Ha-1 Year-1 Research Articles

Short- and long-term carbon emissions from oil palm plantations converted from logged tropical peat swamp forest.

Need for regional economic development and global demand for agro-industrial commodities have resulted in large-scale conversion of forested landscapes to industrial agriculture across South East Asia. However, net emissions of CO2 from tropical peatland conversions may be significant and remain poorly quantified, resulting in controversy around the magnitude of carbon release following conversion. Here we present long-term, whole ecosystem monitoring of carbon exchange from two oil palm plantations on converted tropical peat swamp forest. Our sites compare a newly converted oil palm plantation (OPnew) to a mature oil palm plantation (OPmature) and combine them in the context of existing emission factors. Mean annual net emission (NEE) of CO2 measured at OPnew during the conversion period (137.8MgCO2 ha-1 year-1 ) was an order of magnitude lower during the measurement period at OPmature (17.5MgCO2 ha-1 year-1 ). However, mean water table depth (WTD) was shallower (0.26m) than a typical drainage target of 0.6m suggesting our emissions may be a conservative estimate for mature plantations, mean WTD at OPnew was more typical at 0.54m. Reductions in net emissions were primarily driven by increasing biomass accumulation into highly productive palms. Further analysis suggested annual peat carbon losses of 24.9MgCO2 -Cha-1 year-1 over the first 6years, lower than previous estimates for this early period from subsidence studies, losses reduced to 12.8MgCO2 -Cha-1 year-1 in the later, mature phase. Despite reductions in NEE and carbon loss over time, the system remained a large net source of carbon to the atmosphere after 12years with the remaining 8years of a typical plantation's rotation unlikely to recoup losses. These results emphasize the need for effective protection of tropical peatlands globally and strengthening of legislative enforcement where moratoria on peatland conversion already exist.

Impact of Rubber Leaf Vermicompost on Tea (Camellia sinensis) Yield and Earthworm Population in West Tripura (India)

Background: Vermicompost is a manure produced from organic waste through the activity of epigeic earthworms and microbes. Excessive use of chemical fertilizers for long term to increase the crop productivity have led to deterioration of soil health. Therefore, to assess the effect of vermicompost, as an alternative option to chemical fertilizer, on tea yield and earthworm population, field application of vermicompost on tea plantation was carried out for a period of two years (2015-2016) in Harishnagar Tea Estate, West Tripura, India. Methods: The experimental plot (25 sq. m) was set up using a random block design with 4 different rates of vermicompost viz. T0 (Control), T1 (5 t ha-1 year-1), T2 (10 t ha-1 year-1) and T3 (15 t ha-1 year-1) each having five replications. Composite soil samples were collected at the beginning and at the end of the experiment. Earthworms were also collected during the experimental period.Conclusion: Application of vermicompost significantly influenced the tea plantation soils, increased the tea yield along with earthworm population and was dependent on the vermicompost doses applied.

Major and persistent shifts in below-ground carbon dynamics and soil respiration following logging in tropical forests.

Soil respiration is the largest carbon efflux from the terrestrial ecosystem to the atmosphere, and selective logging influences soil respiration via changes in abiotic (temperature, moisture) and biotic (biomass, productivity, quantity and quality of necromass inputs) drivers. Logged forests are a predominant feature of the tropical forest landscape, their area exceeding that of intact forest. We quantified both total and component (root, mycorrhiza, litter, and soil organic matter, SOM) soil respiration in logged (n=5) and old-growth (n=6) forest plots in Malaysian Borneo, a region which is a global hotspot for emission from forest degradation. We constructed a detailed below-ground carbon budget including organic carbon inputs into the system via litterfall and root turnover. Total soil respiration was significantly higher in logged forests than in old-growth forests (14.3±0.23 and 12.7±0.60MgCha-1 year-1 , respectively, p=0.037). This was mainly due to the higher SOM respiration in logged forests (55±3.1% of the total respiration in logged forests vs. 50±3.0% in old-growth forests). In old-growth forests, annual SOM respiration was equal to the organic carbon inputs into the soil (difference between SOM respiration and inputs 0.18MgCha-1 year-1 , with 90% confidence intervals of -0.41 and 0.74MgCha-1 year-1 ), indicating that the system is in equilibrium, while in logged forests SOM respiration exceeded the inputs by 4.2MgCha-1 year-1 (90% CI of 3.6 and 4.9MgCha-1 year-1 ), indicating that the soil is losing carbon. These results contribute towards understanding the impact of logging on below-ground carbon dynamics, which is one of the key uncertainties in estimating emissions from forest degradation. This study demonstrates how significant perturbation of the below-ground carbon balance, and consequent net soil carbon emissions, can persist for decades after a logging event in tropical forests.

Nutritional balance and recovery rate of macronutrients by ‘Gigante’ cactus pear under different fertilizations

ABSTRACT The objective of this study was to evaluate nutrient export, nutritional balance and macronutrient recovery rate in ‘Gigante cactus pear under different fertilization doses, spacings and configurations during three production cycles. The 72 treatments were arranged in a randomized block design with three repetitions, two configurations in the plots (triple and quadruple row), three spacings in the subplots (3.00 x 1.00 x 0.25 m; 3.00 x 1.00 x 0.16 m and 3.00 x 1.00 x 0.125 m); and 12 types of fertilization in the sub-subplots (with organic, organomineral and mineral sources). Exports of nutrients are higher under fertilizers with higher nutrient supplies, regardless of source. The order of export was K > Ca > N > Mg > S > P for mineral fertilization, organic fertilization with 30 Mg ha-1 year-1 and organomineral fertilization with 30 and 60 Mg ha-1 year-1 plus NPK and PK, and it changed to K > Ca > N > Mg > P > S under organic fertilization with 60 and 90 Mg ha-1 year-1 and organomineral fertilization with 90 Mg ha-1 year-1 plus K. The nutrient balance after three production cycles was positive for N, P and S, negative for Ca and Mg in all fertilizations, and positive for K under mineral fertilization with 600 kg ha-1 of K2O and organomineral fertilization with 30, 60 and 90 Mg ha-1 year-1 plus 600 kg ha-1 of K2O. The highest recovery rates of K and the lowest recovery rates of N occur under organic fertilization.

Estimating the carbon storage potential and greenhouse gas emissions of French arable cropland using high-resolution modeling.

Many studies have assessed the potential of agricultural practices to sequester carbon (C). A comprehensive evaluation of impacts of agricultural practices requires not only considering C storage but also direct and indirect emissions of greenhouse gases (GHG) and their side effects (e.g., on the water cycle or agricultural production). We used a high-resolution modeling approach with the Simulateur mulTIdisciplinaire pour les Cultures Standard soil-crop model to quantify soil organic C (SOC) storage potential, GHG balance, biomass production and nitrogen- and water-related impacts for all arable land in France for current cropping systems (baseline scenario) and three mitigation scenarios: (i) spatial and temporal expansion of cover crops, (ii) spatial insertion and temporal extension of temporary grasslands (two sub-scenarios) and (iii) improved recycling of organic resources as fertilizer. In the baseline scenario, SOC decreased slightly over 30years in crop-only rotations but increased significantly in crop/temporary grassland rotations. Results highlighted a strong trade-off between the storage rate per unit area (kgCha-1 year-1 ) of mitigation scenarios and the areas to which they could be applied. As a result, while the most promising scenario at the field scale was the insertion of temporary grassland (+466kgCha-1 year-1 stored to a depth of 0.3m compared to the baseline, on 0.68Mha), at the national scale, it was by far the expansion of cover crops (+131kgCha-1 year-1 , on 17.62Mha). Side effects on crop production, water irrigation and nitrogen emissions varied greatly depending on the scenario and production situation. At the national scale, combining the three mitigation scenarios could mitigate GHG emissions of current cropping systems by 54% (-11.2 from the current 20.5MtCO2 eyear-1 ), but the remaining emissions would still lie far from the objective of C-neutral agriculture.

Accumulation of humic substances in an Oxisol fertilized with pig slurry for 15 years

ABSTRACT The growth of swine production in Brazil has increased the amount of production and use of pig slurry (PS) as soil fertilizer. This product provides nutrients to plants, and a continuous application of this residue usually increases total soil organic carbon (SOC) content. The objective of this study was to determine the SOC content and its distribution into humic substance fractions (humic acids, fulvic acids, and humin) in an Oxisol annually fertilized with PS for 15 years. The experiment was implemented in 2001 with a maize and oat crop rotation under no-tillage system in Campos Novos, SC, Brazil. The treatments used were: PS at rates of 0 (Control), 25, 50, 100, and 200 m3 ha-1 year-1, mineral fertilizer, and PS combined with mineral fertilizer, applied on the soil surface once a year. The 0-2.5, 2.5-5, 5-10, 10-20, 20-40, and 40-60 cm soil layers were evaluated for SOC content in the fractions humic acid, fulvic acid, and humin, and E4/E6 ratio of humic substances. Increases in PS rates up to 100 m3 ha-1 increased the SOC content in the 5-10 cm soil layer; however, decreased the proportion of the soil fulvic acid and humic acid fractions, favoring the accumulation of organic carbon in the humin fraction. The E4/E6 ratio was higher when using the soil mineral fertilizer than that found in treatments with PS.

Estimativa da vulnerabilidade dos solos à erosão hídrica na bacia hidrográfica do Rio das Mortes (MG)

A erosão hídrica é uma das maiores causas de degradação dos solos no mundo, sendo responsável por perdas de solo superiores às taxas naturais de reposição. Objetivou-se estimar a distribuição espacial do potencial anual médio de perda de solo na bacia hidrográfica do Rio das Mortes (MG), com a finalidade de identificar as áreas mais susceptíveis à erosão hídrica e fornecer subsídio para a gestão dos recursos naturais na região. Para isso, foi aplicado o modelo RUSLE (Revised Universal Soil Loss Equation) implementado em ambiente SIG. O fator erosividade da chuva foi obtido com base em um modelo geográfico multivariado desenvolvido para o Brasil; o fator cobertura e manejo do solo foi derivado do mapa de uso do solo do Brasil; o fator erodibilidade do solo foi obtido pelo mapa de solos de Minas Gerais; e o fator topográfico foi obtido pelo modelo digital de elevação. Os mapas dos fatores foram combinados por meio de álgebra de mapas, originando o mapa de vulnerabilidade dos solos à erosão hídrica. Observou-se que 45,20% dos solos da bacia hidrográfica estudada apresentaram “Ligeira” vulnerabilidade à erosão hídrica. No entanto, 50,28% da área da bacia apresentaram perda de solo superior a 10 t ha-1 ano-1, o que indica a existência de áreas altamente susceptíveis à erosão hídrica e evidencia a necessidade de implementação de melhorias no manejo e práticas conservacionistas do solo.

A Study on Sustainable Modules for Year-Round Green Fodder Production under Irrigated Conditions

Zonal Agricultural Research Station, Vishweswaraiah Canal Farm, Mandya, conducted "Studies on sustainable modules for year-round green fodder production under irrigated conditions" throughout the kharif, rabi, and summer seasons of 2018–19 and 2019–20. The experiment had three replicates and was set up in a randomized whole block design with fifteen fodder cropping system components. Green fodder yield (1636 q ha-1 year-1), dry fodder yield (321 q ha-1 year-1), carbon sequestration (24.87 Mg ha-1) and net returns (Rs. 2,14,232 ha-1 year-1) were all significantly higher for the BN hybrid + Lucerne (2:8) perennial system than they were for the BN hybrid + Cowpea (2:8) perennial system (1552 q ha-1 year-1, 308 q ha-1 year-1, 24.35.

MODEL TO ESTIMATE NUTRITIONAL AND NON-NUTRITIONAL LIMITATIONS OF ‘PRATA-ANÃ’ BANANA CROPS GROWN IN DIFFERENT ENVIRONMENTS

ABSTRACT The obtaining of a high banana yield requires that nutrients are in adequate quantities and proportions in the plant. Therefore, the use of methods that encompass nutritional balance and equilibrium is required for a good nutritional evaluation. The objective of this work was to model and determine nutritional and non-nutritional limitations of 'Prata-Anã' banana grown in the states of Ceará (CE) and Bahia (BA), Brazil, based on nutritional balance and equilibrium. The study was developed using the databank of leaf nutrient contents and banana yields of two farms of the Sítio Barreiras company, in Missão Velha (CE) and Ponto Novo (BA), Brazil. The parcels with banana yield above the average plus 0.5 standard deviation; and parcels with banana yield below of that limit were defined as low-yield areas and were used for nutritional diagnosis. The databank was divided into four: the first with 253 samples and a reference population with banana yield above 39.81 Mg ha-1 year-1; the second with 553 samples and a low-yield population (Ceará); the third with 147 samples and a reference population with banana yield above 41.69 Mg ha-1 year-1; and the fourth with 334 samples and a low-yield population (Bahia). Yield limitations in the 'Prata-Anã' banana crops due to nutritional causes reached 13.37% in Ceará, and 12.17% in Bahia. Non-nutritional factors, such as climate and biotic factors, limited the banana crop yields by up to 28.23% in Ceará, and 50.49% in Bahia.

Soil losses in the State of Rondônia, Brazil

ABSTRACT: In the state of Rondônia, deforestation, and inadequate soil use and management have intensified the water erosion process, causing degradation of agricultural land. Modeling is a tool that can assist in the adoption of targeted and effective measures for soil and water conservation in the region. In this context, the objective of the research was to model soil losses due to water erosion in the state of Rondônia using the Revised Universal Soil Loss Equation (RUSLE). The parameters related to rain erosivity, relief, erodibility, and soil cover, as well as the conservation practices of the state of Rondônia, were considered. The modeling steps were performed with the aid of the Geographic Information System. Results were validated with data of total sediments transported with water discharge. The estimated total soil loss was about 605 million tons per year, corresponding to an average loss of 22.50 Mg ha-1 year-1. In 19% of the state, the erosion rate was higher than the soil loss tolerance(T), and these areas should be prioritized for adopting measures to mitigate the erosion process. The RUSLE underestimated the generation of sediments at 0.56 Mg ha-1 year-1, which corresponds to an error of 18.60%. Results obtained can assist in the development of different soil use and management scenarios and provide options for policymakers to encourage soil conservation in the state of Rondônia.

Potential nutrient-response curves and sufficiency ranges of ‘Grande Naine’ banana cultivated in two environment

Abstract Adequate plant nutrition is essential to attain higher yields. The objective was to determine potential-nutrient response curves and sufficiency ranges using the boundary line approach and balance indices of Kenworthy for interpreting the nutritional status of ‘Grand Nain’ banana cultivated in two environments. The study was carried out using a database containing leaf nutrient concentrations and yields of bananas cultivated on two areas located in Missão Velha-CE, and Ponto Novo-BA, Brazil. Plots with high-yielding plants, which were those with yields above average plus 0.5 standard deviation, were used atem as reference population. The database was subdivided into two sets. One of them contained 46 leaf tissue samples and reference population with yield greater than 58.84 Mg ha-1 year-1, in Missão Velha-CE. The second data set contained 19 samples and reference population with yield greater than 76.12 Mg ha-1 year-1 in Ponto Novo-BA. Potential response curves were fitted to the relationship between relative yield and leaf element concentrations and balance indices of Kenworthy. Models expressed high predictive power. Sufficiency ranges for macro- and micronutrient concentrations and balance indices of Kenworthy were established. The ranges allow an improved nutritional status assessment of irrigated ‘Grand Nain’ bananas.

EFFECTS OF LAND USE AND LAND COVER CHANGES ON SOIL EROSION IN SEMI-ARID REGIONS OF TURKEY; A CASE STUDY IN ALMUS LAKE WATERSHED

Land use and land cover (LULC) changes, which are the major causes of soil erosion in watersheds are important processes of land degradation in the world. Erosion models are useful to investigate temporal changes in the past and estimate the future soil losses that might threat the sustainability of crop production. In this study, temporal changes (between 1990 and 2018) of soil loss under different LULC were investigated in a small watershed located in Almus, Turkey. Universal soil loss equation (USLE) was used to model soil loss in the watershed at a fine spatial resolution using geographic information techniques. Rainfall (R), soil erodibility (K), slope length and steepness (LS) and supporting and conservation practices (P) factors of USLE model were kept constant, while cover and management factor (C) was determined by based on LULC types in 1990 and 2018. Spatial and temporal changes in erosion risk were mapped. The maps obtained indicated that LULC change has have both reducing and increasing effects on erosion risk. The average soil loss in 1990 decreased from 0.312 to 0.308 t ha-1 year-1 in 2018. Coverage of low-risk class areas in the basin increased by 20.19 km2 between 1990 and 2018. The increase in mixed forest cover caused a significant decrease in erosion risk. The results demonstrated that LULC is the driving factor for increasing or decreasing in soil erosion at the watershed. Conversion of forests to agricultural lands disturbed the surface cover and increased the erosion risk. The results revealed the significant impacts of LULC changes on soil erosion potential in the Almus Lake Watershed.

Soil loss and sediment yield in a perennial catchment in southwest Piauí, Brazil.

Soil and water are vital natural resources. However, due to their indiscriminate use, these resources are being seriously threatened. Therefore, it is essential to manage them in a sustainable way and leave them for future generations. Population and agricultural areas have expanded, deforesting native landscapes for cultivation and pastures. As a result, soil loss from agricultural areas is increasing the amount of sediment transport in water courses. The objective of this study was to quantify soil loss and sediment yield from the Corrente dos Matões sub-basin (CMSB). These measurements are essential to quantify the environmental impact of advancing agricultural frontiers. The Universal Soil Loss Equation (USLE) was applied due to its wide use, compatibility with GIS, and data availability. The suspended sediment transport was calculated by collecting samples with DH-48 sampler. From the application of USLE, the average soil erosion contributed very little to sediment delivery in the watercourse, with a magnitude of only 0.37 t ha-1 year-1. The highest soil loss was associated with greater slope and was observed in areas with agriculture or under the absence of vegetation cover. The low transport of suspended sediments in CMSB is due to the existence of preserved sites. About 99% of the sub-basin had a low degree of erosion. The high degree of soil loss was attributed to the cliffs and the development of agricultural activities leaving the soil uncovered. This work will help identify the most susceptible areas to water erosion for optimizing the allocation of financial resources for the preservation of this natural resource.

The effects of conservation land to provide feed in dry land farming on the East Island Indonesia

The study was conducted in South Central Timor and North Central Timor in the month of March to May 2017, the aims are the determinate the additional amount of money value of feed crops planted as a hedge row in vegetative conservation than without conservation, and the value of money of corn plants grown in the hedge row cultivation land for five years. Data were collected through interviews and field observations. The results showed that: (a) Production of biomass feed is grown as a hedge row to increase over time utilization and production will be stable after the fourth year by 25 t ha-1 year-1, (b) The relationship between biomass production and utilization of time to form a linear line with equation y = 6032.63 x - 592.6. (c) The relationship between biomass with time concession revenue line shape with the linear equation Y = 2,021,458.37x-2,444,254.57, (d) Hedge row has the potential to supply cattle feed about 2-3/6 months fattening or 4-6 fish/year, (e) Gross margin vegetative conservation concession for five years at IDR 50,111,138 ha-1 and without conservation of IDR 20,077,617

Assessment of comprehensiveness of soil conservation measures using the DPSIR framework.

The assessment of comprehensiveness of soil conservation measures (SCMs), along with economic, social, and environmental assessments of these projects, is a prerequisite for good governance in a watershed. This study was conducted using the cause-and-effect framework of DPSIR (Driver-Pressure-State-Impact-Response) to assess the comprehensiveness of SCMs in reducing the soil erosion potential of the Kond watershed area and its adverse impacts. Horticultural, mining, and ranching activities; population growth; and road network development were identified as the most important driving forces of the watershed. After determining the indicators, the integrated index was calculated based on weight calculation and standardization of values to detect changes before and after the implementation of SCMs. The results showed a decrease in soil erosion and the corresponding adverse impacts in 2019 compared with the base year, 1997, so that according to the integrated index, the soil erosion status and related impacts have decreased by 16 and 35%, respectively. Despite this decline, the watershed still has a high rate of soil erosion (26.27 t ha-1 year-1). This is because SCMs are more focused on improving the state and impacts, and there are no necessary managerial responses to the components of the driving forces and pressures. Given that the proactive approach has less contribution than the reactive approach in SCMs, in addition to the reactive approach, it is necessary to pay more attention to the proactive approach to reduce the soil erosion rate of the watershed and decrease the relevant negative impacts.

Estratégia Metodológica para Zoneamento pelo Potencial de Perda de Solo na Bacia Hidrográfica Cachoeira Cinco Veados, RS-Brasil

O objetivo do estudo foi propor um arranjo metodológico com auxílio do modelo USLE, de modo a sugerir o melhor uso do espaço em função de variáveis erosivas, utilizando a bacia hidrográfica como unidade de planejamento. Os parâmetros do modelo USLE foram espacializados usando o software ArcGis 10.5, para o estudo de caso da Bacia da Cachoeira Cinco Veados-RS, e os valores erosivos foram categorizados de acordo com a metodologia de Ribeiro 2006. A partir disso, a ideia foi reclassificar as áreas em aptas e não aptas ao uso testado conforme dois critérios limites adotados como máximo aceitável de perdas (20 e 50 t.ha-1.ano-1). A proposta metodológica consiste na construção de duas estratégias de análise: a primeira é a construção de um mapa temático, considerando uma ordem prioritária de usos na bacia, onde o uso mais perdulário foi analisado primeiro (Roteiro de Análise Hierárquica Entre Usos); a segunda, consiste na construção de mapas que correspondem a cenários com áreas da bacia aptas a um determinado uso, segundo o critério de classificação utilizado, e o seu cruzamento com o mapa de uso atual (Roteiro de Análise por Uso). Os resultados mostraram ser possível classificar as áreas em “aptas” e “não aptas” para determinado uso, permitindo com essa estratégia de organização identificar, quantificar e espacializar as áreas em conformidade com limite de perda de solo potencial e apontar aquelas que não toleram o uso testado, informação útil aos tomadores de decisão quando em estudos de planejamento regional. Methodological Strategy for Zoning by using Soil Loss Potential in a Watershed in southern Brazil ABSTRACTThe aim of this study was to propose a methodological approach to determine the best land use based on USLE model parameters, using the watershed as planning unit. The model USLE parameters were spatialized using the software ArcGis 10.5, for the case study of the Cachoeira Cinco Veados watershed, RS-Brazil, and the erosive values were categorized according to the methodology of Ribeiro (2006). We reclassified the areas in “suitable” and “not suitable” to the tested use, according to two limit-criteria adopted as maximum acceptable soil losses (20 and 50 t ha-1 year-1). The methodology consists of constructing two strategies: the first is a construction of a thematic map, considering a priority order of uses in the watershed, where the most spendthrift use was analyzed first (Script of Hierarchical Analysis among Uses); and the second consists of the construction of maps that correspond to scenarios with watershed areas suitable to a given use, according to the classification criterion used, and their crossing with the current use map (Analysis Script by Use). The results show it is possible to classify the areas in “suitable” and “not suitable” for a given use, allowing with this organizational strategy to identify, quantify and spatialize the areas in accordance with the limit of potential soil loss and point out those that do not tolerate the tested use. This is a useful information for decision makers when studying regional planning.Keywords: Zoning; Watershed; Erosion; USLE.

BRS Tainá: new white seedless grape cultivar for the Brazilian semi-arid region

Abstract The new table grape cultivar BRS Taina produces white firm seedless grapes, agreeable flavor, balanced sugar-acid ratio, good berry adherence to the pedicel and yield of 50 ton ha-1 year-1. It is recommended for the tropical conditions of the Submedio do Vale do Sao Francisco. Propagative material is acquired from nurseries licensed by Embrapa.

Effectiveness of Cover Crops for Water Pollutant Reduction from Agricultural Areas

HighlightsNitrogen loss reduction due to a cover crop tends to improve with increased cover crop biomass production.Mixed phosphorus loss reduction results in cold climates where freeze-thaw cycles occur and can increase dissolved phosphorus losses.Cereal rye was the primary cover crop studied and tended to provide the most water quality benefits.Abstract. Mitigating nutrient losses from agricultural fields retains these nutrients for subsequent crop production and reduces the risk to downstream water quality. This study evaluated the impact of cover crops, as part of an annual cropping system, on reducing nutrient losses and enhancing water quality. Cover crop literature focusing on water quality was reviewed to determine important factors regarding cover crop performance and cost. Results show that a grass-based cover crop and mixes with grasses tend to increase nitrate loss reduction (40%) compared to legumes (negligible). Biomass growth was also important, with early seeding or growth of a cover crop in areas with increased growing degree days enhancing performance. For phosphorus loss, benefits did not necessarily increase with increasing biomass. Further, dissolved phosphorus concentrations may increase due to freeze-thaw cycles (23%), although overall dissolved phosphorus losses tend to decrease due to less runoff (34%). Cover crop implementation costs ranged from a savings of $25 to $44 ha-1 year-1 before soybeans and corn, respectively, when implementing a cover crop for five straight years to a cost of $193 ha-1 year-1. Including a cover crop in annual crop rotations with adequate time in the fall for germination and growth can reduce nitrogen and phosphorus losses from production agriculture to help meet water quality goals across the U.S. Keywords: Catch crop, Nitrogen, NRCS, Phosphorus, Practice Code 340, USDA, Water quality.

Genetic gain in grain yield and oil content of Noug (Guizotia abyssinica) in Ethiopia

The primary and extended objective of plant breeding is to advance productivity to match the lengthening food requirements of people. Estimation of genetic advance from a breeding program and periodic evaluation of improvement in the genetic gain of a crop through released varieties is therefore needed to perceive changes and success generated by breeding activities. Periodic valuation of genetic progress of crop varieties is required to perceive the effectiveness of past breeding activities in genetic yield potential and prompt future selection criteria to aid further improvement. A total of 5 varieties have been released in Ethiopia, from 1988 to 2010. However, the level of genetic progress was not quantified. This study aimed to assess the genetic gain in seed yield potential and oil content of Noug (Guizotia abyssinica) and estimate changes made to yield related traits by genetic improvement of the crop. The experiment was conducted using 5 noug improved varieties and one local variety arranged in RCBD with four replications in 2016/17 main cropping season under rainfed condition. Results indicated that seed yield increased significantly during these 22 years. The estimated annual yield gain was 10.36 kg ha-1 year–1(1.58% per year), reflecting the important efforts of the past breeding programs. Number of head per plant, number of seed per head, Seed yield per plant, biomass yield, harvest and oil content were also increased significantly by 1.72%, 1.71%, 1.85%, 0.33%, 1.03% and 0.34% per year, respectively. The endeavor should be encouraged and extended to accomplish more advances in these and other relevant traits. Noug breeding has not ascertained plateau in Ethiopia. Thus, development of higher yielding varieties of noug should persist to lengthen Noug grain yields if past tendency intends the prospective. To see the impact of the accomplishment in the genetic advance of noug research, it is compulsory to covenant huge scale popularization of the released varieties.

Change in the soils’ fertility level of tea agrocenoses in the transition to cultivation without mineral fertilizers in the humid-subtropical zone of Russia

Research was carried out on the basis of preserved field multifactor experiment on tea crop (Camellia sinensis (L.) Kuntze) in the conditions of the Sochi Black Sea coast. The application of NPK fertilizers in different doses and combinations according to the experimental scheme was carried out annually from 1986 to 2011. Since 2012, the use of fertilizers has been completely discontinued. The fertility indicators of long-fertilized brown forest acidic soils (in layers 0-20/20-40 cm) were compared with those after 7-8 years of fertilizer withdrawal. During the period of fertilizers’ application, the level of soils’ nitrogen supply significantly exceeded the control (by 30-75/30-56 mg/kg depending on the doses of nitrogen fertilizers). After the fertilizers’ discontinuity, nitrogen supply level equalization occurred in all experimental options. The content of labile phosphorus in soils previously fertilized with high phosphorus doses (120 kg P2O5 ha-1 year-1 and more), during the period of experiment’s conservation decreased by 450-500/350-450 mg/kg, but exceeded the control in 2-2.5 times; in soils previously fertilized by low doses, the indicators have not changed significantly. In soils highly supplied with labile potassium, the content of the element decreased by 70-140 mg/kg. The yield of tea in 2019-2020 was equally low (12-26 cwt/ha) on all options, 2.2-3 times lower than fertilized plantations. After the fertilizers’ withdrawal, there was a decrease in acidity (an average increase in pH by 0.18-0.24/0.12-0.20 units) of agrogenic-acidized soils and an increase in their oppressed respiratory activity (on average by 1.6 times). These changes reflect the tendency of soil self-restoration after the removal of the fertilizers’ load.