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Tomato is a demanding crop in fertilizers, fungicides, and pesticides. Therefore, producing food with limit use of chemical farm inputs became essential to reduce the harmful effects of these chemicals in agro-ecosystems. Green manures have great potential to limit the dependency on chemical inputs and preserve the soil fertility. Two fodder radish cultivars, used as green manure, were tested, during three consecutive cropping years, for their effects on soil properties and fertility, tomato growth and production, soilborne diseases' severity, and rhizosphere microbial community. Control treatment consisted of bovine manure and a commercial bio-activator of plant and soil systems i.e. biocat−15Ⓡ. All amended soils showed enhancement in their total nitrogen and available potassium and phosphorus levels. The highest increment in the soil organic matter and the soil carbon biomass noted using radish cv. Defender material. Before tomato planting, the monitoring of the soil microbial community structure revealed that the two green manures had increased the soil richness in actinomycetes communities but only cv. Defender had enhanced the bacterial population. For tomato growth and soilborne disease severity parameters, organic amendments had enhanced tomato growth by 17.8 to 41.7% and decreased disease severity by 46.6 to 97.3% at the second cropping year compared to the first one. The present results indicate that the four organic amendments tested would be an effective approach for improving the soil ecological environment for sustainable tomato cropping with significant enhancements of the majority of tested parameters recorded using fodder radish cv. Defender as green manure. [ABSTRACT FROM AUTHOR]

Nigeria's savanna soils where sorghum (Sorghum bicolor L. Moench) is majorly produced are characterized by a lot of challenges. Hence, field experiments were conducted in 2018 and 2019 on sole and combined effects of Panicum maximum, Tithonia diversifolia, and poultry manure (PM) on soil physico-chemical properties, growth, yield, and proximate contents of sorghum. The treatments were: 10 t ha−1Tithonia leaves, 10 t ha−1Panicum leaves, 10 t ha−1 PM, 5 t ha−1Tithonia leaves + 5 t ha−1Panicum leaves, 5 t ha−1Tithonia leaves + 5 t ha−1 PM, 5 t ha−1Panicum leaves + 5 t ha−1 PM (Panicum + PM), control. The treatments were arranged in a randomized complete block design with three replications. Green manures and PM either sole or combined reduced sorghum's grain fiber, fat and carbohydrate, soil bulk density and increased porosity, moisture content, soil organic matter (SOM), nutrient content, growth, yield, and moisture, ash and protein contents of sorghum compared with the control. When manures were combined, Panicum + PM has the highest value of these parameters but the least of grains fiber, fat, carbohydrate, and soil bulk density. The increased growth, yield, and quality of sorghum credited to Panicum + PM was owed to improved soil physical and chemical properties and also due to the fact that slowly decaying Panicum may allow retention of released nutrients from rapidly decomposing PM within the rooting zone. The study revealed that locally available organic materials can be recycled in improving soil and crop productivity especially when they are combined. [ABSTRACT FROM AUTHOR]

The response of plant growth, yield, dry matter (DM), accumulation (NAC) and recovery efficiency (RE) of nutrients in the first crop (broccoli), and its residual effect on DM and NAC in the second crop (Brachiaria brizantha) were determined, using as nutrient sources, the green manure velvet-bean (GM) and mineral fertilization (MF). The treatments were: plant unfertilized (control), 100% of the recommended dose of MF (MF100), 5 t ha−1 of GM (GM5), MF dose similar to GM5 (MF = GM5), GM5 + MF to apply the same dose of MF100 (GM5+ MF = MF100). In broccoli, no differences in canopy area, leaves number, yield, DM and NAC were detected between GM5 and control, while MF = GM5 exceeded GM5. Higher residual effect in B. brizantha was obtained with MF100 and GM5+ MF = MF100. The MF = GM5 stimulated higher RE of N, P, K, Ca, Mg and S than GM5. Higher RE of N and Ca was obtained with MF100 than with GM5+ MF = MF100, both in broccoli and B. brizantha. Our results suggest that the GM affects negatively the plant growth, yield, DM, NAC and RE in sequential crops, and when is combined, it minimizes the effect of the MF. So, that same dose has a better effect when applied through MF. [ABSTRACT FROM AUTHOR]

Soil characteristics were determined in a coffee plantation after fertilization by five consecutive years with compost and green manure. Compost was applied to provide 25%, 50%, 75% and 100% of the recommended N dose for the coffee crop. Each compost dose was applied alone or combined with 3 t ha−1 of sunn hemp (SH). Linear increment of pH, sum of base (cmolc dm−3), base saturation (V%), cation exchange capacity (cmolc dm−3), effective cation exchange capacity (cmolc dm−3), concentration of P, K, Ca and Mg were detected with exclusive compost. Non-linear increments of pH, V%, concentration of P and Ca were obtained with combined fertilization. SH effect was obtained when associated with the dose 25% N. Higher ratio (Ca+Mg)/K was detected with compost 25% N + SH. The continuous and exclusive application of compost at 25% and 50% improves soil chemical characteristics, but at a dose of 100%, causes unbalance of soil characteristics like pH at slightly alkaline levels, high amount of P available and more probability of antagonism between K, Ca and Mg. The application of SH neutralizes the alkalinity of the compost, less antagonism probability between K, Ca and Mg and allows maintaining a better nutrient balance in the soil. [ABSTRACT FROM AUTHOR]

Reliable methods to estimate nitrogen (N) mineralization from organic amendments are needed to improve the fertilization recommendations for organic horticultural crops. With this aim, N mineralization from farmyard manure compost (FYMC), commercial organic fertilizer (COF) based on materials that are prompt to rapid N mineralization and green manure was determined in field situation where environmental factors affect mineralization rates and under controlled laboratory conditions that may not reflect conditions in the field. The ability of field and laboratory incubations to predict N mineralization was estimated during a field organic crop rotation set up with a cover crop of rye and vetch, followed by Portuguese cabbage and carrot. The relationship between mineralized N in field incubation and crop N accumulation suggests that field incubation is effective to predict N mineralization from FYMC, COF and green manure. However, the pattern of N mineralization from FYMC and green manure was different in field and laboratory incubation conditions as opposed to N mineralization from COF that was similar in both incubations. [ABSTRACT FROM AUTHOR]

This study aimed at identifying the proper developmental stage for the cutting of cover crops with high nutrients content in the shoots of plants to be used as green manure on crop rotation in the no-tillage (NT) system. Crotalaria juncea, Cajanus cajan, Mucuna aterrima, and Sorghum bicolor were collected at five different vegetative stages for assessing of fresh weight yield (DWY) and dry weight yield (DWY), as well as determining the carbon (C)/nitrogen (N) ratio and the contents of nutrients in the shoots of plants. The experiment was performed on a completely randomized design, with five replicates. Except for the nutrients contents in S. bicolor, for the assessed legumes the DWY, FWY, C/N ratio, nutrient concentration and nutrient accumulation in the shoots have increased with the development of plants. Therefore, it can be inferred that grasses studied will provide greater soil cover, while the legumes will provide a greater nutrient cycling. [ABSTRACT FROM AUTHOR]

The objectives of this greenhouse experiment were to quantify the benefits of green manure (GM) diversity and to assess effect of GM on a succeeding lettuce crop. Species included barley (B), field pea (P), sunn hemp (S), and buckwheat (U). Treatments included single plantings of B and P and mixtures of B and P (BP), B, P, and S (BPS), and B, P, S, and U (BPSU). The pea GM had the highest shoot concentration of potassium, calcium, magnesium, manganese, zinc, and iron. Roots had higher concentrations of nutrients than shoots. Accumulation of nutrients in legumes was higher than in barley. The CO2flux from the soil suggests that the most intensive mineralization period occurred within two weeks after incorporation of GMs. The mixtures and single planting of P mixtures had a significant benefit over single planting of B regarding fresh and dry weight of the lettuce. [ABSTRACT FROM PUBLISHER]

The aim of this study was to identify the cutting time for winter cover crops used as green manure in no-tillage systems that results in the highest dry weight yield (DWY) and nutrient accumulation. We testedAvena strigosa, Secale cereale, Vicia sativa, Raphanus sativus, andLupinus albus, in five management times, determining the fresh weight yield (FWY), DWY, and the chemical composition of the shoot tissue. The highest FWY was obtained usingR. sativusandL. albus. At 145 days after sowing; these species also had the highest DWYs, over 15 t ha−1.L. albusandS. cerealehad the highest carbon to nitrogen (C:N) ratio (60:1). The nutrient content of most crops decreased over time. However, the accumulation of nutrients increased over time, especially forR. sativus. L. albushad the highest level and manganese (Mn) accumulation, while the zinc (Zn) and cooper (Cu) accumulation was highest inA. strigosa, and that of boron (B) was highest inS. cereale. Thus,R. sativusprovided the best soil cover among the species tested, due to its high biomass yield and greater nutrient cycling. [ABSTRACT FROM AUTHOR]

Carbon (C) and nitrogen (N) determination with traditional methods is more laborious and time-consuming than automated analyzers. Microprocessor-based technologies led to the development of automated analyzers and have reduced the time of analysis. However, these need to be standardized with respect to weight and mesh size of plant/organic material sample used. For standardization of Vario EL III carbon (C), hydrogen (H), nitrogen (N), and sulfur (S) analyzer for the particle size and amount of sample, laboratory studies were carried out for C and N determination by CHNS analyzer in comparison to the traditional methods for different categories of organics such as green manure (cowpea), crop residues (rice straw), animal residues (farmyard manure), and industrial by-product (press mud). Organic samples of <0.25-mm size resulted in greater amounts of C and N with both CHNS analyzer and traditional methods than with other size groups. The C and N contents were greater with a sample weight of 5 than with 10 mg. [ABSTRACT FROM PUBLISHER]

Green manure crops can be used as alternatives to mineral fertilizers because they improve soil structure and nutrient content of soil. Here, we evaluated the effect of partial replacement of mineral nitrogen (N) fertilizer with rapeseed residue green manure on soil properties and rice productivity in a rice–rapeseed double-cropping system. The treatments were comprised of four levels of mineral N fertilizer and recommended levels of phosphate and potash fertilizers. Rice clum and panicle length did not differ between treatments. However, the proportion of ripened grains and 1,000-grain weight of rice plants were greater under rapeseed residue amendments than those under 100% conventional mineral N fertilizer treatments. Paddy soils treated with rapeseed residues had greater soil organic matter and exchangeable cations than those treated with mineral N fertilizer alone. Thus, rapeseed residues applied as green manure can serve as alternative N sources in sustainable rice–rapeseed double-cropping systems. [ABSTRACT FROM AUTHOR]

Net nitrogen (N) balance after rice (Oryza sativaL.) and its relationship with yield and N uptake of succeeding wheat crop was studied in a greenhouse. Three urea-enriched green manures, namely dhaincha (Sesbania aculeataL.), cowpea (Vigna unguiculataL.), and guar (Cyamopsis tetragonolobaL.) were compared with split application of urea in a rice–wheat cropping sequence. After rice, a negative N balance was measured in all treatments; however, the N balance values were greater with urea than with green manures. The N balance was positively correlated with the N content but negatively correlated with lignin content and carbon (C)–N ratio of the green manures. Lignin content was a better index than C/N ratio for predicting the net N balance, which described 82.3% of the total variations. Efficiency of residual N utilization by wheat could be determined by estimating the N balance after rice. Net N balance after rice can be used as a yardstick for the prediction of yield and N uptake by wheat crop. [ABSTRACT FROM AUTHOR]

A vetiver grass and bean cropping system could be used for improving physical properties of deteriorated soils. The objective of this research was to study effects of vetiver grass (Vetiveria zizanioidesNash) and green manure management on properties of Map Bon, a coarse-loamy variant of sandy loam, with low organic matter and medium erosion, at the Khao Hin Son Research Station, Chachoengsao, Thailand, from March 2001 to April 2003. The experiment was carried out in a split-plot design in a randomized complete block design with three replications. There were two main plots (with and without vetiver grass) and four subplots (without bean and with eitherVigna sinensis, Canavalia ensiformis,orDolichos lablab). This work showed that the treatments with vetiver grass could increase organic matter and saturated hydraulic conductivity; however, bulk density and soil hardness decreased and total porosity and available water-holding capacity were not affected. The use of green manure affected soil hardness and saturated hydraulic conductivity. The treatments with vetiver grass and green manure could increase available water-holding capacity of the soil also. [ABSTRACT FROM AUTHOR]

We investigated the chemical and biochemical composition, residue decomposition, and mineralization rate of leguminous (Cajanus cajan, Crotalaria spectabilis, and Lablab purpureus) and spontaneous vegetation in two experimental coffee systems in southeast Brazil. The nitrogen (N) content of the shoot biomass varied from 19.3 to 45.7 g kg-1, and phosphorus (P) content ranged from 1.6 to 3.8 g kg-1. C. cajan contained the greatest values of N and P, whereas spontaneous plants had the lowest values. In both areas, spontaneous vegetation had the greatest values of carbon (C) / P, C/N, polyphenol/N, and (lignin + polyphenol) / N ratios. Decomposition rate increased in the order C. cajan < C. spectabilis < L. purpureus < spontaneous vegetation. There was no correlation between the chemical and biochemical composition and the decomposition rate under field conditions. However, the cumulative carbon dioxide (C-CO2) produced by the residues under laboratory conditions was correlated positively with initial contents of N and P and negatively with polyphenol/N and (lignin + polyphenol) / N ratio (P < 0.01) throughout the sampling period. The low nutrient content, especially for N, of spontaneous vegetation is compensated by the greater decomposition rate under natural conditions than that of introduced species. Management of the spontaneous plants is therefore an attractive alternative for sustainable agriculture. [ABSTRACT FROM AUTHOR]

Adoption of legumes in cereal-based cropping systems and improvement of organic fertilizers are important to reduce chemical fertilizer use. We supplied compost and green manure (GM) of green pea plant residue (GP), without supplementation or supplemented with dried chicken manure (CM) and/or rapeseed oil residue (RR), for wheat and examined the effects of compost and GM (remaining fertilizer) on the rice of pea-wheat-rice system in two factorial pot experiments. Additions of pea residue resulted in an increase of 30% grains of rice compared to without addition, and compost increased 25% grains against GM. Supplementation increased 63-70% of rice grains as compared to the control. Nitrogen (N) and potassium (K) recovery efficiencies were correlated with yield, which suggested that composting and supplementation enabled effective nutrients accumulation in plant, resulting in better yield. Therefore, it is recommended that composting of GP with CM plus RR improves effectiveness of pea on rice of a pea-wheat-rice system. [ABSTRACT FROM AUTHOR]

Green manures are important in tropical cropping systems and are planted in degraded soils, thus affecting early growth. Pot and field experiments evaluated the impact of soil fertility on early growth of two important tropical green manures (Crotalaria juncea and Tithonia diversifolia) when compared to that of maize (Zea mays) with high and low levels of phosphorus fertilizer. Growth of tithonia was not affected by soil fertility level irrespective of phosphorus fertilizer, indicating its suitability for degraded soils. Crotalaria was affected by soil fertility (root growth was stimulated by phosphorus), indicating its potential for soils with some degree of fertility. Maize was significantly affected by soil fertility and phosphorus fertilizers, indicating the requirement of fertile soils for the successful development of a good root and shoot system. The importance of field studies in the tropics is also presented as the diverse field conditions reduces significant effects found in pot studies. [ABSTRACT FROM AUTHOR]

Soil organic matter (SOM) is an essential ecosystem component whose dynamics are affected by soil management practices. To evaluate the impact of two agricultural systems (organic and conventional) on soil organic carbon (C) and nitrogen (N) stocks in a sandy soil, samples were collected from the Amway Nutrilite Brazil farm and from the Central Pivot Horticultural Farmers Association farm, both situated in the Chapada da Ibiapaba region, Ceara State, Brazil. The first area has a large-scale Caribbean Cherry fruit production system under organic management, whereas the second represented a conventional soil cultivation condition, characterized by the use of chisel plow and disc plow, mineral fertilization, and herbicides application. Plots with and without green manure fertilization were compared in the organically cultivated systems by using soil samples collected in the rows and between the rows. Areas under native forest were also sampled to determine the steady-state condition. Total organic C and N contents in the soil (SOC, TN) and in the humic substances were determined at the 0- to 5-, 5- to 15-, 15- to 30-, and 30- to 50-cm soil layers. In addition, oxidizible organic C fractions were measured to calculate the carbon management index (CMI). In general, total SOC levels were low, ranging from 2.5 to 12.6 g kg-1 in the whole soil profile among the organic systems. In the upper soil layer, SOC and TN stocks were greater in the rows in response to organic fertilization. The conventional system presented lower variation on the SOC contents throughout soil layers when compared to the native forest area, indicating the direct effect of plowing on the downward SOC distribution. The CMI data confirmed the reestablishment of SOM levels in the rows of the organic managed systems in relation to the reference area, whereas the reduction of the CMI in the conventional system suggests a decline in the soil quality and greater potential for increased C losses to the atmosphere. [ABSTRACT FROM AUTHOR]

Maize is the most important highland cereal grown in the tropics, generally cultivated under rainfed smallholder conditions in Asia. Field experiments were carried out in Sri Lanka with the objective of determining the impact of three types of organic matter applied as mulch or incorporated on the yields and nitrogen uptake by maize cultivated under rainfed conditions in the South Asian major and minor seasons. The organic matter used was leaves of Gliricidia sepium, Tithonia diversifolia, or rice straw, with the full compliment of recommended mineral fertilizers. Organic matter, especially the two green manures, enhanced yields and nitrogen (N) uptake of maize, and the impact was more prominent in the minor dry season where the yields were lower. Incorporation of organic matter had a greater positive impact in the dry season in terms of N utilization efficiency and seed yields. The beneficial impact of organic matter with low carbon (C):N ratios in enhancing N nutrition and seed yields of rainfed maize in major and more importantly in the minor seasons is presented. [ABSTRACT FROM AUTHOR]

A 7-year-long field trial was conducted on integrated nutrient management for a dry season rice (Boro)-green manure (GM)-wet season rice (T. Aman) cropping system at the Bangladesh Rice Research Institute Farm, Gazipur during 1993-1999. Five packages of inorganic fertilizers, cow dung (CD), and GM dhaincha (Sesbania aculeata) were evaluated for immediate and residual effect on crop productivity, nutrient uptake, soil-nutrient balance sheet, and soil-fertility status. Plant height, active tiller production, and grain and straw yields were significantly increased as a result of the application of inorganic fertilizer and organic manure. Usually, the soil-test-based (STB) fertilizer doses for a high-yield goal produced the highest grain yield of 6.39 t ha-1 (average of 7 years) in Boro rice. Application of CD at the rate of 5 t ha-1 (oven-dry basis) once a year at the time of Boro transplanting supplemented 50% of the fertilizer nutrients other than nitrogen (N) in the subsequent crop of the cropping pattern. A positive effect of GM on the yield of T. Aman rice was observed. Following GM, the application of reduced doses of phosphorus (P), potassium (K), sulfur (S), and zinc (Zn) to the second crop (T. Aman) did not reduce yield, indicating the beneficial residual effect of fertilizer applied to the first crop (Boro rice) of the cropping pattern. The comparable yield of T. Aman was also observed with reduced fertilizer dose in CD-treated plots. The total P, K, and S uptake (kg/ha/yr) in the unfertilized plot under an irrigated rice system gradually decreased over the years. The partial nutrient balance in the unfertilized plot (T1) was negative for all the nutrients. In the fertilized plots, there was an apparent positive balance of P, S, and Zn but a negative balance of N and K. This study showed that the addition of organic manure (CD, dhaincha) gave more positive balances. In the T4c treatment at 0-15 cm, the application of chemical fertilizers along with the organic manures increased soil organic carbon by (C) 0.71%. The highest concentration of total N was observed with T4c followed by T4d and T4b, where CD was applied in Boro season and dhaincha GM was incorporated in T. Aman season. The sixfold increase in soil-available P in T4b-, T4c-, T4a-treated plots was due to the addition of CD. Dhaincha GM with the combination of chemical fertilizer helps to mobilize soil-available P by 3 to 6 ppm. The highest amount of soil-available S was found in T4c- and T4a-treated plots. It was 2.5 times higher than that of the initial soil. The application of CD and dhaincha GM along with chemical fertilizers not only increased organic C, total N, available P, and available S but also increased exchangeable K, available Zn, available iron (Fe), and available manganese (Mn) in soil. [ABSTRACT FROM AUTHOR]

Quantifying the relative contribution of different phosphorus (P) sources to P uptake can lead to greater understanding of the mechanisms that increase available P in integrated P management systems. The 32 P– 33 P double isotope labeling technique was used to determine the relative contribution of green manures (GMs) and P fertilizers to P uptake by Setaria grass ( Setaria sphacelata ) grown in an amended tropical acid soil (Bungor series) in a glasshouse study. The amendments were factorial combinations of GMs ( Calopogonium caeruleum , Gliricidia sepium and Imperata cylindrica ) and P fertilizers [phosphate rocks (PRs) from North Carolina (NCPR), China (CPR) and Algeria (APR), and triple superphosphate (TSP)]. Dry matter yield, P uptake, and P utilization from the amendments were monitored at 4, 8, and 15 weeks after establishment (WAE). The GMs alone or in combination with P fertilizers contributed less than 5% to total P uptake in this soil, but total P uptake into Setaria plants in the GM treatments was three to four times that of the P fertilizers because the GMs mobilized more soil P. Also, the GMs markedly increased fertilizer P utilization in the combined treatments, from 3% to 39% with CPR, from 6–9% to 19–48% with reactive PRs, and from 6% to 37% with TSP in this soil. Both P GM and the other decomposition products were probably involved in reducing soil P‐retention capacity. Mobilization of soil P was most likely the result of the action of the other decomposition products. These results demonstrate the high potential of integrating GMs and PRs for managing P in tropical soils and the importance of the soil P mobilization capacity of the organic components. Even the low‐quality Imperata GM enhanced the effectiveness of the reactive APR more than fourfold. [ABSTRACT FROM AUTHOR]

Aluminum toxicity can affect the growth of crops in the red soil of southern China. The present study investigates the effect of both the long‐term and the short‐term application of organic manure on the aluminum toxicity of the soil. A significant effect of barnyard and green manure on the detoxification of aluminum resulted from the long‐term application of manure in a pot culture. This was due mainly to the considerable accumulation of organic matter in the soil. Organic matter chelates and absorbs active aluminum; as a consequence, the aluminum toxicity was reduced. At the same time, the manure provided the crop with nutrients. In another pot culture, fresh green manure had remarkable effects on aluminum detoxification shortly after application, whereas fresh barnyard manure did not. This indicates the important role of low molecular organic acids, which are released during the decomposition of green manure, in the detoxification of aluminum in the soil. Furthermore, the ash elements, which were released by the decaying manure, may also detoxify soil aluminum. [ABSTRACT FROM AUTHOR]

Shoot samples of oil seed radish and black oat were collected during the winter at 60, 75, 90, and 120 days after planting (dap). At each cutting organic composition of the water soluble fraction (WSF) was determined and its effects on the mobilization of cations in acid soil were evaluated using PVC soil columns. A biological test based in root growth of pre-germinated wheat seeds was conducted for 7 days in soil columns after application of the WSF of plant materials. The relative organic composition of the plant materials changed between cutting times and the greatest values were observed at 60 dap for oil seed radish and 75 dap for black oat. In the later sampling dates, the relative values were decreased sharply. The identified organic compounds were aliphatic and phenolic organic acids. The application of the plant extracts in soil columns increased the pH and the concentrations of exchangeable calcium (Ca), magnesium (Mg), and potassium (K), and decreased exchangeable Al. Few differences between plant extracts were observed in the soil chemistry after extract applications. The extracts obtained at the 60 and 75 dap were more effective in alleviating soil acidity. The black oat plant material showed higher capacity for mobilization of Ca and the oil seed radish for Al. Wheat root growth, used as a biological indicator in the soil column system, was three times greater in the presence of all plant extracts when compared to the water control. The chemical changes in soil were not sufficient for discrimination of wheat root growth in the presence of different plant extracts. Higher efficiency for cation mobilization and acidity mitigation may be reached if plant material is cut before plentiful flowering stage. [ABSTRACT FROM AUTHOR]