Litter Mulch Research Articles

Effect of Various Types of Organic Mulch on Growth and Yield of Soybean (Glycine max L. Merril) Anjasmoro Variety

Cultivation of soybean is currently planted using ground cover as a solution to increase crop productivity. So it is necessary to research the effect of various types of organic mulch on the growth and yield of soybeans (Glycine max L. Merril). This study aims to determine the effect of various types of organic mulch on the growth and yield of soybeans (Glycine max L. Merril). This study was laid out in Randomized Block Design 1 factor, which was composed of 6 levels, with 5 replications, so there are 30 experimental units. There was no mulch, rice straw mulch, coconut coir powder mulch, bamboo leaf litter mulch, wood sawdust mulch, and rice husk mulch. The application during soybean cultivation observed parameters were plant height (cm), number of leaves (leaves), fresh header weight (g), fresh root weight (g), root dry weight (g), root dry header (g), number of pods (fruit), pod weight (g), and weight of 100 seeds (g). Rice straw mulch affected the growth and yield of soybeans on plant height 5-6 weeks after planting with average (40.95; 49.18 cm), header fresh weight (43.04g), number of pods (71.40 fruit), and pod weight (36.02g).

Mulching with Leaf Litter from Municipal Green Waste Favours Predatory Mononchid Nematodes

Although the incorporation of organic amendments into the soil is widely researched, less attention has been given to the impact of in-situ composting of municipal green wastes (MGW), especially leaf litter, on free-living nematodes. In a four year experiment (2016–2019) of tomato cropping cycles, we tested the hypothesis that leaf litter mulch has a positive effect on mononchid predatory nematodes and influences their species composition. Two treatments were applied every year: plots were either mulched with leaf litter or left unmulched. Soil samples were collected every autumn at the end of the growing season. Active, free-living nematodes were extracted by Baermann funnel from soil samples, the density of mononchid predatory nematodes was determined, and the individuals were identified to genus or species. In the first year (2016), mulching did not affect the density of mononchids. From the second year (2017) on, their number significantly increased in mulched plots, compared to in unmulched ones. During the study period the presence of four mononchid genera: Clarkus, Mylonchulus, Prionchulus, and Iotonchus, were detected. Our hypothesis was confirmed, as the number of mononchids increased in the presence of MGW leaf litter mulch layer.

Hydrologic responses of undecomposed litter mulch on compacted soil: Litter water holding capacity, runoff, and sediment

The surface of the mineral soil is covered by the forest floor forming water absorbent layers. This is how the forest floor plays an important role in soil and water conservation. The aim of this study was to individualize three leaf litters (beech, hornbeam, and maple) applied at three density rates (6, 12, and 18 Mg ha−1) to assess their soil protection capacities. A total of nine treatments were conducted (i.e., beech6, beech12, beech18, hornbeam6, hornbeam12, hornbeam18, maple6, maple12, maple18) on skid-compacted soils in the Hyrcanian forests of northern Iran to evaluate effects at reducing runoff and sediment yield, and to determine the oven-dry weights and water holding capacity of litters. A total of nine runoff plots with dimensions of 1 × 2 m were established on the skid trails during the study period from September to December 2017 in a field experiment under natural rainfall. At the study period, 29 events with a total of 752.2 mm rainfall were measured in the open space area, that 26% of the rainfall was intercepted by canopy cover. Regardless of leaf litter species, the runoff and sediment yield significantly decreased as the leaf litter rate increased. The average runoff in litter plots of beech, hornbeam, and maple was 102.71, 94.25, and 116.87 mm, whereas the average sediment yield was 27.07, 22.33, and 36.73 g m−2 for the study period, respectively. The mean water holding capacity of beech, hornbeam, and maple litter plots amounted to 84.1, 59.16, and 25.81 mm for the study period, respectively. Our study shows that the different species of leaf litter have a diverse range of hydrological functions and litter water holding capacities, which reduced runoff and sediment yield.

Effect of Mulch Type on Plant Growth and Production Shallots (Allium Fistulusum L.)

This research aimed to study the mulch's effect on the growth and yield of onion leaves plants. The research at held for three months, from June to September 2020. The research at Lasalepa village, Lasalepa District, Muna Regency, Southeast Sulawesi Province. The materials used in this study were scallion seeds, cow manure, rice straw mulch, reed mulch, corn litter mulch, and krinyuh mulch. The tools used consisted of a machete, hoe, tape measure, cheerful, bucket, raffia rope, scissors, sprayer, camera, digital scales, and writing instruments. The research was arranged base on randomized block design (RBD) consisting of 5 (five) treatment levels, namely without mulch as control (M0), rice straw mulch (M1), reed mulch (M2), corn litter mulch (M3) and krinyuh mulch (M4). Variable observed there was plants height (cm), number of leaves (strands), number of tillers, and production (g/ plant). All data were analyzed based on Analysis of Variance (ANOVA) at a 95% confidence level. The insignificant difference, followed by the Honestly Significant Different (HSD) test at a 95% confidence level. The research showed that the treatment of different types of mulch had a significant effect on plant height, number of leaves, number of tillers, and production. Krinyuh mulch type with a rate of 90 g plant-1 or 10 t ha-1 gave the best growth and production of scallions with an average production of 131.8 g plant-1 or 32.95 ha-1.

Effects of mulching on weed growth and cucumber yield

Cucumber responses to mulching vary by season, region, and mulching material. A field experiment, arranged in a randomized complete block design with four replicates, was established to assess the effect of organic mulches on weed growth and cucumber yield. Treatments consisted of no mulch, palm oil leaf litter mulch, rice husk litter mulch, blady grass litter mulch, coffee husk litter mulch, and black-silvered plastic mulch. Treatment effects were evaluated in terms of the dry weight of weeds (broad and narrow leaf) and yield of cucumber (fruit diameter, fruit length, fruit number plant^-1, fruit weight, total fruit weight plot^-1and weight of marketable fruits plant^-1). Results indicated that the use of mulches effectively reduced weed growth, increased growth, and yield of cucumbers. The effectiveness of black-silvered plastic, coffee husk litter, rice husk litter, palm oil leaf litter, blady grass litter mulches to control weeds were 98, 68, 58, 56, and 54 %, respectively. Cucumbers grown with mulch increased fruit diameter, fruit weight, number of fruit plant^-1, weight of marketable fruits, and total fruit weight plot^-1 that were 7, 91, 25, 78, 134, and 78 % higher than those grown without mulch, respectively. These findings provids a valuable technique for cucumber growers in the low altitude of equatorial areas.

Arboreal arthropod assemblages in chili pepper with different mulches and pest managements in freshwater swamps of South Sumatra, Indonesia

Abstract. Herlinda S, Tricahyati T, Irsan C, Karenina T, Hasbi, Suparman, Lakitan B, Anggraini E, Arsi. 2021. Arboreal arthropod assemblages in chili pepper with different mulches and pest managements in freshwater swamps of South Sumatra, Indonesia. Biodiversitas 22: 3057-3066. In the center of freshwater swamps in South Sumatra, three different chili cultivation practices are generally found, namely differences in mulch and pest management that can affect arthropod assemblages. The effect of mulches and pest management on arboreal arthropod assemblages specific to chili production centers in the freshwater swamps of South Sumatra has never been investigated. This study aimed to observe arboreal arthropod assemblages in chili with different mulches and pest management. Arboreal arthropods were sampled using sweep nets in three locations with plots treated with leaf litter mulch and bioinsecticide, plastic mulch and synthetic insecticide, and weedy plot without mulch with synthetic insecticide. The species number of arboreal arthropods found was 28 species of Arachnids and 23 species of Insects, and consisting of 6 families of the Arachnids and 25 families of Insects. The abundance of arboreal arthropods was 65.60 individuals/5 nets per observation. In the chili field without mulch but with the insecticide, the species biodiversity and abundance of arboreal predatory arthropods were the highest. In contrast, in the chili field, that applied with synthetic insecticides and plastic mulch, the abundance of arboreal predatory arthropods was the lowest. The herbivorous insect populations in chili with plastic mulch and synthetic insecticides and the chili with the leaf litter mulch were higher than those in the chili without mulch. In the chili with the leaf litter mulch and bioinsecticide, the species number and abundance of the spiders were the highest compared to the other chili fields. The weedy chili field without mulch and chili with the leaf litter mulch has proved ideal habitats for the arboreal predatory arthropods.

Effects of mulching on weed growth and cucumber yield

Cucumber responses to mulching vary by season, region, and mulching material. A field experiment, arranged in a randomized complete block design with four replicates, was established to assess the effect of organic mulches on weed growth and cucumber yield. Treatments consisted of no mulch, palm oil leaf litter mulch, rice husk litter mulch, blady grass litter mulch, coffee husk litter mulch, and black-silvered plastic mulch. Treatment effects were evaluated in terms of the dry weight of weeds (broad and narrow leaf) and yield of cucumber (fruit diameter, fruit length, fruit number plant^-1, fruit weight, total fruit weight plot^-1and weight of marketable fruits plant^-1). Results indicated that the use of mulches effectively reduced weed growth, increased growth, and yield of cucumbers. The effectiveness of black-silvered plastic, coffee husk litter, rice husk litter, palm oil leaf litter, blady grass litter mulches to control weeds were 98, 68, 58, 56, and 54 %, respectively. Cucumbers grown with mulch increased fruit diameter, fruit weight, number of fruit plant^-1, weight of marketable fruits, and total fruit weight plot^-1 that were 7, 91, 25, 78, 134, and 78 % higher than those grown without mulch, respectively. These findings provids a valuable technique for cucumber growers in the low altitude of equatorial areas.

Efficiency of leaf litter mulch in the restoration of soil physiochemical properties and enzyme activities in temporary skid roads in mixed high forests

Various engineering measures, such as mulching, have been applied on decommissioned skid trails to suppress the adverse effects of overland flow and flood hazards. However, very little research has been done on the effects of such treatments on soil recovery. The aim of this study is to determine the effectiveness of different leaf litter levels on the restoration of soil properties and enzyme activity, when spread on decommissioned skid trails over a four-year period after soil compaction. In total, 90 soil samples in 18 runoff plots were measured under six treatments, including undisturbed (control) treatment, UND; untreated skid trail, U; and four levels of leaf litter, LML1, LML2, LML3, and LML4, with levels of 0.42, 0.81, 1.31, and 1.69 kg m−2, respectively. Soil bulk density and penetration resistance under the litter mulch treatments were lower than that under the U treatment, and at the lowest in the UND treatment. The total porosity, macroporosity, and aggregate stability were at the highest level in UND, followed by LML4 ≈ LML3 > LML2 ≈ LML1. Soil organic C, total N, C/N ratio, C and N sequestration, available nutrients (i.e., P, K, Ca, and Mg), and fulvic and humic acids were at the highest level in UND followed by LML4, and at the lowest level in U followed by LML1 ≈ LML2. The highest earthworm density and dry mass, fine root biomass, soil microbial respiration, microbial biomass carbon, NH4+, NO3−, nitrogen mineralization, and microbial biomass nitrogen were measured in UND, followed by LML4. Compared with U, all litter mulch treatments enhanced enzyme activity. Four years after mulch application, the values of soil biological and microbial properties and enzyme activity were significantly higher in LML4 ≈ LML3 followed by LML2 ≈ LML1, compared to U, but were still lower than the values of the UND treatment. We can conclude that the increased levels of leaf litter mulch moderately improved soil physio-chemical, biological, and microbial properties, as well as enzyme activity, after mechanized operations over a four year period, compared to the U treatment. However, the values of soil properties and enzyme activity were still lower than those in the UND treatment, indicating that four years is not long enough to restore the soil properties to pre-harvest levels in the study area. In conclusion, leaf litter level of LML3 with 1.31 kg m−2 can be applied as an optimal level for spreading leaf litter on skid trails to modify and enhance soil quality.

Effectiveness of Three Post-Harvest Rehabilitation Treatments for Runoff and Sediment Reduction on Skid Trails in the Hyrcanian Forests

Ground-based skidding operations can lead to soil compaction and displacement, which could cause negative effects on forest soil. Hence, some efforts such as forestry best management practices (BMPs) must be implemented in the prone area to mitigate these possible impacts. Several materials and treatments have been adopted to suppress these adverse effects by increasing the ground cover. However, the effects of mulch treatments on runoff and sediment yield are inconclusive with a diverse range of effectiveness. For these reasons, in this research mulch treatments were tested as to determine how the application of organic mulch amendments such as straw and leaf litter and contour-felled logs would alleviate the runoff and sediment yield on machine operating trails and ensure successful hillslope stabilization. The aims of the study were to analyse and compare the effectiveness of leaf litter (LM) and straw mulch (SM) rate and different distances of contour-felled logs (CFL) to mitigate the runoff and sediment yield, and examine the impact of rainfall intensity on effectiveness of litter mulch, straw mulch, and contour-felled logs. Totally, 30 bounded runoff plots in the machine operating trails and four treatments including litter mulch (LMR1: 0.62, LMR2: 1.24, and LMR3: 1.86 kg m-2), straw mulch (SMR1: 0.45, SMR2: 0.92, and SMR3: 1.34 kg m-2), contour-felled logs (CFL10: 10, CFL20: 20, and CFL30: 30 m), and untreated area were established in triplicate with 4 m width and 100 m length. During the study period, the runoff and sediment yield in the untreated trails (U) were 2.36 mm and 11.84 g m-2. Straw (from 41.5 to 60.6%) and litter mulch (from 38.1 to 55.1%), and contour-felled logs treatments (from 70.8 to 88.1%) significantly decreased the runoff, compared to U treatment. Results show that mulch treatments with three different levels of Litter Mulch Rate, LMR1, LMR2, and LMR3 decreased mean sediment by 46.6, 64.0 and 71.8%, in the treatments with three different levels of Straw Mulch Rate, SMR1, SMR2, and SMR3 decreased mean sediment by 42.9, 62.1, and 69.9%, and in the treatments with three different distances of Contour-Felled Logs, CFL10, CFL20, and CFL30 decreased mean sediment by 90.6, 94.7 and 88.3% comparing to U, respectively. The relationships of the runoff and sediment responses to increasing mulching rate of litter and straw followed as negative logarithmic curves, but the decreasing-increasing trends were observed in runoff and sediment yield as the distance between contour-felled logs increased from 10 to 30 m. Polynomial regression equations were developed for predicting the runoff and sediment yield as a function of the application rate of litter and straw mulch and the distance between contour-felled logs, and rainfall intensity. We concluded that contour-felled logs treatment was more effective than both litter and straw mulch to mitigate the runoff, runoff coefficient, and sediment yield on machine operating trails. As a management measure, it could be possible to propose that the contour-felled logs with a distance of 20 m be prescribed to protect the machine operating trails from the negative effects of surface waterflow.

Poultry litter and fresh mulch of Elephant grass improve the organic potato production

ABSTRACT The organic production system for potato is usually limited by the occurrence of diseases and nutrient shortage. In these cases, fresh grass mulch and organic fertilization can interact in the foliar late blight infestation and increase the yield and quality of marketable potato tubers, in the organic production system. Aiming to validate this hypothesis, four poultry litter doses (0 Mg ha-1, 10 Mg ha-1, 20 Mg ha-1 and 30 Mg ha-1), which were incorporated into the soil at the pre-planting stage of organic grown potato combined with the presence and absence of fresh mulch (60 Mg ha-1) composed of chopped Elephant grass, were tested. The incorporation of poultry litter into the soil at the pre-planting of potato or the use of fresh grass mulch after the potato hilling inhibits the late blight infestation on leaves, in the organic system. The application of fresh grass mulch after the hilling operation enhances the effect of organic fertilization at the pre-planting of potatoes. The pre-planting application of poultry litter increases the yield and decreases the specific gravities of marketable potato tubers in association with fresh grass mulch. The use of poultry litter at pre-planting and fresh grass mulch improve the sustainable potato cropping in the organic production system.

First Report on the Effect of Aqueous Extracts of Hungarian Organic Mulch Materials on Entomopathogenic and Slug-Parasitic Nematodes

Few researches address the compatibility of organic mulching and entomopathogenic (EPN) and slug-parasitic (SPN) nematodes, although organic mulching may provide favourable conditions for these beneficial organisms. Our aim was to examine the effect of different concentrations (0.1, 0.5, 1 and 5%) of aqueous extracts of green waste compost, the dry leaf litters of the common walnut (Juglans regia) and Norway maple (Acer platanoides) on EPN (Heterorhabditis bacteriophora, Steinernema carpocapsae, Steinernema feltiae, Steinernema kraussei) and SPN (Phasmarhabditis hermaphrodita) species. Experiments were set up in 96-well, flat-bottom microplates. After a 24-hour exposure time, the number of dead animals was counted under a transmission microscope. Green waste compost extracts caused quite low or no mortality in case of all examined species. Mortality caused by the 5% Norway maple leaf litter extract was moderate (34.6%) in the case of S. carpocapsae juveniles, while 100% of juveniles of other species died. The highest (5%) concentration of the common walnut leaf litter extract caused 100% mortality in all species. As a conclusion, green waste compost mulch seems to be more compatible with EPN and SPN species than common walnut or Norway maple leaf litter mulch.

Comparative Study on Khar Mulching and Forest Litter Mulching: Soil Nutrient Dynamics in Ginger Cultivation

A study conducted to assess the fertility status under Khar(Pragmites karka) and forest litter mulching practices on ginger cultivation. Ginger field with mulching of Khar and ginger field with mulching of forest litter was identified as two strata to collect soil sample. Thirty soil samples collected from each mulching practices. Simple random sampling procedure was followed to collect soil sample within the strata. Soil fertility parameters such as soil pH, Soil organic carbon, Nitrogen, Phosphorus, Potassium were analyzed for different mulching system. Mulching material significantly effect on Soil pH, Soil organic carbon and soil nitrogen. Soil acidity was found lower with forest litter mulch (5.53) but it was found higher for Khar mulch (5.78). Soil organic carbon was found higher in ginger field with Khar mulch (2.31%) and found lower with forest litter mulch (1.97%). Soil nitrogen level was found higher in ginger field with Khar mulch (0.20%) and found lower with forest litter mulch (0.17%). Soil available phosphorus and Potassium were not found significantly different in both type of mulching system. The result obtained from the study indicates that ginger field with Khar mulch result soil with higher soil organic carbon and Nitrogen. Mulching decision can also be made after testing the soil of respective ginger growing field. Appropriate liming could be done so that it could reduce the soil acidity problems.
 Int. J. Appl. Sci. Biotechnol. Vol 7(3): 335-340

Effects of litter and straw mulch amendments on compacted soil properties and Caucasian alder (Alnus subcordata) growth

Application of mulch on compacted soil is a common engineering measure to suppress runoff and soil loss during ground-based mechanized forest operations. Despite the expanded use, efficacy of these rehabilitation treatments on soil quality as well as seedling survival and growth rate are crucial issues that require further attention. This study aimed to assess the efficacy of two soil amendment techniques including straw (1.27 kg m−2) and litter (1.67 kg m−2) mulch on soil properties and growth properties of Caucasian alder. Three treatments: straw mulch (SM), litter mulch (LM) and untreated trail (U) were applied on newly established machine operating trails subjected to low, medium, and high machine traffic intensity classes and compared to the undisturbed area (i.e., control; UND). Approximately 22 months after ground-based machine traffic and mulching application, seeds of Caucasian alder were sown in each treatment and in the undisturbed area and further extracted after the first growing season to assess their growth rates. Three years after applying mulch on the compacted soil, recovery values of soil physical and chemical properties (with the exception of soil C/N ratio) in all traffic intensities were significantly higher in LM than SM, compared to U treatment. Nevertheless, recovery values of soil physical and chemical properties were still higher than values in UND area over a 3-year period. All the measured growth and biomass responses of Caucasian alder seedlings changed significantly with increasing traffic intensities (all P ≤ 0.05). Significantly higher seed germination percentage was recorded in LM with low traffic intensity (54%). Significantly higher seedling stem height (17.3 cm), main root length (23.6 cm), seedling total (7.68 g), shoot (2.87 g), and root dry (4.81 g) biomass were observed in the UND area followed by LM with low traffic ≈ LM with medium traffic treatments, whereas the lowest values of seedling size and biomass were detected on U with low, medium, and high traffic intensities. Seedling root mass ratio (RMR; 61%) and root to shoot ratio (R/S; 1.89) were greatest in the UND area, while the RMR (40%) and R/S (0.86) were least in the U plots with high traffic intensity. We can conclude that the highest seedling growth, biomass, and allocation ratios and favorable soil physical, chemical, and bio-chemical properties can be attributed to UND, LM with low and medium traffic, and SM with low traffic treatments.

Efficacy of leaf litter mulch to mitigate runoff and sediment yield following mechanized operations in the Hyrcanian mixed forests

Following ground-based skidding operations, understory vegetation and litter layer are commonly damaged or displaced by the movement of machines and timber on the machine operating trails, thus leaving the area vulnerable to increased runoff flow and sediment yield. One of the interim options available to suppress runoff and soil loss is the application of litter mulch directly after mechanized harvesting operations. The goal of the study is to assess the effects of broadleaves litter mulch on runoff and sediment yield immediately after rainfall events on a severely compacted skid trail in a mixed forest in Hyrcanian forests, northern Iran. The study included six treatments (undisturbed area, untreated trail, and four levels of litter rate; 0.42, 0.81, 1.31, and 1.69 kg m2 referred to as LR1, LR2, LR3, LR4, respectively) and two levels of trail gradient (10% and 20%), replicated in three plots (7 m long × 1 m width). The highest runoff values of 1.54 and 1.33 mm were measured at trail gradients of 20 and 10% for the untreated trail, respectively. The litter mulch application resulted in runoff decreasing by 49%, 67%, 75%, and 79% in the LR1, LR2, LR3, and LR4 treatments, respectively. The highest values of runoff coefficient were measured in the untreated trail (U; 4.6%), followed by LR1 > LR2 > LR3 ≈ LR4 treatments. Sediment yield in the untreated treatment was 7.32 g m−2 on the 10% gradient trail and 6.15 g m−2 on the 20% trail gradient. Sediment yield values in the LR1, LR2, LR3, and LR4 treatments were decreased by 76%, 85%, 90%, and 93%, respectively, compared to the untreated treatment. By increasing the litter rate, runoff and sediment yield responses significantly decreased as the rainfall increased. The net differences between the tested litter rates and the runoff and sediment yield reductions were higher with increasing rainfall intensity.

Effect of leaf litter mulch on germination and initial seedling growth of some traditional field crops in Garhwal Himalaya, India

Effect of leaf litter mulch on germination and initial seedling growth of some traditional field crops in Garhwal Himalaya, India

Growth of Spinach Plant (Amaranthus tricolor L.) by Application of Kascing Organic Fertilizer and Bamboo Leaf Litter Mulch

Spinach (Amaranthus tricolor L.). is one of the vegetables that are economically valuable with high nutrient content to support public health so that its production needs to be improved. The purpose of study was to obtained the optimal dosage of kascing organic fertilizer and the thickness of the bamboo leaf litter mulch on increase growth of spinach. The research used experimental method with randomize block design (RBD), two factors and three replications. The first factor was the adding of kascing organic fertilizer (K), consist of five levels doses, i.e: without adding kascing fertilizer (k0); 2.5 g/kg of soil (k1); 5 g/kg of soil (k2); 7.5 g/kg of soil (k3) and 10 g/kg of soil (k4). The second factor was bamboo leaf litter mulch (M), consist of three levels, i.e: without mulch (m0); mulch with thickness of 2.5 cm (m1); mulch with thickness of 5 cm (m2). Parameter observed were the plant height, the number of leaves, the leaf area, the shoot dry weight and the root dry weight. The data obtained was analyze using Anova and Duncan’s Multiple Range Test (α=5%). The results showed that interaction between dosage of kascing fertilizer with bamboos leaves litter mulch could increase the average of plant height (50.17 cm), number of leaves (40.33 leaves), shoot dry weight (5.77 g) and root dry weight (1.78 g) of spinach. Commonly, kascing organic fertilizer dose of 5 g/kg of soil (k2) and bamboos leaves litter mulch on the tickness of 5 cm (m2) combination was the best treatment for growth of spinach.
 Keywords: bamboo leaf litter, mulch, organic fertilizer of kascing, spinach

Characteristics of Nitrogen Loss through Surface-Subsurface Flow on Red Soil Slopes of Southeast China

Soil nitrogen (N) loss related to surface flow and subsurface flow (including interflow and groundwater flow) from slope lands is a global issue. A lysimetric experiment with three types of land cover (grass cover, GC; litter cover, LC; and bare land, BL) were carried out on a red soil slope land in southeast China. Total Nitrogen (TN) loss through surface flow, interflow and groundwater flow was observed under 28 natural precipitation events from 2015 to 2016. TN concentrations from subsurface flow on BL and LC plots were, on average, 2.7–8.2 and 1.5–4.4 times greater than TN concentrations from surface flow, respectively; the average concentration of TN from subsurface flow on GC was about 36–56% of that recorded from surface flow. Surface flow, interflow and groundwater flow contributed 0–15, 2–9 and 76–96%, respectively, of loss load of TN. Compared with BL, GC and LC intercepted 83–86% of TN loss through surface runoff; GC intercepted 95% of TN loss through subsurface flow while TN loss through subsurface flow on LC is 2.3 times larger than that on BL. In conclusion, subsurface flow especially groundwater flow is the dominant hydrological rout for N loss that is usually underestimated. Grass cover has the high retention of N runoff loss while litter mulch will increase N leaching loss. These findings provide scientific support to control N runoff loss from the red soil slope lands by using suitable vegetation cover and mulching techniques.

Characteristics of Phosphorus Output Through Runoff on a Red Soil Slope Under Natural Rainfall Conditions

The development of agriculture in the red soil sloping uplands has been increasingly restricted by low water availability, high temperatures, and low fertilizer use efficiency. Subsurface flow has a significant influence on runoff generation, nutrient loss, and soil erosion. The rainfall-runoff process makes it easy for nutrients on the sloping land to enter water bodies through subsurface flow mainly in the liquid phase, which may lead to environmental problems such as eutrophication and groundwater pollution. Phosphorus as one of the common nutrients causing eutrophication is immobile in the soil because it is easily absorbed and fixed by soil particles. Thus, the principal pathway of phosphorus release from the soil is the surface flow. In some regions, sufficient and concentrated rainfall results in the surface-subsurface flow that enhances phosphorus migration. Recently, researchers have studied the migration patterns of red soil phosphorus through surface flow and the impact factors arising from these migrations, as well as the generation of subsurface flow and its influence on phosphorus outputs. However, there are relatively few investigations that have comprehensively considered the influence of both surface flow and subsurface flow on the migration of red soil phosphorus. In order to investigate the characteristics of phosphorus loss through runoff under natural rainfall, a large-scale field lysimeter experiment was conducted with three treatments i.e., grass cover (GC), litter mulch (LM), and bare land (BL) on a red soil slope land in southeast China. Phosphorus loss through surface flow, interflow at different soil layers (30 cm and 60 cm), and groundwater flow (at 105 cm depth) was observed under each natural precipitation event over a one-year period. The results showed that:① The concentrations of total P (TP) and dissoluble P (DP) in surface flow were slightly higher than those in interflow and groundwater flow; the concentrations of TP and DP showed a gradual downward trend with the increase in soil depth. The total amount of TP runoff loss was ordered as BL (1.61 kg·hm-2) > LM (1.33 kg·hm-2) > GC(0.82 kg·hm-2). ② Surface flow, interflow, and groundwater contributed to 57%, 6%, and 37%, respectively, of the phosphorus runoff loss on BL plot; surface runoff was the main pathway of phosphorus loss. Groundwater flow was the crucial route of phosphorus runoff loss once a vegetation cover was in place; groundwater flow contributed to more than 71% of the phosphorus runoff loss while the surface flow contributed less than 14%. ③ Particulate phosphorus was the primary pattern of phosphorus transport which accounted for 64%-97% of the total amount of phosphorus runoff loss. The effect of phosphorus loss through groundwater flow cannot be neglected on the red soil slope land. The loss load of phosphorus through runoff can be controlled by grass cover and litter mulch treatments, whereas the concentrations of phosphorus in runoff do not significantly reduce.

Allelopathic Effects of Homestead agroforestry Tree Leaf Litter on the Sprouting and Early Growth in Elephant Foot Yam (Amorphophallus paeniifolius)

The allelopathic effects of eight selected agroforestry tree litter on the sprouting and early growth of the understorey tuber crop, elephant foot yam (Amorphophallus paeniifolius) were examined during 2014-’15. Litter leachates at 2% concentration and litter mulch were used for the study and it was found that the effects of litter mulch were significant on sprouting and seedling growth while with the leachate, significant effects were recorded only on shoot growth and leaf production. The effects varied with species, tamarind and wild jack recorded maximum inhibition both as leachate and mulch. Litter of rubber, mango and jack showed stimulatory effects thus bringing to light their potential to be used as organic inputs in elephant foot yam cultivation.

Effect of leaf litter mulching on the pests of tomato

Agricultural techniques essentially change the weed flora, pests and diseases of cultivated plants. Our aim was to investigate the effect of leaf litter mulch on the pests of tomato, especially on the weed flora and on three important plant protection problems: late blight (Phytophthora infestans), cotton bollworm (Helicoverpa armigera) and root-knot nematodes (Meloidogyne spp.). Besides mulching, the experiment consisted of irrigation, mycorrhiza-inoculation and artificial Meloidogyne-infestation. We recorded the natural P. infestans infection, Helicoverpa armigera damage and the species composition and cover of weeds as well. We examined whether leaf litter mulching had any effect on pests, and on the generative and vegetative production of tomato. Our results were that only mulching had a significant positive effect on almost all the measured generative and vegetative production parameters of tomato, while irrigation, mycorrhiza application and artificial nematode infestation had no significant effects on these parameters. Negative correlation was found between P. infestans infection and H. armigera-damage on tomato fruits. Mulching also reduced significantly the number of Meloidogyne-induced galls on the roots of tomato. Application of leaf litter mulch did not affect soil organic matter and soil pH within the growing season. In the beginning of the growing season mulching suppressed weed cover. Later, there was no significant difference between weed cover in the treatments. It can be concluded that leaf litter mulch had a more pronounced influence on the quantity of yield than on the damage and presence of pests and weeds.