Consecutive Crop Cycles Research Articles

Sources and splitting of special fertilizers application in coffee crop

This study assesses special and mineral fertilizers and the splitting of fertilizer application in coffee - a crop with high nutritional requirements for full yield potential. A 4 × 3 factorial scheme was implemented with four fertilizers [mineral, mineral with polymer, organomineral with cellulosic residue (OM-CR), or sugarcane filter cake (OM-FC)] and three application times, or splits (100% at once, 50%+50%, 33.3%+33.3%+33.3%). Coffee plant height, canopy diameter, plagiotropic branch growth, leaf chlorophyll, nutrient contents in the soil and leaves, and harvest yield after fruit maturation were evaluated in two consecutive crop cycles. The results indicated that organomineral fertilizers performed similarly to other fertilizers regarding coffee leaf chlorophyll and plant height. Only one fertilizer application effectively increased canopy diameter in both crop cycles. In the first crop cycle, OM-FC and conventional mineral fertilizers were significantly better for coffee foliar N content. In contrast, in the second crop cycle, mineral-P, OM-CR, and OM-FC achieved satisfactory results with one fertilizer application, whereas conventional mineral fertilizer required three applications for superior results. There are no differences in leaf P content among different sources and frequencies of application. Still, mineral-P and OM-CR had better soil P content than the conventional mineral fertilizer. OM-CR required two applications to reach high levels of leaf K content, while other fertilizers achieved it with one application. Organomineral and protected mineral fertilizers performed similarly in both crop cycles, with two applications resulting in greater coffee yield in the second cycle, regardless of the fertilizer used.

Response of soil microbial glycoside hydrolase family 6 cellulolytic population to lignocellulosic biochar reveals biochar stability toward microbial degradation.

Biochar produced from lignocellulosic biomass offers an opportunity to recycle waste into a valuable soil amendment. The application of biochar has been proposed to mitigate climate change by sequestering carbon in the soil. However, the field impact of biochar treatment on the cellulolytic microbial populations involved in the earlier steps of cellulose degradation is poorly understood. A field trial spanning three consecutive crop cycles of Zea mays was conducted in a degraded tropical Ultisol of Peninsular Malaysia. The soil was amended with two contrasting biochar made from oil palm kernel shells (pyrolyzed at 400°C) and rice husks (gasified at 800°C) with or without fertilizer supplementation. Soil samples were taken at each harvesting stage and analyzed for total organic carbon, labile active organic carbon, total cellulase, and β-glucosidase. Microbial glycoside hydrolase family 6 (GH6) cellulase genes and transcripts, involved in the early steps of cellulose degradation, were quantified from the extracted soil deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), respectively. Total organic carbon, labile active organic carbon, and β-glucosidase activity were significantly increased, while no effect on total cellulase activity was found. Both biochars stimulated the total population (DNA-derived) abundance of soil microorganisms harboring the GH6 cellulase genes. The biochar amendment did not affect the active population (RNA-derived) of the GH6 cellulolytic community, showing no significant changes in transcript expression. This indirectly corroborates the role of biochar as a potential carbon sequester in the soil.

Post-harvest cleaning, sanitization, and microbial monitoring of soilless nutrient delivery systems for sustainable space crop production.

Bioregenerative food systems that routinely produce fresh, safe-to-eat crops onboard spacecraft can supplement the nutrition and variety of shelf-stable spaceflight food systems for use during future exploration missions (i.e., low earth orbit, Mars transit, lunar, and Martian habitats). However, current space crop production systems are not yet sustainable because they primarily utilize consumable granular media and, to date, operate like single crop cycle, space biology experiments where root modules are sanitized prior to launch and discarded after each grow-out. Moreover, real-time detection of the cleanliness of crops produced in spacecraft is not possible. A significant paradigm shift is needed in the design of future space crop production systems, as they transition from operating as single grow-out space biology experiments to becoming sustainable over multiple cropping cycles. Soilless nutrient delivery systems have been used to demonstrate post-harvest sanitization and inflight microbial monitoring technologies to enable sequential cropping cycles in spacecraft. Post-harvest cleaning and sanitization prevent the buildup of biofilms and ensure a favorable environment for seedling establishment of the next crop. Inflight microbial monitoring of food and watering systems ensures food safety in spaceflight food systems. A sanitization protocol, heat sterilization at 60°C for 1 h, and soaking for 12 h in 1% hydrogen peroxide, developed in this study, was compared against a standard hydroponic sanitization protocol during five consecutive crop cycles. Each cropping cycle included protocols for the cultivation of a crop to maturity, followed by post-harvest cleaning and inflight microbial monitoring. Microbial sampling of nutrient solution reservoirs, root modules, and plants demonstrated that the sanitization protocol could be used to grow safe-to-eat produce during multiple crop cycles. The cleanliness of the reservoir and root module surfaces measured with aerobic plate counts was verified in near real time using a qPCR-based inflight microbial monitoring protocol. Post-harvest sanitization and inflight microbial monitoring are expected to significantly transform the design of sustainable bioregenerative food and life support systems for future exploration missions beyond low earth orbit (LEO).

Molecular Cues for Phenological Events in the Flowering Cycle in Avocado.

Reproductively mature horticultural trees undergo an annual flowering cycle that repeats each year of their reproductive life. This annual flowering cycle is critical for horticultural tree productivity. However, the molecular events underlying the regulation of flowering in tropical tree crops such as avocado are not fully understood or documented. In this study, we investigated the potential molecular cues regulating the yearly flowering cycle in avocado for two consecutive crop cycles. Homologues of flowering-related genes were identified and assessed for their expression profiles in various tissues throughout the year. Avocado homologues of known floral genes FT, AP1, LFY, FUL, SPL9, CO and SEP2/AGL4 were upregulated at the typical time of floral induction for avocado trees growing in Queensland, Australia. We suggest these are potential candidate markers for floral initiation in these crops. In addition, DAM and DRM1, which are associated with endodormancy, were downregulated at the time of floral bud break. In this study, a positive correlation between CO activation and FT in avocado leaves to regulate flowering was not seen. Furthermore, the SOC1-SPL4 model described in annual plants appears to be conserved in avocado. Lastly, no correlation of juvenility-related miRNAs miR156, miR172 with any phenological event was observed.

Teor e acúmulo de nutrientes em mini alface em função de estratégias de manejo de fertirrigação

ABSTRACT Determining the amount of nutrients accumulated by crops is an important tool for defining the order in which nutrients are taken up and required. However, the order and amount of accumulated nutrients vary depending on the genetic characteristics of the cultivars, climatic conditions, fertilization, soil and management systems. The aim of this study was to evaluate the influence of irrigation management strategies and doses of nitrogen (N) fertigation on the content and accumulation of macro and micronutrients and the N use efficiency in mini romaine lettuce “Astorga” cultivated in a protected environment, in two consecutive crop cycles. The treatments consisted of three irrigation strategies: continuous irrigation (Cont), intermittent irrigation, with three fractions a day, at 1-hour intervals (Int1); intermittent irrigation, with three fractions a day, at 4-hour intervals (Int2) and two nitrogen doses (100 and 130 kg/ha N), in daily fertigation. Intermittent irrigation management strategies (Int1 and Int2) increased the contents and accumulation of dry matter and N, P, K, Ca, Mg, S, B, Fe, Mn and Zn. The dose of 130 kg/ha N only increased the content and accumulation of P and Mn in the first and second cycles, respectively. In general, lettuce accumulated macronutrients in the following decreasing order: K>N>Ca>P>Mg>S, whereas micronutrients followed the order Fe>Mn>Zn>B>Cu. The treatments Int1, Int2 and 100 kg/ha N optimized the N use efficiency.

Effect of two contrasting biochars on soil microbiota in the humid tropics of Peninsular Malaysia

Report on soil microbial community in tropical soil of humid tropics remained limited despite the current research interest in biochar-microbe study in various climatic regions. A field-trial spanning three consecutive crop cycles of Zea mays var. Masmadu was conducted in tropical Acrisols of Peninsular Malaysia. Palm kernel shell and rice husk biochars of different feedstock and pyrolysis conditions were used for amendment. Soil samples were collected during maize harvesting and were analyzed for physicochemical properties (pH, CEC, organic C, labile active C), microbial biomass (C, N), and seven C-cycle enzymes activity (total cellulase, endoglucanase, β-glucosidase, xylanase, invertase, phenol oxidase, peroxidase). Total soil genomic DNA was extracted and subjected to the analysis of bacterial 16S rRNA and fungal ITS gene abundance quantification. Microbial genetic profiling was fingerprinted by using DGGE. Significant increases of all measured soil physicochemical properties, microbial biomass C, microbial biomass N, and gene abundances were observed in all biochar amended soils. Significant changes of total cellulase, endoglucanase, phenol oxidase, and peroxidase were not detected. A significant shift in microbial genotypic and enzymatic functional diversity based on microbial C-cycle enzymes was not detected. Correlation data revealed significant linkages of soil microbial biomasses and gene abundances with all measured soil physicochemical properties. The biochar influences the microbial community by elevating microbial habitat potential to a more favorable state and increasing labile active carbon sources in the field trial.

CATTLE MANURE APPLICATION AFFECTS BIOAVAILABILITY OF CADMIUM IN SOIL

Cadmium (Cd) in soil could enter human body via food chain contamination. Farmers regularly apply manure to the vegetable growing fields in the up-country in Sri Lanka. Regular manure application could increase concentration of labile C in soil, which could maintain relatively high soluble Cd fraction in soil, resulting soil Cd more bioavailable. A pot experiment was conducted in a greenhouse with soils (Ultisols) collected from an urban vegetable garden in Seethaeliya, Sri Lanka to assess whether the manure application affects the phytoavailability of soil Cd to lettuce. Lettuce was grown for three consecutive crop cycles with and without cattle manure. For one manure-added treatment, dried manure was added as a bulk (i.e. one time at the beginning of the first crop at the rate of 75g of manure per 5kg of soil in fresh weight basis) and as a split dose for the other treatment at the rate of 25g of manure per 5 kg of soil at the beginning of every crop. The concentration of total Cd was 0.72 mg/kg in soil and 0.60 mg/kg in cattle manure. Only 2% of total Cd was easily extractable in soil, whereas 21% of total Cd in the manure was easily extractable. Concentration of Cd in lettuce was significantly higher in manure-added treatments compare to the unamended soil. Manure application (both bulk and split) increased Cd concentration in lettuce. Incorporation of easily extractable Cd and increase of labile C via manure application may have contributed to elevate Cd concentrations in lettuce.

QTL mapping for salt tolerance associated traits in wheat (Triticum aestivum L.)

Soil salinity is major constraint for wheat production globally and breeding wheat cultivars for salt tolerance by conventional means is difficult. Therefore, understanding molecular components associated with salt tolerance is needed to facilitate breeding for salt tolerance in wheat. In this investigation, quantitative trait loci (QTL/s) associated with salt tolerance were identified using recombinant inbred lines (RILs) developed from a cross between Kharchia 65 (KH 65) and HD 2009 cultivars. Parents and RILs were evaluated under controlled and sodic stress conditions for 11 morpho-physiological and yield determining traits for two consecutive crop cycles. Simple sequence repeat (SSR) markers were employed for mapping studies. Using composite interval mapping approach, 11 QTLs on 6 chromosomal regions (1B, 2D, 5D, 6A, 6B and 7D) for 7 different traits were identified explaining proportion of the phenotypic variance (PVEs) (2.5–12.8%) under control condition. Three of the QTLs (QCph.iiwbr-2D.1, QCle.iiwbr-6A and QCle.iiwbr-6B) were most consistent in all the environments and explained PVEs (5.1–12.8%) under control condition. Twenty-five QTLs were detected on 7 chromosomal regions (1A, 1B, 2D, 4D, 5D, 6A and 7D) for 10 different traits explaining PVEs (2.6–15.1%) under salt stress. Six of the QTLs namely QSNa+.iiwbr-1B, QSK+.iiwbr-2D, QStn.iiwbr-4D, QSph.iiwbr-2D.1, QSph.iiwbr-6A and QSdth.iiwbr-2D were consistently reproducible in all the environments and explained PVEs ranging from 2.6 to 15.1%. SSR markers namely gwm 261, wmc 112, and cfd 84 were tightly linked with QTLs for K+ content; DTH and DTA; and TN and NE, respectively. Several QTLs contributing towards salt tolerance were present on 2D chromosome. Most of the QTLs linked with salt tolerant traits were inherited from KH 65 signifying the presence of several genes associated with salt tolerance in this cultivar. The information is very useful in marker assisted breeding to enhance salt tolerance in wheat.

Integrated management strategies of Meloidogyne incognita and Pseudopyrenochaeta lycopersici on tomato using a Bacillus firmus-based product and two synthetic nematicides in two consecutive crop cycles in greenhouse

Because of the restrictions on chemical pesticide use and their negative effects on the environment, as well as on human and animal health, alternative strategies for plant pest and pathogen managements are highly desirable. The objective of this work was to evaluate the suitability of a commercial formulation of Bacillus firmus strain 1-1582, applied either alone or in combination with oxamyl or fosthiazate, to control the southern root-knot nematode Meloidogyne incognita and the fungal plant pathogen Pseudopyrenochaeta lycopersici under greenhouse conditions during two tomato crop cycles. Application of B. firmus suppressed nematode population levels during the second crop cycle and when the treatments were repeated on soil previously amended with organic matter. In contrast, fungal infection was reduced during both crop cycles regardless of the application of organic matter. The combinations of the bioformulation and chemicals induced the lowest Root Galling Index compared to all other treatments in both crop cycles. The suppression of nematode populations levels and infection rate of the fungus induced by B. firmus alone or in combination with the chemicals was more pronounced during the second tomato crop cycle than the first crop cycle, also because the temperatures during the second crop cycle were unfavorable to the nematode development. The greatest increase in tomato yield induced by the combined treatments was observed during the second crop cycle, and it was up 50% compared to the untreated control. The applications of the bionematocide and two chemicals used in this study did not result in dramatic suppression of nematode and fungal populations. However, the application of these products alone or in combination, supplemented by organic amendment increases the yield of tomato plants compared to that of the untreated control, although the plants were infected by the pest and the pathogen. These results indicate that early spring/early fall application of B. firmus is an effective biopesticide treatment for management of the southern root-knot nematode and P. lycopersici on tomato crops growing in the integrated pest management system of this experiment and in the environmental conditions of southern Italy.

Phenology and agronomic components of first and second-cycle strawberry

ABSTRACT Several strawberry growers have cultivated the same plants for two consecutive cycles aiming a greater economic return after seedling transplant. However, the phenological development and the agronomic potential of second-cycle strawberry have to be estimated. This research was installed to estimate the thermal need, leaf appearance rate, phyllochron and yield of strawberry cultivars in two consecutive crop cycles in the region of the Third Planalto Paranaense. Cultivars Camarosa, Camino Real, Albion, Aromas, Monterrey and San Andreas were evaluated in the first and second growing cycles using completely randomized blocks and four replications. Leaf appearance rate was estimated by linear regression coefficient between the number of leaves and the accumulated thermal sum. Phyllochron was estimated by the inverse of regression coefficient. Aromas was the only cultivar with an increased fruit production in the second cycle. On the contrary, there was a considerable reduction of production for ‘Camino Real’, ‘Albion’, ‘Monterrey’ and ‘San Andreas’ in that same cycle. The highest number and mass of marketable fruits of the second and first cycles were observed for ‘Camarosa’ and ‘Camino Real’, respectively. In the second crop cycle, strawberry cultivars required a lower thermal sum to begin flowering and fruit harvest. The plants presented a higher leaf appearance rate and low phyllochron values.

Soil disinfestation with dimethyl disulfide (DMDS) to control Meloidogyne and Fusarium oxysporum f. sp. radicis-lycopersici in a tomato greenhouse

The efficacy of a soil disinfectant, dimethyl disulfide (DMDS), was assessed in a commercial greenhouse with a 12-year history of root-knot nematode infestation. Two trials were carried out over two consecutive crop cycles. Two doses of DMDS (400 L ha−1 and 600 L ha−1) and two plastic covers, VIF (virtually impermeable film) and PE (transparent polyethylene), were tested and compared with two controls: a commercial reference (1,3-dichloropropene with PE film, 120 L ha−1) and untreated (without plastic cover). The results showed a significant reduction in nematodes of the genus Meloidogyne J2 after soil disinfestations, until 151 and 124 days after treatment (DAT) for the first and second crop cycles, respectively. At the end of the tomato crop, the root galling index was lower for DMDS treatments as compared to untreated, for both trials. All treatments containing DMDS significantly decreased the soil populations of F. oxysporum. Phytotoxicity on tomatoes was not observed after two weeks of soil aeration to allow both ventilation and gas dissipation after DMDS applications.

Performance analysis of spring wheat genotypes under rain-fed conditions in warm humid environment of Nepal

Around 25% of total wheat area in Terai of Nepal falls under rain-fed and partially irrigated condition. A Coordinated varietal trial (CVT) was conducted during two consecutive crop cycles (2011-12 and 2012-13) under timely sown rain-fed conditions of Terai. The trial was conducted in Alpha Lattice design with two replications at Nepal Agricultural Research Council, National Wheat Research Program, Bhairahawa and Nepal Agricultural Research Council, Regional Agriculture Research Station, Nepalgunj. Observations were recorded for yield and yield traits and analyzed using statistical software Cropstat 7.2.The combined analysis of coordinated varietal trial showed that BL 3978 possessed the highest yield (2469.2 Kg ha-1) followed by NL 1097 (2373.2 Kg ha-1) and NL 1094 (2334.06 Kg ha-1). Genotype x Environment interaction for grain yield was significant (p<0.05) over locations and years. BL 3978 with early maturity (111 days) escaped the heat stress environment. Among the top three genotypes, BL 3978 was consistently higher in both favorable and unfavorable conditions. Earliness was one of the major traits for heat tolerant genotypes. The three identified genotypes will be further evaluated in participatory varietal selection or coordinated farmers field trial followed by small plot seed multiplication (seed increase) and release in the future for timely sown rain-fed conditions. These lines also appear suitable for inclusion in crossing program targeted for water stress tolerance variety development. DOI: http://dx.doi.org/10.3126/ije.v4i2.12649 International Journal of Environment Vol.4(2) 2015: 289-295

Postharvest quality of strawberry produced during two consecutive seasons

Maintaining plants in the field for two consecutive crop cycles is one of the latest techniques used by strawberry growers to reduce production costs. The goal of this research was to evaluate the postharvest fruit quality of six strawberry cultivars produced for two consecutive seasons with the same plants. They were planted from May to July 2010 under low-tunnel and fruits were evaluated in two growing seasons (season 1= January, February, and March 2011 and season 2= August, September, and October 2011), totaling three harvests of each cultivar in each year season. Fruits were picked up randomly among 500 plants of each cultivar, organized into five replications of five fruits and kept for three days before analysis under refrigeration (average temperature of 4°C). Variables analyzed were: soluble solids content, titratable acidity, soluble solids content/titratable acidity, flesh firmness, C vitamin content, sensory characteristics (sweetness, flavor, acidity, aroma, shape and flesh firmness), and mineral composition (Ca, Fe, K, Mg, Mn, Cu and Zn). 'Albion', 'Monterey' and 'San Andreas' showed good physical, chemical and sensory characteristics in both seasons. In general, fruits produced during the season 1 showed better physical, chemical and sensory characteristics than fruits produced in season 2. 'Palomar' and 'Portola' were better than the other cultivars concerning C vitamin content in both seasons. 'Palomar' showed higher potassium, calcium, magnesium, manganese and zinc levels, and 'Portola' showed higher calcium and iron levels.

Growth and yield responses to amending the sugarcane monoculture: interactions between break history and nitrogen fertiliser

Experiments were established in the Burdekin Irrigation Area in North Queensland, Australia, to measure whether yield improvements from breaking the sugarcane monoculture or fumigating the soil could be modified by the application of different rates of nitrogen (N) fertiliser. Experiments were conducted in consecutive crop cycles (phase 1, planted 1998; phase 2, planted 2001) using the variety Q117, with the interaction between N applications and rotation histories discussed for the two plant crops. Histories consisted of alternate crop, bare fallow or mixed grass–legume pastures for periods of 42–66 months, compared with continuous cane as plough-out replant without (PORP) or with (PORP-F) soil fumigation. The N strategies involved combinations of N rates (0–180 kg N/ha) and application times (at planting, 90 days after planting (DAP) or split between these times) in phase 1 and N rates (0–300 kg N/ha) in phase 2. Histories had differing effects on N available to the cane crop and hence on response to N fertiliser. Some combinations of history and N rate were N-limited and strong linear relationships between biomass production or cane yield and crop N content could be developed. Critical N contents for biomass production (R2 = 0.93) and fresh-weight cane yield (R2 = 0.88) were 1.42 and 0.57 kg N/t, respectively. Application of N fertiliser was shown to have significant impacts on both tiller addition and the retention of tillers to produce harvestable stalks. However, the application of fertiliser N had limited (phase 1) or no (phase 2) capacity to provide the quantum of yield response in soil health benefits associated with breaking the sugarcane monoculture. Increasing N application rates above that required to optimise crop yield resulted in significant decreases in sugar content of cane and thus lower sugar yields. Yield increases solely from improved soil health (i.e. exclusive of N response) constituted advantages averaging 15% (phase 1) to 20% (phase 2) compared with PORP. These effects were manifest early in the establishment of primary shoots in the plant crops, although the longevity of these benefits was limited. Replanting cane after a 3-year crop cycle (plant, 1st and 2nd ratoon) on land that had been under pasture, crop, bare fallow or PORP-F histories (phase 2, cycle 2) showed carryover effects of histories on N availability and fertiliser N responsiveness, but limited yield impacts attributable to residual soil health benefits. These results reinforce the importance of crop rotation during breaks between sugarcane cycles to maintain soil health and improve crop productivity.

Performance of tissue-cultured versus sucker-derived East African highland banana (Musa AAA-EA) under high and low input systems in Uganda

Banana (Musa spp.) is a vegatatively propagated crop and the type of planting material is of great importance for the productivity of banana plantations. Traditionally, sucker derived planting materials have been used to establish banana plantations but there is a risk of transmitting pests such as plant-parasitic nematodes with untreated suckers. Tissue cultured banana plants are pest-free and widely grown in commercial dessert banana plantations but are not common agricultural practice under East African conditions. This study aimed at evaluating the agronomic performance and nematode infestation levels of sucker-derived and tissue cultured planting material of the East African highland cooking banana cultivar Nabusa (Musa spp., genome group AAA-EA) over five crop cycles. A field trial was conducted in Central Uganda using tissue culture plants, untreated suckers, pared suckers or pared and hot water treated suckers.All plants were cultivated under mulched or non-mulched conditions to represent high or low input systems, respectively. Mulch in general improved agronomic performance of banana. Type of planting material also influenced plant growth and yield. Tissue culture plants developed faster and yielded higher during the first crop cycle than sucker-derived material but not thereafter. Plant height and bunch weight of untreated suckers was inferior to all other planting material from the third crop cycle onwards. All mulched plants flowered earlier in all crop cycles. Duration from planting to the first harvest was less for tissue-cultured plants, but planting material had no influence on days to harvest from the third crop cycle onwards. Nematode densities were higher in roots from plants grown from untreated suckers than all other planting material, with Radopholus similis consistently recovered in greater densities than Helicotylenchus multicinctus across treatments. Mulching had no influence on nematode densities, root necrosis, number of root base lesions or number of dead roots. Nematode associated damage was higher in plants from untreated suckers but did not differ among tissue-cultured and pared and hot water treated or pared sucker plants. This study demonstrates the benefits of using clean planting material for cooking banana over five consecutive crop cycles and confirms the beneficial effects of mulching. In order to achieve high banana yields over several crop cycles, clean planting material needs to be supported by the application of mulch. However, this study shows that the application of mulch will not offset the detrimental effects of plant parasitic nematode-infected sucker planting material.

The impact of Chinese mitten crab culture on water quality, sediment and the pelagic and macrobenthic community in the reclamation area of Guchenghu Lake

The effects of crab aquaculture on the water and sediment quality and the pelagic and macrobenthic community of the adjacent reclamation area of Guchenghu Lake, Jiangsu Province were evaluated over two consecutive crop cycles from April 2010 to November 2011. The results indicated that most of the nutrient concentrations in both the water column and the sediment varied temporally and showed significant spatial differences. The peak values of most of the physico-chemical parameters measured were obtained during the summer or autumn, whereas the opposite result was observed for suspended solids. A higher zooplankton density and lower phytoplankton biomass were observed in ponds than in other sampling sites, whereas Cyanophyta (80 %), with Planktothrix rubescens as the dominant taxon, was predominant in the canal closest to the ponds. The benthic community was dominated by Bellamya aeruginosa in the ponds. Limnodrilus hoffmeisteri was the predominant species in the canal. Comparative analysis of the impact of crab culture showed that it produced a relatively low level of disturbance but introduced large quantities of nutrients and organic matter into the canal around the farming ponds. The introduction of these substances increased the risk that Guchenghu Lake would be affected by pollution.

Bud break and enzymatic activity in buds of grapevines cv. Ives treated with Gallesia integrifolia hydrolate

The lack of more sustainable options for inducing bud break in grapevines in mild winter regions is a limiting factor for local viticulture due to restrictions on the use of agrochemicals. Within this context, an experiment was conducted to evaluate the effects of a hydrolate obtained from Gallesia integrifolia (a native Brazilian tree) on the bud break of grapevines cv. Ives. The experiment was conducted in a vineyard located in Marialva, Parana, Brazil, over two consecutive crop cycles: 2011 (September/December) and 2012 (February/May). The treatments consisted of the following doses of Gallesia hydrolate (GH): 0, 100, 150, 200, and 250 mL L−1, as well as 30 mL L−1 of garlic extract and 20 mL L−1 of hydrogen cyanamide, which were used as positive controls. The following variables were evaluated: sprouting percentage per plant, number of clusters per plant, cluster mass, yield (t ha−1), catalase and peroxidase activities. The GH treatments improved bud break in cv. Ives during both crop cycles, demonstrating quadratic effects relative to the applied doses. The same effect was verified for the number of clusters and for the yield. Twenty-four hours after the treatments, a quadratic effect for peroxidase and catalase activity was verified relative to the GH doses applied. For peroxidase activity, the treatment at 200 mL L−1 GH resulted in a 57 % reduction relative to the control. The most abundant component found in GH was dimethyl disulfide. Based on these results, GH at 150 mL L−1 could be a promising alternative to the currently used methods for promoting bud break in cv. Ives, representing a cheaper and more environmentally friendly option for viticulture.

Stalk and sucrose yield in response to nitrogen fertilization of sugarcane under reduced tillage

The objective of this work was to evaluate the agroindustrial production of sugarcane (millable stalks and sucrose yield) after successive nitrogen fertilizations of plant cane and ratoons in a reduced tillage system. The experiment was carried out at Jaboticabal, SP, Brazil, on a Rhodic Eutrustox soil, during four consecutive crop cycles (March 2005 to July 2009). Plant cane treatments consisted of N-urea levels (control, 40, 80, and 120 kg ha-1 N + 120 kg ha-1 P2O5 and K2O in furrow application). In the first and second ratoons, the plant cane plots were subdivided in N-ammonium nitrate treatments (control, 50, 100, and 150 kg ha-1 N + 150 kg ha-1 K2O as top dressing over rows). In the third ratoon, N fertilization was leveled to 100 kg ha-1 in all plots, including controls, to detect residual effects of previous fertilizations on the last crop's cycle. Sugarcane ratoon was mechanically harvested. A weighing truck was used to evaluate stalk yield (TCH), and samples were collected in the field for analysis of sugar content (TSH). Increasing N doses and meteorological conditions promote significant responses in TCH and TSH in cane plant and ratoons, in the average and accumulated yield of the consecutive crop cycles.

Taxocoenosis and Distribution of Nektonic Fauna in the Rice Fields of Kashmir (J and K) India

Present study attempts to identify the taxocoenosis and distribution of nektonic fauna harbouring the rice field ecosystems of Kashmir. The main objective of the study was to provide an overview of the nektonic community composition and physicochemical characteristics of flood waters. 6 sites were selected in Kupwara, Bandipora, Budgam, Srinagar, Pulwama and Anantnag districts of valley Kashmir. A total of 26 taxa belonging to 13 different orders were reported during the study which commenced through 2 consecutive crop cycles. The taxocoenosis was dominated by Coleoptera (10 taxa) followed by Hemiptera (3 taxa), Diptera (2 taxa), Diplostraca (2 taxa), Acarina, Anostraca, Anura, Amphipoda, Basommatophora, Cypriniformes, Cyprinodontiformes, Odonata and Pulmonata (1 taxa each). Diversity was calculated using Simpsons Index (D), Simpsons Index of Diversity (1-D), Simpsons Reciprocal Index (1/D), Shannon-Weiner Index (H'), Margalef Richness Index (d) and Evenness Index (e). Kupwara (34 degrees 02'N; 74 degrees 16'E) formed the most diverse site registering a total of 2384 individuals belonging to 24 taxa. A perusal of the primary data related to the physicochemical attributes of flood waters exhibited that average water temperature varied between 19-30 degrees C, average air temperature varied between 21 and 33 degrees C. pH depicted a variation between 6.0 and 9.0, Dissolved Oxygen varied between a minimum of 1.0 mg L(-1) and a maximum of 10 mg L(-1). Free CO2 ranged between 0 mg L(-1) and 6.1 mg(-1). The results pressed the need for recognizing and preserving rice fields as potential habitats for organisms that have successfully adapted to the highly manipulated and eutrophic conditions of rice paddies.

Field evaluation of Gee Passive Capillary Lysimeters for monitoring drainage in non-gravelly and gravelly alluvial soils: A useful tool to estimate nitrogen leaching from agriculture

The development of accurate methodologies for monitoring drainage and evaluating nitrogen leaching from agricultural land is an absolute necessity, particularly considering the growing problem of nitrogen pollution of groundwater throughout the world. In this context, the Gee Passive Capillary Lysimeter appears to be an innovative tool that allows direct and continuous measurement of drainage and enables drainage water to be sampled for chemical analysis. The main objective of this study was to evaluate how the Gee Passive Capillary Lysimeter works in alluvial soils. The study was conducted at two agricultural field stations: Site 1 (central Spain), with a non-gravelly soil, and Site 2 (north of Spain), with a gravelly soil. An installation procedure that leaves part of the soil profile undisturbed was selected for the soil without gravel, whereas a procedure that may alter the soil physical properties was used for the gravelly soil. The experiment was carried out over two consecutive crop cycles at both field stations. Soil water balances were obtained through two different methods: a direct method based on direct measurements of drainage using the Gee Passive Capillary Lysimeter, and an indirect method based on the calculation of daily crop evapotranspiration. A statistical comparison of results obtained by the two methods showed no significant differences in estimates of drainage or crop evapotranspiration from both the non-gravelly and the gravelly soil. The efficiency of leachate collection with the Gee Passive Capillary Lysimeter in the non-gravelly soil was 101 ± 1% (mean ± standard deviation), while in the gravelly soil, it was 142 ± 52%. Drainage and nitrogen leaching below the root zone were determined to be primarily triggered by excessive irrigation. This study helps to validate the use of the Gee Passive Capillary Lysimeter in gravelly and non-gravelly alluvial soils under irrigated agriculture.