Investigating the response of soil and vegetable crops to poultry and cow manure using ground and satellite data

Prediction Models Based on Soil Characteristics for Evaluation of the Accumulation Capacity of Nine Metals by Forage Sorghum Grown in Agricultural Soils Treated with Varying Amounts of Poultry Manure

Predictive models were generated to evaluate the degree to which nine metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) were absorbed by the leaves, stems and roots of forage sorghum in growing media comprising soil admixed with poultry manure concentrations of 0, 10, 20, 30 and 40 g/kg. The data revealed that the greatest contents of the majority of the metals were evident in the roots rather than in the stems and leaves. A bioaccumulation factor (BAF) < 1 was calculated for Cr, Fe, Ni, Pb and Zn; BAF values for Co, Cu, Mn and Cd were 3.99, 2.33, 1.44 and 1.40, respectively, i.e., > 1. Translocation factor values were < 1 for all metals with the exception of Co, Cr and Ni, which displayed values of 1.20, 1.67 and 1.35 for the leaves, and 1.12, 1.23 and 1.24, respectively, for the stems. The soil pH had a negative association with metal tissues in plant parts. A positive relationship was observed with respect to plant metal contents, electrical conductivity and organic matter quantity. The designed models exhibited a high standard of data precision; any variations between the predicted and experimentally observed contents for the nine metals in the three plant tissue components were nonsignificant. Thus, it was concluded that the presented predictive models constitute a pragmatic tool to establish the safety from risk to human well-being with respect to growing forage sorghum when cultivating media fortified with poultry manure.

Organic manures and inorganic fertilizers effects on soil properties and economic analysis under cassava cultivation in the southern Cameroon

Cassava cultivation causes serious soil fertility depletion in southern Cameroon due to high mining of soil nutrients by the crop. This study aimed to evaluate the effects of Tithonia diversifolia fresh biomass (TB), poultry manure (PM) and inorganic fertilizers (IF) on soil properties, cassava yield, and the economic returns. The treatments consisted of two rates of TB (10 and 20 t ha^-1), two rates of PM (10 and 20 t ha^-1), two rates of combined TB and PM (5 and 10 t ha^-1), a single rate of inorganic fertilizers (100 N:22P:83 K kg ha^-1) and a control. The results showed that soil properties, soil quality index and cassava yield were significantly improved by the application of the organic manures. Tithonia diversifolia fresh biomass (TB) and poultry manure (PM) lowered the soil bulk density, increased soil total porosity, water holding capacity and chemical properties. TB and PM, solely or mixed, improved the aerial dry biomass (ADB) and fresh tuber yield (FTY) of cassava. The organic manures performed better than inorganic fertilizer. The highest yield (51 and 52 t ha^-1 of fresh tubers) was obtained with the mixture of TB and PM applied at 10 t ha^-1 each for the successive years. Positive and significant correlation was found between SQI and cassava yield. TB and PM combined at 10 t ha^-1 each was the most profitable and cost-effective treatment, with a good benefit:cost ratio of 3.2:1 and net return of FCFA 3.736.900 ha^-1. Thus, the use of Tithonia diversifolia fresh biomass and poultry manure is a sustainable method for cassava production in the southern Cameroon.

Improving soil physical properties and cassava productivity through organic manures management in the southern Cameroon

Cassava cultivation causes serious soil fertility depletion in Cameroon. Organic manures can contribute to maintaining the productivity and sustainability of cassava production systems due to their availability and cheapness. This study was conducted during two successive cropping seasons (2016/2017 and 2017/2018) in the Southern Cameroon, to determine the effects of organic manures on soil physical properties, and cassava growth and yield. Tithonia diversifolia fresh biomass (TB) and poultry manure (PM) were used as organic manures. Different treatments were used, namely: (i) control (no amendment), (ii) mineral fertilizer (MF (450 kg ha⁻¹ 13-13-23 NPK + 100 kg ha⁻¹ Urea)), (iii) two rates of TB (applied at 10 and 20 t ha⁻¹), (iv) two rates of PM (applied at 10 and 20 t ha⁻¹) and (v) two rates of the mixture of TB and PM (applied at 5 and 10 t ha⁻¹ each). The experimental designed was randomized complete block with three replicates per treatment. The application of TB, PM and TB + PM (mixture) lowered bulk density by 14–22.6%, 21.5–26.2% and 18.2–25%, respectively. While total porosity and water holding capacity were increased with manure application by 9.8–15.1% and 13.3–30.3%, respectively. The mineral fertilizer had no significant effect on these soil physical parameters. Application of TB and PM either solely or mixed significantly improved growth of cassava. Stem height, stem diameter and canopy diameter increased by 34.3–60%, 17.4–30.4% and 19.7–32.7%, respectively. Organic manures performed better than the mineral fertilizer. Aboveground dry biomass and fresh tubers yield increased by 21.7–59.6 and 76.6–112.2% with organic manures, and by 23.2 and 68.5% with mineral fertilizer, respectively. The best performance of cassava in terms of fresh tubers yield (51.78 t ha⁻¹) occurred with the mixture of TB and PM applied at 10 t ha⁻¹ each. The study revealed that fresh biomass of Tithonia diversifolia and poultry manure can be used to improve cassava production and sustain soil productivity in the humid forest zone of Southern Cameroon.