Influence of organic fertilisers on the yield and quality of cabbage and carrots

Loading...
Thumbnail Image
Date
2008-11
Authors
Mbatha, Alice Nompumelelo
Journal Title
Journal ISSN
Volume Title
Publisher
University of the Free State
Abstract
English: The use of organic fertiliser as an alternative to inorganic fertiliser increased among subsistence farmers in rural areas in KwaZulu Natal. No clear recommendations exist for the application of different organic fertilisers on vegetables. Two field trials were conducted at Umsunduze Training Centre, KwaZulu Natal during the 2005 and 2006 seasons. The effect of three different organic fertilisers (chicken, kraal manure and compost) were investigated on the growth, yield and quality of cabbage cv. Conquistador and carrots cv. Kuroda. Four application rates were used for each organic fertiliser (chicken manure: 0, 6.25, 12.5 and 25 kg 10 m-2; kraal manure: 0, 12.5, 25 and 50 kg 10 m-2; compost: 0, 25, 50 and 100 kg 10 m-2). Each treatment combination was replicated four times. Organic fertilisers were incorporated into the soil one month before planting. Number of leaves and plant height were measured for the first 8 weeks after planting for both crops. Fresh and dry mass was determined at harvesting for both cabbage and carrots. Cabbage head and carrot shoulder diameter, carrot root length and carrot root total soluble solids were measured at harvesting. Both crops were graded (cabbage into 3 and carrots into 5 classes) according to their external appearance. After harvesting, soil analysis (2005 and 2006) and plant analysis (2006) were done for both crops. Chicken manure applied at 12.5 or 25 kg 10 m-2 showed a significant increase in the growth rate of cabbage during the first 8 weeks after transplanting in both seasons. During 2005, fresh mass of cabbage that received 12.5 or 25 kg 10 m-2 chicken manure was significantly higher and of better quality than the other organic fertiliser treatments. In 2006, the fresh mass and quality of cabbage that received 50 kg 10 m-2 kraal manure, 25 kg 10 m-2 chicken manure or 100 kg 10 m-2 compost was significantly higher than the other organic treatments. Dry mass also significantly increased when 25 kg 10 m-2 chicken manure was applied. Compost significantly increased the nitrogen, phosphorus, potassium, sulphur and calcium content, while kraal manure significantly increased the phosphorus, potassium and magnesium content of the soil after two years of application. It was in most cases the two highest application rates (Rate 2 and 3) that significantly influenced the chemical properties of the soil. Only chicken manure significantly influenced the nitrogen content of cabbage heads. Carrot plants that received chicken and kraal manure at Rate 2 or 3 produced the most number of leaves while the tallest carrot plants were obtained where 25 kg 10 m-2 chicken manure or 50 kg 10 m-2 compost was applied, at 8 weeks after planting. Different organic fertilisers and application rates did not significantly influence the fresh mass and root length of carrots. Dry mass of carrots that received 25 kg 10 m-2 chicken manure, 50 kg 10 m-2 kraal manure or 25 kg 10 m-2 compost was significantly greater than plants that did not receive any fertiliser in 2006. High organic fertiliser rates (Rate 3) significantly increased shoulder diameter. In 2005, chicken manure and compost significantly decreased total soluble solid content of carrots. In 2006, the highest total soluble solid content was obtained with 12.5 kg 10 m-2 chicken manure. An increase in the organic fertiliser rate promoted the development of hairy carrots in 2005 and carrots that received compost (Class 3) was of a poorer quality than those that received chicken or kraal manure (Class 2) in 2006. Compost significantly increased the phosphorus, potassium content and NIRS organic matter of the soil and kraal manure only significantly increased the sulphur content of the soil after two years of application. Chicken manure (25 kg 10 m-2) and 100 kg 10 m-2 compost significantly increased the nitrogen content of carrot roots, while the calcium content was significantly lowered where chicken manure was applied. Kraal manure significantly increased the iron content and 6.25 kg 10 m-2 chicken manure increased the total carbon content of carrots.
Afrikaans: Bestaansboere in die plattelandse gebiede van KwaZulu Natal gebruik al hoe meer organiese bemesting as ‘n alternatief vir anorganiese bemesting. Daar bestaan geen duidelike aanbevelings vir toedieningspeile van organiese bemesting op groente. Twee veldproewe is in 2005 en 2006 by die Umsunduze Opleidingssentrum, in KwaZulu Natal uitgevoer. Die invloed van drie organiese bemestingstowwe (hoendermis, kraalmis en kompos) op die groei, opbrengs en kwaliteit van kool cv. Conquistador en geelwortels cv. Kuroda is ondersoek. Organiese bemesting is teen vier peile toegedien (hoendermis: 0, 6.25, 12.5 and 25 kg 10 m-2; kraalmis: 0, 12.5, 25 and 50 kg 10 m-2; kompos: 0, 25, 50 and 100 kg 10 m-2). Elke behandelingskombinasie is vier keer herhaal. Organiese bemestingstowwe is een maand voor plant in die grond ingewerk. Aantal blare en planthoogte is weekliks vir die eerste agt weke na plant vir beide gewasse bepaal. Tydens oes is die nat- en droëmass van beide kool en geelwortels bepaal. Kool se kopdeursnee en geelwortels se skouerdeursnee asook wortellengte en totale oplosbare vastestowwe is gemeet. Beide gewasse is tydens oes volgens hul eksterne voorkoms gegradeer (kool in 3 klasse en geelwortels in 5 klasse). Na oes is grondontledings (2005 en 2006) asook plantontledings (2006) gedoen vir beide gewasse. Die groei en ontwikkeling van koolplante is tydens die eerste agt weke na plant betekenisvol deur 12.5 en 25 kg 10 m-2 hoendermis verhoog in beide seisoene. In 2005 was die varsmassa en kwaliteit van kool wat 12.5 of 25 kg 10 m-2 hoendermis ontvang het betekenisvol hoër as die van kool wat ander organiese bemesting toedienings ontvang het. Die varsmassa en kwaliteit van kool wat 50 kg 10 m-2 kraalmis, 25 kg 10 m-2 hoendermis of 100 kg 10 m-2 kompos ontvang het in 2006 was betekenisvol hoër as die ander behandelings en die droëmassa was ook hoër waar 25 kg 10 m-2 hoendermis toegedien is. Kompos het die stikstof-, fosfor-, kalium-, swawel- en kalsiuminhoud van die grond betekenisvol verhoog terwyl kraalmis die fosfor, kalsium en magnesiuminhoud betekenisvol na twee jaar verhoog het. Die twee hoogste toedienings peile (Peil 2 en 3) van organiese bemesting het in die meeste gevalle die grootste invloed gehad op die chemiese eienskappe van die grond. Dit was slegs hoendermis wat die stikstofinhoud van koolkoppe betekenisvol beïnvloed het. Tydens die eerste agt weke na plant het geelwortelplante wat hoender- of kraalmis (Peil 2 of 3) ontvang het, meeste aantal blare gevorm en die hoogste plante is waargeneem waar 25 kg 10 m-2 hoendermis of 50 kg 10 m-2 kompos toegedien is. Verskillende organiese bemesting en verskillende toedieningspeile het nie die varsmassa of die lengte van die wortels betekenisvol beïnvloed nie. In 2006 was die droëmassa van geelwortels wat 25 kg 10 m-2 hoendermis, 50 kg 10 m-2 kraalmis of 25 kg 10 m-2 kompos ontvang het betekenisvol hoër as die wat geen bemesting ontvang het nie. Die hoogste toedieningspeil van organiese bemesting het die skouerdeursnee van wortels betekenisvol vergroot. Die totale oplosbare vastestowwe in geelwortels is deur hoendermis en kompos betekenisvol verlaag (2005). In 2006 is die hoogste totale oplosbare vastestofinhoud verkry met 12.5 kg 10 m-2 hoendermis. In 2005 het hoë toedieningspeile die voorkoms van harige wortels verhoog en die swakste kwaliteit is verkry waar kompos in 2006 toegedien is. Kompos het die fosfor-, kaliuminhoud en die NIRS organiese materiaal inhoud van die grond betekenisvol verhoog. Kraalmis het slegs die swawel inhoud van die grond verhoog. Stikstofinhoud van geelwortels is betekenisvol deur 100 kg 10 m-2 kompos of 25 kg 10 m-2 hoendermis verhoog. Die kalsiuminhoud van geelwortels is betekenisvol verlaag waar hoendermis toegedien is, terwyl die ysterinhoud betekenisvol deur kraalmis verhoog is en 6.25 kg 10 m-2 hoendermis die koolstofinhoud verhoog het.
Description
Keywords
Dissertation (M.Sc.Agric (Soil, Crop and Climate Sciences))--University of the Free State, 2008, Cabbage -- Fertilizers, Carrots -- Fertilizers, Fertilizer requirements
Citation