes. In the test kit activities of 11 soil enzymes were measured simultaneously from diluted soil slurries on multiwell plates. After incubation for 3 h the fluorescence was measured quantitatively using an automated plate reader. The test kit was evaluated in a field experiment designed to investigate various management practices. During the years 1981–1993 the experimental field was divided into four sites. One of the plots received full mineral fertilization on the basis of chemical soil analysis, another received 50% of the recommended mineral fertilization, the third plot received green manure (harvested crop residues) and the fourth plot received composted crop residues. Since 1994 the sampling area included sites in a transitional stage to organic cultivation and the minerally fertilized site. Season, crop plant and management practice all gave rise to differences in the enzyme activity profile. The fluorogenic analysis was sensitive and allowed quantification of all the enzyme activities in all the samples. When four replicate measurements were used the standard deviation was usually less than 10%, depending on the enzyme.