Guava Waste to Sustain Guava (Psidium guajava) Agroecosystem: Nutrient “Balance” Concepts

Abstract

The Brazilian guava processing industry generates 5.5 M Mg guava waste year−1 that could be recycled sustainably in guava agro-ecosystems as slow-release fertilizer. Our objectives were to elaborate nutrient budgets and to diagnose soil, foliar, and fruit nutrient balances in guava orchards fertilized with guava waste. We hypothesized that (1) guava waste are balanced fertilizer sources that can sustain crop yield and soil nutrient stocks, and (2) guava agroecosystems remain productive within narrow ranges of nutrient balances. A 6-year experiment was conducted in 8-year old guava orchard applying 0–9–18–27–36 Mg ha−1 guava waste (dry mass basis) and the locally recommended mineral fertilization. Nutrient budgets were compiled as balance sheets. Foliar and fruit nutrient balances were computed as isometric log ratios to avoid data redundancy or resonance due to nutrient interactions and the closure to measurement unit. The N, P, and several other nutrients were applied in excess of crop removal while K was in deficit whatever the guava waste treatment. The foliar diagnostic accuracy reached 93% using isometric log ratios and knn classification, generating reliable foliar nutrient and concentration ranges at high yield level. The plant mined the soil K reserves without any significant effect on fruit yield and foliar nutrient balances involving K. High guava productivity can be reached at lower soil test K and P values than thought before. Parsimonious dosage of fresh guava waste should be supplemented with mineral K fertilizers to recycle guava waste sustainably in guava agroecosystems. Brazilian growers can benefit from this research by lowering soil test P and K threshold values to avoid over-fertilization and using fresh guava waste supplemented with mineral fertilizers, especially K. Because yield was negatively correlated with fruit acidity and Brix index, balanced plant nutrition and fertilization diagnosis will have to consider not only fruit yield targets but also fruit quality to meet requirements for guava processing.

Influence of bunch bagging on the development of banana Prata (AAB) and prevention of chilling injury in the field

“…Dry matter was determined by loss mass of samples pulp and peel of 10 g fresh mass following 48 h drying in a forced air oven (65±2C). The contents of nutrients were determined in the dry matter of peel and pulp according to Souza et al (2016).…”

Potential Functional Byproducts from Guava Purée Processing

“…The mass processing of fruit generates great amounts of waste and byproducts. Approximately 80 kg of waste per metric ton of fresh fruits is produced during guava processing (Souza et al., ). Malaysia, one of the leading countries producing guava purée, discards 25% of pink guava byproducts.…”

Valorizing guava (Psidium guajava L.) seeds through germination-induced carbohydrate changes

“…The mass processing of fruits and vegetables generates a great amount of waste and by-products such as peel, pomace and seeds. About 80 kg waste per metric ton of fresh fruits is produced in guava processing (Souza et al 2016). Brazil is the greatest producer of red guava fruits, which produce 4-30% of their weight in wastes.…”