Explore essential questions on optimal nutrient management practices for paddy fields, covering fertilizer use, deficiency symptoms, timing, and sustainable strategies for rice cultivation.
Which growth stage in paddy cultivation is most critical for the first major nitrogen application to maximize yield?
Explanation: The tillering stage is crucial for the first major nitrogen application as it supports active vegetative growth and tiller formation. Applying nitrogen before transplanting can lead to losses due to runoff or volatilization. Panicle initiation and after flowering are too late; most of the needed biomass accumulation has already occurred by those stages.
A paddy field shows older leaves turning yellow while younger leaves remain green; which nutrient is most likely deficient?
Explanation: Nitrogen deficiency typically appears as yellowing in the older leaves because it is a mobile nutrient and reallocates to new growth. Potassium and phosphorus deficiencies often show witholder leaf discoloration too but manifest differently (e.g., leaf edge browning or purple coloration). Zinc deficiency initially affects young leaves with stunted growth.
What is the primary role of potassium fertilizer in paddy rice nutrition?
Explanation: Potassium is essential for grain filling and increasing resistance to diseases in rice. While chlorophyll production mainly relies on nitrogen, potassium does not directly initiate flowering or reduce plant height, although it does contribute to overall plant health.
Which strategy is considered most sustainable for maintaining long-term soil nutrient balance in paddy cultivation?
Explanation: Crop rotation with legumes enhances soil fertility by naturally fixing atmospheric nitrogen and improving nutrient balance. Exclusive chemical use can degrade soil health, doubling nitrogen rates may cause environmental harm and does not ensure balance, and continuous flooding alone does not address nutrient management.
Farmers notice stunted growth and white streaks on young rice leaves; which micronutrient should they consider supplementing?
Explanation: Zinc deficiency in paddy often results in stunted seedlings and white streaks on young leaves. Iron deficiency usually causes yellowing (chlorosis) at leaf bases, sulfur affects older leaves with pale coloring, and calcium is less commonly a problem in paddy but leads to general tip burn rather than streaks.