施肥对冬闲稻田紫花苜蓿生长及苜蓿绿肥对轮作水稻产量的影响

Effects of fertilizer on alfalfa growth in winter fallow paddy fields and alfalfa green manure on rice yield

紫花苜蓿(Medicago sativa)与水稻(Oryza sativa)轮作是南方苜蓿种植的新模式,许多关键技术有待深入研究。本研究探讨了施肥(基肥和追肥)轮作苜蓿和土壤养分以及紫花苜蓿绿肥还田对轮作水稻产量的影响。结果表明,225和450 kg·hm^(−2)基肥处理的苜蓿产量分别比不施肥增加了22.6%和41.9%,追施氮(N)、磷(P)、钾(K)肥进一步提高了基肥的增产效果,5月上旬的干草产量达到11198 kg·hm^(−2),促进苜蓿分枝是增产的主要原因之一,同时明显提高了苜蓿地0–20 cm土层的全氮、速效磷和有机质含量以及苜蓿茎、叶的蛋白质和磷含量,其中,450 kg·hm^(−2) NPK基肥+追肥对茎、叶蛋白质和磷含量的增加作用最显著(P<0.05)。NPK基肥显著增加了苜蓿叶和茎的K含量(P<0.05),而追肥明显促进了K由茎向叶的转移。紫花苜蓿再生草作为绿肥还田明显提高了轮作水稻的产量(P<0.05),籽实产量比对照(未种苜蓿且未施绿肥)增加了18.2%。综上分析可知,紫花苜蓿与水稻周年轮作既可收获一定数量的紫花苜蓿,又可促进轮作水稻增产,是南方紫花苜蓿产业发展的一条有效途径。

The rotation of alfalfa(Medicago sativa)and rice(Oryza sativa)is a new model for alfalfa plantations in southern China and many key technologies need to be studied.The effects of using fertilizer(basal and topical applications)and alfalfa green manure on plant growth and soil nutrient content in the alfalfa-rice rotation system were studied in winter fallow paddy soil.The results showed that nitrogen,phosphorus and potassium(NPK)fertilizer application greatly increased alfalfa growth,with biomass yield increasing by 22.6%and 41.9%,compared with no-fertilizer,when 225 and 450 kg·ha^(−1) NPK,respectively,were applied basally.The yield increased further when this was combined with a topical application of NPK,reaching 11198 kg·ha^(−1) in early May of the following year under a combined basal(450 kg·ha^(−1) NPK)and topical(450 kg·ha^(−1) NPK)application treatment.An increase in shoot numbers was one of the main reasons for the increased yield.The increase in total N,available P,and organic matter in soil 0-20 cm was significant(P<0.05)for the combined basal and topical application;the increase in the protein and P content of the alfalfa plants were also significant(P<0.05),particularly for a combined basal and topical application at 450 kg·ha−1.The increase in K content was significant(P<0.05)for both the basal and topical application;however,the latter increased the translocation of K from the shoots to leaves to a significant degree(P<0.05).The increase in rice growth with the application of alfalfa green manure was significant(P<0.05),with grain yield increasing by 18.2%compared to the treatment of not planted with alfalfa and not fertilized with green manure.The results indicate that an alfalfa-rice rotation is a highly efficient system that can produce a high yield of alfalfa while also increasing rice grain yield and alleviating soil nutrient levels.The alfalfa-rice model provides an effective way to develop alfalfa cultivation in southern China.