Production of agriculture and timber commodities leads generation of enormous quantity of wastes. Improper disposal of these agroindustrial wastes pollutes the environment. This problem could be reduced by adding value to them. Therefore, a study was carried out to analyse and compare the nutrients content of RS, RH, SD, and EFB of composts and crude humic substances; furthermore, their effect on growth, dry matter production, and nutrient uptake for Zea mays L., and selected soil chemical properties were evaluated. Standard procedures were used to analyze humic acids (HA), crude fulvic acids (CFA), crude humin (CH), soil, dry matter production and nutrient uptake. Sawdust and RS compost matured at 42 and 47 days, respectively, while RH and EFB composts were less matured at 49th day of composting. Rice straw compost had higher ash, N, P, CEC, HA, K, and Fe contents with lower organic matter, total organic carbon, and C/N and C/P ratios. The HA of sawdust compost showed higher carbon, carboxylic, K, and Ca contents compared to those of RS, RH, and EFB. Crude FA of RS compost showed highest pH, total K, Ca, Mg, and Na contents. Crude humin from RS compost had higher contents of ash, N, P, and CEC. Rice straw was superior in compost, CFA, and CH, while sawdust compost was superior in HA. Application of sawdust compost significantly increased maize plants' diameter, height, dry matter production, N, P, and cations uptake. It also reduced N, P, and K based chemical fertilizer use by 90%. Application of CH and the composts evaluated in this study could be used as an alternative for chemical fertilizers in maize cultivation.

Purpose The study aimed to assess the influence of poultry litter (PL) after co-composting with sugarcane and cabbage waste on phosphorus (P) losses in runoff from soils under natural rainfall conditions. Methods Co-composted PL was amended in silt loam and sandy clay soils. The soil applied with PL without agro-waste was considered as control treatment. Before the soil application, PL was co-composted with agro-wastes, i.e., sugarcane waste and cabbage waste at four levels (0, 25, 33, and 50%). Soils were packed in wooden trays layered with plastic. The surface soil was mixed with the co-composted PL at rates 200 and 400 kg P ha −1 . Runoff samples were collected from the sloped trays during two rainfall events and P concentration was determined. Results Phosphorus concentration was found higher in the runoff in the PL treatment without agro-waste. Poultry litter application along with agro-waste profoundly lowered P losses in the runoff as compared to the control especially at higher application of agro-waste. Application of PL composted with higher level of agro-waste (%) reduced the P losses from soils. Phosphorus losses in the runoff enhanced with higher amount of PL application depending on the soil type and initial P content in the soil. Silt loam soil amended with co-composted poultry litter/agro-waste reduced P losses more significantly as compared to sandy clay soil. Conclusion The application of manure amendments with agro-wastes decreased the losses of soluble P and would reduce detrimental environmental effects.

The availability of paddy husk from rice processing plants remains high owing to increase in the worldwide rice consumption. Increasing demand for chicken products leads to poultry wastes production. Co-composting of the aforementioned wastes could solve the indiscriminate disposal of these wastes. Thus, co-composting of paddy husk and chicken slurry with clinoptilolite zeolite and urea as additive was carried out. Clinoptilolite zeolite was used to enhance ammonium and nitrate retention in the compost. Temperature of the compost was monitored three times daily for 55 days. Cation exchange capacity, organic matter, ash, humic acids, pH, total C, N, C/N ratio; total P, exchangeable Ca, Mg, K, NH4+, NO3-, and heavy metals contents were determined using standard procedures. pH, total N, humic acids, ash, NH4+, NO3-, P, Ca, Mg, and K contents increased but the salinity, heavy metals contents, and microbial population were low after the co-composting process. Zea mays L. (test crop) seed germination rate in distilled water and the compost were not significantly different. Growth of Spinach oleracea (test crop) on a peat-based growing medium and the compost was also not significantly different. These findings were possible because the clinoptilolite zeolite used in co-composting reduced accumulation of heavy metals that may have damage effects on the test crops. Mature compost with good agronomic properties can be produced by co-composting chicken slurry and paddy husk using clinoptilolite zeolite and urea as additives.

Adoption of new management techniques, such as clinoptilolite zeolite (CZ) utilization has attracted much attention in the fertilizer industry. Accordingly, the aims of this study is to evaluate: if CZ, acting as an inert material, when applied to the soil, might improve the selected soil properties, height, dry matter, nutrient concentration, nutrient uptake, nutrient use efficiency on maize cultivation; the potential for (N:P:K) compound fertilizer when incorporated with CZ to serve same standard as the commercial fertilizer in fertilizer industry. The effect of T 1 , T 3 and T 6 on soil total N was found to be significant, when compared with T 7 . Treatments with CZ on soil total P, K and available P, K differed significantly relatively to T 1 and T 7 . The treatments T 5 and T 6 had the highest accumulation of exchangeable NH 4 + and available NO 3 -relatively to T 1 and T 7 . The significant effect of the treatments having CZ on N concentration, in uptake and use efficiency, suggests that CZ incorporated with fertilizer can reduce NH 3 loss, triggering the formation of NH 4 + and NO 3 -over ammonia and increase maize uptake. Relatively to P concentration, uptake and use efficiency, it was found that in most treatments having CZ, lower values were obtained, relatively to the commercial fertilizer, although T 3 clearly improved P uptake in roots. Most of the treatments with CZ remained statistically similar in K concentration, uptake and use efficiency compared to commercial fertilizer. It may be concluded that treatments with higher amounts clinoptilolite zeolite ensured good retention of soil exchangeable cations, available P, and NO 3 -within the soil. Treatments with CZ improved N uptake and use efficiency in the maize crop tested.

Acid soil is an obstacle to agricultural development and a concern regarding food and environmental security. Therefore, a study was carried out for two consecutive years to see how lime and organic manure (OM) amendments affect yield and nutrient absorption in the Transplanted (T.) Aman–Mustard–Boro cropping pattern in an acidic terrace soil. With nine treatments and three replications, the experiment was set in a randomized complete block design. The treatments were applied to the first crop, T. Aman, with different dosages of lime (dololime at the rate of 1 and 2 t ha−1), OM (cow dung at 5 t ha−1, poultry manure at 3 t ha−1) and lime–OM combination, and their residual effects were studied in the following mustard and boro rice crops. Results demonstrate that the effect of lime and manure was more pronounced in the case of the second and third crops in the first year and of all crops in the pattern in the second year. In the first year, grain and straw yield of T. Aman as well as the overall system productivity were not influenced significantly by the application of lime and manure, but significant increases were obtained in the second year. As an average of both years, the highest grain yield of 5.2 t ha−1 (12% over control) was recorded for T. Aman, 1.7 t ha−1 (41% over control) for mustard and 5.9 t ha−1 (47% over control, 3.9 t ha−1) for boro rice when dololime was applied in combination with poultry manure. In both years, N, P, K and S uptake were significantly increased compared to the control in all the crops due to the combined application of lime and cow dung or poultry manure. Combined application of lime and manure amendment significantly improved nutrient availability and soil quality. Therefore, applying lime in combination with manure can be practiced to uplift crop productivity in acidic terrace soils.

High cation exchange capacity and organic matter content of crude humic substances from compost could be exploited to reduce ammonia loss from urea and to as well improve rice growth and soil chemical properties for efficient nutrients utilization in lowland rice cultivation. Close-dynamic air flow system was used to determine the effects of crude humic substances on ammonia volatilization. A pot experiment was conducted to determine the effects of crude humic substances on rice plant growth, nutrients uptake, nutrients recovery, and soil chemical properties using an acid soil mixed with three rates of crude humic substances (20, 40, and 60 g pot−1). Standard procedures were used to evaluate rice plant dry matter production, nutrients uptake, nutrients recovery, and soil chemical properties. Application of crude humic substances increased ammonia volatilization. However, the lowest rate of crude humic substances (20 g pot−1) significantly improved total dry matter, nutrients uptake, nutrients recovery, and soil nutrients availability compared with crude humic substances (40 and 60 g pot−1) and the normal fertilization. Apart from improving growth of rice plants, crude humic substances can be used to ameliorate acid soils in rice cultivation. The findings of this study are being validated in our ongoing field trials.

Insufficient supply of P for initial growth of crops does not only limit N uptake but it also leads to poor yield of crops. In acidic soils of the tropics, sorption of P occurs mainly on surfaces of Fe and Al oxides and hydroxides. Most of the P added through mineral fertilizers is fixed by high Al and Fe oxide concentrations and transformed into insoluble P compounds. Reduction of Al and Fe is important so as to ensure adequate supply and readily available P for crops uptake. A number of studies using zeolites as an amendment in the fertilization programs of crops have improved crops production, nutrients uptake, and nutrients use efficiency. However, there is dearth of information on the use of clinoptilolite zeolite (CZ) to reduce P fixation not to mention reduction of N, P, and K fertilizers use in agriculture. This study was conducted to: (i) determine dry matter production, nutrients concentration, nutrients uptake, and use efficiency of Zea mays (Hibrimas variety) by including CZ in the fertilization program of Zea mays planted on an acidic soil, and (ii) determine the effect of including CZ in the fertilization program of Zea mays on selected chemical properties of an acidic soil. Egypt rock phosphate (ERP), urea, and muriate of potash were used in this study. Seventy five percent (w/w) of the recommended N, P, and K fertilizers for Zea mays were combined with CZ. Standard procedures were used to determine soil pH, inorganic nitrogen, available phosphorus, exchangeable aluminium, iron, potassium, calcium, magnesium, and organic matter before and after planting. Zea mays were harvested at tasselling stage and measured for dry matter production, nutrients uptake and use efficiency. The effect of CZ application with 75% of fertilizers (E2) and 100% fertilizers (E1) were statistically similar for selected soil chemical properties, dry matter production, nutrients concentration, uptake of nutrients, and nutrients use efficiency except for N. Nitrogen use efficiency for E2 was better than that of E1. These findings suggest that adoption of CZ with 25% reduction of N, P, and K fertilizers are useful. Further field trials and economic analysis are recommended to confirm the findings of this study. These aspects are being investigated in our on-going field experiments.

Problem statement: Exchangeable ammonium (NH 4 + ) could be recovered by humic and fulvic acids from humic substances. The ability of these acids in fixing or retaining NH 4 + has been demonstrated in many findings and reports. Both acids could affect the plant growth, nutrients uptake by enhancing photosynthesis rate and root growth among others. Thus, in this study, the effect of both acids (in liquid form) on soil exchangeable NH 4 + , dry matter production and available nitrate (NO 3¯) was investigated. Approach: Humic molecules were isolated using standard procedures, followed by liquid organic N fertilizers formulation. Organic based N fertilizers were applied to soil in pots at 10 Days After Planting (DAP) and 28 DAP. Treated soils and plant parts were sampled at 54 DAP or at tasselling stage. Soil samples were analyzed for pH, ammonium and nitrate content. The plant samples were weighed to assess dry matter production. Results: Under acid condition, organic based liquid N fertilizers (fulvic acid or both, humic and fulvic acids) increased accumulation of NH 4 + in soil. The presence of carboxylic groups in humic molecules increased NH 4 + retention with increasing soil's stock labile carbon. However, low percentage of these acids reduced their full effect on dry matter production. The availability of nitrate was not statistically different for all treatments. Low soil pH could had reduced nitrification processes and simultaneously soil NO 3¯ content. Conclusion: Liquid form of humic and/or fulvic acids could play an important role in enhancing urea efficiency. However, their contribution needs to be studied in detail in relation to humic molecules characteristics. This study had a potential in the development of liquid and foliar organic fertilizers.