Ravi Bhat

IMPACT OF VERMICOMPOST AND NITROGEN-PHOSPHORUS- POTASSIUM APPLICATION ON BIOMASS PARTITIONING, NUTRIENT UPTAKE AND PRODUCTIVITY OF ARECANUT

A long-term field experiment (1998 to 2010) investigated the effects of vermicompost (VC) and chemical fertilizers (CF) application alone or in combination on biomass partitioning, nutrient uptake and productivity of arecanut. Trunk biomass (kg palm−1) was significantly higher with integrated treatments (40.8–43.0) than control (23.9). Biomass partitioning to kernel varied between 4.6% in control to 7.7% in CF 100 and 200% nitrogen (N)- phosphorus (P)- potassium (K). The leaf P and K content varied significantly among treatments. The N immobilized in trunk (g palm−1) was significantly higher in integrated treatments (119-127) than in control (93). Phosphorus and K uptake by trunk followed same trend. The leaf K uptake and total K removed were found significant. The nutrition treatments registered significantly higher kernel yield (2508–3176 kg ha−1) than control (1721 kg ha−1). The increased yield of arecanut from chemical fertilizers (73–85%) was more pronounced when compared to VC (48–59%) and integrated treatments (46–63%) over control.

Impacts of Vermicompost and Nitrogen, Phosphorus, and Potassium Application on Soil Fertility Status in Arecanut Grown on a Laterite Soil

A field experiment (1998 to 2010) investigated the effects of vermicompost (VC) and chemical fertilizer (CF) application alone or in combination on soil fertility status in arecanut. Vermicompost significantly increased the soil pH (6.3) over CF and integrated treatments (5.7–5.8). Greater soil organic carbon was noticed with VC (2.85–3.00%) than with CF (1.72–1.89%) and VC + CF (1.89–2.55%) in 2009. Soil test phosphorus (P) (mg kg–1) significantly increased with VC 200% nitrogen (N) equivalency (35.3) compared to other treatments (8.5–23.3) at the 0- to 30-cm depth in 2009. In 2003, soil test potassium (K) (mg kg–1) was significantly greater with CF at depths of both 0–30 cm (162–187) and 30–60 cm (172–214) than VC and control. Soil test K depleted with VC application in 2009. Application of VC significantly improved soil test calcium (Ca) and magnesium (Mg) compared to CF, CF + VC, and control at 0–30 cm deep. Soil test values for micronutrients increased in 2009 compared to initial status.

ESTABLISHING LEAF NUTRIENT NORMS FOR ARECANUT BY BOUNDARY LINE APPROACH

Critical and optimum leaf nutrient standards for arecanut are unknown. As nutrients are becoming yield limiting factors in arecanut, corrective measures require development of leaf nutritional standards. The objective of this paper was to determine optimum concentration and range of all nutrients through boundary line approach. Optimum foliar concentrations for nitrogen (N), phosphorus (P), potassium (K), calcium (Ca) and magnesium (Mg) were established as 2.70, 0.23, 1.12, 0.61, and 0.20%, respectively, using leaf composition data from 12-year old arecanut plantation. Optima of major nutrient concentrations were nearly identical between boundary line approach and mean of high yielding population. Optimum micronutrient concentrations (mg kg−1) were estimated at 146 for iron (Fe), 56.5 for manganese (Mn), 2.6 for copper (Cu), 45.8 for zinc (Zn), 39.5 for boron (B), 432 for aluminum (Al) and 63 for sodium (Na). Optimum ranges and ratios of different nutrients were found out from second degree polynomial equations.

Influence of Biomass Partitioning and Nutrient Uptake on Yield of Arecanut Grown on a Laterite Soil

The present investigation was conducted on a laterite soil to study biomass partitioning and nutrient-uptake pattern in the aboveground parts of arecanut palm and their relationships to yield. Total biomass production was significantly greater in high-yielding plants (43.6 kg palm−1) than in low-yielding plants (30.8 kg palm−1). Total standing biomass of trunk accounted for 69–74% of the total aboveground biomass in arecanut palm. Dry-matter partitioning to kernel was only 4–10% of the total biomass. The uptake of major nutrients varied significantly between low- and high-yielding plants. Calcium (Ca) uptake was greater by trunk than by other parts, while magnesium (Mg) accumulation was similar in trunk and leaf. The uptake of micronutrients by aboveground parts except leaf was significantly different between low- and high-yielding plants. The present study indicated that combined effect of greater biomass production and nutrient uptake had direct impact on marketable yield of arecanut.

Recycling potential of organic wastes of arecanut and cocoa in India: a short review

Organic wastes from arecanut and cocoa are rich in lignin, cellulose and polyphenol content, and slowly biodegradable. In India, the recyclable biomass from arecanut and cocoa is estimated at 4.5–5.4 and 0.7–0.8 million tonnes per year, respectively. The studies have shown that there is huge potential for utilizing plantation wastes for income generation through suitable technologies and to avoid environmental pollution. Their utilization for production of vermicompost, oyster mushrooms, livestock feed and other value-added products prove to be sustainable and profitable options. Vermicompost has a better nutrient profile than organic wastes and has potential to meet nitrogen and phosphorus demand of plantations crops. The findings of long-term field studies revealed that vermicompost sustains the productivity of arecanut and other component crops and improves soil fertility. But supplementation of potassium is required for improving and sustaining the yields in perennial crops in the long run.

Impact of Organic and Inorganic Nutrition on Soil-Plant Nutrient Balance in Arecanut (Areca catechu L.) on a Laterite Soil

ABSTRACT The study assessed the impact of continuous application of vermicompost and chemical fertilizers nitrogen, phosphorus and potassium (NPK) on arecanut in India. Key parameters examined were biomass production, nutrient uptake, yield, soil fertility and net benefit. Pooled analysis of 8-year data revealed that nutrient application registered significantly higher yield (2585–3331 kg ha−1) than no nutrition (1827 kg ha−1). Yields in organic nutrition were around 85% of the yields obtained in inorganic NPK. The concentrations of leaf N and K were significantly higher with NPK than with vermicompost. Vermicompost significantly increased soil organic carbon and the availability of calcium (Ca), magnesium (Mg), manganese (Mn) and copper (Cu), but reduced exchangeable K in soil. The total uptake of K and Ca together contributed positively to 75% variability in total biomass production. Nutrient removal of iron (Fe), P, K and Cu positively influenced the yield with about 81% variability. Biomass partitioning and nutrient uptake pattern are important for fertilization program of arecanut.

Soil Fertility Changes due to Drip Fertigation in Arecanut-Cocoa System

The effects of drip fertigation of NPK and vermicompost extract (VCE) on soil fertility status of arecanut-only and arecanut-cocoa systems were assessed in a 4-year field study. In arecanut, soil pH was reduced over initial levels. At 0–30 cm deep, fertigation of 75 percent NPK to arecanut only and organic-matter recycling in arecanut + cocoa maintained significantly greater soil organic carbon (SOC) and soil-test phosphorus (P). At the first depth, soil potassium (K) was significantly greater with 75 percent NPK (246 mg kg−1) than other treatments. In cocoa, soil pH varied significantly due to fertigation at both depths. The SOC was reduced due to 75 percent NPK at the first depth. In cocoa, the P availability increased significantly with application of VCE at 20 percent N. Fertigation of 75 percent NPK maintained significantly greater soil K and soil Mg than other treatments. The results suggest that drip fertigation of NPK sustains the soil fertility status in arecanut and cocoa.

Soil Fertility Status and Disorders in Arecanut (Areca Catechu L.) Grown on Clay and Laterite Soils of India

In arecanut, disorders like crown choking and crown bending lead to death of palms within a short span. Spatial and temporal variability in soil and leaf nutrient status was used as a tool to find out the causes for disorders in clay and laterite soils. Availability of nutrients in soils was sufficient to excess. Deviation from optimum percentage index was negative for nitrogen (N), phosphorus (P), and zinc (Zn) in both soils. Zinc deficits of –26 to –63 in higher number of palms (84–97%) indicate the reduction in Zn uptake. Regression between leaf Zn and soil fertility parameters indicated negative relation with soil Zn and calcium (Ca) in clay and soil organic carbon, soil P, and soil boron (B) in laterite soils. Multiple regression indicated negative relation of diethylenetriaminepentaacetic acid (DTPA)-extractable Zn with nutrients like Ca, magnesium (Mg), potassium (K), and iron (Fe) in soil in different years. The grouping of soil nutrients in opposite directions in first two components of principal component analysis supports negative nutrient interactions in both soil types. The results reveal that nutrient interactions in soil affect the uptake of nutrients despite sufficient nutrient availability. Zinc deficiency in arecanut may be the result of complex interactions between DTPA-extractable Zn and other nutrients in soil.

Role of Nutrient Imbalance on Yellow Leaf Disease in Smallholder Arecanut Systems on a Laterite Soil in India

ABSTRACT On-farm trials in India investigated the role of nutrient imbalance on yellow leaf disease (YLD) in arecanut on a laterite soil using compositional nutrient diagnosis (CND) approach. Soil fertility status was imbalanced with high organic carbon status and low phosphorus (P) and potassium (K). The CND norms indicated that the order of nutrient demand was changed with nutrient application. Interventions increased yield by 50% during 2007–2010. The correlations indicated positive effect of nitrogen (N) and K and negative effect of manganese (Mn) on yield. The CND indices for NPK were important discriminators between yellowed and apparently healthy populations both in 2007 and 2010. Linear regressions between leaf nutrient concentrations and CND indices were significant for P, K, iron (Fe), Mn, and copper (Cu) (R2 = 0.44–0.53). Results suggest that the predisposing factor for YLD might be nutrient imbalance in the soil leading to deficit of major nutrients in plant.