Crop Production


A study was conducted to determine the increased yield and improved nutritional quality of sweet potato and purple yam through isolating microorganisms that are capable of releasing micronutrients from soil minerals in various soil environments. Given the study, availability of micronutrients in soil is significant to improve nutritional quality and yield increase of a crop.

Seven fertilizer treatments were applied to each soil in the pot experiment; for the Purple yam trial, T1 serve as control, T2 for 150-50-150 kg/ha (N-P2O5-K2O) which is the recommended rate for yam, T3 consisting T2 + 8 kg/ha Biozome-200, T4 with T2 + Mycovam-1 (5 g/plant, manufacturer’s recommended rate), T5 with T2 + 4 kg/ha microbial inoculant, T6 having T2 + 8 kg/ha microbial inoculant and T7 containing T2 + 12 kg/ha microbial inoculant. Same goes with sweet potato, it also had the same amount of treatments however, they differ only on treatment T2 since sweet potato contains a recommended rate having 60-60-60 kg/ha (N-p2O5-K2O).

Sweet potato. Results showed that VSU and Ormoc soil have significant higher yields of sweet potato. Showing this result, it differs from the other soil types despite having the same treatment however, T7 and T3 obtained higher yields than the rest of the treatments though similar soils were used in the trial. For Samar soil, it had a slight improvement compared to that on the first trial of sweet potato since the frequent rainfall reduced the bulk density of the soil during hot weather making better root growth or tuber development. Further, microbial inoculants with Biozome-200 treatment gave higher yields compared to the treatments added with fertilizers only.

Purple yam. Tuber yield for purple yam was significantly affected by the micronutrient supplement and microbial inoculants, grown under five different soil types of Leyte. Seemingly, no viable growth nor tubers were developed under Samar soil.

For treatment effects, it showed that tuber yield grown under VSU soil was obtained highest in T5 (150-150-150 kg/ha N-P-K + 4 kg/ha micronutrient inoculant) at 445 g/pot. On the other hand, T5 (150-150-150 kg/ha N-P-K + 4 kg/ha micronutrient inoculant), T6 (150-150-150 kg/ha N-P-K + 8 kg/ha micronutrient inoculant) and T7 (150-150-150 kg/ha micronutrient inoculant) obtained larger effects against T3 (150-150-150 kg/ha N-P-K + 8 kg/ha Biozome-200) a commercially available micronutrient fertilizer.

The highest yield was obtained in T7 at 379g/pot and at 287.3 g/pot both in Ormoc and Matalom basic soil respectively. Further, the highest tuber yield was observed in T3 using Matalom acidic soil with available micro nutrient fertilizer at 215.3 g/pot.

About PhilRootcrops

The Philippine Root Crop Research and Training Center (PhilRootcrops) is a government research, development and training institution for root and tuber crops: cassava, sweetpotato, taro, yam, yambean, arrowroot and other rootcrops.
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Vision, Mission & Goal

Creating wealth, enhancing health, improving lives through roots and tubers
To provide the national leadership in formulating and implementing strategic root crop research and development programs that can reduce poverty and food insecurity
To generate and promote root crop innovations and information that can improve the lives of stakeholders along the root crop value chain.

Contact Information

PhilRootcrops, VSU,Visca, Baybay City, Leyte, Philippines 6521-A
Telephone / Fax No.: +63 (053)563-7229 Trunkline: +63 (053) 565 0600 local 1063
Email: [email protected] | [email protected]
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