Agric (Dec 2021)
CHARACTERISTICS EVALUATION, NUTRITION CONTRIBUTION OF IRRIGATION WATER AND STRAW TOWARD RESPONSE TO NUTRITIONAL POTASSIUM FERTILIZATION IN PADDY FIELD
Abstract
Potassium is one of the primary macro nutrients along with N and P nutrients, which plants need in large quantities. Lack of K nutrients, one of which can inhibit photosynthetic transport to plant seeds. The availability of K nutrients in paddy soil varies greatly depending on the chemical properties of other soils. This paper aims to evaluate the nutrient K characteristics of paddy fields, the K contribution from irrigation water and harvested straw, and the response of fertilization to rice yields. The availability of K nutrients, apart from being influenced by clay mineral composition, clay content, organic C and soil CEC, is also influenced by N fertilization, soil pH, exchangeable of Ca and Mg, and N-total. The content of potential K and exchangeable of K increases in paddy fields which are further east of Java Island because they have soil with parent material that is rich in potassium minerals. The content of exchangeable K is very closely related to the potential K with R2 = 0.53 (n = 73). Based on the map of the nutrient status of K rice fields with a scale of 1:250,000 in 23 provinces in Indonesia, it is known that most of the paddy fields have moderate K status at 37% and high 48%. The K content in paddy soil can be contributed by irrigation water as much as 7-74 kg K/ha/season. If all of the remaining rice straw from crop yields is returned to the field, the K nutrient requirements for rice plants in the medium and high K nutrient status fields have been fulfilled. The response to K fertilization in rice plants was only visible when the exchangeable K content < 0.10 cmol(+)/ kg. The policy implication of this paper is that K fertilization is focused on paddy fields with low K content, the effectiveness of K fertilization can be increased by returning rice straw from crop residues and proper N fertilization.
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